SOUTHERN CO, 10-K filed on 2/20/2025
Annual Report
v3.25.0.1
Cover Page - USD ($)
$ in Billions
 12 Months Ended
Dec. 31, 2024
Jan. 31, 2025
Jun. 30, 2024
Document Information [Line Items]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2024    
Current Fiscal Year End Date --12-31    
Document Transition Report false    
Entity File Number 1-3526    
Entity Registrant Name The Southern Company    
Entity Tax Identification Number 58-0690070    
Entity Incorporation, State or Country Code DE    
Entity Address, Address Line One 30 Ivan Allen Jr. Boulevard, N.W.    
Entity Address, City or Town Atlanta    
Entity Address, State or Province GA    
Entity Address, Postal Zip Code 30308    
City Area Code 404    
Local Phone Number 506-5000    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag true    
Document Financial Statement Error Correction false    
Entity Shell Company false    
Entity Public Float     $ 84.9
Entity Common Stock, Shares Outstanding (in shares)   1,096,802,197  
Documents Incorporated by Reference specified portions of The Southern Company's Definitive Proxy Statement on Schedule 14A relating to the 2025 Annual Meeting of Stockholders are incorporated by reference into PART III.
Each of Alabama Power Company, Georgia Power Company, Mississippi Power Company, Southern Power Company, and Southern Company Gas meets the conditions set forth in General Instructions I(1)(a) and (b) of Form 10-K and is therefore filing this Form 10-K with the reduced disclosure format specified in General Instructions I(2)(b), (c), and (d) of Form 10-K.
This combined Form 10-K is separately filed by The Southern Company, Alabama Power Company, Georgia Power Company, Mississippi Power Company, Southern Power Company, and Southern Company Gas. Information contained herein relating to any individual registrant is filed by such registrant on its own behalf. Each registrant makes no representation as to information relating to the other registrants.
    
Entity Central Index Key 0000092122    
Amendment Flag false    
Document Fiscal Year Focus 2024    
Document Fiscal Period Focus FY    
Common Stock, par value $5 per share      
Document Information [Line Items]      
Title of 12(b) Security Common Stock, par value $5 per share    
Trading Symbol SO    
Security Exchange Name NYSE    
Series 2017B 5.25% Junior Subordinated Notes due 2077      
Document Information [Line Items]      
Title of 12(b) Security Series 2017B 5.25% Junior Subordinated Notes due 2077    
Trading Symbol SOJC    
Security Exchange Name NYSE    
Series 2020A 4.95% Junior Subordinated Notes due 2080      
Document Information [Line Items]      
Title of 12(b) Security Series 2020A 4.95% Junior Subordinated Notes due 2080    
Trading Symbol SOJD    
Security Exchange Name NYSE    
Series 2020C 4.20% Junior Subordinated Notes due 2060      
Document Information [Line Items]      
Title of 12(b) Security Series 2020C 4.20% Junior Subordinated Notes due 2060    
Trading Symbol SOJE    
Security Exchange Name NYSE    
Series 2021B 1.875% Fixed-to-Fixed Reset Rate Junior Subordinated Notes due 2081      
Document Information [Line Items]      
Title of 12(b) Security Series 2021B 1.875% Fixed-to-Fixed Reset Rate Junior Subordinated Notes due 2081    
Trading Symbol SO 81    
Security Exchange Name NYSE    
Series 2025A 6.50% Junior Subordinated Notes due 2085      
Document Information [Line Items]      
Title of 12(b) Security Series 2025A 6.50% Junior Subordinated Notes due 2085    
Trading Symbol SOJF    
Security Exchange Name NYSE    
Alabama Power      
Document Information [Line Items]      
Entity File Number 1-3164    
Entity Registrant Name Alabama Power Company    
Entity Tax Identification Number 63-0004250    
Entity Incorporation, State or Country Code AL    
Entity Address, Address Line One 600 North 18th Street    
Entity Address, City or Town Birmingham    
Entity Address, State or Province AL    
Entity Address, Postal Zip Code 35203    
City Area Code 205    
Local Phone Number 257-1000    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag false    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding (in shares)   30,537,500  
Entity Central Index Key 0000003153    
Georgia Power      
Document Information [Line Items]      
Entity File Number 1-6468    
Entity Registrant Name Georgia Power Company    
Entity Tax Identification Number 58-0257110    
Entity Incorporation, State or Country Code GA    
Entity Address, Address Line One 241 Ralph McGill Boulevard, N.E.    
Entity Address, City or Town Atlanta    
Entity Address, State or Province GA    
Entity Address, Postal Zip Code 30308    
City Area Code 404    
Local Phone Number 506-6526    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag false    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding (in shares)   9,261,500  
Entity Central Index Key 0000041091    
Georgia Power | Series 2017A 5.00% Junior Subordinated Notes due 2077      
Document Information [Line Items]      
Title of 12(b) Security Series 2017A 5.00% Junior Subordinated Notes due 2077    
Trading Symbol GPJA    
Security Exchange Name NYSE    
Mississippi Power      
Document Information [Line Items]      
Entity File Number 001-11229    
Entity Registrant Name Mississippi Power Company    
Entity Tax Identification Number 64-0205820    
Entity Incorporation, State or Country Code MS    
Entity Address, Address Line One 2992 West Beach Boulevard    
Entity Address, City or Town Gulfport    
Entity Address, State or Province MS    
Entity Address, Postal Zip Code 39501    
City Area Code 228    
Local Phone Number 864-1211    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag false    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding (in shares)   1,121,000  
Entity Central Index Key 0000066904    
Southern Power      
Document Information [Line Items]      
Entity File Number 001-37803    
Entity Registrant Name Southern Power Company    
Entity Tax Identification Number 58-2598670    
Entity Incorporation, State or Country Code DE    
Entity Address, Address Line One 30 Ivan Allen Jr. Boulevard, N.W.    
Entity Address, City or Town Atlanta    
Entity Address, State or Province GA    
Entity Address, Postal Zip Code 30308    
City Area Code 404    
Local Phone Number 506-5000    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag false    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding (in shares)   1,000  
Entity Central Index Key 0001160661    
Southern Power | Series 2016B 1.850% Senior Notes due 2026      
Document Information [Line Items]      
Title of 12(b) Security Series 2016B 1.850% Senior Notes due 2026    
Trading Symbol SO/26A    
Security Exchange Name NYSE    
Southern Company Gas      
Document Information [Line Items]      
Entity File Number 1-14174    
Entity Registrant Name Southern Company Gas    
Entity Tax Identification Number 58-2210952    
Entity Incorporation, State or Country Code GA    
Entity Address, Address Line One Ten Peachtree Place, N.E.    
Entity Address, City or Town Atlanta    
Entity Address, State or Province GA    
Entity Address, Postal Zip Code 30309    
City Area Code 404    
Local Phone Number 584-4000    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag false    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding (in shares)   100  
Entity Central Index Key 0001004155    
v3.25.0.1
Audit Information
 12 Months Ended
Dec. 31, 2024
Auditor [Line Items]  
Auditor Name Deloitte & Touche LLP
Auditor Firm ID 34
Auditor Location Atlanta, Georgia
Alabama Power  
Auditor [Line Items]  
Auditor Name Deloitte & Touche LLP
Auditor Firm ID 34
Auditor Location Birmingham, Alabama
Georgia Power  
Auditor [Line Items]  
Auditor Name Deloitte & Touche LLP
Auditor Firm ID 34
Auditor Location Atlanta, Georgia
Mississippi Power  
Auditor [Line Items]  
Auditor Name Deloitte & Touche LLP
Auditor Firm ID 34
Auditor Location Atlanta, Georgia
Southern Power  
Auditor [Line Items]  
Auditor Name Deloitte & Touche LLP
Auditor Firm ID 34
Auditor Location Atlanta, Georgia
Southern Company Gas  
Auditor [Line Items]  
Auditor Name Deloitte & Touche LLP
Auditor Firm ID 34
Auditor Location Atlanta, Georgia
Southern Natural Gas Company, LLC  
Auditor [Line Items]  
Auditor Name BDO USA, P.C.
Auditor Firm ID 243
Auditor Location Houston, Texas
v3.25.0.1
Consolidated Statements of Income - Southern - USD ($)
shares in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Operating Revenues:      
Total operating revenues $ 26,724 $ 25,253 $ 29,279
Operating Expenses:      
Other operations and maintenance 6,539 6,093 6,824
Depreciation and amortization 4,755 4,525 3,663
Taxes other than income taxes 1,540 1,425 1,411
Estimated loss on Plant Vogtle Units 3 and 4 (21) (68) 183
Total operating expenses 19,656 19,427 23,909
Operating Income 7,068 5,826 5,370
Other Income and (Expense):      
Allowance for equity funds used during construction 235 268 224
Earnings from equity method investments 139 144 151
Interest expense, net of amounts capitalized (2,743) (2,446) (2,022)
Other income (expense), net 530 553 500
Total other income and (expense) (1,839) (1,481) (1,147)
Earnings Before Income Taxes 5,229 4,345 4,223
Income taxes (benefit) 969 496 795
Net Income 4,260 3,849 3,428
Dividends on preferred stock of subsidiaries 0 0 11
Net loss attributable to noncontrolling interests (141) (127) (107)
Consolidated Net Income $ 4,401 $ 3,976 $ 3,524
Earnings per share —      
Basic (in dollars per share) $ 4.02 $ 3.64 $ 3.28
Diluted (in dollars per share) $ 3.99 $ 3.62 $ 3.26
Average number of shares of common stock outstanding — (in millions)      
Basic (in shares) 1,096 1,092 1,075
Diluted (in shares) 1,102 1,098 1,081
Retail electric revenues      
Operating Revenues:      
Total operating revenues $ 17,790 $ 16,343 $ 18,197
Wholesale electric revenues      
Operating Revenues:      
Total operating revenues 2,431 2,467 3,641
Other electric revenues      
Operating Revenues:      
Total operating revenues 896 792 747
Natural gas revenues      
Operating Revenues:      
Total operating revenues 4,456 4,702 5,962
Other revenues      
Operating Revenues:      
Total operating revenues 1,151 949 732
Operating Expenses:      
Cost of sales 668 560 396
Fuel      
Operating Expenses:      
Cost of sales 4,096 4,365 6,835
Purchased power      
Operating Expenses:      
Cost of sales 883 883 1,593
Natural gas      
Operating Expenses:      
Cost of sales $ 1,196 $ 1,644 $ 3,004
v3.25.0.1
Consolidated Statements of Comprehensive Income - Southern - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Statement of Comprehensive Income [Abstract]      
Net Income $ 4,260 $ 3,849 $ 3,428
Qualifying hedges:      
Changes in fair value, net of tax (5) (41) (60)
Reclassification adjustment for amounts included in net income, net of tax 80 69 73
Pension and other postretirement benefit plans:      
Benefit plan net gain (loss), net of tax 23 (39) 48
Reclassification adjustment for amounts included in net income, net of tax 1 1 10
Total other comprehensive income (loss) 99 (10) 71
Dividends on preferred stock of subsidiaries 0 0 11
Comprehensive loss attributable to noncontrolling interests (141) (127) (107)
Comprehensive Income $ 4,500 $ 3,966 $ 3,595
v3.25.0.1
Consolidated Statements of Comprehensive Income - Southern (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Statement of Comprehensive Income [Abstract]      
Qualifying hedges, change in fair value, tax $ (2) $ (17) $ (19)
Qualifying hedges, reclassification adjustment, tax 28 27 23
Pension and other postretirement benefit plans, gain (loss), tax 10 (14) 18
Reclassification adjustment for amounts included in net income, tax $ 0 $ 0 $ 3
v3.25.0.1
Consolidated Statements of Cash Flows - Southern - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Operating Activities:      
Consolidated net income $ 4,260 $ 3,849 $ 3,428
Adjustments to reconcile consolidated net income to net cash provided from operating activities —      
Depreciation and amortization, total 5,266 4,986 4,064
Deferred income taxes 536 63 670
Utilization of federal tax credit carryforward 90 353 88
Allowance for equity funds used during construction (235) (268) (224)
Pension, postretirement, and other employee benefits (556) (527) (436)
Settlement of asset retirement obligations (566) (617) (455)
Storm damage and reliability reserve accruals 163 124 430
Stock based compensation expense 132 137 127
Estimated loss on Plant Vogtle Units 3 and 4 (21) (68) 183
Retail fuel cost under recovery – long-term (32) (206) (2,166)
Natural gas cost under recovery – long-term 0 0 207
Storm damage cost recovery – long-term (631) 0 0
Other, net (39) (138) 226
Changes in certain current assets and liabilities —      
-Receivables (372) 482 (771)
-Retail fuel cost under recovery 984 686 (100)
-Fossil fuel for generation 140 (368) (125)
-Materials and supplies (189) (345) (160)
-Natural gas cost under recovery 0 108 158
-Other current assets (47) (106) (186)
-Accounts payable 492 (863) 1,021
-Customer refunds 83 (157) 119
-Natural gas cost over recovery (21) 214 0
-Other current liabilities 145 191 153
Net cash provided from operating activities 9,788 7,553 6,302
Investing Activities:      
Property additions (8,955) (9,095) (7,923)
Nuclear decommissioning trust fund purchases (1,551) (1,142) (1,125)
Nuclear decommissioning trust fund sales 1,535 1,121 1,112
Proceeds from dispositions 369 164 275
Cost of removal, net of salvage (632) (592) (649)
Change in construction payables, net 106 18 203
Payments pursuant to LTSAs (108) (99) (190)
Other investing activities (164) (43) (133)
Net cash used for investing activities (9,400) (9,668) (8,430)
Financing Activities:      
Increase (decrease) in notes payable, net (648)   (337)
Increase (decrease) in notes payable, net   973  
Proceeds —      
Long-term debt 6,159 8,972 5,132
Short-term borrowings 700 350 2,650
Common stock 143 36 1,808
Redemptions and repurchases —      
Long-term debt (2,222) (4,294) (2,158)
Short-term borrowings (1,020) (1,630) (1,150)
Preferred stock 0 0 (298)
Distributions to noncontrolling interests (185) (234) (259)
Payment of common stock dividends (2,954) (3,035) (2,907)
Other financing activities (181) (139) (145)
Net cash provided from (used for) financing activities (208) 999 2,336
Net Change in Cash, Cash Equivalents, and Restricted Cash 180 (1,116) 208
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year 921 2,037 1,829
Cash, Cash Equivalents, and Restricted Cash at End of Year 1,101 921 2,037
Supplemental Cash Flow Information:      
Interest, net of amounts capitalized 2,538 2,184 1,758
Income taxes, net (excludes credit transfers) 176 132 146
Noncash transactions —      
Accrued property additions at year-end 1,199 1,027 1,024
LTSA credits utilized from the sale of spare parts 13 23 0
Contributions from noncontrolling interests 0 0 15
Issuance of common stock under dividend reinvestment plan $ 179 $ 0 $ 0
v3.25.0.1
Consolidated Statements of Cash Flows - Southern (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Statement of Cash Flows [Abstract]      
Net cash paid for capitalized interest $ 103 $ 132 $ 103
v3.25.0.1
Consolidated Balance Sheets - Southern - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Current Assets:    
Cash and cash equivalents $ 1,070 $ 748
Receivables —    
Customer accounts 2,228 2,030
Unbilled revenues 825 786
Under recovered fuel clause revenues 713 696
Other accounts and notes 597 519
Accumulated provision for uncollectible accounts (74) (68)
Materials and supplies 2,178 1,989
Fossil fuel for generation 803 943
Natural gas for sale 388 420
Prepaid expenses 294 406
Assets from risk management activities, net of collateral 39 36
Regulatory assets – asset retirement obligations 353 274
Other regulatory assets 804 1,120
Other current assets 476 533
Total current assets 10,694 10,432
Property, Plant, and Equipment:    
In service 137,143 128,428
Less: Accumulated depreciation 40,126 37,725
Plant in service, net of depreciation 97,017 90,703
Other utility plant, net 410 499
Nuclear fuel, at amortized cost 873 858
Construction work in progress 6,389 7,784
Total property, plant, and equipment 104,689 99,844
Other Property and Investments:    
Goodwill 5,161 5,161
Nuclear decommissioning trusts, at fair value 2,621 2,424
Equity investments in unconsolidated subsidiaries 1,416 1,368
Other intangible assets, net of amortization 332 368
Miscellaneous property and investments 668 665
Other Property and Investments 10,198 9,986
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 1,386 1,432
Deferred charges related to income taxes 889 886
Prepaid pension costs 2,674 2,079
Unamortized loss on reacquired debt 203 220
Deferred under recovered retail fuel clause revenues 485 1,261
Regulatory assets – asset retirement obligations, deferred 5,458 5,459
Other regulatory assets, deferred 7,037 6,264
Other deferred charges and assets 1,467 1,468
Total deferred charges and other assets 19,599 19,069
Total Assets 145,180 139,331
Current Liabilities:    
Securities due within one year 4,718 2,476
Notes payable 1,338 2,314
Accounts payable 3,701 2,898
Customer deposits 486 503
Accrued taxes —    
Accrued income taxes 57 8
Other accrued taxes 997 860
Accrued interest 682 652
Accrued compensation 1,261 1,151
Asset retirement obligations 731 744
Liabilities from risk management activities, net of collateral 160 294
Operating lease obligations 200 183
Natural gas cost over recovery 193 214
Other regulatory liabilities 369 141
Other current liabilities 1,100 1,029
Total current liabilities 15,993 13,467
Long-Term Debt 58,768 57,210
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 11,730 10,990
Deferred credits related to income taxes 4,434 4,674
Accumulated deferred ITCs 2,056 2,067
Employee benefit obligations 1,011 1,115
Operating lease obligations, deferred 1,253 1,307
Asset retirement obligations, deferred 9,203 9,573
Other cost of removal obligations 2,016 1,957
Other regulatory liabilities, deferred 692 715
Other deferred credits and liabilities 1,350 1,031
Total deferred credits and other liabilities 33,745 33,429
Total Liabilities 108,506 104,106
Common Stockholders' Equity:    
Common stock 5,446 5,423
Paid-in capital 14,149 13,775
Treasury, at cost (59) (59)
Retained earnings 13,750 12,482
Accumulated other comprehensive loss (78) (177)
Total common stockholders' equity 33,208 31,444
Noncontrolling Interests 3,466 3,781
Total stockholders' equity 36,674 35,225
Total Liabilities and Stockholders' Equity 145,180 139,331
Commitments and Contingent Matters
v3.25.0.1
Consolidated Balance Sheets - Southern (Parenthetical) - USD ($)
shares in Millions, $ in Millions
Dec. 31, 2024
Dec. 31, 2023
Statement of Financial Position [Abstract]    
Other intangible assets, amortization $ 412 $ 376
Common Stockholders' Equity:    
Common stock, par value (in dollars per share) $ 5 $ 5
Common stock, shares authorized (in shares) 1,500.0 1,500.0
Common stock, shares issued (in shares) 1,100.0 1,100.0
Treasury stock (in shares) 1.0 1.0
v3.25.0.1
Consolidated Statements of Stockholders' Equity - Southern - USD ($)
shares in Millions, $ in Millions
Total
Common Stock
Treasury
Paid-In Capital
Retained Earnings
Accumulated Other Comprehensive Income (Loss)
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Beginning balance (in shares)     (1.0)        
Beginning balance (in shares) at Dec. 31, 2021   1,061.0          
Beginning balance at Dec. 31, 2021 $ 32,276 $ 5,279 $ (47) $ 11,950 $ 10,929 $ (237) $ 4,402
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Consolidated net income (loss) 3,417       3,524   (107)
Other comprehensive income (loss) 71         71  
Stock issued (in shares)   29.0          
Stock issued 1,808 $ 138   1,670      
Stock-based compensation 44     44      
Cash dividends on common stock (2,907)       (2,907)    
Capital contributions from noncontrolling interests 88           88
Distributions to noncontrolling interests (259)           (259)
Other (6)   (6) 9 (8) (1)  
Ending balance (in shares) at Dec. 31, 2022   1,090.0          
Ending balance at Dec. 31, 2022 34,532 $ 5,417 $ (53) 13,673 11,538 (167) 4,124
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Beginning balance (in shares)     (1.0)        
Consolidated net income (loss) 3,849       3,976   (127)
Other comprehensive income (loss) (10)         (10)  
Stock issued (in shares)   2.0          
Stock issued 36 $ 6   30      
Stock-based compensation 73     73      
Cash dividends on common stock (3,035)       (3,035)    
Capital contributions from noncontrolling interests 21           21
Distributions to noncontrolling interests (236)           (236)
Other (5)   $ (6) (1) 3   (1)
Ending balance (in shares) at Dec. 31, 2023   1,092.0          
Ending balance at Dec. 31, 2023 $ 35,225 $ 5,423 $ (59) 13,775 12,482 (177) 3,781
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Beginning balance (in shares) (1.0)   (1.0)        
Consolidated net income (loss) $ 4,260       4,401   (141)
Other comprehensive income (loss) 99         99  
Stock issued (in shares)   6.0          
Stock issued 322 $ 23   299      
Stock-based compensation 56     56      
Cash dividends on common stock (3,133)       (3,133)    
Capital contributions from noncontrolling interests 11           11
Distributions to noncontrolling interests (185)           (185)
Other (in shares)   0.0 0.0        
Other 19 $ 0 $ 0 19 0 0 0
Ending balance (in shares) at Dec. 31, 2024   1,098.0          
Ending balance at Dec. 31, 2024 $ 36,674 $ 5,446 $ (59) $ 14,149 $ 13,750 $ (78) $ 3,466
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Beginning balance (in shares) (1.0)   (1.0)        
v3.25.0.1
Consolidated Statements of Stockholders' Equity - Southern (Parenthetical) - $ / shares
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Statement of Stockholders' Equity [Abstract]      
Cash dividends (in dollars per share) $ 2.8600 $ 2.7800 $ 2.7000
v3.25.0.1
Statements of Income - APC - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Operating Revenues:      
Total operating revenues $ 26,724 $ 25,253 $ 29,279
Operating Expenses:      
Other operations and maintenance 6,539 6,093 6,824
Depreciation and amortization 4,755 4,525 3,663
Taxes other than income taxes 1,540 1,425 1,411
Total operating expenses 19,656 19,427 23,909
Operating Income 7,068 5,826 5,370
Other Income and (Expense):      
Allowance for equity funds used during construction 235 268 224
Interest expense, net of amounts capitalized (2,743) (2,446) (2,022)
Other income (expense), net 530 553 500
Total other income and (expense) (1,839) (1,481) (1,147)
Earnings Before Income Taxes 5,229 4,345 4,223
Income taxes 969 496 795
Net Income 4,260 3,849 3,428
Dividends on Preferred Stock 0 0 11
Consolidated Net Income 4,401 3,976 3,524
Retail revenues      
Operating Revenues:      
Total operating revenues 17,790 16,343 18,197
Other revenues      
Operating Revenues:      
Total operating revenues 1,151 949 732
Operating Expenses:      
Cost of sales 668 560 396
Fuel      
Operating Expenses:      
Cost of sales 4,096 4,365 6,835
Purchased power, non-affiliates      
Operating Expenses:      
Cost of sales 883 883 1,593
Alabama Power      
Operating Revenues:      
Total operating revenues 7,554 7,050 7,817
Operating Expenses:      
Other operations and maintenance 1,895 1,769 1,935
Depreciation and amortization 1,459 1,401 875
Taxes other than income taxes 471 442 424
Total operating expenses 5,557 5,415 5,875
Operating Income 1,997 1,635 1,942
Other Income and (Expense):      
Allowance for equity funds used during construction 57 82 70
Interest expense, net of amounts capitalized (448) (425) (382)
Other income (expense), net 157 159 144
Total other income and (expense) (234) (184) (168)
Earnings Before Income Taxes 1,763 1,451 1,774
Income taxes 360 81 423
Net Income 1,403 1,370 1,351
Dividends on Preferred Stock 0 0 11
Consolidated Net Income 1,403 1,370 1,340
Alabama Power | Retail revenues      
Operating Revenues:      
Total operating revenues 6,639 6,159 6,470
Alabama Power | Wholesale revenues      
Operating Revenues:      
Total operating revenues 337 424 726
Alabama Power | Wholesale revenues, affiliates      
Operating Revenues:      
Total operating revenues 139 60 202
Alabama Power | Other revenues      
Operating Revenues:      
Total operating revenues 439 407 419
Alabama Power | Fuel      
Operating Expenses:      
Cost of sales 1,358 1,299 1,840
Alabama Power | Purchased power, non-affiliates      
Operating Expenses:      
Cost of sales 199 253 441
Alabama Power | Purchased power, affiliates      
Operating Expenses:      
Cost of sales $ 175 $ 251 $ 360
v3.25.0.1
Statements of Comprehensive Income - APC - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Net Income $ 4,260 $ 3,849 $ 3,428
Qualifying hedges:      
Changes in fair value, net of tax (5) (41) (60)
Reclassification adjustment for amounts included in net income, net of tax 80 69 73
Total other comprehensive income (loss) 99 (10) 71
Comprehensive Income 4,500 3,966 3,595
Alabama Power      
Net Income 1,403 1,370 1,351
Qualifying hedges:      
Changes in fair value, net of tax 0 0 (1)
Reclassification adjustment for amounts included in net income, net of tax 2 2 5
Total other comprehensive income (loss) 2 2 4
Comprehensive Income $ 1,405 $ 1,372 $ 1,355
v3.25.0.1
Statements of Comprehensive Income - APC (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Qualifying hedges, change in fair value, tax $ (2) $ (17) $ (19)
Qualifying hedges, reclassification adjustment, tax 28 27 23
Alabama Power      
Qualifying hedges, change in fair value, tax 0 0 0
Qualifying hedges, reclassification adjustment, tax $ 1 $ 1 $ 2
v3.25.0.1
Statements of Cash Flows - APC - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Operating Activities:      
Net Income $ 4,260 $ 3,849 $ 3,428
Adjustments to reconcile consolidated net income to net cash provided from operating activities —      
Depreciation and amortization, total 5,266 4,986 4,064
Deferred income taxes 536 63 670
Allowance for equity funds used during construction (235) (268) (224)
Pension, postretirement, and other employee benefits (556) (527) (436)
Settlement of asset retirement obligations (566) (617) (455)
Natural disaster reserve and reliability reserve accruals 163 124 430
Retail fuel cost under recovery – long-term (32) (206) (2,166)
Other, net (39) (138) 226
Changes in certain current assets and liabilities —      
-Receivables (372) 482 (771)
-Fossil fuel stock 140 (368) (125)
-Materials and supplies (189) (345) (160)
-Retail fuel cost under recovery 984 686 (100)
-Other current assets (47) (106) (186)
-Accounts payable 492 (863) 1,021
-Other current liabilities 145 191 153
Net cash provided from operating activities 9,788 7,553 6,302
Investing Activities:      
Property additions (8,955) (9,095) (7,923)
Nuclear decommissioning trust fund purchases (1,551) (1,142) (1,125)
Nuclear decommissioning trust fund sales 1,535 1,121 1,112
Cost of removal, net of salvage (632) (592) (649)
Other investing activities (164) (43) (133)
Net cash used for investing activities (9,400) (9,668) (8,430)
Financing Activities:      
Increase (decrease) in notes payable, net (648)   (337)
Increase (decrease) in notes payable, net   973  
Proceeds —      
Short-term borrowings 700 350 2,650
Redemptions and repurchases —      
Preferred stock 0 0 (298)
Short-term borrowings (1,020) (1,630) (1,150)
Payment of common stock dividends (2,954) (3,035) (2,907)
Other financing activities (181) (139) (145)
Net cash provided from (used for) financing activities (208) 999 2,336
Net Change in Cash, Cash Equivalents, and Restricted Cash 180 (1,116) 208
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year 921 2,037 1,829
Cash, Cash Equivalents, and Restricted Cash at End of Year 1,101 921 2,037
Cash paid during the period for —      
Interest, net of amounts capitalized 2,538 2,184 1,758
Income taxes, net 176 132 146
Noncash transactions — Accrued property additions at year-end 1,199 1,027 1,024
Alabama Power      
Operating Activities:      
Net Income 1,403 1,370 1,351
Adjustments to reconcile consolidated net income to net cash provided from operating activities —      
Depreciation and amortization, total 1,608 1,554 1,014
Deferred income taxes (55) (242) 355
Allowance for equity funds used during construction (57) (82) (70)
Pension, postretirement, and other employee benefits (213) (204) (118)
Settlement of asset retirement obligations (254) (270) (205)
Natural disaster reserve and reliability reserve accruals 96 70 185
Retail fuel cost under recovery – long-term 0 0 (520)
Other, net 102 4 (50)
Changes in certain current assets and liabilities —      
-Receivables (32) (24) (321)
-Fossil fuel stock 55 (165) (70)
-Materials and supplies (57) (105) (7)
-Retail fuel cost under recovery 246 376 (102)
-Other current assets (32) (20) (23)
-Accounts payable (127) (162) 249
-Other current liabilities 212 (21) (29)
Net cash provided from operating activities 2,895 2,079 1,639
Investing Activities:      
Property additions (1,881) (2,022) (2,016)
Nuclear decommissioning trust fund purchases (593) (301) (355)
Nuclear decommissioning trust fund sales 592 300 354
Cost of removal, net of salvage (166) (178) (234)
Change in construction payables, net of joint owner portion 10 (44) 50
Other investing activities 51 49 (62)
Net cash used for investing activities (1,987) (2,196) (2,263)
Financing Activities:      
Increase (decrease) in notes payable, net (40)    
Increase (decrease) in notes payable, net   40 0
Proceeds —      
Senior notes 0 500 1,700
Revenue bonds 0 326 0
Short-term borrowings 50 0 0
Other long-term debt 8 29 0
Redemptions and repurchases —      
Senior notes 0 (300) (750)
Preferred stock 0 0 (298)
Revenue bonds (21) 0 0
Short-term borrowings (50) 0 0
Other long-term debt (22) 0 0
Capital contributions from parent company 527 407 649
Payment of common stock dividends (1,182) (1,141) (1,016)
Other financing activities (2) (22) (34)
Net cash provided from (used for) financing activities (732) (161) 251
Net Change in Cash, Cash Equivalents, and Restricted Cash 176 (278) (373)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year 409 687 1,060
Cash, Cash Equivalents, and Restricted Cash at End of Year 585 409 687
Cash paid during the period for —      
Interest, net of amounts capitalized 428 397 342
Income taxes, net 387 315 121
Noncash transactions — Accrued property additions at year-end $ 148 $ 138 $ 182
v3.25.0.1
Statements of Cash Flows - APC (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Net cash paid for capitalized interest $ 103 $ 132 $ 103
Alabama Power      
Net cash paid for capitalized interest $ 18 $ 27 $ 20
v3.25.0.1
Balance Sheets - APC - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Current Assets:    
Cash and cash equivalents $ 1,070 $ 748
Receivables —    
Customer accounts and affiliated 2,228 2,030
Unbilled revenues 825 786
Other accounts and notes 597 519
Accumulated provision for uncollectible accounts (74) (68)
Fossil fuel stock 803 943
Materials and supplies 2,178 1,989
Prepaid expenses 294 406
Other regulatory assets 804 1,120
Other current assets 476 533
Total current assets 10,694 10,432
Property, Plant, and Equipment:    
In service 137,143 128,428
Less: Accumulated depreciation 40,126 37,725
Plant in service, net of depreciation 97,017 90,703
Other utility plant, net 410 499
Nuclear fuel, at amortized cost 873 858
Construction work in progress 6,389 7,784
Total property, plant, and equipment 104,689 99,844
Other Property and Investments:    
Nuclear decommissioning trusts, at fair value 2,621 2,424
Equity investments in unconsolidated subsidiaries 1,416 1,368
Miscellaneous property and investments 668 665
Other Property and Investments 10,198 9,986
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 1,386 1,432
Deferred charges related to income taxes 889 886
Regulatory assets – asset retirement obligations 5,458 5,459
Other regulatory assets, deferred 7,037 6,264
Other deferred charges and assets 1,467 1,468
Total deferred charges and other assets 19,599 19,069
Total Assets 145,180 139,331
Current Liabilities:    
Securities due within one year 4,718 2,476
Notes payable 1,338 2,314
Accounts payable —    
Customer deposits 486 503
Accrued interest 682 652
Accrued compensation 1,261 1,151
Asset retirement obligations 731 744
Other regulatory liabilities 369 141
Other current liabilities 1,100 1,029
Total current liabilities 15,993 13,467
Long-Term Debt 58,768 57,210
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 11,730 10,990
Deferred credits related to income taxes 4,434 4,674
Accumulated deferred ITCs 2,056 2,067
Employee benefit obligations 1,011 1,115
Operating lease obligations 1,253 1,307
Asset retirement obligations, deferred 9,203 9,573
Other regulatory liabilities, deferred 692 715
Other deferred credits and liabilities 1,350 1,031
Total deferred credits and other liabilities 33,745 33,429
Total Liabilities 108,506 104,106
Common Stockholders' Equity:    
Common stock 5,446 5,423
Paid-in capital 14,149 13,775
Retained earnings 13,750 12,482
Accumulated other comprehensive loss (78) (177)
Total common stockholders' equity 33,208 31,444
Total Liabilities and Stockholders' Equity 145,180 139,331
Commitments and Contingent Matters
Alabama Power    
Current Assets:    
Cash and cash equivalents 585 324
Receivables —    
Customer accounts and affiliated 512 513
Unbilled revenues 187 191
Other accounts and notes 126 109
Accumulated provision for uncollectible accounts (22) (16)
Fossil fuel stock 339 394
Materials and supplies 699 655
Prepaid expenses 63 62
Regulatory assets – under recovered retail fuel clause revenues 0 246
Other regulatory assets 332 385
Other current assets 79 142
Total current assets 2,991 3,077
Property, Plant, and Equipment:    
In service 36,501 35,429
Less: Accumulated depreciation 11,741 11,131
Plant in service, net of depreciation 24,760 24,298
Other utility plant, net 410 499
Nuclear fuel, at amortized cost 262 253
Construction work in progress 1,377 1,095
Total property, plant, and equipment 26,809 26,145
Other Property and Investments:    
Nuclear decommissioning trusts, at fair value 1,386 1,261
Equity investments in unconsolidated subsidiaries 48 52
Miscellaneous property and investments 129 155
Other Property and Investments 1,563 1,468
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 84 87
Deferred charges related to income taxes 264 262
Prepaid pension and other postretirement benefit costs 841 659
Regulatory assets – asset retirement obligations 1,780 1,810
Other regulatory assets, deferred 1,815 1,858
Other deferred charges and assets 391 414
Total deferred charges and other assets 5,175 5,090
Total Assets 36,538 35,780
Current Liabilities:    
Securities due within one year 655 223
Notes payable 0 40
Accounts payable —    
Affiliated and other 625 630
Customer deposits 113 105
Accrued taxes 78 51
Accrued interest 120 122
Accrued compensation 240 222
Asset retirement obligations 364 346
Other regulatory liabilities 165 44
Other current liabilities 219 191
Total current liabilities 2,878 2,304
Long-Term Debt 10,499 10,960
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 4,178 4,170
Deferred credits related to income taxes 1,398 1,506
Accumulated deferred ITCs 113 74
Employee benefit obligations 148 155
Operating lease obligations 76 81
Asset retirement obligations, deferred 3,694 3,812
Other regulatory liabilities, deferred 271 291
Other deferred credits and liabilities 195 94
Total deferred credits and other liabilities 10,073 10,183
Total Liabilities 23,450 23,447
Common Stockholders' Equity:    
Common stock 1,222 1,222
Paid-in capital 7,657 7,125
Retained earnings 4,214 3,993
Accumulated other comprehensive loss (5) (7)
Total common stockholders' equity 13,088 12,333
Total Liabilities and Stockholders' Equity 36,538 35,780
Commitments and Contingent Matters
Alabama Power | Related Party    
Receivables —    
Customer accounts and affiliated 91 72
Accounts payable —    
Affiliated and other $ 299 $ 330
v3.25.0.1
Balance Sheets - APC (Parenthetical) - $ / shares
shares in Millions
Dec. 31, 2024
Dec. 31, 2023
Common Stockholders' Equity:    
Common stock, par value (in dollars per share) $ 5 $ 5
Common stock, shares authorized (in shares) 1,500 1,500
Alabama Power    
Common Stockholders' Equity:    
Common stock, par value (in dollars per share) $ 40 $ 40
Common stock, shares authorized (in shares) 40 40
Common stock, shares outstanding (in shares) 31 31
v3.25.0.1
Statements of Common Stockholders' Equity - APC - USD ($)
shares in Millions, $ in Millions
Total
Common Stock
Paid-In Capital
Retained Earnings
Accumulated Other Comprehensive Income (Loss)
Alabama Power
Alabama Power
Common Stock
Alabama Power
Paid-In Capital
Alabama Power
Retained Earnings
Alabama Power
Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2021   1,061         31      
Beginning balance at Dec. 31, 2021           $ 10,713 $ 1,222 $ 6,056 $ 3,448 $ (13)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Net income after dividends on preferred stock $ 3,524         1,340     1,340  
Capital contributions from parent company           654   654    
Other comprehensive income (loss) 71       $ 71 4       4
Cash dividends on common stock (2,907)     $ (2,907)   (1,016)     (1,016)  
Other (6)   $ 9 (8) (1) (8)     (8)  
Ending balance (in shares) at Dec. 31, 2022   1,090         31      
Ending balance at Dec. 31, 2022           11,687 $ 1,222 6,710 3,764 (9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Net income after dividends on preferred stock 3,976         1,370     1,370  
Capital contributions from parent company           415   415    
Other comprehensive income (loss) (10)       (10) 2       2
Cash dividends on common stock (3,035)     (3,035)   (1,141)     (1,141)  
Other (5)   (1) 3            
Ending balance (in shares) at Dec. 31, 2023   1,092         31      
Ending balance at Dec. 31, 2023 31,444         12,333 $ 1,222 7,125 3,993 (7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Net income after dividends on preferred stock 4,401         1,403     1,403  
Capital contributions from parent company           532   532    
Other comprehensive income (loss) 99       99 2       2
Cash dividends on common stock (3,133)     (3,133)   (1,182)     (1,182)  
Other (in shares)   0                
Other 19 $ 0 $ 19 $ 0 $ 0          
Ending balance (in shares) at Dec. 31, 2024   1,098         31      
Ending balance at Dec. 31, 2024 $ 33,208         $ 13,088 $ 1,222 $ 7,657 $ 4,214 $ (5)
v3.25.0.1
Statements of Income - GPC - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Operating Revenues:      
Total operating revenues $ 26,724 $ 25,253 $ 29,279
Operating Expenses:      
Other operations and maintenance 6,539 6,093 6,824
Depreciation and amortization 4,755 4,525 3,663
Taxes other than income taxes 1,540 1,425 1,411
Estimated loss on Plant Vogtle Units 3 and 4 (21) (68) 183
Total operating expenses 19,656 19,427 23,909
Operating Income 7,068 5,826 5,370
Other Income and (Expense):      
Allowance for equity funds used during construction 235 268 224
Interest expense, net of amounts capitalized (2,743) (2,446) (2,022)
Other income (expense), net 530 553 500
Total other income and (expense) (1,839) (1,481) (1,147)
Earnings Before Income Taxes 5,229 4,345 4,223
Income taxes (benefit) 969 496 795
Net Income 4,260 3,849 3,428
Retail revenues      
Operating Revenues:      
Total operating revenues 17,790 16,343 18,197
Other revenues      
Operating Revenues:      
Total operating revenues 1,151 949 732
Operating Expenses:      
Cost of sales 668 560 396
Fuel      
Operating Expenses:      
Cost of sales 4,096 4,365 6,835
Purchased power, non-affiliates      
Operating Expenses:      
Cost of sales 883 883 1,593
Georgia Power      
Operating Revenues:      
Total operating revenues 11,331 10,118 11,584
Operating Expenses:      
Other operations and maintenance 2,372 2,083 2,349
Depreciation and amortization 1,774 1,681 1,430
Taxes other than income taxes 647 541 527
Estimated loss on Plant Vogtle Units 3 and 4 (21) (68) 183
Total operating expenses 7,790 7,299 9,232
Operating Income 3,541 2,819 2,352
Other Income and (Expense):      
Allowance for equity funds used during construction 152 165 140
Interest expense, net of amounts capitalized (725) (626) (485)
Other income (expense), net 178 170 176
Total other income and (expense) (395) (291) (169)
Earnings Before Income Taxes 3,146 2,528 2,183
Income taxes (benefit) 603 448 370
Net Income 2,543 2,080 1,813
Georgia Power | Retail revenues      
Operating Revenues:      
Total operating revenues 10,187 9,222 10,792
Georgia Power | Wholesale revenues      
Operating Revenues:      
Total operating revenues 265 188 235
Georgia Power | Other revenues      
Operating Revenues:      
Total operating revenues 879 708 557
Georgia Power | Fuel      
Operating Expenses:      
Cost of sales 1,658 1,781 2,486
Georgia Power | Purchased power, non-affiliates      
Operating Expenses:      
Cost of sales 615 517 856
Georgia Power | Purchased power, affiliates      
Operating Expenses:      
Cost of sales $ 745 $ 764 $ 1,401
v3.25.0.1
Statements of Comprehensive Income - GPC - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Net Income $ 4,260 $ 3,849 $ 3,428
Qualifying hedges:      
Changes in fair value, net of tax (5) (41) (60)
Reclassification adjustment for amounts included in net income, net of tax 80 69 73
Total other comprehensive income (loss) 99 (10) 71
Comprehensive Income 4,500 3,966 3,595
Georgia Power      
Net Income 2,543 2,080 1,813
Qualifying hedges:      
Changes in fair value, net of tax 18 (2) 23
Reclassification adjustment for amounts included in net income, net of tax 4 5 5
Total other comprehensive income (loss) 22 3 28
Comprehensive Income $ 2,565 $ 2,083 $ 1,841
v3.25.0.1
Statements of Comprehensive Income - GPC (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Qualifying hedges, change in fair value, tax $ (2) $ (17) $ (19)
Qualifying hedges, reclassification adjustment, tax 28 27 23
Georgia Power      
Qualifying hedges, change in fair value, tax 6 (1) 8
Qualifying hedges, reclassification adjustment, tax $ 1 $ 2 $ 2
v3.25.0.1
Statements of Cash Flows - GPC - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Operating Activities:      
Net Income $ 4,260 $ 3,849 $ 3,428
Adjustments to reconcile consolidated net income to net cash provided from operating activities —      
Depreciation and amortization, total 5,266 4,986 4,064
Deferred income taxes 536 63 670
Allowance for equity funds used during construction (235) (268) (224)
Pension, postretirement, and other employee benefits (556) (527) (436)
Settlement of asset retirement obligations (566) (617) (455)
Estimated loss on Plant Vogtle Units 3 and 4 (21) (68) 183
Storm damage cost recovery – long-term (631) 0 0
Other, net (39) (138) 226
Changes in certain current assets and liabilities —      
-Receivables (372) 482 (771)
-Retail fuel cost under recovery 984 686 (100)
-Fossil fuel stock 140 (368) (125)
-Materials and supplies (189) (345) (160)
-Other current assets (47) (106) (186)
-Accounts payable 492 (863) 1,021
-Accrued taxes 206 23 51
-Customer refunds 83 (157) 119
-Other current liabilities 145 191 153
Net cash provided from operating activities 9,788 7,553 6,302
Investing Activities:      
Property additions (8,955) (9,095) (7,923)
Nuclear decommissioning trust fund purchases (1,551) (1,142) (1,125)
Nuclear decommissioning trust fund sales 1,535 1,121 1,112
Cost of removal, net of salvage (632) (592) (649)
Payments pursuant to LTSAs (108) (99) (190)
Other investing activities (164) (43) (133)
Net cash used for investing activities (9,400) (9,668) (8,430)
Financing Activities:      
Increase (decrease) in notes payable, net   973  
Increase (decrease) in notes payable, net (648)   (337)
Proceeds —      
Short-term borrowings 700 350 2,650
Redemptions and repurchases —      
Short-term borrowings (1,020) (1,630) (1,150)
Payment of common stock dividends (2,954) (3,035) (2,907)
Other financing activities (181) (139) (145)
Net cash provided from (used for) financing activities (208) 999 2,336
Net Change in Cash, Cash Equivalents, and Restricted Cash 180 (1,116) 208
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year 921 2,037 1,829
Cash, Cash Equivalents, and Restricted Cash at End of Year 1,101 921 2,037
Cash paid during the period for —      
Interest, net of amounts capitalized 2,538 2,184 1,758
Income taxes, net (excludes credit transfers) 176 132 146
Noncash transactions — Accrued property additions at year-end 1,199 1,027 1,024
Georgia Power      
Operating Activities:      
Net Income 2,543 2,080 1,813
Adjustments to reconcile consolidated net income to net cash provided from operating activities —      
Depreciation and amortization, total 2,080 1,914 1,622
Deferred income taxes 369 184 313
Allowance for equity funds used during construction (152) (165) (140)
Pension, postretirement, and other employee benefits (288) (272) (240)
Settlement of asset retirement obligations (270) (304) (212)
Storm damage accruals 31 31 213
Estimated loss on Plant Vogtle Units 3 and 4 (21) (68) 183
Retail fuel cost under recovery – long-term 0 (157) (1,646)
Storm damage cost recovery – long-term (631) 0 0
Other, net (144) (82) 81
Changes in certain current assets and liabilities —      
-Receivables (268) (57) (286)
-Retail fuel cost under recovery 738 308 0
-Fossil fuel stock 96 (189) (43)
-Materials and supplies (81) (154) (73)
-Other current assets (51) (63) (83)
-Accounts payable 633 (206) 264
-Accrued taxes 212 74 173
-Customer refunds (4) (117) 113
-Other current liabilities 1 (5) (14)
Net cash provided from operating activities 4,793 2,752 2,038
Investing Activities:      
Property additions (4,816) (4,786) (3,809)
Nuclear decommissioning trust fund purchases (958) (841) (770)
Nuclear decommissioning trust fund sales 942 821 758
Cost of removal, net of salvage (336) (279) (274)
Change in construction payables, net of joint owner portion 68 50 186
Payments pursuant to LTSAs (74) (49) (44)
Proceeds from dispositions 357 59 56
Other investing activities (79) (54) (57)
Net cash used for investing activities (4,896) (5,079) (3,954)
Financing Activities:      
Increase (decrease) in notes payable, net   811  
Increase (decrease) in notes payable, net (811)   0
Proceeds —      
Senior notes 2,117 2,450 1,500
Short-term borrowings 350 350 2,100
Revenue bonds 0 229 200
Redemptions and repurchases —      
Senior notes (400) (800) (400)
Short-term borrowings (670) (1,430) (500)
FFB loan (86) (86) (88)
Revenue bonds 0 0 (53)
Other long-term debt 0 0 (125)
Capital contributions from parent company 1,780 2,291 1,471
Payment of common stock dividends (2,051) (1,855) (1,691)
Other financing activities (83) (38) (51)
Net cash provided from (used for) financing activities 146 1,922 2,363
Net Change in Cash, Cash Equivalents, and Restricted Cash 43 (405) 447
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year 75 480 33
Cash, Cash Equivalents, and Restricted Cash at End of Year 118 75 480
Cash paid during the period for —      
Interest, net of amounts capitalized 680 592 432
Income taxes, net (excludes credit transfers) (14) 220 30
Noncash transactions — Accrued property additions at year-end $ 739 $ 680 $ 626
v3.25.0.1
Statements of Cash Flows - GPC (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Net cash paid for capitalized interest $ 103 $ 132 $ 103
Georgia Power      
Net cash paid for capitalized interest $ 57 $ 86 $ 73
v3.25.0.1
Balance Sheets - GPC - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Current Assets:    
Cash and cash equivalents $ 1,070 $ 748
Receivables —    
Customer accounts, net and affiliated 2,228 2,030
Unbilled revenues 825 786
Under recovered fuel clause revenues 713 696
Other accounts and notes 597 519
Fossil fuel stock 803 943
Materials and supplies 2,178 1,989
Regulatory assets – asset retirement obligations 353 274
Other regulatory assets 804 1,120
Other current assets 476 533
Total current assets 10,694 10,432
Property, Plant, and Equipment:    
In service 137,143 128,428
Less: Accumulated depreciation 40,126 37,725
Plant in service, net of depreciation 97,017 90,703
Nuclear fuel, at amortized cost 873 858
Construction work in progress 6,389 7,784
Total property, plant, and equipment 104,689 99,844
Other Property and Investments:    
Nuclear decommissioning trusts, at fair value 2,621 2,424
Equity investments in unconsolidated subsidiaries 1,416 1,368
Miscellaneous property and investments 668 665
Other Property and Investments 10,198 9,986
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 1,386 1,432
Deferred charges related to income taxes 889 886
Prepaid pension costs 2,674 2,079
Deferred under recovered retail fuel clause revenues 485 1,261
Regulatory assets – asset retirement obligations, deferred 5,458 5,459
Other regulatory assets, deferred 7,037 6,264
Other deferred charges and assets 1,467 1,468
Total deferred charges and other assets 19,599 19,069
Total Assets 145,180 139,331
Current Liabilities:    
Securities due within one year 4,718 2,476
Notes payable 1,338 2,314
Accounts payable —    
Customer deposits 486 503
Accrued interest 682 652
Accrued compensation 1,261 1,151
Operating lease obligations 200 183
Asset retirement obligations 731 744
Other regulatory liabilities 369 141
Other current liabilities 1,100 1,029
Total current liabilities 15,993 13,467
Long-Term Debt 58,768 57,210
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 11,730 10,990
Deferred credits related to income taxes 4,434 4,674
Accumulated deferred ITCs 2,056 2,067
Employee benefit obligations 1,011 1,115
Operating lease obligations, deferred 1,253 1,307
Asset retirement obligations, deferred 9,203 9,573
Other deferred credits and liabilities 1,350 1,031
Total deferred credits and other liabilities 33,745 33,429
Total Liabilities 108,506 104,106
Common Stockholders' Equity:    
Common stock 5,446 5,423
Paid-in capital 14,149 13,775
Retained earnings 13,750 12,482
Accumulated other comprehensive loss (78) (177)
Total common stockholders' equity 33,208 31,444
Total Liabilities and Stockholders' Equity 145,180 139,331
Commitments and Contingent Matters
Georgia Power    
Current Assets:    
Cash and cash equivalents 97 9
Receivables —    
Customer accounts, net and affiliated 985 843
Unbilled revenues 341 275
Under recovered fuel clause revenues 713 694
Joint owner accounts 101 119
Other accounts and notes 92 81
Fossil fuel stock 385 480
Materials and supplies 968 883
Regulatory assets – asset retirement obligations 222 98
Other regulatory assets 373 423
Other current assets 262 305
Total current assets 4,604 4,261
Property, Plant, and Equipment:    
In service 55,036 49,370
Less: Accumulated depreciation 14,806 13,955
Plant in service, net of depreciation 40,230 35,415
Nuclear fuel, at amortized cost 611 605
Construction work in progress 3,197 4,975
Total property, plant, and equipment 44,038 40,995
Other Property and Investments:    
Nuclear decommissioning trusts, at fair value 1,236 1,163
Equity investments in unconsolidated subsidiaries 43 47
Miscellaneous property and investments 192 151
Other Property and Investments 1,471 1,361
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 1,331 884
Deferred charges related to income taxes 596 594
Prepaid pension costs 897 706
Deferred under recovered retail fuel clause revenues 453 1,211
Regulatory assets – asset retirement obligations, deferred 3,436 3,407
Other regulatory assets, deferred 3,814 2,890
Other deferred charges and assets 615 508
Total deferred charges and other assets 11,142 10,200
Total Assets 61,255 56,817
Current Liabilities:    
Securities due within one year 966 502
Notes payable 200 1,329
Accounts payable —    
Affiliated and other 1,837 1,147
Customer deposits 256 250
Accrued taxes 803 582
Accrued interest 190 175
Accrued compensation 276 250
Operating lease obligations 169 135
Asset retirement obligations 309 338
Other regulatory liabilities 150 22
Other current liabilities 296 365
Total current liabilities 6,436 5,935
Long-Term Debt 17,384 16,198
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 4,385 4,018
Deferred credits related to income taxes 2,047 2,161
Accumulated deferred ITCs 343 326
Employee benefit obligations 205 248
Operating lease obligations, deferred 1,159 740
Asset retirement obligations, deferred 5,106 5,327
Other deferred credits and liabilities 509 481
Total deferred credits and other liabilities 13,754 13,301
Total Liabilities 37,574 35,434
Common Stockholders' Equity:    
Common stock 398 398
Paid-in capital 19,708 17,923
Retained earnings 3,562 3,071
Accumulated other comprehensive loss 13 (9)
Total common stockholders' equity 23,681 21,383
Total Liabilities and Stockholders' Equity 61,255 56,817
Commitments and Contingent Matters
Georgia Power | Related Party    
Receivables —    
Customer accounts, net and affiliated 65 51
Accounts payable —    
Affiliated and other $ 984 $ 840
v3.25.0.1
Balance Sheets - GPC (Parenthetical) - shares
Dec. 31, 2024
Dec. 31, 2023
Common Stockholders' Equity:    
Common stock, shares authorized (in shares) 1,500,000,000 1,500,000,000
Georgia Power    
Common Stockholders' Equity:    
Common stock, shares authorized (in shares) 20,000,000 20,000,000
Common stock, shares outstanding (in shares) 9,000,000 9,000,000
v3.25.0.1
Statements of Common Stockholders' Equity - GPC - USD ($)
shares in Millions, $ in Millions
Total
Common Stock
Paid-In Capital
Retained Earnings
Accumulated Other Comprehensive Income (Loss)
Georgia Power
Georgia Power
Common Stock
Georgia Power
Paid-In Capital
Georgia Power
Retained Earnings
Georgia Power
Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2021   1,061         9      
Beginning balance at Dec. 31, 2021           $ 17,234 $ 398 $ 14,153 $ 2,724 $ (41)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Net Income $ 3,428         1,813     1,813  
Capital contributions from parent company           1,473   1,473    
Other comprehensive income 71       $ 71 28       28
Cash dividends on common stock (2,907)     $ (2,907)   (1,691)     (1,691)  
Other (6)   $ 9 (8) (1) 1       1
Ending balance (in shares) at Dec. 31, 2022   1,090         9      
Ending balance at Dec. 31, 2022           18,858 $ 398 15,626 2,846 (12)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Net Income 3,849         2,080     2,080  
Capital contributions from parent company           2,297   2,297    
Other comprehensive income (10)       (10) 3       3
Cash dividends on common stock (3,035)     (3,035)   (1,855)     (1,855)  
Other (5)   (1) 3            
Ending balance (in shares) at Dec. 31, 2023   1,092         9      
Ending balance at Dec. 31, 2023 31,444         21,383 $ 398 17,923 3,071 (9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Net Income 4,260         2,543     2,543  
Capital contributions from parent company           1,785   1,785    
Other comprehensive income 99       99 22       22
Cash dividends on common stock (3,133)     (3,133)   (2,051)     (2,051)  
Other (in shares)   0         0      
Other 19 $ 0 $ 19 $ 0 $ 0 (1) $ 0 0 (1) 0
Ending balance (in shares) at Dec. 31, 2024   1,098         9      
Ending balance at Dec. 31, 2024 $ 33,208         $ 23,681 $ 398 $ 19,708 $ 3,562 $ 13
v3.25.0.1
Statements of Income - MPC - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Operating Revenues:      
Total operating revenues $ 26,724 $ 25,253 $ 29,279
Operating Expenses:      
Other operations and maintenance 6,539 6,093 6,824
Depreciation and amortization 4,755 4,525 3,663
Taxes other than income taxes 1,540 1,425 1,411
Total operating expenses 19,656 19,427 23,909
Operating Income 7,068 5,826 5,370
Other Income and (Expense):      
Interest expense, net of amounts capitalized (2,743) (2,446) (2,022)
Other income (expense), net 530 553 500
Total other income and (expense) (1,839) (1,481) (1,147)
Earnings Before Income Taxes 5,229 4,345 4,223
Income taxes 969 496 795
Net Income 4,260 3,849 3,428
Retail revenues      
Operating Revenues:      
Total operating revenues 17,790 16,343 18,197
Other revenues      
Operating Revenues:      
Total operating revenues 1,151 949 732
Operating Expenses:      
Fuel and purchased power 668 560 396
Mississippi Power      
Operating Revenues:      
Total operating revenues 1,463 1,474 1,694
Operating Expenses:      
Other operations and maintenance 370 362 376
Depreciation and amortization 193 190 181
Taxes other than income taxes 127 124 124
Total operating expenses 1,167 1,214 1,470
Operating Income 296 260 224
Other Income and (Expense):      
Interest expense, net of amounts capitalized (77) (71) (56)
Other income (expense), net 27 35 33
Total other income and (expense) (50) (36) (23)
Earnings Before Income Taxes 246 224 201
Income taxes 47 36 37
Net Income 199 188 164
Mississippi Power | Retail revenues      
Operating Revenues:      
Total operating revenues 965 963 935
Mississippi Power | Wholesale revenues, non-affiliates      
Operating Revenues:      
Total operating revenues 228 272 252
Mississippi Power | Wholesale revenues, affiliates      
Operating Revenues:      
Total operating revenues 218 200 460
Mississippi Power | Other revenues      
Operating Revenues:      
Total operating revenues 52 39 47
Mississippi Power | Fuel and purchased power      
Operating Expenses:      
Fuel and purchased power $ 477 $ 538 $ 789
v3.25.0.1
Statements of Comprehensive Income - MPC - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Net Income $ 4,260 $ 3,849 $ 3,428
Qualifying hedges:      
Changes in fair value, net of tax (5) (41) (60)
Total other comprehensive income (loss) 99 (10) 71
Comprehensive Income 4,500 3,966 3,595
Mississippi Power      
Net Income 199 188 164
Qualifying hedges:      
Changes in fair value, net of tax 5 0 0
Total other comprehensive income (loss) 5 0 0
Comprehensive Income $ 204 $ 188 $ 164
v3.25.0.1
Statements of Comprehensive Income - MPC (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Qualifying hedges, change in fair value, tax $ (2) $ (17) $ (19)
Mississippi Power      
Qualifying hedges, change in fair value, tax $ 2 $ 0 $ 0
v3.25.0.1
Statements of Cash Flows - MPC - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Operating Activities:      
Net Income $ 4,260 $ 3,849 $ 3,428
Adjustments to reconcile consolidated net income to net cash provided from operating activities —      
Depreciation and amortization, total 5,266 4,986 4,064
Deferred income taxes 536 63 670
Pension, postretirement, and other employee benefits (556) (527) (436)
Settlement of asset retirement obligations (566) (617) (455)
Retail fuel cost under recovery – long-term (32) (206) (2,166)
Other, net (39) (138) 226
Changes in certain current assets and liabilities —      
-Receivables (372) 482 (771)
-Materials and supplies (189) (345) (160)
-Other current assets (47) (106) (186)
-Accounts payable 492 (863) 1,021
-Accrued taxes 206 23 51
-Other current liabilities 145 191 153
Net cash provided from operating activities 9,788 7,553 6,302
Investing Activities:      
Property additions (8,955) (9,095) (7,923)
Cost of removal net of salvage (632) (592) (649)
Payments pursuant to LTSAs (108) (99) (190)
Other investing activities (164) (43) (133)
Net cash used for investing activities (9,400) (9,668) (8,430)
Financing Activities:      
Increase (decrease) in notes payable, net   973  
Increase (decrease) in notes payable, net (648)   (337)
Proceeds —      
Payment of common stock dividends (2,954) (3,035) (2,907)
Other financing activities (181) (139) (145)
Net cash provided from (used for) financing activities (208) 999 2,336
Net Change in Cash, Cash Equivalents, and Restricted Cash 180 (1,116) 208
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year 921 2,037 1,829
Cash, Cash Equivalents, and Restricted Cash at End of Year 1,101 921 2,037
Noncash transactions —      
Interest 2,538 2,184 1,758
Income taxes, net 176 132 146
Noncash transactions — Accrued property additions at year-end 1,199 1,027 1,024
Mississippi Power      
Operating Activities:      
Net Income 199 188 164
Adjustments to reconcile consolidated net income to net cash provided from operating activities —      
Depreciation and amortization, total 209 232 223
Deferred income taxes 16 (13) (6)
Pension, postretirement, and other employee benefits (21) (20) (18)
Settlement of asset retirement obligations (17) (18) (20)
System restoration rider and reliability reserve accruals 35 23 32
Retail fuel cost under recovery – long-term (32) (50) 0
Other, net 5 (5) 21
Changes in certain current assets and liabilities —      
-Receivables (14) 85 (82)
-Materials and supplies (13) (9) (10)
-Other current assets (21) 7 (15)
-Accounts payable (10) (81) 97
-Accrued taxes (2) (7) 5
-Retail fuel cost over recovery 55 27 0
-Other current liabilities 17 10 (8)
Net cash provided from operating activities 406 369 383
Investing Activities:      
Property additions (311) (319) (257)
Cost of removal net of salvage (41) (32) (27)
Change in construction payables 0 9 (3)
Payments pursuant to LTSAs (19) (26) (29)
Other investing activities (2) (2) (1)
Net cash used for investing activities (373) (370) (317)
Financing Activities:      
Increase (decrease) in notes payable, net 14    
Increase (decrease) in notes payable, net   0 0
Proceeds —      
Senior notes 250 100 0
Revenue bonds 0 0 35
Redemptions — Senior notes (200) 0 0
Capital contributions from parent company 68 68 68
Payment of common stock dividends (188) (185) (170)
Other financing activities (2) (3) (1)
Net cash provided from (used for) financing activities (58) (20) (68)
Net Change in Cash, Cash Equivalents, and Restricted Cash (25) (21) (2)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year 38 59 61
Cash, Cash Equivalents, and Restricted Cash at End of Year 13 38 59
Noncash transactions —      
Interest 74 66 55
Income taxes, net 51 52 33
Noncash transactions — Accrued property additions at year-end $ 36 $ 34 $ 22
v3.25.0.1
Balance Sheets - MPC - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Current Assets:    
Cash and cash equivalents $ 1,070 $ 748
Receivables —    
Customer accounts, net and affiliated 2,228 2,030
Unbilled revenues 825 786
Other accounts and notes 597 519
Fossil fuel stock 803 943
Materials and supplies 2,178 1,989
Other regulatory assets 804 1,120
Other current assets 476 533
Total current assets 10,694 10,432
Property, Plant, and Equipment:    
In service 137,143 128,428
Less: Accumulated depreciation 40,126 37,725
Plant in service, net of depreciation 97,017 90,703
Construction work in progress 6,389 7,784
Total property, plant, and equipment 104,689 99,844
Other Property and Investments:    
Other Property and Investments 10,198 9,986
Deferred Charges and Other Assets:    
Deferred charges related to income taxes 889 886
Prepaid pension costs 2,674 2,079
Deferred under recovered retail fuel clause revenues 485 1,261
Regulatory assets – asset retirement obligations 5,458 5,459
Other regulatory assets, deferred 7,037 6,264
Other deferred charges and assets 1,467 1,468
Total deferred charges and other assets 19,599 19,069
Total Assets 145,180 139,331
Current Liabilities:    
Securities due within one year 4,718 2,476
Notes payable 1,338 2,314
Accounts payable —    
Accrued compensation 1,261 1,151
Asset retirement obligations 731 744
Other regulatory liabilities 369 141
Other current liabilities 1,100 1,029
Total current liabilities 15,993 13,467
Long-Term Debt 58,768 57,210
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 11,730 10,990
Deferred credits related to income taxes 4,434 4,674
Employee benefit obligations 1,011 1,115
Asset retirement obligations, deferred 9,203 9,573
Other cost of removal obligations 2,016 1,957
Other regulatory liabilities, deferred 692 715
Other deferred credits and liabilities 1,350 1,031
Total deferred credits and other liabilities 33,745 33,429
Total Liabilities 108,506 104,106
Common Stockholders' Equity:    
Common stock 5,446 5,423
Paid-in capital 14,149 13,775
Accumulated deficit 13,750 12,482
Accumulated other comprehensive loss (78) (177)
Total common stockholders' equity 33,208 31,444
Total Liabilities and Stockholders' Equity 145,180 139,331
Commitments and Contingent Matters
Mississippi Power    
Current Assets:    
Cash and cash equivalents 13 38
Receivables —    
Customer accounts, net and affiliated 45 36
Unbilled revenues 39 40
Other accounts and notes 24 20
Fossil fuel stock 56 47
Materials and supplies 103 89
Other regulatory assets 43 56
Other current assets 28 10
Total current assets 384 365
Property, Plant, and Equipment:    
In service 5,697 5,523
Less: Accumulated depreciation 1,833 1,792
Plant in service, net of depreciation 3,864 3,731
Construction work in progress 253 203
Total property, plant, and equipment 4,117 3,934
Other Property and Investments:    
Other Property and Investments 152 158
Deferred Charges and Other Assets:    
Deferred charges related to income taxes 27 28
Prepaid pension costs 124 99
Deferred under recovered retail fuel clause revenues 32 50
Regulatory assets – asset retirement obligations 243 244
Other regulatory assets, deferred 259 285
Accumulated deferred income taxes 82 96
Other deferred charges and assets 74 85
Total deferred charges and other assets 841 887
Total Assets 5,494 5,344
Current Liabilities:    
Securities due within one year 12 201
Notes payable 14 0
Accounts payable —    
Affiliated and other 83 73
Accrued taxes 115 117
Accrued compensation 46 43
Asset retirement obligations 32 29
Over recovered retail fuel clause revenues 32 27
Other regulatory liabilities 5 17
Other current liabilities 95 90
Total current liabilities 502 679
Long-Term Debt 1,681 1,443
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 492 469
Deferred credits related to income taxes 219 229
Employee benefit obligations 65 67
Asset retirement obligations, deferred 116 139
Other cost of removal obligations 170 186
Other regulatory liabilities, deferred 121 92
Other deferred credits and liabilities 39 37
Total deferred credits and other liabilities 1,222 1,219
Total Liabilities 3,405 3,341
Common Stockholders' Equity:    
Common stock 38 38
Paid-in capital 4,791 4,721
Accumulated deficit (2,745) (2,756)
Accumulated other comprehensive loss 5 0
Total common stockholders' equity 2,089 2,003
Total Liabilities and Stockholders' Equity 5,494 5,344
Commitments and Contingent Matters
Mississippi Power | Related Party    
Receivables —    
Customer accounts, net and affiliated 33 29
Accounts payable —    
Affiliated and other $ 68 $ 82
v3.25.0.1
Balance Sheets - MPC (Parenthetical) - shares
shares in Millions
Dec. 31, 2024
Dec. 31, 2023
Common Stockholders' Equity:    
Common stock, shares authorized (in shares) 1,500 1,500
Mississippi Power    
Common Stockholders' Equity:    
Common stock, shares authorized (in shares) 50 50
Common stock, shares outstanding (in shares) 1 1
v3.25.0.1
Statements of Common Stockholders' Equity - MPC - USD ($)
shares in Millions, $ in Millions
Total
Common Stock
Retained Earnings
Accumulated Other Comprehensive Income (Loss)
Mississippi Power
Mississippi Power
Common Stock
Mississippi Power
Paid-In Capital
Mississippi Power
Retained Earnings
Mississippi Power
Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2021   1,061       1      
Beginning balance at Dec. 31, 2021         $ 1,867 $ 38 $ 4,582 $ (2,753) $ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income $ 3,524       164     164  
Capital contributions from parent company         70   70    
Other comprehensive income 71     $ 71          
Cash dividends on common stock (2,907)   $ (2,907)   (170)     (170)  
Ending balance (in shares) at Dec. 31, 2022   1,090       1      
Ending balance at Dec. 31, 2022         1,931 $ 38 4,652 (2,759) 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 3,976       188     188  
Capital contributions from parent company         69   69    
Other comprehensive income (10)     (10)          
Cash dividends on common stock (3,035)   (3,035)   (185)     (185)  
Ending balance (in shares) at Dec. 31, 2023   1,092       1      
Ending balance at Dec. 31, 2023 31,444       2,003 $ 38 4,721 (2,756) 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 4,401       199     199  
Capital contributions from parent company         70   70    
Other comprehensive income 99     $ 99 5       5
Cash dividends on common stock (3,133)   $ (3,133)   (188)     (188)  
Ending balance (in shares) at Dec. 31, 2024   1,098       1      
Ending balance at Dec. 31, 2024 $ 33,208       $ 2,089 $ 38 $ 4,791 $ (2,745) $ 5
v3.25.0.1
Consolidated Statements of Income - SPC - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Operating Revenues:      
Total operating revenues $ 26,724 $ 25,253 $ 29,279
Operating Expenses:      
Other operations and maintenance 6,539 6,093 6,824
Depreciation and amortization 4,755 4,525 3,663
Taxes other than income taxes 1,540 1,425 1,411
Total operating expenses 19,656 19,427 23,909
Operating Income 7,068 5,826 5,370
Other Income and (Expense):      
Interest expense, net of amounts capitalized (2,743) (2,446) (2,022)
Other income (expense), net 530 553 500
Total other income and (expense) (1,839) (1,481) (1,147)
Earnings Before Income Taxes 5,229 4,345 4,223
Income taxes (benefit) 969 496 795
Net Income 4,260 3,849 3,428
Net loss attributable to noncontrolling interests (141) (127) (107)
Consolidated Net Income 4,401 3,976 3,524
Other revenues      
Operating Revenues:      
Total operating revenues 1,151 949 732
Operating Expenses:      
Cost of sales 668 560 396
Fuel      
Operating Expenses:      
Cost of sales 4,096 4,365 6,835
Purchased power      
Operating Expenses:      
Cost of sales 883 883 1,593
Southern Power      
Operating Revenues:      
Total operating revenues 2,014 2,189 3,369
Operating Expenses:      
Other operations and maintenance 516 473 483
Depreciation and amortization 522 504 516
Taxes other than income taxes 41 51 49
Gain on dispositions, net 0 (20) (2)
Total operating expenses 1,736 1,830 2,971
Operating Income 278 359 398
Other Income and (Expense):      
Interest expense, net of amounts capitalized (117) (129) (138)
Other income (expense), net 13 12 7
Total other income and (expense) (104) (117) (131)
Earnings Before Income Taxes 174 242 267
Income taxes (benefit) (13) 12 20
Net Income 187 230 247
Net loss attributable to noncontrolling interests (141) (127) (107)
Consolidated Net Income 328 357 354
Southern Power | Wholesale revenues, non-affiliates      
Operating Revenues:      
Total operating revenues 1,606 1,597 2,458
Southern Power | Wholesale revenues, affiliates      
Operating Revenues:      
Total operating revenues 371 537 875
Southern Power | Other revenues      
Operating Revenues:      
Total operating revenues 37 55 36
Southern Power | Fuel      
Operating Expenses:      
Cost of sales 579 706 1,614
Southern Power | Purchased power      
Operating Expenses:      
Cost of sales $ 78 $ 116 $ 311
v3.25.0.1
Consolidated Statements of Comprehensive Income - SPC - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Net Income $ 4,260 $ 3,849 $ 3,428
Qualifying hedges:      
Changes in fair value, net of tax (5) (41) (60)
Reclassification adjustment for amounts included in net income, net of tax 80 69 73
Pension and other postretirement benefit plans:      
Benefit plan net gain (loss), net of tax 23 (39) 48
Reclassification adjustment for amounts included in net income, net of tax 1 1 10
Total other comprehensive income (loss) 99 (10) 71
Comprehensive loss attributable to noncontrolling interests (141) (127) (107)
Comprehensive Income 4,500 3,966 3,595
Southern Power      
Net Income 187 230 247
Qualifying hedges:      
Changes in fair value, net of tax (31) (3) (91)
Reclassification adjustment for amounts included in net income, net of tax 39 11 81
Pension and other postretirement benefit plans:      
Benefit plan net gain (loss), net of tax 7 (7) 18
Reclassification adjustment for amounts included in net income, net of tax 0 0 2
Total other comprehensive income (loss) 15 1 10
Comprehensive loss attributable to noncontrolling interests (141) (127) (107)
Comprehensive Income $ 343 $ 358 $ 364
v3.25.0.1
Consolidated Statements of Comprehensive Income - SPC (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Qualifying hedges, change in fair value, tax $ (2) $ (17) $ (19)
Qualifying hedges, reclassification adjustment, tax 28 27 23
Pension and other postretirement benefit plans, gain (loss), tax 10 (14) 18
Reclassification adjustment for amounts included in net income, tax 0 0 3
Southern Power      
Qualifying hedges, change in fair value, tax (10) (1) (30)
Qualifying hedges, reclassification adjustment, tax 12 4 26
Pension and other postretirement benefit plans, gain (loss), tax 2 (2) 6
Reclassification adjustment for amounts included in net income, tax $ 0 $ 0 $ 1
v3.25.0.1
Consolidated Statements of Cash Flows - SPC - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Operating Activities:      
Net Income $ 4,260 $ 3,849 $ 3,428
Adjustments to reconcile consolidated net income to net cash provided from operating activities —      
Depreciation and amortization, total 5,266 4,986 4,064
Deferred income taxes 536 63 670
Other, net (39) (138) 226
Changes in certain current assets and liabilities —      
-Receivables (372) 482 (771)
-Other current assets (47) (106) (186)
-Accounts payable 492 (863) 1,021
-Other current liabilities 145 191 153
Net cash provided from operating activities 9,788 7,553 6,302
Investing Activities:      
Property additions (8,955) (9,095) (7,923)
Proceeds from dispositions 369 164 275
Payments pursuant to LTSAs (108) (99) (190)
Other investing activities (164) (43) (133)
Net cash used for investing activities (9,400) (9,668) (8,430)
Financing Activities:      
Increase (decrease) in notes payable, net (648)   (337)
Increase (decrease) in notes payable, net   973  
Distributions to noncontrolling interests (185) (234) (259)
Payment of common stock dividends (2,954) (3,035) (2,907)
Other financing activities (181) (139) (145)
Net cash provided from (used for) financing activities (208) 999 2,336
Net Change in Cash, Cash Equivalents, and Restricted Cash 180 (1,116) 208
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year 921 2,037 1,829
Cash, Cash Equivalents, and Restricted Cash at End of Year 1,101 921 2,037
Supplemental Cash Flow Information:      
Interest, net of amounts capitalized 2,538 2,184 1,758
Income taxes, net (excludes credit transfers) 176 132 146
Noncash transactions —      
Accrued property additions at year-end 1,199 1,027 1,024
LTSA credits utilized from the sale of spare parts 13 23 0
Contributions from noncontrolling interests 0 0 15
Southern Power      
Operating Activities:      
Net Income 187 230 247
Adjustments to reconcile consolidated net income to net cash provided from operating activities —      
Depreciation and amortization, total 537 524 543
Deferred income taxes (7) 16 9
Utilization of federal tax credit carryforward 75 332 49
Amortization of ITCs (58) (58) (58)
Gain on dispositions, net 0 (20) (2)
Other, net 36 28 19
Changes in certain current assets and liabilities —      
-Receivables (39) 121 (82)
-Prepaid income taxes 2 2 22
-Other current assets (24) (24) (11)
-Accounts payable (3) (60) 68
-Other current liabilities 2 5 11
Net cash provided from operating activities 708 1,096 815
Investing Activities:      
Acquisitions, net of cash acquired 0 (181) 0
Property additions (344) (118) (100)
Change in construction payables 35 21 (69)
Proceeds from dispositions 0 59 48
Payments pursuant to LTSAs (45) (50) (71)
Other investing activities 24 4 (2)
Net cash used for investing activities (330) (265) (194)
Financing Activities:      
Increase (decrease) in notes payable, net (129) (83)  
Increase (decrease) in notes payable, net     10
Redemptions — Senior notes 0 (290) (677)
Capital contributions from parent company 216 18 430
Capital contributions from noncontrolling interests 11 21 73
Distributions to noncontrolling interests (185) (234) (259)
Payment of common stock dividends (262) (252) (198)
Other financing activities (5) 0 (2)
Net cash provided from (used for) financing activities (354) (820) (623)
Net Change in Cash, Cash Equivalents, and Restricted Cash 24 11 (2)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year 144 133 135
Cash, Cash Equivalents, and Restricted Cash at End of Year 168 144 133
Supplemental Cash Flow Information:      
Interest, net of amounts capitalized 107 122 142
Income taxes, net (excludes credit transfers) (32) (254) (15)
Noncash transactions —      
Accrued property additions at year-end 84 59 24
LTSA credits utilized from the sale of spare parts 13 23 0
Contributions from noncontrolling interests $ 0 $ 0 $ 15
v3.25.0.1
Consolidated Statements of Cash Flows - SPC (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Net cash paid for capitalized interest $ 103 $ 132 $ 103
Southern Power      
Net cash paid for capitalized interest $ 7 $ 3 $ 0
v3.25.0.1
Consolidated Balance Sheets - SPC - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Current Assets:    
Cash and cash equivalents $ 1,070 $ 748
Receivables —    
Customer accounts, net and affiliated 2,228 2,030
Other 597 519
Materials and supplies 2,178 1,989
Other current assets 476 533
Total current assets 10,694 10,432
Property, Plant, and Equipment:    
In service 137,143 128,428
Less: Accumulated provision for depreciation 40,126 37,725
Plant in service, net of depreciation 97,017 90,703
Construction work in progress 6,389 7,784
Total property, plant, and equipment 104,689 99,844
Other Property and Investments:    
Other Property and Investments 10,198 9,986
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 1,386 1,432
Other deferred charges and assets 1,467 1,468
Total deferred charges and other assets 19,599 19,069
Total Assets 145,180 139,331
Current Liabilities:    
Securities due within one year 4,718 2,476
Notes payable 1,338 2,314
Accounts payable —    
Accrued interest 682 652
Operating lease obligations 200 183
Other current liabilities 1,100 1,029
Total current liabilities 15,993 13,467
Long-Term Debt 58,768 57,210
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 11,730 10,990
Accumulated deferred ITCs 2,056 2,067
Operating lease obligations, deferred 1,253 1,307
Other deferred credits and liabilities 1,350 1,031
Total deferred credits and other liabilities 33,745 33,429
Total Liabilities 108,506 104,106
Common Stockholders' Equity:    
Common stock 5,446 5,423
Paid-in capital 14,149 13,775
Retained earnings 13,750 12,482
Accumulated other comprehensive loss (78) (177)
Total common stockholders' equity 33,208 31,444
Noncontrolling Interests 3,466 3,781
Total Stockholders' Equity (See accompanying statements) 36,674 35,225
Total Liabilities and Stockholders' Equity 145,180 139,331
Commitments and Contingent Matters
Southern Power    
Current Assets:    
Cash and cash equivalents 159 124
Receivables —    
Customer accounts, net and affiliated 122 136
Other 90 54
Materials and supplies 107 80
Other current assets 82 92
Total current assets 599 523
Property, Plant, and Equipment:    
In service 14,961 14,690
Less: Accumulated provision for depreciation 4,540 4,119
Plant in service, net of depreciation 10,421 10,571
Construction work in progress 317 278
Total property, plant, and equipment 10,738 10,849
Other Property and Investments:    
Intangible assets, net of amortization of $168 and $148, respectively 223 243
Net investment in sales-type leases 143 148
Other Property and Investments 366 391
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 484 488
Prepaid LTSAs 234 248
Other deferred charges and assets 232 262
Total deferred charges and other assets 950 998
Total Assets 12,653 12,761
Current Liabilities:    
Securities due within one year 500 0
Notes payable 0 138
Accounts payable —    
Affiliated and other 100 91
Accrued taxes 18 26
Accrued interest 26 27
Operating lease obligations 29 29
Other current liabilities 96 97
Total current liabilities 849 490
Long-Term Debt 2,180 2,711
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 712 614
Accumulated deferred ITCs 1,440 1,498
Operating lease obligations, deferred 511 517
Other deferred credits and liabilities 279 233
Total deferred credits and other liabilities 2,942 2,862
Total Liabilities 5,971 6,063
Common Stockholders' Equity:    
Common stock 0 0
Paid-in capital 1,306 1,088
Retained earnings 1,912 1,846
Accumulated other comprehensive loss (2) (17)
Total common stockholders' equity 3,216 2,917
Noncontrolling Interests 3,466 3,781
Total Stockholders' Equity (See accompanying statements) 6,682 6,698
Total Liabilities and Stockholders' Equity 12,653 12,761
Commitments and Contingent Matters
Southern Power | Related Party    
Receivables —    
Customer accounts, net and affiliated 39 37
Accounts payable —    
Affiliated and other $ 80 $ 82
v3.25.0.1
Consolidated Balance Sheets - SPC (Parenthetical) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Other intangible assets, amortization $ 412 $ 376
Common Stockholders' Equity:    
Common stock, shares authorized (in shares) 1,500,000,000 1,500,000,000
Southern Power    
Other intangible assets, amortization $ 168 $ 148
Cumulative preferred stock    
Par value (in dollars per share) $ 0.01 $ 0.01
Common Stockholders' Equity:    
Common stock, shares authorized (in shares) 1,000,000 1,000,000
Common stock, shares outstanding (in shares) 1,000 1,000
v3.25.0.1
Consolidated Statements of Stockholders' Equity - SPC - USD ($)
$ in Millions
Total
Paid-In Capital
Retained Earnings
Accumulated Other Comprehensive Income (Loss)
Noncontrolling Interests
Southern Power
Southern Power
Total Common Stockholder's Equity
Southern Power
Paid-In Capital
Southern Power
Retained Earnings
Southern Power
Accumulated Other Comprehensive Income (Loss)
Southern Power
Noncontrolling Interests
Beginning balance at Dec. 31, 2021 $ 32,276 $ 11,950 $ 10,929 $ (237) $ 4,402 $ 6,598 $ 2,196 $ 638 $ 1,585 $ (27) $ 4,402
Increase (Decrease) in Stockholders' Equity [Roll Forward]                      
Net income (loss) 3,428         247 354   354   (107)
Capital contributions from parent company           431 431 431      
Other comprehensive income (loss) 71     71   10 10     10  
Cash dividends on common stock (2,907)   (2,907)     (198) (198)   (198)    
Capital contributions from noncontrolling interests 88       88 88         88
Distributions to noncontrolling interests (259)       (259) (259)         (259)
Other (6) 9 (8) (1)   (1) (1) 0 0 (1)  
Ending balance at Dec. 31, 2022 34,532 13,673 11,538 (167) 4,124 6,916 2,792 1,069 1,741 (18) 4,124
Increase (Decrease) in Stockholders' Equity [Roll Forward]                      
Net income (loss) 3,849         230 357   357   (127)
Capital contributions from parent company           19 19 19      
Other comprehensive income (loss) (10)     (10)   1 1     1  
Cash dividends on common stock (3,035)   (3,035)     (252) (252)   (252)    
Capital contributions from noncontrolling interests 21       21 21         21
Distributions to noncontrolling interests (236)       (236) (236)         (236)
Other (5) (1) 3   (1) (1)         (1)
Ending balance at Dec. 31, 2023 35,225 13,775 12,482 (177) 3,781 6,698 2,917 1,088 1,846 (17) 3,781
Increase (Decrease) in Stockholders' Equity [Roll Forward]                      
Net income (loss) 4,260         187 328   328   (141)
Capital contributions from parent company           218 218 218      
Other comprehensive income (loss) 99     99   15 15     15  
Cash dividends on common stock (3,133)   (3,133)     (262) (262)   (262)    
Capital contributions from noncontrolling interests 11       11 11         11
Distributions to noncontrolling interests (185)       (185) (185)         (185)
Other 19 19 0 0 0            
Ending balance at Dec. 31, 2024 $ 36,674 $ 14,149 $ 13,750 $ (78) $ 3,466 $ 6,682 $ 3,216 $ 1,306 $ 1,912 $ (2) $ 3,466
v3.25.0.1
Consolidated Statements of Income - GAS - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Operating Revenues:      
Total operating revenues $ 26,724 $ 25,253 $ 29,279
Operating Expenses:      
Other operations and maintenance 6,539 6,093 6,824
Depreciation and amortization 4,755 4,525 3,663
Taxes other than income taxes 1,540 1,425 1,411
Total operating expenses 19,656 19,427 23,909
Operating Income 7,068 5,826 5,370
Other Income and (Expense):      
Earnings from equity method investments 139 144 151
Interest expense, net of amounts capitalized (2,743) (2,446) (2,022)
Other income (expense), net 530 553 500
Total other income and (expense) (1,839) (1,481) (1,147)
Earnings Before Income Taxes 5,229 4,345 4,223
Income taxes 969 496 795
Net Income 4,260 3,849 3,428
Southern Company Gas      
Operating Revenues:      
Total operating revenues 4,456 4,702 5,962
Operating Expenses:      
Cost of natural gas 1,196 1,644 3,004
Other operations and maintenance 1,235 1,187 1,172
Depreciation and amortization 650 582 559
Taxes other than income taxes 248 262 282
Impairment charges 0 0 131
Estimated loss on regulatory disallowance 0 88 0
Total operating expenses 3,329 3,763 5,148
Operating Income 1,127 939 814
Other Income and (Expense):      
Earnings from equity method investments 146 140 148
Interest expense, net of amounts capitalized (341) (310) (263)
Other income (expense), net 66 57 53
Total other income and (expense) (129) (113) (62)
Earnings Before Income Taxes 998 826 752
Income taxes 258 211 180
Net Income $ 740 $ 615 $ 572
v3.25.0.1
Consolidated Statements of Income - GAS (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Southern Company Gas      
Excise taxes collected $ 115 $ 133 $ 162
v3.25.0.1
Consolidated Statements of Comprehensive Income - GAS - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Net Income $ 4,260 $ 3,849 $ 3,428
Qualifying hedges:      
Changes in fair value, net of tax (5) (41) (60)
Reclassification adjustment for amounts included in net income, net of tax 80 69 73
Pension and other postretirement benefit plans:      
Benefit plan net gain (loss), net of tax 23 (39) 48
Reclassification adjustment for amounts included in net income, net of tax 1 1 10
Total other comprehensive income (loss) 99 (10) 71
Comprehensive Income 4,500 3,966 3,595
Southern Company Gas      
Net Income 740 615 572
Qualifying hedges:      
Changes in fair value, net of tax (9) (45) 13
Reclassification adjustment for amounts included in net income, net of tax 30 46 (24)
Pension and other postretirement benefit plans:      
Benefit plan net gain (loss), net of tax 11 (15) 18
Reclassification adjustment for amounts included in net income, net of tax 0 (1) 0
Total other comprehensive income (loss) 32 (15) 7
Comprehensive Income $ 772 $ 600 $ 579
v3.25.0.1
Consolidated Statements of Comprehensive Income - GAS (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Qualifying hedges, change in fair value, tax $ (2) $ (17) $ (19)
Qualifying hedges, reclassification adjustment, tax 28 27 23
Pension and other postretirement benefit plans, gain (loss), tax 10 (14) 18
Reclassification adjustment for amounts included in net income, tax 0 0 3
Southern Company Gas      
Qualifying hedges, change in fair value, tax (3) (18) 5
Qualifying hedges, reclassification adjustment, tax 12 19 (9)
Pension and other postretirement benefit plans, gain (loss), tax 5 (7) 8
Reclassification adjustment for amounts included in net income, tax $ (1) $ 0 $ 0
v3.25.0.1
Consolidated Statements of Cash Flows - GAS - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Operating Activities:      
Consolidated net income $ 4,260 $ 3,849 $ 3,428
Adjustments to reconcile consolidated net income to net cash provided from operating activities —      
Depreciation and amortization, total 5,266 4,986 4,064
Deferred income taxes 536 63 670
Natural gas cost under recovery – long-term 0 0 207
Other, net (39) (138) 226
Changes in certain current assets and liabilities —      
-Receivables (372) 482 (771)
-Natural gas cost under recovery 0 108 158
-Other current assets (47) (106) (186)
-Accounts payable 492 (863) 1,021
-Other current liabilities 145 191 153
Net cash provided from operating activities 9,788 7,553 6,302
Investing Activities:      
Property additions (8,955) (9,095) (7,923)
Cost of removal, net of salvage (632) (592) (649)
Change in construction payables, net 106 18 203
Proceeds from dispositions 369 164 275
Other investing activities (164) (43) (133)
Net cash used for investing activities (9,400) (9,668) (8,430)
Financing Activities:      
Increase (decrease) in notes payable, net   973  
Increase (decrease) in notes payable, net (648)   (337)
Proceeds —      
Short-term borrowings 700 350 2,650
Redemptions and repurchases —      
Short-term borrowings (1,020) (1,630) (1,150)
Payment of common stock dividends (2,954) (3,035) (2,907)
Other financing activities (181) (139) (145)
Net cash provided from (used for) financing activities (208) 999 2,336
Net Change in Cash, Cash Equivalents, and Restricted Cash 180 (1,116) 208
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year 921 2,037 1,829
Cash, Cash Equivalents, and Restricted Cash at End of Year 1,101 921 2,037
Cash paid during the period for —      
Interest, net of amounts capitalized 2,538 2,184 1,758
Income taxes, net 176 132 146
Noncash transactions — Accrued property additions at year-end 1,199 1,027 1,024
Southern Company Gas      
Operating Activities:      
Consolidated net income 740 615 572
Adjustments to reconcile consolidated net income to net cash provided from operating activities —      
Depreciation and amortization, total 643 582 558
Deferred income taxes 132 126 17
Impairment charges 0 0 131
Natural gas cost under recovery – long-term 0 0 207
Estimated loss on regulatory disallowance 0 (96) 0
Other, net 3 (74) (24)
Changes in certain current assets and liabilities —      
-Receivables 28 431 (345)
-Natural gas for sale, net of temporary LIFO liquidation 32 19 (77)
-Prepaid income taxes 63 (11) 19
-Natural gas cost under recovery 0 108 158
-Other current assets (52) (17) (6)
-Accounts payable (6) (276) 299
-Natural gas cost over recovery (21) 214 0
-Other current liabilities (10) (51) 10
Net cash provided from operating activities 1,552 1,762 1,519
Investing Activities:      
Property additions (1,541) (1,561) (1,533)
Cost of removal, net of salvage (88) (104) (112)
Change in construction payables, net (19) (38) 65
Investments in unconsolidated subsidiaries (82) (11) (165)
Proceeds from dispositions 3 42 150
Other investing activities 16 16 15
Net cash used for investing activities (1,711) (1,656) (1,580)
Financing Activities:      
Increase (decrease) in notes payable, net 40    
Increase (decrease) in notes payable, net   (153) (341)
Proceeds —      
Senior notes 450 500 500
First mortgage bonds 275 275 175
Short-term borrowings 0 0 50
Other long-term debt 8 37 22
Redemptions and repurchases —      
First mortgage bonds 0 (50) 0
Short-term borrowings 0 (200) (150)
Medium-term notes 0 (350) (46)
Capital contributions from parent company 16 373 406
Payment of common stock dividends (605) (585) (519)
Other financing activities (16) (1) (1)
Net cash provided from (used for) financing activities 168 (154) 96
Net Change in Cash, Cash Equivalents, and Restricted Cash 9 (48) 35
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year 35 83 48
Cash, Cash Equivalents, and Restricted Cash at End of Year 44 35 83
Cash paid during the period for —      
Interest, net of amounts capitalized 329 291 258
Income taxes, net 59 91 208
Noncash transactions — Accrued property additions at year-end $ 113 $ 139 $ 177
v3.25.0.1
Consolidated Statements of Cash Flows - GAS (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Net cash paid for capitalized interest $ 103 $ 132 $ 103
Southern Company Gas      
Net cash paid for capitalized interest $ 21 $ 16 $ 10
v3.25.0.1
Consolidated Balance Sheets - GAS - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Current Assets:    
Cash and cash equivalents $ 1,070 $ 748
Receivables —    
Customer accounts 2,228 2,030
Unbilled revenues 825 786
Other accounts and notes 597 519
Accumulated provision for uncollectible accounts (74) (68)
Natural gas for sale 388 420
Prepaid expenses 294 406
Other regulatory assets 804 1,120
Other current assets 476 533
Total current assets 10,694 10,432
Property, Plant, and Equipment:    
In service 137,143 128,428
Less: Accumulated depreciation 40,126 37,725
Plant in service, net of depreciation 97,017 90,703
Construction work in progress 6,389 7,784
Total property, plant, and equipment 104,689 99,844
Other Property and Investments:    
Goodwill 5,161 5,161
Equity investments in unconsolidated subsidiaries 1,416 1,368
Other intangible assets, net of amortization 332 368
Miscellaneous property and investments 668 665
Other Property and Investments 10,198 9,986
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 1,386 1,432
Prepaid pension costs 2,674 2,079
Other regulatory assets, deferred 7,037 6,264
Other deferred charges and assets 1,467 1,468
Total deferred charges and other assets 19,599 19,069
Total Assets 145,180 139,331
Current Liabilities:    
Securities due within one year 4,718 2,476
Notes payable 1,338 2,314
Accounts payable —    
Customer deposits 486 503
Accrued compensation 1,261 1,151
Natural gas cost over recovery 193 214
Other regulatory liabilities 369 141
Other current liabilities 1,100 1,029
Total current liabilities 15,993 13,467
Long-Term Debt 58,768 57,210
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 11,730 10,990
Deferred credits related to income taxes 4,434 4,674
Employee benefit obligations 1,011 1,115
Operating lease obligations 1,253 1,307
Other cost of removal obligations 2,016 1,957
Other deferred credits and liabilities 1,350 1,031
Total deferred credits and other liabilities 33,745 33,429
Total Liabilities 108,506 104,106
Common Stockholders' Equity:    
Paid-in capital 14,149 13,775
Retained earnings (accumulated deficit) 13,750 12,482
Accumulated other comprehensive income (78) (177)
Total common stockholders' equity 33,208 31,444
Total Liabilities and Stockholders' Equity 145,180 139,331
Commitments and Contingent Matters
Southern Company Gas    
Current Assets:    
Cash and cash equivalents 43 33
Receivables —    
Customer accounts 399 405
Unbilled revenues 244 261
Other accounts and notes 45 47
Accumulated provision for uncollectible accounts (33) (44)
Natural gas for sale 388 420
Prepaid expenses 45 107
Other regulatory assets 187 141
Other current assets 121 116
Total current assets 1,439 1,486
Property, Plant, and Equipment:    
In service 22,338 20,840
Less: Accumulated depreciation 5,887 5,534
Plant in service, net of depreciation 16,451 15,306
Construction work in progress 1,057 1,110
Total property, plant, and equipment 17,508 16,416
Other Property and Investments:    
Goodwill 5,015 5,015
Equity investments in unconsolidated subsidiaries 1,279 1,235
Other intangible assets, net of amortization 9 16
Miscellaneous property and investments 25 25
Other Property and Investments 6,328 6,291
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 38 47
Prepaid pension costs 191 158
Other regulatory assets, deferred 481 504
Other deferred charges and assets 192 181
Total deferred charges and other assets 902 890
Total Assets 26,177 25,083
Current Liabilities:    
Securities due within one year 302 0
Notes payable 455 415
Accounts payable —    
Affiliated and other 437 424
Customer deposits 98 126
Accrued taxes 85 77
Accrued compensation 129 112
Natural gas cost over recovery 193 214
Other regulatory liabilities 7 19
Other current liabilities 237 232
Total current liabilities 2,018 1,708
Long-Term Debt 8,229 7,833
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 1,796 1,671
Deferred credits related to income taxes 755 759
Employee benefit obligations 78 110
Operating lease obligations 30 40
Other cost of removal obligations 1,846 1,771
Accrued environmental remediation 198 192
Other deferred credits and liabilities 231 196
Total deferred credits and other liabilities 4,934 4,739
Total Liabilities 15,181 14,280
Common Stockholders' Equity:    
Paid-in capital 10,863 10,836
Retained earnings (accumulated deficit) 85 (49)
Accumulated other comprehensive income 48 16
Total common stockholders' equity 10,996 10,803
Total Liabilities and Stockholders' Equity 26,177 25,083
Commitments and Contingent Matters
Southern Company Gas | Related Party    
Accounts payable —    
Affiliated and other $ 75 $ 89
v3.25.0.1
Consolidated Balance Sheets - GAS (Parenthetical) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Other intangible assets, amortization $ 412 $ 376
Common Stockholders' Equity:    
Common stock, par value (in dollars per share) $ 5 $ 5
Common stock, shares authorized (in shares) 1,500,000,000 1,500,000,000
Southern Company Gas    
Other intangible assets, amortization $ 173 $ 166
Common Stockholders' Equity:    
Common stock, par value (in dollars per share) $ 0.01 $ 0.01
Common stock, shares authorized (in shares) 100,000,000 100,000,000
Common stock, shares outstanding (in shares) 100 100
v3.25.0.1
Consolidated Statements of Common Stockholders' Equity - GAS - USD ($)
$ in Millions
Total
Paid-In Capital
Retained Earnings
Accumulated Other Comprehensive Income (Loss)
Southern Company Gas
Southern Company Gas
Paid-In Capital
Southern Company Gas
Retained Earnings
Southern Company Gas
Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2021         $ 9,916 $ 10,024 $ (132) $ 24
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Net Income $ 3,428       572   572  
Capital contributions from parent company         421 421    
Other comprehensive income (loss) 71     $ 71 7     7
Cash dividends on common stock (2,907)   $ (2,907)   (519)   (519)  
Other (6) $ 9 (8) (1)        
Ending balance at Dec. 31, 2022         10,397 10,445 (79) 31
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Net Income 3,849       615   615  
Capital contributions from parent company         391 391    
Other comprehensive income (loss) (10)     (10) (15)     (15)
Cash dividends on common stock (3,035)   (3,035)   (585)   (585)  
Other (5) (1) 3          
Ending balance at Dec. 31, 2023 31,444       10,803 10,836 (49) 16
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Net Income 4,260       740   740  
Capital contributions from parent company         27 27    
Other comprehensive income (loss) 99     99 32     32
Cash dividends on common stock (3,133)   (3,133)   (605)   (605)  
Other 19 $ 19 $ 0 $ 0 (1)   (1)  
Ending balance at Dec. 31, 2024 $ 33,208       $ 10,996 $ 10,863 $ 85 $ 48
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]  
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
General
Southern Company is the parent company of three traditional electric operating companies, as well as Southern Power, Southern Company Gas, SCS, Southern Linc, Southern Holdings, Southern Nuclear, PowerSecure, and other direct and indirect subsidiaries. The traditional electric operating companies – Alabama Power, Georgia Power, and Mississippi Power – are vertically integrated utilities providing electric service in three Southeastern states. Southern Power develops, constructs, acquires, owns, operates, and manages power generation assets, including renewable energy projects, and sells electricity at market-based rates in the wholesale market. Southern Company Gas distributes natural gas through natural gas distribution utilities, including Nicor Gas (Illinois), Atlanta Gas Light (Georgia), Virginia Natural Gas, and Chattanooga Gas (Tennessee). Southern Company Gas is also involved in several other complementary businesses including gas pipeline investments and gas marketing services. SCS, the system service company, provides, at cost, specialized services to Southern Company and its subsidiary companies. Southern Linc provides digital wireless communications for use by Southern Company and its subsidiary companies and also markets these services to the public and provides fiber optics services within the Southeast. Southern Holdings is an intermediate holding company subsidiary. Southern Nuclear operates and provides services to the Southern Company system's nuclear power plants, including Alabama Power's Plant Farley and Georgia Power's Plants Hatch and Vogtle. PowerSecure develops distributed energy and resilience solutions and deploys microgrids for commercial, industrial, governmental, and utility customers.
The Registrants' financial statements reflect investments in subsidiaries on a consolidated basis. Intercompany transactions have been eliminated in consolidation. The equity method is used for investments in entities in which a Registrant has significant influence but does not have control and for VIEs where a Registrant has an equity investment but is not the primary beneficiary. Southern Power has controlling ownership in certain legal entities for which the contractual provisions represent profit-sharing arrangements because the allocations of cash distributions and tax benefits are not based on fixed ownership percentages. For these arrangements, the noncontrolling interest is accounted for under a balance sheet approach utilizing the HLBV method. The HLBV method calculates each partner's share of income based on the change in net equity the partner can legally claim in an HLBV at the end of the period compared to the beginning of the period. See "Variable Interest Entities" herein and Note 7 for additional information.
The traditional electric operating companies, Southern Power, certain subsidiaries of Southern Company Gas, and certain other subsidiaries are subject to regulation by the FERC, and the traditional electric operating companies and the natural gas distribution utilities are also subject to regulation by their respective state PSCs or other applicable state regulatory agencies. As such, the respective financial statements of the applicable Registrants reflect the effects of rate regulation in accordance with GAAP and comply with the accounting policies and practices prescribed by relevant state PSCs or other applicable state regulatory agencies.
The preparation of financial statements in conformity with GAAP requires the use of estimates, and the actual results may differ from those estimates. Certain prior years' data presented in the financial statements have been reclassified to conform to the current year presentation. These reclassifications had no impact on the Registrants' results of operations, financial position, or cash flows.
Recently Adopted Accounting Standards
In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (ASU 2023-07), which requires entities to disclose significant segment expenses, other segment items, the title and position of the CODM, and information related to how the CODM assesses segment performance and allocates resources, among certain other required disclosures. Additionally, previous annual disclosures will be required in interim periods. The Registrants adopted ASU 2023-07 and applied the guidance retrospectively effective for the fiscal year beginning January 1, 2024. ASU 2023-07 will be applied retrospectively for the interim periods beginning January 1, 2025. See Note 16 for additional information and related disclosures.
Affiliate Transactions
The traditional electric operating companies, Southern Power, and Southern Company Gas have agreements with SCS under which certain of the following services are rendered to them at direct or allocated cost: general executive and advisory, general and design engineering, operations, purchasing, accounting, finance, treasury, legal, tax, information technology, marketing, auditing, insurance and pension administration, human resources, systems and procedures, digital wireless communications, cellular tower space, and other services with respect to business and operations, construction management, and Southern
Company power pool transactions. These costs are primarily included in other operations and maintenance expenses or capitalized to property, plant, and equipment. Costs for these services from SCS in 2024, 2023, and 2022 were as follows:
Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern Company Gas
(in millions)
2024$813 $1,197 $130 $93 $290 
2023611 857 113 86 261 
2022549 762 115 86 262 
Alabama Power and Georgia Power also have agreements with Southern Nuclear under which Southern Nuclear renders the following nuclear-related services at cost: general executive and advisory services; general operations, management, and technical services; administrative services including procurement, accounting, employee relations, systems, and procedures services; strategic planning and budgeting services; and other services with respect to business and operations. These costs are primarily included in other operations and maintenance expenses or capitalized to property, plant, and equipment. Costs for these services in 2024, 2023, and 2022 amounted to $260 million, $251 million, and $267 million, respectively, for Alabama Power and $835 million, $899 million, and $895 million, respectively, for Georgia Power.
Cost allocation methodologies used by SCS and Southern Nuclear prior to the repeal of the Public Utility Holding Company Act of 1935, as amended, were approved by the SEC. Subsequently, additional cost allocation methodologies have been reported to the FERC and management believes they are reasonable. The FERC permits services to be rendered at cost by system service companies.
Alabama Power's and Georgia Power's power purchases from affiliates through the Southern Company power pool are included in purchased power, affiliates on their respective statements of income. Mississippi Power's and Southern Power's power purchases from affiliates through the Southern Company power pool are included in purchased power on their respective statements of income and were as follows:
Mississippi
Power		Southern
Power
(in millions)
2024$8 $17 
20234 13 
20224 29 
Georgia Power has entered into several PPAs with Southern Power and one PPA with Mississippi Power for capacity and energy. Georgia Power's total expenses associated with these PPAs were $203 million, $143 million, and $151 million in 2024, 2023, and 2022, respectively. Southern Power's total revenues from all PPAs with Georgia Power, included in wholesale revenue affiliates on Southern Power's consolidated statements of income, were $149 million, $145 million, and $154 million for 2024, 2023, and 2022, respectively. Included within these revenues were affiliate PPAs accounted for as operating leases, which totaled $121 million, $116 million, and $116 million for 2024, 2023, and 2022, respectively. Mississippi Power's total revenues from its PPA with Georgia Power, which commenced in 2024, were $60 million in 2024 and are included in wholesale revenue affiliates on Mississippi Power's statements of income. See Notes 2 and 9 for additional information.
SCS (as agent for Alabama Power, Georgia Power, and Southern Power) and certain subsidiaries of Southern Company Gas have long-term interstate natural gas transportation agreements with SNG that are governed by the terms and conditions of SNG's natural gas tariff and are subject to FERC regulation. See Note 7 under "Southern Company Gas" for additional information. Transportation costs under these agreements in 2024, 2023, and 2022 were as follows:
Alabama
Power		Georgia
Power		Southern
Power		Southern Company Gas
(in millions)
2024$13 $103 $35 $28 
202312 101 34 28 
202218 99 37 27 
SCS, as agent for the traditional electric operating companies and Southern Power, has agreements with certain subsidiaries of Southern Company Gas to purchase natural gas. Natural gas purchases made under these agreements were immaterial for Alabama Power, Georgia Power, Mississippi Power, and Southern Power for all periods presented.
Alabama Power and Mississippi Power jointly own Plant Greene County. The companies have an agreement under which Alabama Power operates Plant Greene County and Mississippi Power reimburses Alabama Power for its proportionate share of non-fuel operations and maintenance expenses, which totaled $7 million, $5 million, and $6 million in 2024, 2023, and 2022, respectively. See Notes 2 and 5 under "Mississippi Power – Integrated Resource Plans" and "Joint Ownership Agreements," respectively, for additional information.
Alabama Power, Georgia Power, and Mississippi Power each have agreements with PowerSecure for equipment purchases and/or services related to utility infrastructure construction, distributed energy, and energy efficiency projects. Costs under these agreements were immaterial for all periods presented.
Southern Company Gas has a $74 million contract with the U.S. General Services Administration to increase energy efficiency at certain federal buildings across Georgia, which is expected to be completed in 2025. Southern Company Gas engaged PowerSecure to provide the majority of the construction services under the contract. During 2024, 2023, and 2022, Southern Company Gas paid $13 million, $29 million, and $10 million, respectively, to PowerSecure related to this agreement.
See Note 7 under "SEGCO" for information regarding Alabama Power's and Georgia Power's equity method investment in SEGCO and related affiliate purchased power costs, as well as Alabama Power's gas pipeline ownership agreement with SEGCO.
Southern Power has several agreements with SCS for transmission services, which are billed to Southern Power based on the Southern Company Open Access Transmission Tariff as filed with the FERC. Transmission services purchased by Southern Power from SCS totaled $25 million, $33 million, and $39 million for 2024, 2023, and 2022, respectively, and were charged to other operations and maintenance expenses in Southern Power's consolidated statements of income.
The traditional electric operating companies and Southern Power may jointly enter into various types of wholesale energy, natural gas, and certain other contracts, either directly or through SCS as agent. Each participating company may be jointly and severally liable for the obligations incurred under these agreements. See Note 14 under "Contingent Features" for additional information. Southern Power and the traditional electric operating companies generally settle amounts related to the above transactions on a monthly basis in the month following the performance of such services or the purchase or sale of electricity. See "Revenues – Southern Power" herein for additional information.
The traditional electric operating companies, Southern Power, and Southern Company Gas provide incidental services to and receive such services from other Southern Company subsidiaries which are generally minor in duration and amount. Except as described herein, the traditional electric operating companies, Southern Power, and Southern Company Gas neither provided nor received any material services to or from affiliates in any year presented.
Regulatory Assets and Liabilities
The traditional electric operating companies and the natural gas distribution utilities are subject to accounting requirements for the effects of rate regulation. Regulatory assets represent probable future revenues associated with certain costs that are expected to be recovered from customers through the ratemaking process. Regulatory liabilities represent costs recovered that are expected to be incurred in the future or probable future reductions in revenues associated with amounts that are expected to be credited to customers through the ratemaking process.
In the event that a portion of a traditional electric operating company's or a natural gas distribution utility's operations is no longer subject to applicable accounting rules for rate regulation, such company would be required to write off to income or reclassify to AOCI related regulatory assets and liabilities that are not specifically recoverable through regulated rates. In addition, the traditional electric operating company or the natural gas distribution utility would be required to determine if any impairment to other assets, including plant, exists and write down the assets, if impaired, to their fair values. All regulatory assets and liabilities are to be reflected in rates. See Note 2 for additional information including details of regulatory assets and liabilities reflected in the balance sheets for Southern Company, the traditional electric operating companies, and Southern Company Gas.
Revenues
The Registrants generate revenues from a variety of sources which are accounted for under various revenue accounting guidance, including revenue from contracts with customers, lease, derivative, and regulatory accounting. See Notes 4, 9, and 14 for additional information.
Traditional Electric Operating Companies
The majority of the revenues of the traditional electric operating companies are generated from contracts with retail electric customers. These revenues, generated from the integrated service to deliver electricity when and if called upon by the customer, are recognized as a single performance obligation satisfied over time, at a tariff rate, and as electricity is delivered to the customer during the month. Unbilled revenues related to retail sales are recognized for estimated deliveries of electricity not yet billed to these customers from the last bill date to the end of the accounting period. Retail rates may include provisions to adjust revenues for fluctuations in fuel costs, fuel hedging, the energy component of purchased power costs, and certain other costs. Revenues are adjusted for differences between these actual costs and amounts billed in current regulated rates. Under or over recovered regulatory clause revenues are recorded in the balance sheets and are recovered from or returned to customers, respectively, through adjustments to the billing factors. See Note 2 for additional information regarding regulatory matters of the traditional electric operating companies.
Wholesale capacity revenues from PPAs are recognized in amounts billable under the contract terms. Energy and other revenues are generally recognized as services are provided. The contracts for capacity and energy in a wholesale PPA have multiple performance obligations where the contract's total transaction price is allocated to each performance obligation based on the standalone selling price. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, the traditional electric operating companies recognize revenue as the performance obligations are satisfied over time as electricity is delivered to the customer or as generation capacity is available to the customer.
For both retail and wholesale revenues, the traditional electric operating companies have elected to recognize revenue for their sales of electricity and capacity using the invoice practical expedient as they generally have a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and that may be invoiced. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of the Registrants' performance obligation.
Southern Power
Southern Power sells capacity and energy at rates specified under contractual terms in long-term PPAs. These PPAs are accounted for as leases, normal sale derivatives, or contracts with customers. Capacity revenues from PPAs classified as operating leases are recognized on a straight-line basis over the term of the agreement. Energy revenues are recognized in the period the energy is delivered. Capacity revenues from PPAs classified as sales-type leases are recognized by accounting for interest income on the net investment in the lease.
Southern Power's non-lease contracts commonly include capacity and energy which are considered separate performance obligations. In these contracts, the total transaction price is allocated to each performance obligation based on the standalone selling price. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, Southern Power recognizes revenue as the performance obligations are satisfied over time, as electricity is delivered to the customer or as generation capacity is made available to the customer.
Southern Power generally has a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and may recognize revenue in the amount to which the entity has a right to invoice. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of Southern Power's performance obligation.
When multiple contracts exist with the same counterparty, the revenues from each contract are accounted for as separate arrangements.
Southern Power may also enter into contracts to sell short-term capacity in the wholesale electricity markets. These sales are generally classified as mark-to-market derivatives and net unrealized gains and losses on such contracts are recorded in wholesale revenues. See Note 14 and "Financial Instruments" herein for additional information.
Southern Company Gas
Southern Company Gas records revenues when goods or services are provided to customers. Those revenues are based on rates approved by the state regulatory agencies of the natural gas distribution utilities.The majority of the revenues of Southern Company Gas are generated from contracts with natural gas distribution customers. Revenues from this integrated service to deliver gas when and if called upon by the customer are recognized as a single performance obligation satisfied over time and are recognized at a tariff rate as gas is delivered to the customer during the month.
Revenues from sales and transportation services are recognized in the same period in which the related volumes are delivered to customers. Revenues from residential and certain commercial and industrial customers are recognized on the basis of scheduled meter readings. Additionally, unbilled revenues are recognized for estimated deliveries of gas not yet billed to these customers, from the last bill date to the end of the accounting period. For other commercial and industrial customers, revenues are based on actual deliveries through the end of the period.
Southern Company Gas has elected to recognize revenue for sales of gas using the invoice practical expedient as it generally has a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and that may be invoiced. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of Southern Company Gas' performance obligation.
Gas Distribution Operations
Atlanta Gas Light operates in a deregulated natural gas market whereby Marketers, rather than a traditional utility, sell natural gas to end-use customers in Georgia and handle customer billing functions. As required by the Georgia PSC, Atlanta Gas Light bills Marketers in equal monthly installments for each residential, commercial, and industrial end-use customer's distribution costs as well as for capacity costs utilizing a seasonal rate design for the calculation of each residential end-use customer's annual straight-fixed-variable charge, which reflects the historic volumetric usage pattern for the entire residential class. With the exception of Atlanta Gas Light, the natural gas distribution utilities have rate structures that include volumetric rate designs that allow the opportunity to recover certain costs based on gas usage.
The tariffs for the natural gas distribution utilities include provisions which allow for the recognition of certain revenues prior to the time such revenues are billed to customers. These provisions are referred to as alternative revenue programs and provide for the recognition of certain revenues prior to billing, as long as the amounts recognized will be collected from customers within 24 months of recognition. Revenue related to alternative revenue programs was $43 million, $20 million, and $(5) million in 2024, 2023, and 2022, respectively. These programs primarily consist of:
•Weather normalization adjustments – reduce customer bills when winter weather is colder than normal and increase customer bills when weather is warmer than normal and are included in the tariffs for Virginia Natural Gas and Chattanooga Gas;
•Revenue normalization mechanisms – mitigate the impact of conservation and declining customer usage and are contained in the tariffs for Virginia Natural Gas and Nicor Gas; and
•Revenue true-up adjustment – included within the provisions of the GRAM program in which Atlanta Gas Light participates as a short-term alternative to formal rate case filings, the revenue true-up feature provides for a positive (or negative) adjustment to record revenue in the amount of any variance to budgeted revenues, which are submitted and approved annually as a requirement of GRAM. Such adjustments are reflected in customer billings in a subsequent program year.
Gas Marketing Services
Gas marketing services is comprised of several choice-based natural gas marketers operating in various deregulated jurisdictions. While gas marketing services follows the same general approach to revenue recognition described for Southern Company Gas above, it recognizes revenues on certain 12-month utility-bill management contracts as the lesser of cumulative earned or cumulative billed amounts.
Concentration of Revenue
Southern Company, Alabama Power, Georgia Power, Mississippi Power (with the exception of its full requirements cost-based MRA electric tariffs described below), Southern Power, and Southern Company Gas each have a diversified base of customers and no single customer comprises 10% or more of each company's revenues.
Mississippi Power provides service under long-term contracts with rural electric cooperative associations and a municipality located in southeastern Mississippi under requirements cost-based MRA electric tariffs which are subject to regulation by the FERC. The contracts with these wholesale customers represented 13.9% of Mississippi Power's total operating revenues in 2024.
Fuel Costs
Fuel costs for the traditional electric operating companies and Southern Power are expensed as the fuel is used. Fuel expense generally includes fuel transportation costs and the cost of purchased emissions allowances as they are used. For Alabama Power and Georgia Power, fuel expense also includes the amortization of the cost of nuclear fuel. For the traditional electric operating companies, fuel costs also include gains and/or losses from fuel-hedging programs as approved by their respective state PSCs.
Cost of Natural Gas
Excluding Atlanta Gas Light, which does not sell natural gas to end-use customers, Southern Company Gas charges its utility customers for natural gas consumed using natural gas cost recovery mechanisms set by the applicable state regulatory agencies. Under these mechanisms, all prudently-incurred natural gas costs are passed through to customers without markup, subject to regulatory review. Southern Company Gas defers or accrues the difference between the actual cost of natural gas and the amount of commodity revenue earned in a given period such that no operating income is recognized related to these costs. The deferred or accrued amount is either billed or refunded to customers prospectively through adjustments to the commodity rate. Deferred and accrued natural gas costs are included in the balance sheets as regulatory assets and regulatory liabilities, respectively.
Southern Company Gas' gas marketing services' customers are charged for actual or estimated natural gas consumed. Within cost of natural gas, Southern Company Gas also includes costs of lost and unaccounted for gas and gains and losses associated with certain derivatives.
Income Taxes
The Registrants use the liability method of accounting for deferred income taxes and provide deferred income taxes for all significant income tax temporary differences. In accordance with regulatory requirements, deferred federal ITCs for the traditional electric operating companies are amortized over the average life of the related property, with such amortization normally applied as a credit to reduce depreciation and amortization in the statements of income. Southern Power's and the natural gas distribution utilities' deferred federal ITCs, as well as certain state ITCs for Nicor Gas, are amortized to income tax expense over the life of the respective asset.
Under current tax law, certain projects at Southern Power related to the construction of renewable facilities are eligible for federal ITCs. Southern Power estimates eligible costs which, as they relate to acquisitions, may not be finalized until the allocation of the purchase price to assets has been finalized. Southern Power applies the deferred method to ITCs, whereby the ITCs are recorded as a deferred credit and amortized to income tax expense over the life of the respective asset. Furthermore, the tax basis of the asset is reduced by 50% of the ITCs received, which, together with the deferred credit, results in a net deferred tax asset. Southern Power has elected to recognize the tax benefit of this basis difference as a reduction to income tax expense in the year in which the plant reaches commercial operation. State ITCs are recognized as an income tax benefit in the period in which the credits are generated. In addition, certain projects are eligible for federal and state PTCs, which are recognized as an income tax benefit based on KWH production.
Federal ITCs and PTCs, as well as state ITCs and other state tax credits available to reduce income taxes payable, were not fully utilized in 2024 and will be carried forward and utilized in future years. In addition, Southern Company is expected to have various state net operating loss (NOL) carryforwards for certain of its subsidiaries, including Mississippi Power and Southern Power, which would result in income tax benefits in the future, if utilized. See Note 10 under "Deferred Tax Assets and Liabilities – Tax Credit Carryforwards" and " – Net Operating Loss Carryforwards" for additional information.
In April 2024, the IRS issued final regulations related to the transferability of certain tax credits under the IRA. Southern Company and certain subsidiaries have tax credits that are eligible to be transferred at a discount to the generated credit value. The discount will be recorded as a reduction in tax credits recognized in the financial statements. See Note 10 under "Current and Deferred Income Taxes" for additional information.
Under current tax law, Georgia Power is eligible to generate advanced nuclear PTCs for Plant Vogtle Units 3 and 4, which are recognized as an income tax benefit based on KWH production and are eligible to be transferred. Pursuant to the Vogtle Joint Ownership Agreements (as defined in Note 2 under "Georgia Power – Nuclear Construction – Cost and Schedule"), Georgia Power is purchasing advanced nuclear PTCs for Plant Vogtle Units 3 and 4 from the other Vogtle Owners. The gain recognized on the purchase of the joint owner PTCs is recognized as an income tax benefit.
The Registrants recognize tax positions that are "more likely than not" of being sustained upon examination by the appropriate taxing authorities. See Note 10 under "Unrecognized Tax Benefits" for additional information.
Other Taxes
Taxes imposed on and collected from customers on behalf of governmental agencies are presented net on the Registrants' statements of income and are excluded from the transaction price in determining the revenue related to contracts with a customer.
Southern Company Gas is taxed on its gas revenues by various governmental authorities, but is allowed to recover these taxes from its customers. Revenue taxes imposed on the natural gas distribution utilities are recorded at the amount charged to customers, which may include a small administrative fee, as operating revenues, and the related taxes imposed on Southern Company Gas are recorded as operating expenses on the statements of income. Revenue taxes included in operating expenses were $112 million, $129 million, and $158 million in 2024, 2023, and 2022, respectively.
Allowance for Funds Used During Construction and Interest Capitalized
The traditional electric operating companies and the natural gas distribution utilities record AFUDC, which represents the estimated debt and equity costs of capital funds that are necessary to finance the construction of new regulated facilities. While cash is not realized currently, AFUDC increases the revenue requirement and is recovered over the service life of the asset through a higher rate base and higher depreciation. The equity component of AFUDC is not taxable.
Interest related to financing the construction of new facilities at Southern Power and new facilities not included in the traditional electric operating companies' and Southern Company Gas' regulated rates is capitalized in accordance with standard interest capitalization requirements.
Total AFUDC and interest capitalized for the applicable Registrants in 2024, 2023, and 2022 was as follows:
Southern CompanyAlabama
Power
Georgia
Power(*)
Southern
Power		Southern Company Gas
(in millions)
2024$339 $76 $209 $7 $47 
2023400 109 251 3 37 
2022327 90 213 — 24 
(*)See Note 2 under "Georgia Power – Nuclear Construction" for information on the inclusion of a portion of construction costs related to Plant Vogtle Units 3 and 4 in Georgia Power's rate base through each unit's respective in-service date.
The average AFUDC composite rates for 2024, 2023, and 2022 for the traditional electric operating companies and the natural gas distribution utilities were as follows:
202420232022
Alabama Power8.1 %8.1 %7.9 %
Georgia Power(a)
7.7 %7.6 %7.3 %
Mississippi Power(b)
— %— %5.3 %
Southern Company Gas:
Atlanta Gas Light7.7 %7.4 %7.6 %
Chattanooga Gas7.1 %7.1 %7.1 %
Nicor Gas5.6 %4.6 %2.0 %
(a)Excludes AFUDC related to the construction of Plant Vogtle Units 3 and 4 in 2022 and 2023 and Plant Vogtle Unit 4 in 2024. See Note 2 under "Georgia Power – Nuclear Construction" for additional information.
(b)Mississippi Power's AFUDC was immaterial in 2024 and 2023.
Impairment of Long-Lived Assets
The Registrants evaluate long-lived assets for impairment when events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. The determination of whether an impairment has occurred is based on either a specific regulatory disallowance, a sales transaction price that is less than the asset group's carrying amount, or an estimate of undiscounted future cash flows attributable to the asset group, as compared with the carrying amount of the assets. If an impairment has occurred, the amount of the impairment loss recognized is determined by either the amount of regulatory disallowance or by the amount the carrying amount exceeds the estimated fair value of the assets. For assets identified as held for sale, the carrying amount is compared to the estimated fair value less the cost to sell in order to determine if an impairment loss is required. Until the assets are disposed of, their estimated fair value is re-evaluated when circumstances or events change.
In the third quarter 2024, Alabama Power discontinued the development of a multi-use commercial facility. Given the decision to discontinue commercial development, Alabama Power performed an impairment test using a comparative market analysis and determined the carrying amount of the asset exceeded its fair value, net of selling costs. This resulted in a pre-tax impairment loss of $36 million ($27 million after tax) reflected in other operations and maintenance on the statements of income.
See Note 15 under "Southern Company Gas" for information regarding impairment charges recorded during 2022.
Goodwill and Other Intangible Assets
Goodwill and other intangible assets not subject to amortization are evaluated for impairment on an annual basis and when events or changes in circumstances necessitate an evaluation for impairment. Other intangible assets subject to amortization are
evaluated for impairment when events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable.
Southern Power's intangible assets consist primarily of certain PPAs acquired, which are amortized over the term of the respective PPA. Southern Company Gas' goodwill and other intangible assets primarily relate to its 2016 acquisition by Southern Company. In addition to these items, Southern Company's goodwill and other intangible assets also relate to its 2016 acquisition of PowerSecure.
For its 2024 annual goodwill impairment test, Southern Company Gas management performed the quantitative assessment, which resulted in the fair value of its reporting units with goodwill exceeding their carrying amounts. For its 2023 and 2022 annual goodwill impairment tests, Southern Company Gas management performed the qualitative assessment and determined that it was more likely than not that the fair value of its reporting units with goodwill exceeded their carrying amounts, and therefore no quantitative assessment was required.
For its 2024 annual goodwill impairment test, PowerSecure management performed the qualitative assessment and determined that it was more likely than not that the fair value of PowerSecure exceeded its carrying amount, and therefore no quantitative assessment was required. For its 2023 annual goodwill impairment test, PowerSecure management performed the quantitative assessment, which resulted in the fair value of PowerSecure exceeding its carrying amount. For its 2022 annual goodwill impairment test, PowerSecure management performed the quantitative assessment, which resulted in the fair value of PowerSecure being lower than its carrying amount. The fair value was estimated using a discounted cash flow analysis. The decline in fair value primarily resulted from declining macroeconomic conditions, reducing sales growth and estimated cash flows. As a result, a goodwill impairment of $119 million was recorded in the fourth quarter 2022.
At December 31, 2024 and 2023, goodwill was as follows:
At December 31, 2024At December 31, 2023
(in millions)
Southern Company$5,161 $5,161 
Southern Company Gas:
Gas distribution operations$4,034 $4,034 
Gas marketing services981 981 
Southern Company Gas total$5,015 $5,015 
At December 31, 2024 and 2023, other intangible assets were as follows:
At December 31, 2024At December 31, 2023
Gross Carrying AmountAccumulated AmortizationOther
Intangible Assets, Net		Gross Carrying AmountAccumulated AmortizationOther
Intangible Assets, Net
(in millions)(in millions)
Southern Company
Subject to amortization:
Customer relationships$212 $(182)$30 $212 $(172)$40 
Trade names64 (59)5 64 (53)11 
PPA fair value adjustments390 (168)222 390 (148)242 
Other3 (3)— 3 (3)— 
Total subject to amortization$669 $(412)$257 $669 $(376)$293 
Not subject to amortization:
FCC licenses75 — 75 75 — 75 
Total other intangible assets$744 $(412)$332 $744 $(376)$368 
Southern Power(*)
PPA fair value adjustments$390 $(168)$222 $390 $(148)$242 
Southern Company Gas(*)
Gas marketing services
Customer relationships$156 $(150)$6 $156 $(145)$11 
Trade names26 (23)3 26 (21)5 
Total other intangible assets$182 $(173)$9 $182 $(166)$16 
(*)All subject to amortization.
Amortization associated with other intangible assets in 2024, 2023, and 2022 was as follows:
202420232022
(in millions)
Southern Company(a)
$35 $38 $39 
Southern Power(b)
20 20 20 
Southern Company Gas
Gas marketing services7 10 11 
(a)Includes $20 million annually recorded as a reduction to operating revenues.
(b)Recorded as a reduction to operating revenues.
At December 31, 2024, the estimated amortization associated with other intangible assets for the next five years is as follows:
20252026202720282029
(in millions)
Southern Company$32 $27 $23 $23 $23 
Southern Power20 20 20 20 19 
Southern Company Gas
Gas marketing services6 3 — — — 
Acquisition Accounting
At the time of an acquisition, management will assess whether acquired assets and activities meet the definition of a business. Acquisitions that meet the definition of a business are accounted for under the acquisition method, and operating results from the date of acquisition are included in the acquiring entity's financial statements. Identifiable assets acquired, liabilities assumed, and
any noncontrolling interests (including any intangible assets) are recognized and measured at fair value. Assets acquired that do not meet the definition of a business are accounted for as an asset acquisition. The purchase price of each asset acquisition is allocated based on the relative fair value of assets acquired. See Note 15 for additional information, including recent and proposed acquisitions.
Determining the fair value of assets acquired and liabilities assumed requires management judgment and management may engage independent valuation experts to assist in this process. Fair values are determined by using market participant assumptions and typically include the timing and amounts of future cash flows, incurred construction costs, the nature of acquired contracts, discount rates, power market prices, and expected asset lives. For potential or successful acquisitions that meet the definition of a business, any due diligence or transaction costs incurred are expensed as incurred. If the acquisition is accounted for as an asset acquisition, direct and incremental transaction costs can be capitalized as a component of the cost of the assets acquired.
Historically, any contingent consideration relates to fixed amounts due to the seller once an acquired construction project is placed in service. For contingent consideration with variable payments, management fair values the arrangement with any changes recorded in the statements of income. See Note 13 for additional fair value information.
Development Costs
For Southern Power, development costs are capitalized once a project is probable of completion, primarily based on a review of its economics and operational feasibility, as well as the status of power off-take agreements and regulatory approvals, if applicable. Southern Power's capitalized development costs are included in CWIP on the balance sheets. All of Southern Power's development costs incurred prior to the determination that a project is probable of completion are expensed as incurred and included in other operations and maintenance expense in the statements of income. If it is determined that a project is no longer probable of completion, any of Southern Power's capitalized development costs are expensed and included in other operations and maintenance expense in the statements of income.
Long-Term Service Agreements
The traditional electric operating companies and Southern Power have entered into LTSAs for the purpose of securing maintenance support for certain of their generating facilities. The LTSAs cover all planned inspections on the covered equipment, which generally includes the cost of all labor and materials. The LTSAs also obligate the counterparties to cover the costs of unplanned maintenance on the covered equipment subject to limits and scope specified in each contract.
Payments made under the LTSAs for the performance of any planned inspections or unplanned capital maintenance are recorded in the statements of cash flows as investing activities. Receipts of major parts into materials and supplies inventory prior to planned inspections are treated as noncash transactions in the statements of cash flows. Any payments made prior to the work being performed are recorded as prepayments in other current assets and non-current assets on the balance sheets or reduce existing payables for LTSA-related work already completed. At the time work is performed, an appropriate amount is accrued for future payments or transferred from the prepayment and recorded as property, plant, and equipment or expensed.
Transmission Receivables/Prepayments
As a result of Southern Power's acquisition and construction of generating facilities, Southern Power has transmission receivables and/or prepayments representing the portion of interconnection network and transmission upgrades that will be reimbursed to Southern Power. Upon completion of the related project, transmission costs are generally reimbursed by the interconnection provider within a five-year period and the receivable/prepayments are reduced as payments or services are received.
Cash, Cash Equivalents, and Restricted Cash
For purposes of the financial statements, temporary cash investments are considered cash equivalents. Temporary cash investments are securities with original maturities of 90 days or less.
The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets that total to the amount shown in the statements of cash flows for the applicable Registrants:
Southern
Company
Alabama Power
Georgia
Power		Southern
Power		Southern
Company Gas
(in millions)
At December 31, 2024
Cash and cash equivalents$1,070 $585 $97 $159 $43 
Restricted cash(a):
Other current assets31 — 21 9 1 
Total cash, cash equivalents, and restricted cash(b)
$1,101 $585 $118 $168 $44 
At December 31, 2023
Cash and cash equivalents$748 $324 $9 $124 $33 
Restricted cash(a):
Other current assets141 85 37 17 2 
Other deferred charges and assets31 — 29 3 — 
Total cash, cash equivalents, and restricted cash(b)
$921 $409 $75 $144 $35 
(a)For Alabama Power and Georgia Power, reflects proceeds from the issuance of solid waste disposal facility revenue bonds in 2023 and 2022, respectively. See Note 8 under "Long-term Debt" for additional information. For Southern Power, reflects $9 million and $17 million at December 31, 2024 and 2023, respectively, resulting from an arbitration award held to fund future replacement costs and $3 million at December 31, 2023 held to fund estimated construction completion costs at the Deuel Harvest wind facility. For Southern Company Gas, reflects collateral for workers' compensation, life insurance, and long-term disability insurance.
(b)Total may not add due to rounding.
Storm Damage and Reliability Reserves
In accordance with their respective state PSC orders, the traditional electric operating companies accrue certain amounts annually related to storm damage recovery. Each traditional electric operating company maintains a reserve to cover or is allowed to defer and recover the cost of damages from major storms to its transmission and distribution facilities and, for Mississippi Power, the cost of uninsured damages to its generation facilities and other property. Alabama Power and Mississippi Power also have authority from the Alabama PSC and the Mississippi PSC, respectively, to accrue certain additional amounts as circumstances warrant. Alabama Power recorded an additional accrual of $21 million in 2024, which is included in the table below.
Storm damage reserve activity for the traditional electric operating companies during 2023 and 2024 was as follows:
Southern
Company
Alabama Power
Georgia Power
Mississippi
Power
 (in millions)
Balance at December 31, 2022$216 $97 $83 $36 
Accrual61 18 31 12 
Weather-related damages
(211)(39)(168)(4)
Balance at December 31, 2023$66 $76 $(54)$44 
Accrual79 34 31 14 
Weather-related damages
(850)(40)(804)(6)
Balance at December 31, 2024$(705)$70 $(827)$52 
The traditional electric operating companies accrued the following amounts related to storm damage recovery in 2022:
Southern
Company
Alabama
Power
Georgia
Power
Mississippi
Power
(in millions)
2022$239 $19 $213 $7 
In 2022, costs for weather-related damages charged against storm damage reserves totaled $24 million and $82 million for Alabama Power and Georgia Power, respectively, and were immaterial for Mississippi Power.
See Note 2 under "Alabama Power – Rate NDR," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" for additional information regarding each company's storm damage reserve.
During 2022, the Alabama PSC and the Mississippi PSC authorized Alabama Power and Mississippi Power, respectively, to make accruals to a reliability reserve if certain conditions are met. During 2024, 2023, and 2022, Alabama Power and Mississippi Power accrued the following amounts to their reliability reserves:
Southern
Company		Alabama
Power		Mississippi
Power
(in millions)
2024$84 $63 $21 
202363 52 11 
2022191 166 25 
See Note 2 under "Alabama Power – Reliability Reserve Accounting Order" and "Mississippi Power – Reliability Reserve Accounting Order" for additional information.
Materials and Supplies
Materials and supplies for the traditional electric operating companies generally includes the average cost of transmission, distribution, and generating plant materials. Materials and supplies for Southern Company Gas generally includes the average cost of propane gas inventory, liquefied natural gas inventory, fleet fuel, and other materials and supplies. Materials and supplies for Southern Power generally includes the average cost of generating plant materials.
Materials are recorded to inventory when purchased and then expensed or capitalized to property, plant, and equipment, as appropriate, at weighted average cost when installed. In addition, certain major parts are recorded as inventory when acquired and then capitalized at cost when installed to property, plant, and equipment.
Fuel Inventory
Fuel inventory for the traditional electric operating companies includes the average cost of coal, natural gas, oil, transportation, and emissions allowances. Fuel inventory for Southern Power, which is included in other current assets, includes the average cost of oil, natural gas, and emissions allowances. Fuel is recorded to inventory when purchased and then expensed, at weighted average cost, as used. Emissions allowances granted by the EPA are included in inventory at zero cost. The traditional electric operating companies recover fuel expense through fuel cost recovery rates approved by each state PSC or, for wholesale rates, the FERC.
Natural Gas for Sale
With the exception of Nicor Gas, Southern Company Gas records natural gas inventories on a weighted average cost of gas basis. In Georgia's deregulated, competitive environment, Marketers sell natural gas to firm end-use customers at market-based prices. On a monthly basis, Atlanta Gas Light assigns to Marketers the majority of the pipeline storage services that it has under contract, along with a corresponding amount of inventory. Atlanta Gas Light retains and manages a portion of its pipeline storage assets and related natural gas inventories for system balancing and to serve system demand.
Nicor Gas' natural gas inventory is carried at cost on a LIFO basis. Inventory decrements occurring during the year that are restored prior to year-end are charged to cost of natural gas at the estimated annual replacement cost. Inventory decrements that are not restored prior to year-end are charged to cost of natural gas at the actual LIFO cost of the inventory layers liquidated. The cost of natural gas, including inventory costs, is recovered from customers under a purchased gas recovery mechanism adjusted for differences between actual costs and amounts billed; therefore, LIFO liquidations have no impact on Southern Company's or Southern Company Gas' net income. At December 31, 2024, the Nicor Gas LIFO inventory balance was $188 million. Based on the average cost of gas purchased in December 2024, the estimated replacement cost of Nicor Gas' inventory at December 31, 2024 was $326 million.
Provision for Uncollectible Accounts
The customers of the traditional electric operating companies and the natural gas distribution utilities are billed monthly. For the majority of receivables, a provision for uncollectible accounts is established based on historical collection experience and other factors. For the remaining receivables, if the company is aware of a specific customer's inability to pay, a provision for
uncollectible accounts is recorded to reduce the receivable balance to the amount reasonably expected to be collected. If circumstances change, the estimate of the recoverability of accounts receivable could change as well. Circumstances that could affect this estimate include, but are not limited to, customer credit issues, customer deposits, and general economic conditions. Customers' accounts are written off once they are deemed to be uncollectible. For all periods presented, uncollectible accounts averaged less than 1% of revenues for each Registrant.
Credit risk exposure at Nicor Gas is mitigated by a bad debt rider approved by the Illinois Commission. The bad debt rider provides for the recovery from (or refund to) customers of the difference between Nicor Gas' actual bad debt experience on an annual basis and the benchmark bad debt expense used to establish its base rates for the respective year.
Concentration of Credit Risk
Concentration of credit risk occurs at Atlanta Gas Light for amounts billed for services and other costs to its customers, which consist of 14 Marketers in Georgia (including SouthStar). The credit risk exposure to the Marketers varies seasonally, with the lowest exposure in the non-peak summer months and the highest exposure in the peak winter months. Marketers are responsible for the retail sale of natural gas to end-use customers in Georgia. The functions of the retail sale of gas include the purchase and sale of natural gas, customer service, billings, and collections. The provisions of Atlanta Gas Light's tariff allow Atlanta Gas Light to obtain credit security support in an amount equal to a minimum of two times a Marketer's highest month's estimated bill from Atlanta Gas Light.
Financial Instruments
The traditional electric operating companies and Southern Power use derivative financial instruments to limit exposure to fluctuations in interest rates, the prices of certain fuel purchases, electricity purchases and sales, and occasionally foreign currency exchange rates. Southern Company Gas uses derivative financial instruments to limit exposure to fluctuations in natural gas prices, weather, and interest rates. All derivative financial instruments are recognized as either assets or liabilities on the balance sheets (included in "Other" or shown separately as "Risk Management Activities") and are measured at fair value. See Note 13 for additional information regarding fair value. Substantially all of the traditional electric operating companies', Southern Power's, and Southern Company Gas' bulk energy purchases and sales contracts that meet the definition of a derivative are excluded from fair value accounting requirements because they qualify for the "normal" scope exception and are accounted for under the accrual method. Derivative contracts that qualify as cash flow hedges of anticipated transactions or are recoverable through the traditional electric operating companies' and the natural gas distribution utilities' fuel-hedging programs result in the deferral of related gains and losses in AOCI or regulatory assets and liabilities, respectively, until the hedged transactions occur. Other derivative contracts that qualify as fair value hedges are marked to market through current period income and are recorded on a net basis in the statements of income. Cash flows from derivatives are classified on the statements of cash flows in the same category as the hedged item. See Note 14 for additional information regarding derivatives.
The Registrants offset fair value amounts recognized for multiple derivative instruments executed with the same counterparty under netting arrangements. The Registrants had no outstanding collateral repayment obligations or rights to reclaim collateral arising from derivative instruments recognized at December 31, 2024.
The Registrants are exposed to potential losses related to financial instruments in the event of counterparties' nonperformance. The Registrants have established risk management policies and controls to determine and monitor the creditworthiness of counterparties in order to mitigate their exposure to counterparty credit risk.
Southern Company Gas
Southern Company Gas enters into weather derivative contracts as economic hedges of natural gas revenues in the event of warmer-than-normal weather in the Heating Season. Exchange-traded options are carried at fair value, with changes reflected in natural gas revenues. Non-exchange-traded options are accounted for using the intrinsic value method. Changes in the intrinsic value for non-exchange-traded contracts are also reflected in natural gas revenues in the statements of income.
Southern Company Gas enters into transactions to secure transportation capacity between delivery points in order to serve its customers and various markets. NYMEX futures and OTC contracts are used to capture the price differential or spread between the locations served by the capacity to substantially protect the natural gas revenues that will ultimately be realized when the physical flow of natural gas between delivery points occurs. These contracts generally meet the definition of derivatives and are carried at fair value on the balance sheets, with changes in fair value included in earnings in the period of change. These contracts are not designated as hedges for accounting purposes.
The purchase, transportation, storage, and sale of natural gas are accounted for on a weighted average cost or accrual basis, as appropriate, rather than on the fair value basis utilized for the derivatives used to mitigate the natural gas price risk associated with the storage and transportation portfolio. Monthly demand charges are incurred for the contracted storage and transportation
capacity and payments associated with asset management agreements, and these demand charges and payments are recognized on the statements of income in the period they are incurred. This difference in accounting methods can result in volatility in reported earnings, even though the economic margin is substantially unchanged from the dates the transactions were consummated.
Comprehensive Income
The objective of comprehensive income is to report a measure of all changes in common stock equity of an enterprise that result from transactions and other economic events of the period other than transactions with owners. Comprehensive income consists of net income attributable to the Registrant, changes in the fair value of qualifying cash flow hedges, and reclassifications for amounts included in net income. Comprehensive income also consists of certain changes in pension and other postretirement benefit plans for Southern Company, Southern Power, and Southern Company Gas.
AOCI (loss) balances, net of tax effects, for Southern Company, Southern Power, and Southern Company Gas were as follows:
Qualifying
Hedges		Pension and Other
Postretirement
Benefit Plans
Accumulated Other
Comprehensive
Income (Loss)(*)
(in millions)
Southern Company
Balance at December 31, 2021$(162)$(76)$(237)
Current period change13 58 71 
Balance at December 31, 2022(149)(18)(167)
Current period change28 (38)(10)
Balance at December 31, 2023(121)(56)(177)
Current period change75 24 99 
Balance at December 31, 2024$(46)$(32)$(78)
Southern Power
Balance at December 31, 2021$1 $(29)$(27)
Current period change(10)20 10 
Balance at December 31, 2022(9)(9)(18)
Current period change8 (7)1 
Balance at December 31, 2023(1)(16)(17)
Current period change8 7 15 
Balance at December 31, 2024$7 $(9)$(2)
Southern Company Gas
Balance at December 31, 2021$(14)$38 $24 
Current period change(11)18 7 
Balance at December 31, 2022(25)56 31 
Current period change1 (16)(15)
Balance at December 31, 2023(24)40 16 
Current period change21 11 32 
Balance at December 31, 2024$(3)$51 $48 
(*)May not add due to rounding.
Variable Interest Entities
The Registrants may hold ownership interests in a number of business ventures with varying ownership structures. Partnership interests and other variable interests are evaluated to determine if each entity is a VIE. The primary beneficiary of a VIE is required to consolidate the VIE when it has both the power to direct the activities of the VIE that most significantly impact the VIE's economic performance and the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE. See Note 7 for additional information regarding VIEs.
v3.25.0.1
REGULATORY MATTERS
 12 Months Ended
Dec. 31, 2024
Regulated Operations [Abstract]  
REGULATORY MATTERS REGULATORY MATTERS
Regulatory Assets and Liabilities
Details of regulatory assets and (liabilities) reflected in the balance sheets at December 31, 2024 and 2023 are provided in the following tables:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2024
AROs(*)
$5,810 $1,906 $3,658 $248 $— 
Retiree benefit plans(*)
2,605 680 892 134 44 
Remaining net book value of retired assets
1,198 454 729 15 — 
Deferred income tax charges
927 264 634 27 — 
Storm damage
859 — 827 32 — 
Deferred depreciation
535 286 249 — — 
Environmental remediation(*)
249 — 16 — 233 
Vacation pay(*)
224 85 112 12 15 
Loss on reacquired debt
219 32 183 4 — 
Software and cloud computing costs
200 76 116 4 4 
Under recovered regulatory clause revenues
167 119 — 17 31 
Regulatory clauses
162 82 — — 80 
Nuclear outage
92 39 53 — — 
Fuel-hedging (realized and unrealized) losses
69 23 29 17 — 
Qualifying repairs of natural gas distribution systems
53 — — — 53 
Long-term debt fair value adjustment
52 — — — 52 
Plant Daniel Units 3 and 4
23 — — 23 — 
Other regulatory assets
184 42 40 30 72 
Deferred income tax credits
(4,536)(1,398)(2,149)(219)(755)
Other cost of removal obligations
(1,176)24 816 (170)(1,846)
Over recovered regulatory clause revenues
(285)(29)(52)— (204)
Reliability reserves
(188)(131)— (57)— 
Storm/property damage reserves
(122)(70)— (52)— 
Nuclear fuel disposal cost recovery
(100)(100)— — — 
Other regulatory liabilities
(180)(28)(14)(6)(31)
Total regulatory assets (liabilities), net$7,041 $2,356 $6,139 $59 $(2,252)
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2023
AROs(*)
$5,733 $1,936 $3,505 $247 $— 
Retiree benefit plans(*)
3,011 815 976 140 146 
Remaining net book value of retired assets
1,357 499 841 17 — 
Deferred income tax charges
897 262 605 28 — 
Under recovered regulatory clause revenues
413 381 — 12 20 
Fuel-hedging (realized and unrealized) losses
270 100 121 49 — 
Deferred depreciation
270 143 127 — — 
Environmental remediation(*)
255 — 20 — 235 
Loss on reacquired debt
238 35 197 5 1 
Vacation pay(*)
217 83 107 11 16 
Software and cloud computing costs
150 59 84 2 5 
Regulatory clauses
140 112 — — 28 
Storm damage
92 — 54 38 — 
Nuclear outage
83 50 33 — — 
Long-term debt fair value adjustment
60 — — — 60 
Qualifying repairs of natural gas distribution systems
40 — — — 40 
Plant Daniel Units 3 and 4
25 — — 25 — 
Other regulatory assets
189 39 33 25 93 
Deferred income tax credits
(4,686)(1,506)(2,161)(241)(759)
Other cost of removal obligations
(1,312)28 617 (186)(1,771)
Over recovered regulatory clause revenues
(287)(3)(46)— (238)
Reliability reserves
(179)(143)— (36)— 
Storm/property damage reserves
(120)(76)— (44)— 
Other regulatory liabilities
(333)(94)(23)(2)(101)
Total regulatory assets (liabilities), net$6,523 $2,720 $5,090 $90 $(2,225)
(*)Generally not earning a return as they are excluded from rate base or are offset in rate base by a corresponding asset or liability.
Unless otherwise noted, the following recovery and amortization periods for these regulatory assets and (liabilities) have been approved by the respective state PSC or regulatory agency:
AROs and other cost of removal obligations – Generally recorded over the related property lives, which may range up to 64 years for Alabama Power, 54 years for Georgia Power, 67 years for Mississippi Power, and 85 years for Southern Company Gas. AROs and other cost of removal obligations are settled and trued up following completion of the related activities. Alabama Power is recovering CCR ARO expenditures over a 38-year period ending in 2054 through Rate CNP Compliance. Effective January 1, 2023, Georgia Power is recovering CCR ARO expenditures over four-year periods through its ECCR tariff. Prior to 2023, expenditures were recovered over three-year periods. See "Georgia Power – Rate Plans" herein and Note 6 for additional information.
Retiree benefit plans – Recovered and amortized over the average remaining service period, which may range up to 14 years for Alabama Power, Georgia Power, Mississippi Power, and Southern Company Gas. Southern Company's balances also include amounts at SCS and Southern Nuclear that are allocated to the applicable regulated utilities. See Note 11 for additional information.
Remaining net book value of retired assets –
Alabama Power: Primarily represents the net book value of Plant Gorgas Unit 10 ($419 million at December 31, 2024) being amortized over 13 years (through 2037) and Plant Barry Unit 4 ($35 million at December 31, 2024) being amortized over 10 years (through 2034). See "Alabama Power – Environmental Accounting Order" herein for additional information.
Georgia Power: Net book values of Plant Wansley Units 1 and 2 and Plant Hammond Units 3 and 4 (totaling $418 million and $302 million, respectively, at December 31, 2024) are being amortized over remaining periods between one and 11 years (between 2025 and 2035). Balance also includes unusable materials and supplies inventories, for which the Georgia PSC will determine a recovery period in a future base rate case.
Mississippi Power: Represents net book value of certain environmental compliance assets at Plant Watson and Plant Greene County. The retail portion is being amortized over 10 years (through 2033) and the wholesale portion is being amortized over 10 years (through 2034). See "Mississippi Power – Environmental Compliance Overview Plan" herein for additional information.
Deferred income tax charges and credits – Charges are recovered and credits are primarily amortized over the related property lives, which may range up to 64 years for Alabama Power, 54 years for Georgia Power, 67 years for Mississippi Power, and 85 years for Southern Company Gas. See Note 10 for additional information. These accounts include certain deferred income tax assets and liabilities not subject to normalization, as described further below:
Alabama Power: Related amounts at December 31, 2024 include excess federal deferred income tax liabilities that are available for the benefit of customers in 2025, as discussed under "Alabama Power – Excess Accumulated Deferred Income Tax Accounting Order" herein. Remaining amounts are being recovered and amortized ratably over the related property lives.
Georgia Power: Related amounts at December 31, 2024 include $135 million of deferred income tax assets related to construction costs for Plant Vogtle Units 3 and 4 being recovered over 10 years (through 2034) and $102 million of excess state deferred income tax liabilities that will be returned to customers in 2025. See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4.
Southern Company Gas: Related amounts at December 31, 2024 include $24 million of deferred income tax liabilities being amortized over periods generally not exceeding five years, primarily related to excess state deferred income tax liabilities. See "Southern Company Gas – Rate Proceedings" herein for additional information.
Storm damage – See "Georgia Power – Storm Damage Recovery" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. Mississippi Power's balance represents deferred storm costs associated with Hurricanes Ida and Zeta being recovered through PEP over seven years (through 2029).
Deferred depreciation –
Alabama Power: Represents deferred depreciation for Plant Barry Unit 5 ($114 million at December 31, 2024) and Plant Barry common coal assets ($48 million at December 31, 2024) to be amortized until 2036 beginning when Plant Barry Unit 5 is retired and Plant Gaston Unit 5 coal assets ($124 million at December 31, 2024) to be amortized until 2039 beginning when the assets are retired.
Georgia Power: Represents deferred depreciation for Plant Scherer Units 1 through 3 ($139 million at December 31, 2024) to be amortized over six years beginning in 2029 and Plant Bowen Units 1 and 2 ($80 million at December 31, 2024) to be amortized over four years beginning in 2031, both as approved under Georgia Power's 2022 ARP, and Plant Vogtle Unit 3 and common facilities ($29 million at December 31, 2024) being amortized over 10 years (through 2034). See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4.
Environmental remediation – Effective January 1, 2023, Georgia Power is recovering $5 million annually for environmental remediation under the 2022 ARP. Southern Company Gas' costs are recovered through environmental cost recovery mechanisms when the remediation work is performed. See Note 3 under "Environmental Remediation" for additional information.
Vacation pay – Recorded as earned by employees and recovered as paid, generally within one year. Includes both vacation and banked holiday pay, if applicable.
Loss on reacquired debt – Recovered over either the remaining life of the original issue or, if refinanced, over the remaining life of the new issue. At December 31, 2024, the remaining amortization periods do not exceed 23 years for Alabama Power, 28 years for Georgia Power, 17 years for Mississippi Power, and three years for Southern Company Gas.
Software and cloud computing costs – Represents certain deferred operations and maintenance costs associated with software and cloud computing projects. For Alabama Power, costs are amortized ratably over the life of the related software, which ranges up to 10 years (through 2034). For Georgia Power, costs incurred through 2022 are being amortized over five years (through 2027), and the recovery period for costs incurred after 2022 will be determined in its next base rate case. For Mississippi Power, the recovery period will be determined in Mississippi Power's annual PEP filing process following the completion of the projects and is expected to begin no earlier than 2026. For Southern Company Gas, costs are being amortized ratably over the life of the related software, which ranges up to 10 years (through 2034).
Under and over recovered regulatory clause revenues –
Alabama Power: Balances are recorded monthly and expected to be recovered over periods of up to six years, with the majority expected to be recovered within one year. See "Alabama Power – Rate CNP PPA," " – Rate CNP Compliance," and " – Rate ECR" herein for additional information.
Georgia Power: Balances are recorded monthly and expected to be recovered or returned within two years. See "Georgia Power – Rate Plans" herein for additional information.
Mississippi Power: At December 31, 2024, $17 million is expected to be recovered through various rate recovery mechanisms over a period to be determined in future rate filings. See "Mississippi Power – Ad Valorem Tax Adjustment" herein for additional information.
Southern Company Gas: Balances are recorded and recovered or amortized over periods generally not exceeding five years. In addition to natural gas cost recovery mechanisms, the natural gas distribution utilities have various other cost recovery mechanisms for the recovery of costs, including those related to infrastructure replacement programs.
Regulatory clauses –
Alabama Power: Effective January 1, 2023, balance is being amortized through Rate RSE over a five-year period ending in 2027.
Southern Company Gas: Represents amounts related to Nicor Gas' volume balancing adjustment rider expected to be recovered over a period of less than two years.
Nuclear outage – Costs are deferred to a regulatory asset when incurred and amortized over a subsequent period of 18 months for Alabama Power and up to 24 months for Georgia Power. See Note 5 for additional information.
Fuel-hedging (realized and unrealized) losses and gains – Assets and liabilities are recorded over the life of the underlying hedged purchase contracts. Upon final settlement, actual costs incurred are recovered through the applicable traditional electric operating company's fuel cost recovery mechanism. Purchase contracts generally do not exceed three and a half years for Alabama Power, three years for Georgia Power, and four years for Mississippi Power. Immaterial amounts for fuel-hedging gains at December 31, 2024 and 2023 are included in other regulatory liabilities.
Qualifying repairs of natural gas distribution systems – Represents deferred costs of certain repairs at Atlanta Gas Light being amortized over 20 years.
Long-term debt fair value adjustment – Recovered over the remaining lives of the original debt issuances at acquisition, which range up to 14 years at December 31, 2024.
Plant Daniel Units 3 and 4 – Represents the difference between Mississippi Power's revenue requirement for Plant Daniel Units 3 and 4 under purchase accounting and operating lease accounting. At December 31, 2024, consists of the $16 million retail portion being amortized through 2039 over the remaining life of the related property and the $8 million wholesale portion being amortized over 10 years (through 2034).
Other regulatory assets – Comprised of numerous immaterial components with remaining amortization periods at December 31, 2024 generally not exceeding 19 years for Alabama Power, 10 years for Georgia Power, 10 years for Mississippi Power, and 15 years for Southern Company Gas.
Reliability reserves and storm/property damage reserves – Utilized as related expenses are incurred. See "Alabama Power – Rate NDR" and " – Reliability Reserve Accounting Order," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" and " – Reliability Reserve Accounting Order" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information.
Nuclear fuel disposal cost recovery – Represents award resulting from litigation related to nuclear fuel disposal costs. See Note 3 under "Nuclear Fuel Disposal Costs" for additional information.
Other regulatory liabilities – Comprised of numerous immaterial components with remaining amortization periods at December 31, 2024 generally not exceeding one year for Alabama Power, three years for Georgia Power, one year for Mississippi Power, and 20 years for Southern Company Gas.
Alabama Power
Alabama Power's revenues from regulated retail operations are collected through various rate mechanisms subject to the oversight of the Alabama PSC. Alabama Power currently recovers its costs from the regulated retail business primarily through Rate RSE, Rate CNP, Rate ECR, and Rate NDR. In addition, the Alabama PSC issues accounting orders to address current events impacting Alabama Power.
Petition for Certificate of Convenience and Necessity
On October 24, 2024, Alabama Power entered into an agreement to acquire all of the equity interests in Tenaska Alabama Partners, L.P. for a total purchase price of approximately $622 million, subject to working capital adjustments. Tenaska Alabama Partners, L.P. owns and operates the Lindsay Hill Generating Station, an approximately 855-MW combined cycle generation facility in Autauga County, Alabama. On October 30, 2024, Alabama Power filed a petition for a CCN with the Alabama PSC for authorization to procure additional generating capacity through the acquisition of the Lindsay Hill Generating Station.
As part of the acquisition, Alabama Power will assume an existing power sales agreement under which the full output of the generating facility remains committed to a third party through April 2027. Upon expiration of the power sales agreement, Alabama Power expects to recover costs associated with the Lindsay Hill Generating Station acquisition through Rate CNP New Plant, Rate CNP Compliance, Rate ECR, and Rate RSE.
The completion of the acquisition is subject to the satisfaction or waiver of certain conditions, including, among other customary closing conditions, approval by the Alabama PSC and the FERC, as well as the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act. Alabama Power expects to complete the acquisition by the end of the third quarter 2025.
The ultimate outcome of this matter cannot be determined at this time.
Renewable Generation Certificate
Through the issuance of a Renewable Generation Certificate (RGC), Alabama Power is authorized by the Alabama PSC to procure renewable capacity and energy and to market the related energy and environmental attributes to customers and other third parties. Under the original RGC, Alabama was authorized to procure up to 500 MWs of renewable capacity and energy. In June 2023, the Alabama PSC issued an order approving modifications to Alabama Power's RGC. The modifications authorized Alabama Power to procure an additional 2,400 MWs of renewable capacity and energy by June 14, 2029 and to market the related energy and environmental attributes to customers and other third parties. The modifications also increased the size of allowable renewable projects from 80 MWs to 200 MWs and increased the annual approval limit from 160 MWs to 400 MWs. Through December 31, 2024, Alabama Power has procured solar capacity totaling approximately 498 MWs under the RGC.
Rate RSE
The Alabama PSC has adopted Rate RSE that provides for periodic annual adjustments based upon Alabama Power's projected weighted common equity return (WCER) compared to an allowable range. Rate RSE adjustments are based on forward-looking information for the applicable upcoming calendar year. Rate RSE adjustments for any two-year period, when averaged together, cannot exceed 4.0% and any annual adjustment is limited to 5.0%. When the projected WCER is under the allowed range, there is an adjusting point of 5.98% and eligibility for a performance-based adder of seven basis points, or 0.07%, to the WCER adjusting point if Alabama Power (i) has an "A" credit rating equivalent with at least one of the recognized rating agencies or (ii) is in the top one-third of a designated customer value benchmark survey.
Alabama Power continues to reduce growth in total debt by increasing equity, with corresponding reductions in debt issuances, thereby de-leveraging its capital structure. Alabama Power's goal is to achieve an equity ratio of approximately 55% by the end of 2025. At December 31, 2024 and 2023, Alabama Power's equity ratio was approximately 53.9% and 52.3%, respectively.
Generally, during a year without a Rate RSE upward adjustment, if Alabama Power's actual WCER is between 6.15% and 7.65%, customers will receive 25% of the amount between 6.15% and 6.65%, 40% of the amount between 6.65% and 7.15%, and 75% of the amount between 7.15% and 7.65%. Customers will receive all amounts in excess of an actual WCER of 7.65%. During a year with a Rate RSE upward adjustment, if Alabama Power's actual WCER exceeds 6.15%, customers receive 50% of the amount between 6.15% and 6.90% and all amounts in excess of an actual WCER of 6.90%. Alabama Power's ability to retain a portion of the revenue that causes the actual WCER for a given year to exceed the allowed range positions Alabama Power to address the pressure on its credit quality, without increasing retail rates under Rate RSE in the near term. There is no provision for additional customer billings should the actual retail return fall below the WCER range.
Retail rates under Rate RSE did not change for 2023 or 2024.
For the years ended December 31, 2022, 2023, and 2024, Alabama Power's WCER exceeded 6.15%, resulting in Alabama Power establishing a current regulatory liability of $62 million, $15 million, and $12 million, respectively, for Rate RSE refunds. In accordance with an Alabama PSC order issued in February 2023, Alabama Power refunded the 2022 amount to customers through bill credits in August 2023. The $15 million regulatory liability at December 31, 2023 was refunded to customers through bill credits in April 2024. The $12 million regulatory liability at December 31, 2024 will be refunded to customers through bill credits in May 2025.
On November 27, 2024, Alabama Power made its required annual Rate RSE submission to the Alabama PSC of projected data for calendar year 2025, resulting in an increase of 4.87%, or $325 million annually, that became effective for the billing month of January 2025.
Excess Accumulated Deferred Income Tax Accounting Order
In 2022, the Alabama PSC directed Alabama Power to accelerate the amortization of a regulatory liability associated with excess federal accumulated deferred income taxes. Under this order, in 2023, approximately $304 million was returned to customers through bill credits to offset the impact of the rate increase discussed under "Rate CNP Depreciation" herein.
In October 2023, the Alabama PSC issued an order modifying its 2022 order and authorizing Alabama Power to (i) flow back in 2023 approximately $24 million of certain federal excess accumulated deferred income taxes resulting from the Tax Reform Legislation and (ii) make available any remaining balance of excess accumulated deferred income taxes at the end of 2023 for the benefit of customers in 2024 and/or 2025. At December 31, 2023, the remaining balance was $81 million, of which approximately $67 million was flowed back in 2024 and $14 million will flow back in 2025 for the benefit of customers.
Rate CNP New Plant
Rate CNP New Plant allows for recovery of Alabama Power's retail costs associated with newly developed or acquired certificated generating facilities placed into retail service.
In July 2022, the Alabama PSC approved a CCN authorizing Alabama Power to complete the acquisition of the Calhoun Generating Station. The transaction closed in September 2022, and, in October 2022, Alabama Power filed Rate CNP New Plant with the Alabama PSC to recover the related costs. The filing reflected an increase in annual revenues of $34 million, or 0.6%, effective with November 2022 billings.
In 2020, the Alabama PSC approved a CCN authorizing Alabama Power to complete the acquisition of the Central Alabama Generating Station, which occurred in August 2020. Through May 2023, Alabama Power recovered substantially all costs associated with the Central Alabama Generating Station through Rate RSE, offset by revenues from a power sales agreement. Beginning in July 2022, fuel costs associated with Central Alabama Generating Station are being recovered through Rate ECR. In March 2023, Alabama Power filed Rate CNP New Plant with the Alabama PSC to recover costs associated with the acquisition of the Central Alabama Generating Station. The filing reflected an annual increase in retail revenues of $78 million, or 1.1%, effective with June 2023 billings. On May 24, 2023, the Central Alabama Generating Station was placed into retail service.
The Alabama PSC's 2020 CCN also authorized Alabama Power to construct an approximately 720-MW combined cycle facility at Alabama Power's Plant Barry (Plant Barry Unit 8) and the recovery of estimated in-service costs. On November 1, 2023, the unit was placed in service. In December 2023, Alabama Power filed Rate CNP New Plant with the Alabama PSC to recover the related costs. The filing reflected an annual increase in retail revenues of $91 million, or 1.4%, effective with January 2024 billings.
Rate CNP PPA
Rate CNP PPA allows for the recovery of Alabama Power's retail costs associated with certificated PPAs. Revenues for Rate CNP PPA, as recorded on the financial statements, are adjusted for differences in actual recoverable costs and amounts billed in current regulated rates. Accordingly, changes in the billing factors will have no significant effect on Southern Company's or Alabama
Power's revenues or net income but will affect annual cash flow. No adjustments to Rate CNP PPA occurred during the period 2022 through 2024 and no adjustment is expected for 2025. At December 31, 2024 and 2023, Alabama Power had an under recovered Rate CNP PPA balance of $84 million and $103 million, respectively, of which $17 million and $18 million, respectively, is included in other regulatory assets, current and $67 million and $85 million, respectively, is included in other regulatory assets, deferred on Southern Company's and Alabama Power's balance sheets.
Rate CNP Compliance
Rate CNP Compliance allows for the recovery of Alabama Power's retail costs associated with laws, regulations, and other such mandates directed at the utility industry involving the environment, security, reliability, safety, sustainability, or similar considerations impacting Alabama Power's facilities or operations. Rate CNP Compliance is based on forward-looking information and provides for the recovery of these costs pursuant to factors that are calculated and submitted to the Alabama PSC by December 1 with rates effective for the following calendar year. Compliance costs to be recovered include operations and maintenance expenses, depreciation, and a return on certain invested capital. Revenues for Rate CNP Compliance, as recorded on the financial statements, are adjusted for differences in actual recoverable costs and amounts billed in current regulated rates. Accordingly, changes in the billing factors will have no significant effect on Southern Company's or Alabama Power's revenues or net income, but will affect annual cash flow. Changes in Rate CNP Compliance-related operations and maintenance expenses and depreciation generally will have no effect on net income.
In December 2022, December 2023, and November 2024, Alabama Power submitted calculations to the Alabama PSC associated with its cost of complying with governmental mandates for the following calendar year, as provided under Rate CNP Compliance. The 2022 filing reflected a $255 million, or 3.7%, annual increase effective with January 2023 billings, primarily due to updated depreciation rates. The 2023 filing reflected a $23 million, or 0.3%, annual decrease effective with January 2024 billings. The 2024 filing reflected a projected under recovered retail revenue requirement of $50 million. On December 3, 2024, the Alabama PSC issued a consent order requiring Alabama Power to leave the 2024 Rate CNP Compliance factors in effect for 2025, with any prior year under collected amount deemed recovered before any current year amounts are recovered, and any remaining under recovered amounts reflected in the 2025 filing.
At December 31, 2024, Alabama Power had an under recovered Rate CNP Compliance balance of $35 million which is included in other regulatory assets, deferred on Southern Company's and Alabama Power's balance sheets. At December 31, 2023, Alabama Power had an under recovered Rate CNP Compliance balance of $33 million, of which $8 million is included in other regulatory assets, current and $25 million is included in other regulatory assets, deferred on Southern Company's and Alabama Power's balance sheets.
Rate CNP Depreciation
In 2022, the Alabama PSC approved Rate CNP Depreciation, which allows Alabama Power to recover changes in depreciation resulting from updates to certain depreciation rates, excluding any depreciation recovered through Rate CNP New Plant, Rate CNP Compliance, or costs associated with the capitalization of asset retirement costs. Rate CNP Depreciation resulted in an annual revenue increase of approximately $318 million, or 4.6%, effective with January 2023 billings. No adjustments to Rate CNP Depreciation occurred during 2024 and no adjustment is expected for 2025.
Rate ECR
Rate ECR recovers Alabama Power's retail energy costs based on an estimate of future energy costs and the current over or under recovered balance. Revenues recognized under Rate ECR and recorded on the financial statements are adjusted for the difference in actual recoverable fuel costs and amounts billed in current regulated rates. The difference in the recoverable fuel costs and amounts billed gives rise to the over or under recovered amounts recorded as regulatory assets or liabilities. Alabama Power, along with the Alabama PSC, continually monitors the over or under recovered cost balance to determine whether an adjustment to billing rates is required. Changes in the Rate ECR factor have no significant effect on Southern Company's or Alabama Power's net income but will impact the related operating cash flows. The Alabama PSC may approve billing rates under Rate ECR of up to 5.910 cents per KWH.
The Alabama PSC approved adjustments to Rate ECR from 1.960 cents per KWH to 2.557 cents per KWH, or approximately $310 million annually, effective with August 2022 billings and from 2.557 cents per KWH to 3.510 cents per KWH, or approximately $500 million annually, effective with December 2022 billings. In November 2023, the Alabama PSC approved a decrease to Rate ECR from 3.510 cents per KWH to 3.270 cents per KWH, or approximately $126 million annually, effective with December 2023 billings. On May 7, 2024, the Alabama PSC approved a decrease to Rate ECR from 3.270 cents per KWH to 3.015 cents per KWH, or approximately $135 million annually, effective with July 2024 billings. On December 3, 2024, the Alabama PSC approved an additional reduction to Rate ECR from 3.015 cents per KWH to 2.600 cents per KWH, or
$218 million annually, effective with January 2025 billings. The rate will adjust to 5.910 cents per KWH in January 2026 absent a further order from the Alabama PSC.
At December 31, 2024, Alabama Power's over recovered fuel costs totaled $29 million and is included in other regulatory liabilities, current on Southern Company's and Alabama Power's balance sheets. At December 31, 2023, Alabama Power's under recovered fuel costs totaled $246 million and is included in regulatory assets – under recovered retail fuel clause revenues on Southern Company's and Alabama Power's balance sheets. These classifications are based on estimates, which include such factors as weather, generation availability, energy demand, and the price of energy. A change in any of these factors could have a significant impact on the timing of any recovery or return of fuel costs.
Plant Greene County
Alabama Power jointly owns Plant Greene County Units 1 and 2 with an affiliate, Mississippi Power. See Note 5 under "Joint Ownership Agreements" for additional information. Mississippi Power's 2024 IRP includes a schedule to retire Mississippi Power's 40% ownership interest in Plant Greene County Units 1 and 2 by the end of 2028. Alabama Power currently expects to retire Plant Greene County Units 1 and 2 (300 MWs based on 60% ownership) by the end of 2028. Alabama Power and Mississippi Power have continued to evaluate operating conditions and business needs relevant to the anticipated retirement of Plant Greene County Units 1 and 2. The ultimate outcome of this matter cannot be determined at this time. See "Mississippi Power – Integrated Resource Plans" herein for additional information.
Rate NDR
Based on an order from the Alabama PSC, Alabama Power maintains a reserve for operations and maintenance expenses to cover the cost of damages from major storms to its transmission and distribution facilities. The order approves a separate monthly Rate NDR charge to customers consisting of two components. The first component is intended to establish and maintain a reserve balance for future storms and is an on-going part of customer billing. When the reserve balance falls below $50 million, a reserve establishment charge will be activated (and the on-going reserve maintenance charge concurrently suspended) until the reserve balance reaches $75 million.
The second component of the Rate NDR charge is intended to allow recovery of any existing deferred storm-related operations and maintenance costs and any future reserve deficits over a 48-month period (24-month period prior to modifications approved by the Alabama PSC in 2022). The Alabama PSC order gives Alabama Power authority to record a deficit balance in the NDR when costs of storm damage exceed any established reserve balance. The maximum total Rate NDR charge was limited to $10.00 per month per non-residential customer account and $5.00 per month per residential customer account through July 12, 2022. Subsequently, modifications approved by the Alabama PSC replaced the maximum total Rate NDR charge with a maximum charge to recover a deficit of $5.00 per month per non-residential customer account and $2.50 per month per residential customer account. Alabama Power has the authority, based on an order from the Alabama PSC, to accrue certain additional amounts as circumstances warrant, which can be used to offset storm charges. Alabama Power made an additional accrual of $21 million in 2024.
Alabama Power collected approximately $12 million, $12 million, and $14 million in 2024, 2023, and 2022, respectively, under Rate NDR. Beginning with August 2022 billings, the reserve establishment charge was suspended and the reserve maintenance charge was activated as a result of the NDR balance exceeding $75 million. Alabama Power expects to collect approximately $12 million annually under Rate NDR unless the NDR balance falls below $50 million. At December 31, 2024 and 2023, the NDR balance was $70 million and $76 million, respectively, and is included in other regulatory liabilities, deferred on Southern Company's and Alabama Power's balance sheets.
As revenue from the Rate NDR charge is recognized, an equal amount of operations and maintenance expenses related to the NDR will also be recognized. As a result, the Rate NDR charge will not have an effect on net income but will impact operating cash flows.
Reliability Reserve Accounting Order
In 2022, the Alabama PSC approved an accounting order authorizing Alabama Power to create a reliability reserve separate from the NDR and transition the previous Rate NDR authority related to reliability expenditures to the reliability reserve. Alabama Power may make accruals to the reliability reserve if the NDR balance exceeds $35 million. In July 2023, the Alabama PSC issued an order authorizing Alabama Power to expand the existing authority of its reliability reserve to include certain production-related expenses that are intended to maintain reliability in between scheduled generating unit maintenance outages.
At December 31, 2022, Alabama Power accrued $166 million to the reserve. In August 2023 and on September 18, 2024, Alabama Power notified the Alabama PSC of its intent to use a portion of its reliability reserve balance in 2023 and 2024, respectively. As a result, Alabama Power had usage of the reliability reserve in the amount of $23 million and $12 million during
the fourth quarter 2023 and 2024, respectively, for reliability-related transmission, distribution, and generation expenses and nuclear production-related expenses.
At December 31, 2024 and 2023, Alabama Power's reliability reserve balance was $131 million and $143 million, respectively, and is included in other regulatory liabilities, deferred on Southern Company's and Alabama Power's balance sheets.
Environmental Accounting Order
Based on an order from the Alabama PSC, Alabama Power is authorized to establish a regulatory asset to record the unrecovered investment costs, including the unrecovered plant asset balance and the unrecovered costs associated with site removal and closure associated with future unit retirements, caused by environmental regulations. The regulatory asset is amortized and recovered over the affected unit's remaining useful life, as established prior to the decision regarding early retirement, through Rate CNP Compliance.
With the completion of the Calhoun Generating Station acquisition, Alabama Power expected to retire Plant Barry Unit 5 in late 2023 or early 2024, subject to certain operating conditions. In 2022, Alabama Power reclassified approximately $600 million for Plant Barry Unit 5 from plant in service, net of depreciation to other utility plant, net and will continue to depreciate the asset according to the original depreciation rates. Alabama Power has continued to evaluate operating conditions relevant to the expected retirement of Plant Barry Unit 5 and now expects to retire the unit on or before December 31, 2028. At retirement, Alabama Power will reclassify the remaining net investment costs of the unit to a regulatory asset to be recovered over the unit's remaining useful life, as established prior to the decision to retire, through Rate CNP Compliance. See "Rate CNP New Plant" herein for additional information.
Georgia Power
Georgia Power's revenues from regulated retail operations are collected through various rate mechanisms subject to the oversight of the Georgia PSC. Georgia Power recovers its costs from the regulated retail business through traditional base tariffs, Demand-Side Management (DSM) tariffs, the ECCR tariff, and Municipal Franchise Fee (MFF) tariffs. These tariffs were set under the 2019 ARP for the years 2020 through 2022 and under the 2022 ARP for the years 2023 through 2025 as described herein. In addition, fuel costs are collected through a separate fuel cost recovery tariff.
See "Nuclear Construction – Regulatory Matters" herein for information regarding the approved recovery through retail base rates of certain costs related to Plant Vogtle Unit 3 and the common facilities shared between Plant Vogtle Units 3 and 4 (Common Facilities) that became effective August 1, 2023 based on the in-service date of July 31, 2023 for Unit 3, as well as base rate adjustments for the remaining costs related to Plant Vogtle Units 3 and 4 that became effective May 1, 2024 based on the in-service date of April 29, 2024 for Unit 4. Financing costs on certified construction costs of Plant Vogtle Units 3 and 4 were collected through Georgia Power's NCCR tariff until the inclusion of certified construction costs in rate base. When the base rate adjustments occurred following commercial operation of Unit 4, the NCCR tariff ceased to be collected and financing costs are now included in Georgia Power's general retail revenue requirements. See "Nuclear Construction" herein for additional information on Plant Vogtle Units 3 and 4.
Rate Plans
2022 ARP
In 2022, the Georgia PSC voted to approve the 2022 ARP, under which Georgia Power increased its rates on January 1, 2023. In November 2023 and on December 17, 2024, the Georgia PSC approved tariff adjustments effective January 1, 2024 and 2025, respectively. Details of tariff adjustments are provided in the following table:
Tariff202320242025
(in millions)
Traditional base(a)
$194 $275 $194 
ECCR(21)(99)126 
DSM37 10 (22)
MFF6 5 9 
Total(b)
$216 $191 $306 
(a)For 2025, net of $122 million related to the Georgia state tax rate reduction.
(b)Totals may not add due to rounding.
In the 2022 ARP, the Georgia PSC approved recovery through the ECCR tariff of estimated CCR ARO compliance costs for 2023, 2024, and 2025 over four-year periods beginning January 1 of each respective year, with recovery of construction contingency beginning in the year following actual expenditures, resulting in $20 million and $60 million reductions in the related amortization for 2023 and 2024, respectively, and an increase of $123 million in the related amortization for 2025. Compliance costs incurred were $300 million and $265 million in 2023 and 2024, respectively, and are expected to be $330 million in 2025. The CCR ARO costs are expected to be revised for actual expenditures and updated estimates through future annual compliance filings.
Further, under the 2022 ARP, Georgia Power's retail ROE is set at 10.50% and its equity ratio is set at 56%. Earnings will be evaluated against a retail ROE range of 9.50% to 11.90%. Any retail earnings above 11.90% will be shared, with 40% being applied to reduce regulatory assets, 40% directly refunded to customers, and the remaining 20% retained by Georgia Power. There will be no recovery of any earnings shortfall below 9.50% on an actual basis. However, if at any time during the term of the 2022 ARP, Georgia Power projects that its retail earnings will be below 9.50% for any calendar year, it may petition the Georgia PSC for implementation of the Interim Cost Recovery (ICR) tariff to adjust Georgia Power's retail rates to achieve a 9.50% ROE. The Georgia PSC would have 90 days to rule on Georgia Power's request. The ICR tariff would expire at the earlier of January 1, 2026 or the end of the calendar year in which the ICR tariff becomes effective. In lieu of requesting implementation of an ICR tariff, or if the Georgia PSC chooses not to implement the ICR tariff, Georgia Power may file a full rate case. In 2023 and 2024, Georgia Power's retail ROE was within the allowed retail ROE range.
Georgia Power is required to file a general base rate case by July 1, 2025, in response to which the Georgia PSC would be expected to determine whether the 2022 ARP should be continued, modified, or discontinued.
2019 ARP
Georgia Power's retail ROE under the 2019 ARP was set at 10.50% and earnings were evaluated against a retail ROE range of 9.50% to 12.00%. Any retail earnings above 12.00% were shared, with 40% applied to reduce regulatory assets, 40% directly refunded to customers, and the remaining 20% retained by Georgia Power. In 2022, Georgia Power's retail ROE exceeded 12.00%, and Georgia Power reduced regulatory assets by $117 million and refunded $117 million to customers through bill credits in the first quarter 2023.
Integrated Resource Plans
2022 IRP
In 2022, the Georgia PSC approved Georgia Power's 2022 IRP, as modified by a stipulation among Georgia Power, the staff of the Georgia PSC, and certain intervenors and as further modified by the Georgia PSC.
In the 2022 IRP decision, the Georgia PSC approved, among other things, the certification of six PPAs (including five affiliate PPAs with Southern Power that are subject to approval by the FERC) with capacities of 1,567 MWs beginning in 2024, 380 MWs beginning in 2025, and 228 MWs beginning in 2028, procured through a capacity request for proposals (RFP) authorized in the 2019 IRP. On June 27, 2024, the FERC approved the five affiliate PPAs with Southern Power. See Note 9 for additional information.
In the third quarter 2024, Georgia Power entered into an agreement for engineering, procurement, and construction of a 265-MW battery energy storage facility, which is projected to be placed in service in 2026, as authorized in the 2022 IRP. Georgia Power is required to file quarterly construction monitoring reports with the Georgia PSC through commercial operation. The ultimate outcome of this matter cannot be determined at this time.
As included in the 2022 IRP final order, Georgia Power initiated an RFP of up to 8,500 MWs of capacity from a variety of resources with expected CODs or delivery commencement dates between 2028 and 2030. The RFP included Georgia Power-owned proposals. In conjunction with those proposals, Georgia Power entered into agreements for engineering, procurement, and construction through January 2025. Winning participants are expected to be notified in June 2025, and the Georgia PSC is anticipated to render a decision related to the certification of the winning submissions in the fourth quarter 2025. Depending on the outcomes of the RFP and certification processes, Georgia Power could spend up to $14 billion, excluding AFUDC, on approved Georgia Power-owned proposals and related transmission investments through 2029. The ultimate outcome of this matter cannot be determined at this time.
2023 IRP Update
On April 16, 2024, the Georgia PSC approved Georgia Power's updated IRP as modified by a stipulation among Georgia Power, the staff of the Georgia PSC, and certain intervenors (2023 IRP Update), which set forth a plan to support the recent increase in
the state of Georgia's economic development and Georgia Power's projected energy needs since the 2022 IRP. In the 2023 IRP Update decision, the Georgia PSC approved the following requests:
•Authority to develop, own, and operate up to 1,400 MWs from three simple cycle combustion turbines at Plant Yates with the recoverable costs not to exceed the certified amount, which was approved by the Georgia PSC on August 20, 2024. With this approval, the Georgia PSC recognized the potential for circumstances beyond Georgia Power's control that could cause the project costs to exceed the certified amount, in which case Georgia Power would provide documentation to the Georgia PSC to explain and justify potential recovery of additional reasonable and prudent costs. Georgia Power is required to file semi-annual construction monitoring reports with the Georgia PSC through commercial operation, the first of which was filed on February 14, 2025.
•Certification of an affiliate PPA with Mississippi Power for 750 MWs, which began January 1, 2024 and will continue through December 2028.
•Certification of a non-affiliate PPA for 230 MWs, which began May 1, 2024 and will continue through December 2028.
•Authority to develop, own, and operate up to 500 MWs of battery energy storage facilities, including storage systems co-located with existing Georgia Power-owned solar facilities with the recoverable costs not to exceed the certified amount, as approved by the Georgia PSC on December 3, 2024, as well as the issuance of an expedited RFP for an additional 500 MWs of battery energy storage facilities. Georgia Power is required to file quarterly construction monitoring reports for Georgia Power-owned resources with the Georgia PSC through commercial operation.
•Approval of transmission projects necessary to support the generation resources approved in the 2023 IRP Update.
The 2023 IRP Update assumed a retirement date at the end of 2035 for Plant Bowen Units 1 and 2 (1,400 MWs). See "2025 IRP" herein for additional information.
On January 12, 2024, Georgia Power entered into an agreement for engineering, procurement, and construction to construct three 442-MW simple cycle combustion turbine units at Plant Yates (Plant Yates Units 8, 9, and 10), which are projected to be placed in service in the fourth quarter 2026, the second quarter 2027, and the third quarter 2027, respectively.
In the third quarter 2024, Georgia Power entered into agreements for engineering, procurement, and construction of four battery energy storage facilities totaling 500 MWs, which are projected to be placed in service in 2026.
At December 31, 2024, Georgia Power had recorded approximately $760 million of combined capital costs, excluding AFUDC, for the 265-MW battery energy storage facility approved in the 2022 IRP, the 500 MWs of battery energy storage facilities approved in the 2023 IRP Update, and the 1,400 MWs from three simple cycle combustion turbines at Plant Yates approved in the 2023 IRP Update. The total certified amounts related to these projects are approximately $2.8 billion, excluding AFUDC.
The ultimate outcome of these matters cannot be determined at this time.
2025 IRP
On January 31, 2025, Georgia Power filed its triennial IRP (2025 IRP). The filing includes a request to extend the operation of Plant Scherer Unit 3 (614 MWs based on 75% ownership) through at least December 31, 2035 and Plant Gaston Units 1 through 4 (500 MWs based on 50% ownership through SEGCO) through at least December 31, 2034. See Note 7 under "SEGCO" for additional information.
As in the 2023 IRP Update, Plant Bowen Units 1 and 2 are also assumed to operate through at least the end of 2035.
In addition, the 2025 IRP includes, among other things, requests for approval of the following:
•Pursuit of installation of environmental controls and natural gas co-firing at Plant Bowen Units 1 through 4 (3,160 MWs), Plant Scherer Units 1 and 2 (137 MWs based on 8.4% ownership), and Plant Scherer Unit 3 for compliance with both ELG supplemental rules and GHG rules.
•Upgrades to Plant McIntosh Units 10 and 11 (1,319 MWs) for a projected 194 MWs of incremental capacity by 2028 and Plant McIntosh Units 1 through 8 (640 MWs) for a projected 74 MWs of incremental capacity by 2033.
•Upgrades to Plant Hatch Units 1 and 2 (900 MWs based on 50.1% ownership) and Plant Vogtle Units 1 and 2 (1,060 MWs based on 45.7% ownership) for a projected 112 MWs of incremental capacity, some of which would be available as early as 2028.
•Investments related to the continued reliable hydro operations of nine facilities, as well as the authority to develop, own, and operate a projected incremental 16 MWs from Plant Goat Rock Units 3 through 6.
•RFPs for at least 1,100 MWs of utility scale and distributed generation renewable resources. Georgia Power is seeking to add up to 4,000 MWs of incremental renewable resources by 2035.
•Issuance of a capacity RFP to procure resources to meet capacity needs in 2032 and 2033.
•Strategic power delivery infrastructure plan necessary to help ensure adequate reliability and serve the projected future load growth expected in Georgia.
•Certification of approximately 187 MWs of wholesale capacity associated with Plant Scherer Unit 3 to be placed in retail rate base, some of which is projected to be available in 2026.
A decision from the Georgia PSC on the 2025 IRP is expected in July 2025. The ultimate outcome of these matters cannot be determined at this time.
Transmission Asset Sales
On March 7, 2024, the FERC approved the sale of transmission line assets under the integrated transmission system agreement, with a net book value of $236 million. On April 24, 2024, the sale, with a purchase price of $351 million, was completed resulting in a pre-tax gain of approximately $114 million ($84 million after tax) recorded in the second quarter 2024.
Fuel Cost Recovery
Georgia Power has established fuel cost recovery rates approved by the Georgia PSC. During 2022, Georgia Power's under recovered fuel balance increased significantly due to higher fuel and purchased power costs. In May 2023, the Georgia PSC approved a stipulation between Georgia Power and the staff of the Georgia PSC to increase annual fuel billings by 54%, or approximately $1.1 billion, effective June 1, 2023. The increase includes a three-year recovery period for $2.2 billion of Georgia Power's under recovered fuel balance at May 31, 2023. Under the approved stipulation, Georgia Power is allowed to adjust its fuel cost recovery rates under an interim fuel rider prior to the next fuel case, subject to a maximum 40% cumulative change, if its under or over recovered fuel balance accumulated since May 31, 2023 exceeds $200 million. Georgia Power is scheduled to file its next fuel case no later than February 28, 2026.
Georgia Power's under recovered fuel balance totaled $1.2 billion at December 31, 2024, of which $713 million is included in under recovered fuel clause revenues and under recovered retail fuel clause revenues on Southern Company's and Georgia Power's balance sheets, respectively, and $453 million is included in deferred under recovered retail fuel clause revenues on Southern Company's and Georgia Power's balance sheets. The under recovered fuel balance totaled $1.9 billion at December 31, 2023, of which $694 million is included in under recovered fuel clause revenues and under recovered retail fuel clause revenues on Southern Company's and Georgia Power's balance sheets, respectively, and $1.2 billion is included in deferred under recovered retail fuel clause revenues on Southern Company's and Georgia Power's balance sheets.
Georgia Power's fuel cost recovery mechanism includes costs associated with a natural gas hedging program, as revised and approved by the Georgia PSC, allowing the use of an array of derivative instruments within a 36-month time horizon.
Fuel cost recovery revenues as recorded on the financial statements are adjusted for differences in actual recoverable fuel costs and amounts billed in current regulated rates. Accordingly, changes in the billing factor will not have a significant effect on Southern Company's or Georgia Power's revenues or net income but will affect operating cash flows.
Storm Damage Recovery
Georgia Power defers and recovers certain costs related to damages from major storms as mandated by the Georgia PSC. During 2022, Georgia Power recovered $213 million annually under the 2019 ARP. Beginning January 1, 2023, Georgia Power is recovering $31 million annually under the 2022 ARP. At December 31, 2023, Georgia Power's regulatory asset balance related to storm damage was $54 million, of which $31 million is included in other regulatory assets, current and $23 million is included in other regulatory assets, deferred on Southern Company's and Georgia Power's balance sheets. During September 2024, Hurricane Helene caused significant damage to Georgia Power's transmission and distribution facilities. The incremental restoration costs related to this hurricane totaled approximately $870 million, of which approximately $750 million was deferred in the regulatory asset for storm damage, approximately $90 million was capitalized to property, plant, and equipment, and approximately $30 million was deferred to be billed in 2025 to open access transmission tariff customers. At December 31, 2024, Georgia Power's regulatory asset balance related to storm damage was $827 million, of which $31 million is included in other regulatory assets, current and $795 million is included in other regulatory assets, deferred on Southern Company's and Georgia Power's balance sheets. The rate of storm damage cost recovery is expected to be adjusted in future regulatory proceedings as necessary. As a result of this regulatory treatment, costs related to storms are not expected to have a material impact on Southern Company's or Georgia Power's net income but do impact the related operating cash flows. See Note 1 under "Storm Damage and Reliability Reserves" for additional information.
Nuclear Construction
In 2009, the Georgia PSC certified construction of Plant Vogtle Units 3 and 4, in which Georgia Power holds a 45.7% ownership interest. In 2012, the NRC issued the related combined construction and operating licenses, which allowed full construction of the two AP1000 nuclear units (with electric generating capacity of approximately 1,100 MWs each) and related facilities to begin.
In 2017, Georgia Power, acting for itself and as agent for the other Vogtle Owners, executed the Bechtel Agreement, under which Bechtel is reimbursed for actual costs plus a base fee and an at-risk fee, subject to adjustment based on Bechtel's performance against cost and schedule targets. Each Vogtle Owner is severally (not jointly) liable for its proportionate share, based on its ownership interest, of all amounts owed to Bechtel under the Bechtel Agreement.
See Note 8 under "Long-term Debt – DOE Loan Guarantee Borrowings" for information on the Amended and Restated Loan Guarantee Agreement, including applicable covenants, events of default, and mandatory prepayment events.
Cost and Schedule
Georgia Power placed Unit 3 and Unit 4 in service on July 31, 2023 and April 29, 2024, respectively. During the second quarter 2024, following Unit 4's in-service date, Southern Nuclear evaluated the remaining expected site demobilization costs and other contractor obligations and reduced the remaining estimate to complete forecast by approximately $21 million, including the impact of joint owner cost-sharing described below. Accordingly, Georgia Power recorded a pre-tax credit to income of approximately $21 million ($16 million after tax), including the joint owner impacts described below, in the second quarter 2024 to recognize forecasted capital costs previously charged to income.
Georgia Power's net capital costs incurred through December 31, 2024 in connection with Plant Vogtle Units 3 and 4, and its approximate proportionate share of additional capital costs to be incurred after December 31, 2024, including completion of site demobilization and remaining contractor obligations, is as follows:
(in millions)
Total project capital cost forecast(a)(b)
$10,732 
Net investment at December 31, 2024(b)
(10,663)
Remaining estimate to complete$69 
(a)Includes approximately $1.2 billion of costs that are not shared with the other Vogtle Owners. Excludes financing costs capitalized through AFUDC of approximately $440 million accrued through Unit 4's in-service date.
(b)Net of $1.7 billion received from Toshiba under the Guarantee Settlement Agreement and approximately $188 million in related customer refunds.
Georgia Power's financing costs for construction of Plant Vogtle Units 3 and 4 totaled approximately $3.53 billion, of which $3.08 billion had been recovered through Unit 4's in-service date.
Pursuant to the regulatory orders discussed below, any further changes to the capital cost forecast will not be recoverable through regulated rates and will be required to be charged or credited to income. Such charges or credits are not expected to be material.
Georgia Power previously reached agreements with MEAG Power, OPC, and Dalton to resolve its respective dispute with each regarding the cost-sharing and tender provisions of the joint ownership agreements, as amended (Vogtle Joint Ownership Agreements). Under the terms of these agreements, among other items, Georgia Power will reimburse a portion of MEAG Power's, OPC's, and Dalton's costs of construction for Plant Vogtle Units 3 and 4 as such costs are incurred and with no further adjustment for force majeure costs, which payments (including amounts paid to date) will total approximately $91 million, $99 million, and $5.3 million for MEAG Power, OPC, and Dalton, respectively, based on the current project capital cost forecast. Georgia Power will also reimburse 20% of MEAG Power's costs of construction and 66% of each of OPC's and Dalton's costs of construction with respect to any amounts over the current project capital cost forecast, with no further adjustment for force majeure costs.
Georgia Power recorded pre-tax charges to income through 2023 of $567 million ($424 million after tax) and a pre-tax credit to income in the second quarter 2024 of $7.6 million ($5.7 million after tax) associated with the cost-sharing provisions of the Vogtle Joint Ownership Agreements, including the settlements with the other Vogtle Owners described above. These charges are included in the total project capital cost forecast and will not be recovered from retail customers.
The ultimate impact of these matters on the project capital cost forecast for Plant Vogtle Units 3 and 4 is not expected to be material.
Regulatory Matters
In 2009, the Georgia PSC voted to certify construction of Plant Vogtle Units 3 and 4 with a certified capital cost of $4.418 billion. In addition, in 2009 the Georgia PSC approved inclusion of the Plant Vogtle Units 3 and 4 related CWIP accounts in rate base,
and the State of Georgia enacted the Georgia Nuclear Energy Financing Act, which allowed Georgia Power to recover financing costs for Plant Vogtle Units 3 and 4. Financing costs were recovered on all applicable certified costs through annual adjustments to the NCCR tariff up to the certified capital cost of $4.418 billion. Financing costs related to capital costs above $4.418 billion up to $7.562 billion approved for recovery as described below were recognized through AFUDC and are being recovered through retail rates over the life of Plant Vogtle Units 3 and 4; however, Georgia Power did not record AFUDC related to any capital costs in excess of $7.562 billion. In 2022, the Georgia PSC approved Georgia Power's filing to increase the NCCR tariff by $36 million annually, effective January 1, 2023. In November 2023, Georgia Power filed a request to continue for 2024 the NCCR tariff that was effective during 2023. The staff of the Georgia PSC accepted the proposal and no further approval from the Georgia PSC was required. See additional information below on AFUDC and the NCCR tariff following commercial operation of Unit 4.
In 2021, the Georgia PSC approved an order under which Georgia Power would include in rate base an allocation of $2.1 billion to Plant Vogtle Unit 3 and the Common Facilities from the $3.6 billion of Plant Vogtle Units 3 and 4 costs previously deemed prudent by the Georgia PSC and would recover the related depreciation through retail base rates effective the month after Unit 3 is placed in service. In compliance with the Georgia PSC order, Georgia Power increased annual retail base rates by $318 million effective August 1, 2023 based on the in-service date of July 31, 2023 for Unit 3. The related increase in annual retail base rates included recovery of all projected operations and maintenance expenses for Unit 3 and the Common Facilities and other related costs of operation, partially offset by the related PTCs. Financing costs (debt and equity) on the remaining portion of the total Unit 3 and the Common Facilities construction costs continued to be recovered through the NCCR tariff or deferred. Georgia Power deferred as a regulatory asset the debt component of financing costs as well as the remaining depreciation until Unit 4 costs were placed in retail base rates as described below. The regulatory assets for the debt component of financing costs and depreciation are being recovered over 10 years beginning May 2024, as approved by the Georgia PSC, with a remaining balance of $23 million and $29 million, respectively, at December 31, 2024. The equity component of financing costs ($39 million at December 31, 2024) represents an unrecognized ratemaking amount that is not reflected on Georgia Power's balance sheets. This amount will be recognized in Georgia Power's income statements in the periods it is billable to customers.
In December 2023, the Georgia PSC approved Georgia Power's application to adjust rates to include reasonable and prudent Plant Vogtle Units 3 and 4 costs as modified by the related stipulation (Prudency Stipulation) among Georgia Power, the staff of the Georgia PSC, and certain intervenors.
Under the terms of the approved Prudency Stipulation, Georgia Power will recover $7.562 billion in total construction and capital costs and associated retail rate base items of $1.02 billion, which includes AFUDC financing costs above $4.418 billion (the Georgia PSC-certified amount) up to $7.562 billion. Georgia Power will also recover projected operations and maintenance expenses, depreciation, nuclear decommissioning accruals, and property taxes, net of projected PTCs. After considering construction and capital costs already in retail base rates of $2.1 billion and $362 million of associated retail rate base items for Unit 3 and Common Facilities (approved by the Georgia PSC in 2021), Georgia Power included in retail rate base the remaining $5.462 billion of construction and capital costs as well as $647 million of associated retail rate base items effective with the April 29, 2024 in-service date for Unit 4. Annual retail base revenues increased approximately $730 million and the average retail base rates were adjusted by approximately 5% (net of the elimination of the NCCR tariff described below) effective May 1, 2024.
Reductions to the ROE used to calculate the NCCR tariff (pursuant to prior Georgia PSC orders) negatively impacted earnings by approximately $80 million through the second quarter 2024 and $310 million and $300 million in 2023 and 2022, respectively. Further, as included in the approved Prudency Stipulation, since commercial operation for Unit 4 was not achieved by March 31, 2024, Georgia Power's ROE used to determine the NCCR tariff and calculate AFUDC was reduced to zero effective April 1, 2024, which resulted in a negative impact to earnings of approximately $10 million (for one month) in the second quarter 2024 based on the April 29, 2024 in-service date. Effective May 1, 2024, following commercial operation of Unit 4, Georgia Power's NCCR tariff was eliminated and financing costs are included in Georgia Power's general retail revenue requirements. Financing costs of $10 million that were not recovered through the NCCR tariff will be addressed in Georgia Power's next retail base rate case proceeding.
As of each Unit's respective first refueling outage, if the respective Unit's performance has materially deviated from expected performance, the Georgia PSC may order Georgia Power to credit customers for operations and maintenance expenses or disallow costs associated with the repair or replacement of any system, structure, or component found to have caused the material deviation in performance if proven to be the result of imprudent engineering, construction, procurement, testing, or start-up. Unit 3 demonstrated high performance and reliability during the first 14 months of operation leading up to its first refueling outage, which took place in the fall of 2024 and no performance-related disallowance is expected. Unit 4 has also demonstrated high performance and reliability since being placed in service and its first refueling outage is projected to begin in the fall of 2025. The ultimate outcome of these matters cannot be determined at this time.
The approval of the Prudency Stipulation resolved all issues for determination by the Georgia PSC regarding the reasonableness, prudence, and cost recovery for the remaining Plant Vogtle Units 3 and 4 construction and capital costs not already in retail base rates.
As a result of the Georgia PSC's approval of the Prudency Stipulation, Georgia Power recorded a pre-tax credit to income of approximately $228 million ($170 million after tax) in the fourth quarter 2023 to recognize CWIP costs previously charged to income, which are now recoverable through retail rates. Associated AFUDC on these costs, which totaled approximately $14 million, was also recognized.
Mississippi Power
Mississippi Power's rates and charges for service to retail customers are subject to the regulatory oversight of the Mississippi PSC. Mississippi Power's rates are a combination of base rates and several separate cost recovery clauses for specific categories of costs. These separate cost recovery clauses address such items as fuel and purchased power, ad valorem taxes, property damage, and the costs of compliance with environmental laws and regulations. Costs not addressed through one of the specific cost recovery clauses are expected to be recovered through Mississippi Power's base rates.
Performance Evaluation Plan
Mississippi Power's retail base rates generally are set under the PEP, a rate plan approved by the Mississippi PSC. In recognition that Mississippi Power's long-term financial success is dependent upon how well it satisfies its customers' needs, PEP includes performance indicators that directly tie customer service indicators to Mississippi Power's allowed ROE. PEP measures Mississippi Power's performance on a 10-point scale as a weighted average of results in three areas: average customer price, as compared to prices of other regional utilities (weighted at 40%); service reliability, measured in percentage of time customers had electric service (40%); and customer satisfaction, measured in a survey of residential customers (20%). Typically, two PEP filings are made for each calendar year: the PEP projected filing in March of the current year and the PEP lookback filing in March of the subsequent year. The annual PEP projected filings utilize a historic test year adjusted for "known and measurable" changes and discounted cash flow and regression formulas to determine base ROE. The PEP lookback filing reflects the actual revenue requirement.
In June 2022, the Mississippi PSC approved Mississippi Power's annual retail PEP filing, resulting in an annual increase in revenues of approximately $18 million, or 1.9%, effective with the first billing cycle of April 2022. In June 2023 and on June 13, 2024, the Mississippi PSC approved Mississippi Power's annual retail PEP filings for 2023 and 2024, respectively, with no change in retail rates.
Integrated Resource Plans
In 2020, the Mississippi PSC issued an order requiring Mississippi Power to incorporate into its 2021 IRP a schedule of early or anticipated retirement of 950 MWs of fossil-steam generation by year-end 2027 to reduce the excess reserve margin Mississippi Power anticipated at that time. The order stated that Mississippi Power will be allowed to defer any retirement-related costs as regulatory assets for future recovery.
In 2021, the Mississippi PSC concluded its review of Mississippi Power's 2021 IRP. The 2021 IRP included a schedule to retire Plant Watson Unit 4 (268 MWs) and Plant Greene County Units 1 and 2 (206 MWs based on 40% ownership) in December 2023, 2025, and 2026, respectively, consistent with each unit's remaining useful life in the most recent approved depreciation studies. In addition, the schedule reflected the early retirement of Plant Daniel Units 1 and 2 (502 MWs based on 50% ownership) by the end of 2027.
In October 2023, Mississippi Power signed an affiliate PPA with Georgia Power for 750 MWs of capacity, which began January 1, 2024 and will continue through December 2028.
On April 26, 2024, Mississippi Power filed its 2024 IRP with the Mississippi PSC. The Mississippi PSC did not note any deficiencies within the prescribed 120-day review period; therefore, the filing is concluded. The 2024 IRP included a schedule to retire Plant Watson Unit 4 and Plant Greene County Units 1 and 2 and to retire early Plant Daniel Units 1 and 2, all by the end of 2028, which is consistent with the completion of Mississippi Power's affiliate PPA with Georgia Power. On January 9, 2025, Mississippi Power notified the Mississippi PSC of its intent to extend the retirement date of Plant Daniel Unit 2 and potentially extend the retirement dates of other fossil steam units beyond their current 2028 retirement dates in order to serve recently signed economic development loads of approximately 600 MWs.
The remaining net book value of Plant Daniel Units 1 and 2 was approximately $478 million at December 31, 2024, and Mississippi Power is continuing to depreciate these units using the current approved rates. Mississippi Power expects to reclassify the net book value remaining at retirement to a regulatory asset to be amortized over a period to be determined by the Mississippi
PSC in future proceedings, consistent with the 2020 order. The Plant Watson and Plant Greene County units are expected to be fully depreciated upon retirement.
The ultimate outcome of these matters cannot be determined at this time.
Plant Daniel
On November 8, 2024, Mississippi Power entered into an agreement with FP&L to acquire FP&L's 50% ownership interest in Plant Daniel Units 1 and 2. This acquisition will include a payment by FP&L to Mississippi Power of between $35 million and $38 million, which represents an estimate of the incremental cost to Mississippi Power to assume ownership of FP&L's interest, based on the timing of the completion of the transaction. On January 7, 2025, the Mississippi PSC approved Mississippi Power's request for (i) the inclusion of the acquired assets and the associated costs at Plant Daniel in Mississippi Power's retail rate base, upon completion of the transaction, (ii) the establishment of a new regulatory liability account in which all of the proceeds to be paid by FP&L will be recorded, and (iii) Mississippi Power's ability to amortize that regulatory liability by charging certain expenditures against it. The completion of the transaction is subject to the satisfaction or waiver of certain conditions, including, among other customary closing conditions, approval by the Florida PSC. The ultimate outcome of this matter cannot be determined at this time.
Environmental Compliance Overview Plan
The Mississippi PSC has authorized Mississippi Power to defer in a regulatory asset for future recovery all plant retirement- or partial retirement-related costs resulting from environmental regulations.
In April 2022, April 2023, and May 2024, the Mississippi PSC approved Mississippi Power's annual ECO Plan filings, resulting in increases in revenues of approximately $1 million annually effective with the first billing cycle of May 2022, $3 million annually effective with the first billing cycle of May 2023, and $9 million annually effective with the first billing cycle of June 2024, respectively.
On February 14, 2025, Mississippi Power submitted its annual ECO Plan filing to the Mississippi PSC, which requested a $6 million annual increase in revenues. The ultimate outcome of this matter cannot be determined at this time.
Fuel Cost Recovery
Mississippi Power annually establishes, and is required to file for an adjustment to, the retail fuel cost recovery factor that is approved by the Mississippi PSC. The Mississippi PSC approved an increase of $43 million effective in February 2022. On February 6, 2024, the Mississippi PSC approved Mississippi Power's request to increase retail fuel revenues by $18 million annually effective with the first billing cycle of March 2024. The approved filing included the deferral of approximately $61 million of under recovered fuel costs as of October 2023. On January 7, 2025, the Mississippi PSC approved Mississippi Power's request for no change in retail fuel revenues effective with the first billing cycle of February 2025. The approved filing included the deferral of approximately $25 million of under recovered fuel costs as of October 2024, which is expected to be included in Mississippi Power's next fuel filing. Mississippi Power will continue to accrue its weighted-average cost of capital on any under or over fuel recovery balance.
At December 31, 2024, Mississippi Power had $32 million of deferred under recovered retail fuel clause revenues primarily associated with its fuel-hedging program and $32 million of over recovered retail fuel clause revenues primarily related to lower recoverable fuel costs on its balance sheet. At December 31, 2023, Mississippi Power had $50 million of deferred under recovered retail fuel clause revenues and $27 million of over recovered retail fuel clause revenues primarily associated with its fuel-hedging program on its balance sheet. See Note 1 under "Fuel Costs" for additional information.
Mississippi Power has wholesale MRA and Market Based (MB) fuel cost recovery factors. Effective with the first billing cycles for January 2023, 2024, and 2025, annual revenues under the wholesale MRA fuel rate increased $22 million, decreased $4 million, and decreased $19 million, respectively. At December 31, 2024 and 2023, wholesale MRA fuel costs were over recovered $19 million and $5 million, respectively, and were included in other current liabilities on Mississippi Power's balance sheets. The wholesale MB fuel rate did not change materially in any period presented. The wholesale MB fuel cost recovery was immaterial for both periods presented.
Mississippi Power's operating revenues are adjusted for differences in actual recoverable fuel cost and amounts billed in accordance with the currently approved cost recovery rate. Accordingly, changes in the billing factor should have no significant effect on Mississippi Power's revenues or net income but will affect operating cash flows.
Ad Valorem Tax Adjustment
Mississippi Power annually establishes an ad valorem tax adjustment factor that is approved by the Mississippi PSC. Any changes are not expected to have a significant effect on Mississippi Power's net income but will affect operating cash flows. Effective with
the first billing cycle of July 2022, June 2023, and July 2024, the Mississippi PSC approved changes in annual revenues collected through the ad valorem tax adjustment factor resulting in a $5 million increase, a $7 million decrease, and a $5 million decrease, respectively.
System Restoration Rider
Mississippi Power carries insurance for the cost of certain types of damage to generation plants and general property. However, Mississippi Power is self-insured for the cost of storm, fire, and other uninsured casualty damage to its property, including transmission and distribution facilities. As permitted by the Mississippi PSC and the FERC, Mississippi Power accrues for the cost of such damage through an annual expense accrual which is credited to regulatory liability accounts for the retail and wholesale jurisdictions. The cost of repairing actual damage resulting from such events that individually exceed $50,000 is charged to the reserve. Every year, the Mississippi PSC, the MPUS, and Mississippi Power agree on SRR revenue level(s). In the event the expected annual charges exceed the annual accrual or the target balance has been met, Mississippi Power and the Mississippi PSC will determine the appropriate change to the annual accrual. Additionally, if PEP earnings are above a certain threshold, Mississippi Power has the ability to apply any required PEP refund as an additional accrual to the property damage reserve in lieu of customer refunds.
Mississippi Power's net retail SRR accrual, which includes carrying costs and previously included amortization of related excess deferred income tax benefits, was $12.6 million in 2024, $11.7 million in 2023, and $6.9 million in 2022. At December 31, 2024 and 2023, the retail property damage reserve balance was $52 million and $45 million, respectively, and is included in other regulatory liabilities, deferred on Mississippi Power's balance sheets.
In 2021, the Mississippi PSC approved Mississippi Power's annual SRR filing, which requested an increase in retail revenues of approximately $9 million annually effective with the first billing cycle of March 2022. In April 2023, the Mississippi PSC approved Mississippi Power's annual SRR filing, with no change in retail rates. Mississippi Power's minimum annual SRR accrual was increased from $8.3 million to $11.7 million. On April 11, 2024, the Mississippi PSC approved Mississippi Power's annual SRR filing to the Mississippi PSC, with no change in retail rates. Mississippi Power's minimum annual SRR accrual was increased from $11.7 million to $12.6 million.
Reliability Reserve Accounting Order
In 2022, the Mississippi PSC approved an accounting order authorizing Mississippi Power to create a reliability reserve to offset future generation, transmission, and distribution reliability-related expenditures for use in a future year. Mississippi Power may make accruals to the reliability reserve each year after meeting with the MPUS and Mississippi PSC staff. Mississippi Power will provide annually, through its capital plan, energy delivery plan, or PEP filing, any amounts to be charged against the reliability reserve during the current year. During 2024, 2023, and 2022, Mississippi Power accrued $21 million, $11 million, and $25 million, respectively, to the reliability reserve. At December 31, 2024 and 2023, the reliability reserve balance was $57 million and $36 million, respectively, and is included in other regulatory liabilities, deferred on Mississippi Power's balance sheets.
Municipal and Rural Associations Tariff
Mississippi Power provides wholesale electric service to Cooperative Energy, East Mississippi Electric Power Association, and the City of Collins, all located in southeastern Mississippi, under a long-term, cost-based, FERC-regulated MRA tariff.
In 2017, Mississippi Power and Cooperative Energy executed, and the FERC accepted, a Shared Service Agreement (SSA), as part of the MRA tariff, under which Mississippi Power and Cooperative Energy share in providing electricity to the Cooperative Energy delivery points under the tariff. In August 2022, the FERC accepted an amended SSA between Mississippi Power and Cooperative Energy, effective July 1, 2022, under which Cooperative Energy will continue to decrease its use of Mississippi Power's generation services under the MRA tariff up to 2.5% annually through 2035. At December 31, 2024, Mississippi Power is serving approximately 385 MWs of Cooperative Energy's annual demand. Beginning in 2036, Cooperative Energy will provide 100% of its electricity requirements at the MRA delivery points under the tariff. Neither party has the option to cancel the amended SSA.
In October 2023, the FERC approved a settlement agreement filed by Mississippi Power and Cooperative Energy in July 2023 related to Mississippi Power's July 2022 request for a $23 million increase in annual wholesale base revenues under the MRA tariff. The settlement agreement provided for a $16 million increase in annual wholesale base revenues, effective September 14, 2022, and a refund to customers of approximately $6 million, which was completed in November 2023, primarily related to the difference between the approved rates and interim rates.
On May 28, 2024, the FERC issued an order accepting Mississippi Power's request for an $8 million increase in annual wholesale base revenues under the MRA tariff, effective May 29, 2024, subject to refund. On December 23, 2024, Mississippi Power and
Cooperative Energy filed a settlement agreement with the FERC. The settlement agreement provides for (i) a $1 million increase in annual wholesale base revenues and a refund to customers of approximately $4 million, (ii) a rate escalation of 2.5% on an annual basis in periods subsequent to December 31, 2024 and continuing through the end of the SSA on December 31, 2035, and (iii) a waiver of rights by Mississippi Power and Cooperative Energy to file for any changes in non-fuel rates through the end of the term of the SSA. The settlement agreement is subject to approval by the FERC. The ultimate outcome of this matter cannot be determined at this time.
Southern Company Gas
Utility Regulation and Rate Design
The natural gas distribution utilities are subject to regulation and oversight by their respective state regulatory agencies. Rates charged to customers vary according to customer class (residential, commercial, or industrial) and rate jurisdiction. These agencies approve rates designed to provide the opportunity to generate revenues to recover all prudently-incurred costs, including a return on rate base sufficient to pay interest on debt and provide a reasonable ROE.
As a result of operating in a deregulated environment, Atlanta Gas Light earns revenue by charging rates to its customers based primarily on monthly fixed charges that are set by the Georgia PSC and adjusted periodically. The Marketers add these fixed charges when billing their respective customers. This mechanism, called a straight-fixed-variable rate design, minimizes the seasonality of Atlanta Gas Light's revenues since the monthly fixed charge is not volumetric or directly weather dependent.
With the exception of Atlanta Gas Light, the earnings of the natural gas distribution utilities can be affected by customer consumption patterns that are largely a function of weather conditions and price levels for natural gas. Specifically, customer demand substantially increases during the Heating Season when natural gas is used for heating purposes. Southern Company Gas has various mechanisms, such as weather and revenue normalization mechanisms and weather derivative instruments, that limit exposure to weather changes within typical ranges in these utilities' respective service territories.
In addition to natural gas cost recovery mechanisms, other cost recovery mechanisms and regulatory riders, which vary by utility, allow recovery of certain costs, such as those related to infrastructure replacement programs as well as environmental remediation, energy efficiency plans, and bad debts. In traditional rate designs, utilities recover a significant portion of the fixed customer service and pipeline infrastructure costs based on assumed natural gas volumes used by customers. With the exception of Chattanooga Gas, the natural gas distribution utilities have decoupled regulatory mechanisms that Southern Company Gas believes encourage conservation by separating the recoverable amount of these fixed costs from the amounts of natural gas used by customers. See "Rate Proceedings" herein for additional information. Also see "Infrastructure Replacement Programs and Capital Projects" herein for additional information regarding infrastructure replacement programs at certain of the natural gas distribution utilities.
The following table provides regulatory information for Southern Company Gas' natural gas distribution utilities:
Nicor
Gas
Atlanta Gas
Light
Virginia
Natural Gas
Chattanooga
Gas
Authorized ROE at December 31, 2024
9.51%10.25%9.70%9.80%
Weather normalization mechanisms(a)
üü
Decoupled, including straight-fixed-variable rates(b)
üüü
Regulatory infrastructure program rate(c)
üüü
Bad debt rider(d)
üüü
Energy efficiency plan(e)
üü
Annual base rate adjustment mechanism(f)
üü
Year of last base rate case decision2023201920232018
(a)Designed to help stabilize operating results by allowing recovery of costs in the event of unseasonal weather, but are not direct offsets to the potential impacts on earnings of weather and customer consumption.
(b)Allows for recovery of fixed residential customer service costs separately from assumed natural gas volumes used by customers and provides a benchmark level of revenue for recovery.
(c)See "Infrastructure Replacement Programs and Capital Projects" herein for additional information. Chattanooga Gas' pipeline replacement program costs are recovered through its annual base rate review mechanism.
(d)The recovery (refund) of bad debt expense over (under) an established benchmark expense. The gas portion of bad debt expense is recovered through purchased gas adjustment mechanisms. Nicor Gas also has a rider to recover the non-gas portion of bad debt expense.
(e)Recovery of costs associated with plans to achieve specified energy savings goals.
(f)Regulatory mechanism allowing annual adjustments to base rates up or down based on authorized ROE and/or ROE range.
Infrastructure Replacement Programs and Capital Projects
In addition to capital expenditures recovered through base rates by each of the natural gas distribution utilities, Virginia Natural Gas has a separate rate rider that provides timely recovery of capital expenditures for specific infrastructure replacement programs, and Atlanta Gas Light has a separate rate rider that provides for the timely recovery of capital expenditures for a specific reinforcement capital program. Total capital expenditures incurred during 2024 for all gas distribution operations were $1.7 billion.
The following table and discussions provide updates on the infrastructure replacement programs and capital projects at the natural gas distribution utilities at December 31, 2024. These programs are risk-based and designed to update and replace cast iron, bare steel, and mid-vintage plastic materials or expand Southern Company Gas' distribution systems to improve reliability and meet operational flexibility and growth.
UtilityProgramRecovery
Capital Expenditures in 2024
Capital Expenditures Since Project Inception
Pipe
Installed Since
Project Inception		Scope of
Program		Program DurationLast
Year of Program
(in millions)(miles)(miles)(years)
Virginia Natural Gas
SAVE
Rider$75 $561 598 938 182029
Atlanta Gas LightSystem Reinforcement RiderRider99 279 29 N/A62027
Chattanooga GasPipeline Replacement ProgramRate Base12 28 24 73 72027
Total$186 $868 651 1,011 
Virginia Natural Gas
The SAVE program, an accelerated infrastructure replacement program, allows Virginia Natural Gas to continue replacing aging pipeline infrastructure. The program included authorized annual investments of $70 million in each year from 2022 through 2024, with a total potential variance of up to $5 million allowed for the program, for a maximum total investment over the previous six-year term (2019 through 2024) of $365 million.
On June 7, 2024, the Virginia Commission approved the extension of the existing SAVE program through 2029. The extension of the program includes investments of $70 million in each year from 2025 through 2029, with a potential variance of up to $5 million allowed for the program, for a maximum total investment over the five-year extension (2025 through 2029) of $355 million.
The SAVE program is subject to annual review by the Virginia Commission. In accordance with the base rate case approved by the Virginia Commission in 2023, Virginia Natural Gas is recovering program costs incurred prior to January 1, 2023 through base rates. Program costs incurred subsequent to January 1, 2023 are currently being recovered through a separate rider and are subject to future base rate case proceedings. See "Rate Proceedings – Virginia Natural Gas" herein for additional information.
Atlanta Gas Light
In 2019, the Georgia PSC approved the continuation of GRAM as part of Atlanta Gas Light's 2019 rate case order. Various infrastructure programs previously authorized by the Georgia PSC, including the Integrated Vintage Plastic Replacement Program to replace aging plastic pipe and the Integrated System Reinforcement Program to upgrade Atlanta Gas Light's distribution system and LNG facilities in Georgia, continue under GRAM and the recovery of and return on the infrastructure program investments are included in annual base rate adjustments. The amounts to be recovered through rates related to allowed, but not incurred, costs have been quantified as an unrecognized ratemaking amount that is not reflected on the balance sheets. These allowed costs are primarily the equity return on the capital investment under the infrastructure programs in place prior to GRAM and are being recovered through GRAM and base rates until the earlier of the full recovery of such amounts or December 31, 2025. The under recovered balance at December 31, 2024 was $22 million, including $11 million of unrecognized equity return, and is expected to be recovered by December 31, 2025. The Georgia PSC reviews Atlanta Gas Light's performance annually under GRAM. See "Unrecognized Ratemaking Amounts" herein for additional information.
Atlanta Gas Light and the staff of the Georgia PSC previously agreed to a variation of the Integrated Customer Growth Program to extend pipeline facilities to serve customers in areas without pipeline access and create new economic development opportunities in Georgia. A separate tariff provides recovery of up to $15 million annually for strategic economic development projects approved by the Georgia PSC.
See "Rate Proceedings – Atlanta Gas Light" herein for additional information regarding the Georgia PSC's 2021 approval of Atlanta Gas Light's GRAM filing and Integrated Capacity and Delivery Plan (i-CDP). The Georgia PSC also approved a new System Reinforcement Rider for authorized large pressure improvement and system reliability projects, which is expected to recover related capital investments totaling $286 million for the years 2022 through 2024, of which $99 million, $104 million, and $76 million was incurred in 2024, 2023, and 2022, respectively.
Chattanooga Gas
In 2021, the Tennessee Public Utilities Commission approved Chattanooga Gas' pipeline replacement program to replace approximately 73 miles of distribution main over a seven-year period. The estimated total cost of the program is $118 million, which will be recovered through Chattanooga Gas' annual base rate review mechanism.
Nicor Gas
Illinois legislation allowed Nicor Gas to provide more widespread safety and reliability enhancements to its distribution system through 2023 and stipulated that rate increases to customers as a result of any infrastructure investments did not exceed a cumulative annual average of 4.0% or, in any given year, 5.5% of base rate revenues. In 2014, the Illinois Commission approved the nine-year regulatory infrastructure program, Investing in Illinois, which concluded in 2023 and is subject to annual review, as discussed further below. In accordance with orders from the Illinois Commission, Nicor Gas recovered program costs incurred through a separate rider and base rates. See "Rate Proceedings – Nicor Gas" herein for additional information.
In June 2023, the Illinois Commission concluded its review of the Qualifying Infrastructure Plant (QIP) capital investments by Nicor Gas for calendar year 2019 under the QIP rider, also referred to as Investing in Illinois program. The Illinois Commission disallowed $32 million of the $415 million of capital investments commissioned in 2019, together with the related return on investment. Nicor Gas recorded a pre-tax charge to income in the second quarter 2023 of $38 million ($28 million after tax) associated with the disallowance of capital investments placed in service in 2019. The disallowance is reflected on the statement of income as an $8 million reduction to revenues and $30 million in estimated loss on regulatory disallowance. On August 3, 2023, the Illinois Commission denied a rehearing request filed by Nicor Gas. On August 24, 2023, Nicor Gas filed a notice of appeal with the Illinois Appellate Court. On November 25, 2024, the Illinois Appellate Court agreed with the Illinois Commission's review of the QIP capital investments by Nicor Gas for calendar year 2019 under the QIP rider apart from one immaterial item. On December 24, 2024, Nicor Gas filed a petition for leave to appeal $14 million of the 2019 QIP disallowance with the Illinois Supreme Court. Nicor Gas defends these investments in infrastructure as prudently incurred.
The following table provides a summary of QIP capital investments during the nine-year program:
Year Status of QIP Annual Review Proceeding
Capital Investments
DisallowedMonth of Disallowance
(in millions)
2015 – 2018Complete$1,246 $— 
2019
Complete(a)
415 32 June 2023
2020
Filed March 2021
402 
(b)
2021
Filed March 2022
392 
(b)
2022
Filed March 2023
408 
(b)
6 
(c)(d)
November 2023
2023
Filed March 2024
365 
(b)
25 
(c)(d)
November 2023
$3,228 $63 
(a)Petition for leave to appeal filed to the Illinois Supreme Court for $14 million.
(b)Capital investments are subject to the required QIP annual review proceeding; years 2020 through 2023 are pending with the Illinois Commission.
(c)Appealed to the Illinois Appellate Court.
(d)Disallowed in Nicor Gas' 2023 general base rate case proceeding. See "Rate Proceedings – Nicor Gas" herein for additional information regarding the Illinois Commission's disallowance of certain capital investments.
Any further cost disallowances by the Illinois Commission in the pending cases could be material to the financial statements of Southern Company Gas. The ultimate outcome of these matters cannot be determined at this time.
Natural Gas Cost Recovery
With the exception of Atlanta Gas Light, the natural gas distribution utilities are authorized by the relevant regulatory agencies in the states in which they serve to use natural gas cost recovery mechanisms that adjust rates to reflect changes in the wholesale cost of natural gas and ensure recovery of all costs prudently incurred in purchasing natural gas for customers. The natural gas distribution utilities defer or accrue the difference between the actual cost of natural gas and the amount of commodity revenue
earned in a given period. The deferred or accrued amount is either billed or refunded to customers prospectively through adjustments to the commodity rate. Deferred natural gas costs are reflected as regulatory assets and accrued natural gas costs are reflected as regulatory liabilities. Natural gas costs generally do not have a significant effect on Southern Company's or Southern Company Gas' net income but could have a significant effect on cash flows. Since Atlanta Gas Light does not sell natural gas directly to its end-use customers, it does not utilize a traditional natural gas cost recovery mechanism. However, Atlanta Gas Light does maintain natural gas inventory for the Marketers in Georgia and recovers the cost through recovery mechanisms approved by the Georgia PSC. At December 31, 2024 and 2023, the over recovered balance was $193 million and $214 million, respectively, which is included in natural gas cost over recovery on Southern Company's and Southern Company Gas' balance sheets.
Rate Proceedings
Nicor Gas
In November 2023, the Illinois Commission approved a $223 million annual base rate increase for Nicor Gas, which became effective December 1, 2023. The base rate increase was based on an ROE of 9.51% and an equity ratio of 50.00%.
In connection with Nicor Gas' 2023 general base rate case proceeding, the Illinois Commission disallowed $126.8 million of capital investments that have been completed or were planned to be completed through December 31, 2024. This includes $31 million for capital investments placed in service in 2022 and 2023 under the Investing in Illinois program and $95.9 million for other transmission and distribution capital investments. Nicor Gas recorded a pre-tax charge to income in the fourth quarter 2023 of $58 million ($44 million after tax) associated with the disallowances, with the remaining $69 million related to prospective projects that will be postponed and/or reevaluated. The disallowance is reflected on the statement of income in estimated loss on regulatory disallowance. See "Infrastructure Replacement Programs and Capital Projects – Nicor Gas" herein for additional information regarding the Illinois Commission's disallowance of certain capital investments. On January 3, 2024, the Illinois Commission denied a request by Nicor Gas for rehearing on the base rate case disallowances associated with capital investment, as well as on other issues determined in the Illinois Commission's November 2023 base rate case decision. On February 6, 2024, Nicor Gas filed a notice of appeal with the Illinois Appellate Court related to the Illinois Commission's rate case ruling.
On January 3, 2025, Nicor Gas filed a general base rate case with the Illinois Commission requesting a $309 million increase in annual base rate revenues. The requested increase is based on a projected test year for the 12-month period ending December 31, 2026, an ROE of 10.35%, and an equity ratio of 54.6%. The Illinois Commission is expected to rule on the requested increase within the 11-month statutory time limit, after which rate adjustments will be effective.
The ultimate outcome of these matters cannot be determined at this time.
Atlanta Gas Light
The Georgia PSC evaluates Atlanta Gas Light's earnings against an ROE range of 10.05% to 10.45%, with disposition of any earnings above 10.45% to be determined by the Georgia PSC. Additionally, the Georgia PSC allows inclusion in base rates of the recovery of and return on the infrastructure program investments, including, but not limited to, GRAM adjustments. GRAM filing rate adjustments are based on an authorized ROE of 10.25%. GRAM adjustments for 2021 could not exceed 5% of 2020 base rates. The 5% limitation does not set a precedent in any future rate proceedings by Atlanta Gas Light.
In April 2021, Atlanta Gas Light filed its i-CDP with the Georgia PSC, which included a series of ongoing and proposed pipeline safety, reliability, and growth programs for the next 10 years (2022 through 2031), as well as the required capital investments and related costs to implement the programs. The i-CDP reflected capital investments totaling approximately $0.5 billion to $0.6 billion annually.
In November 2021, the Georgia PSC approved a stipulation between Atlanta Gas Light and the staff of the Georgia PSC, under which, for the years 2022 through 2024, Atlanta Gas Light would incrementally reduce its combined GRAM and System Reinforcement Rider request by 10% through Atlanta Gas Light's GRAM mechanism, which resulted in a reduction of $5 million for 2022, $7 million for 2023, and $9 million for 2024. The stipulation also provided for $1.7 billion of total capital investment for the years 2022 through 2024.
In December 2022 and December 2023, the Georgia PSC approved Atlanta Gas Light's annual GRAM filings, which resulted in annual base rate increases of $53 million effective January 1, 2023 and $53 million effective January 1, 2024, respectively. On December 12, 2024, the Georgia PSC approved Atlanta Gas Light's annual GRAM filing, which included annual base rate increases of $72 million, $73 million, and $74 million effective January 1, 2025, 2026, and 2027, respectively.
On July 2, 2024, the Georgia PSC approved a stipulation related to Atlanta Gas Light's 2024 i-CDP, which included a series of ongoing and proposed pipeline safety, reliability, and growth programs for the next 10 years (2025 through 2034), as well as the
required capital investments and related cost to implement the programs. The i-CDP allows capital investments totaling approximately $0.6 billion annually for the years 2025 through 2027 with related revenue requirement recovery through either the annual GRAM filing or the System Reinforcement Rider surcharge adjustment. Additionally, the Georgia PSC approved a surcharge recovery mechanism for capital projects related to municipal, county, and Georgia Department of Transportation infrastructure work. Rate changes associated with the new surcharge will be based on requests filed annually on September 1. If approved, new rates will become effective January 1 of the following year.
Virginia Natural Gas
In August 2023, the Virginia Commission approved a stipulation related to Virginia Natural Gas' August 2022 general base rate case filing, which allowed for a $48 million increase in annual base rate revenues based on an ROE of 9.70% and an equity ratio of 49.06%. Interim rates became effective as of January 1, 2023, subject to refund, based on Virginia Natural Gas' original requested increase of approximately $69 million. Refunds to customers related to the difference between the approved rates effective September 1, 2023 and the interim rates were completed during the fourth quarter 2023.
On August 1, 2024, Virginia Natural Gas filed a base rate case with the Virginia Commission seeking an increase in annual base revenues of $63 million, including $17 million related to the recovery of investments under the SAVE program, primarily to recover investments and increased costs associated with infrastructure and technology. The requested increase is based on a projected 12-month period beginning January 1, 2025, an ROE of 10.45%, and an equity ratio of 54.92%. Rate adjustments were effective January 1, 2025, subject to refund. The Virginia Commission is expected to issue an order on the requested increase in the fourth quarter 2025. The ultimate outcome of this matter cannot be determined at this time.
Unrecognized Ratemaking Amounts
The following table illustrates Southern Company Gas' authorized ratemaking amounts that are not recognized on its balance sheets. These amounts are primarily comprised of an allowed equity rate of return on assets associated with certain regulatory infrastructure programs. These amounts will be recognized as revenues in Southern Company Gas' financial statements in the periods they are billable to customers, the majority of which will be recovered by 2025.
December 31, 2024December 31, 2023
(in millions)
Atlanta Gas Light$11 $23 
Virginia Natural Gas10 10 
Chattanooga Gas7 7 
Nicor Gas— 3 
Total$28 $43 
v3.25.0.1
CONTINGENCIES, COMMITMENTS, AND GUARANTEES
 12 Months Ended
Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]  
CONTINGENCIES, COMMITMENTS, AND GUARANTEES CONTINGENCIES, COMMITMENTS, AND GUARANTEES
General Litigation Matters
The Registrants are involved in various matters being litigated and regulatory matters. The ultimate outcome of such pending or potential litigation or regulatory matters against each Registrant and any subsidiaries cannot be determined at this time; however, for current proceedings not specifically reported herein, management does not anticipate that the ultimate liabilities, if any, arising from such current proceedings would have a material effect on such Registrant's financial statements.
The Registrants intend to dispute the allegations raised in and vigorously defend against the pending legal challenges discussed below; however, the ultimate outcome of each of these matters cannot be determined at this time.
Southern Company and Mississippi Power
In 2010, the DOE, through a cooperative agreement with SCS, agreed to fund $270 million of the Kemper County energy facility through the grants awarded to the project by the DOE under the Clean Coal Power Initiative Round 2. In 2016, additional DOE grants in the amount of $137 million were awarded to the Kemper County energy facility. In 2018, Mississippi Power filed with the DOE its request for property closeout certification under the contract related to the $387 million of total grants received. In 2020, Mississippi Power and Southern Company executed an agreement with the DOE completing Mississippi Power's request, which enabled Mississippi Power to proceed with full dismantlement of the abandoned gasifier-related assets and site restoration activities. In connection with the DOE closeout discussions, in 2019, the Civil Division of the Department of Justice informed Southern Company and Mississippi Power of a civil investigation related to the DOE grants. In August 2023, the U.S. District Court for the Northern District of Georgia unsealed a civil action in which defendants Southern Company, SCS, and Mississippi
Power are alleged to have violated certain provisions of the False Claims Act by fraudulently inducing the DOE to disburse funds pursuant to the grants. The federal government declined to intervene in the action. In October 2023, the plaintiff, a former SCS employee, filed an amended complaint, again alleging certain violations of the False Claims Act. The plaintiff seeks to recover all damages incurred personally and on behalf of the federal government caused by the defendants' alleged violations, as well as treble damages and attorneys' fees, among other relief. On February 2, 2024, the defendants moved to dismiss the amended complaint. On August 28, 2024, the court granted the defendants' motion in part and denied it in part, dismissing the plaintiff's False Claims Act count along with its accompanying treble damages and attorneys' fees but allowing the employment retaliation claim to proceed. The plaintiff requested interlocutory appeal of the court's decision on October 4, 2024. On October 14, 2024, the defendants asserted counterclaims for conversion and misappropriation of trade secrets. On November 20, 2024, the defendants filed a motion for judgment on the pleadings on the plaintiff's employment retaliation claim. On December 23, 2024, the plaintiff filed a motion to dismiss the defendants' counterclaims. An adverse outcome could have a material impact on Southern Company's and Mississippi Power's financial statements.
Alabama Power
In September 2022, Mobile Baykeeper filed a citizen suit in the U.S. District Court for the Southern District of Alabama alleging that Alabama Power's plan to close the Plant Barry surface impoundment utilizing a closure-in-place methodology violates the Resource Conservation and Recovery Act (RCRA) and regulations governing CCR. Among other relief requested, Mobile Baykeeper sought a declaratory judgment that the RCRA and regulations governing CCR were being violated, preliminary and injunctive relief to prevent implementation of Alabama Power's closure plan, and the development of a closure plan that satisfies regulations governing CCR requirements. In December 2022, Alabama Power filed a motion to dismiss the case. On January 4, 2024, the lawsuit was dismissed without prejudice by the U.S. District Court judge. On February 1, 2024, the plaintiff filed a motion to reconsider, which was denied by the U.S. District Court judge on July 22, 2024. On August 20, 2024, the plaintiff filed a notice of appeal in the U.S. Court of Appeals for the Eleventh Circuit challenging the denial of the motion to reconsider the order of dismissal.
In January 2023, the EPA issued a Notice of Potential Violations (NOPV) associated with Alabama Power's plan to close the Plant Barry surface impoundment. On September 26, 2024, Alabama Power reached a settlement with the EPA resolving two of the three allegations in the NOPV related to the groundwater monitoring system and the emergency action plan at the Plant Barry surface impoundment. The settlement did not resolve the EPA's allegation relating to Alabama Power's plan to close the Plant Barry surface impoundment. Alabama Power has affirmed to the EPA its position that it is in compliance with CCR requirements.
These matters could have a material impact on Alabama Power's and Southern Company's financial statements, including ARO estimates and cash flows. See Note 6 for a discussion of Alabama Power's ARO liabilities.
Georgia Power
In July 2020, a group of individual plaintiffs filed a complaint, which was amended in December 2022, in the Superior Court of Fulton County, Georgia against Georgia Power alleging that the construction and operation of Plant Scherer has impacted groundwater and air, resulting in alleged personal injuries and property damage. The plaintiffs sought an unspecified amount of monetary damages including punitive damages, a medical monitoring fund, and injunctive relief. In December 2022, the Superior Court of Fulton County, Georgia granted Georgia Power's motion to transfer the case to the Superior Court of Monroe County, Georgia. In May 2023, the Superior Court of Monroe County, Georgia denied Georgia Power's motion to dismiss the case for lack of subject matter jurisdiction. In July 2023, the Superior Court of Monroe County, Georgia denied the remaining motions to dismiss certain claims and plaintiffs that Georgia Power filed at the outset of the case. On March 11, 2024, Georgia Power filed a motion to dismiss certain claims. On March 14, 2024, Georgia Power filed motions for summary judgment. In May 2024, Georgia Power filed additional motions for summary judgment. In August 2024, the court denied certain motions for summary judgment, while granting other motions for summary judgment, eliminating some claims from the first one-plaintiff trial.
In October 2021, February 2022, and January 2023, a total of eight additional complaints were filed in the Superior Court of Monroe County, Georgia against Georgia Power alleging that releases from Plant Scherer have impacted groundwater and air, resulting in alleged personal injuries and property damage. The plaintiffs sought an unspecified amount of monetary damages including punitive damages. After Georgia Power removed these cases to the U.S. District Court for the Middle District of Georgia, the plaintiffs voluntarily dismissed their complaints without prejudice in November 2022 and January 2023. In May 2023, the plaintiffs in the cases originally filed in October 2021, February 2022, and January 2023 refiled their eight complaints in the Superior Court of Monroe County, Georgia. Also in May 2023, a new complaint was filed in the Superior Court of Monroe County, Georgia against Georgia Power alleging that the construction and operation of Plant Scherer have impacted groundwater and air, resulting in alleged personal injuries. The plaintiff sought an unspecified amount of monetary damages, including punitive damages. Also in May 2023, Georgia Power removed all of these cases to the U.S. District Court for the Middle District of Georgia. The plaintiffs requested the court remand the cases back to the Superior Court of Monroe County, Georgia.
On November 18, 2024, the parties reached an agreement to resolve all pending lawsuits in the Superior Court of Fulton County, Georgia and the Superior Court of Monroe County, Georgia. On November 22, 2024, the Superior Court of Monroe County, Georgia entered an order granting Georgia Power's motions for summary judgment, finding there is no evidence that Georgia Power's operations negatively impacted drinking water wells or caused personal injury or property damage. On November 25, 2024, the plaintiffs voluntarily dismissed with prejudice all remaining claims in the litigation. The settlement amount did not have a material impact on Georgia Power's financial statements. These matters are now concluded.
Environmental Remediation
The Southern Company system must comply with environmental laws and regulations governing the handling and disposal of waste and releases of hazardous substances. Under these various laws and regulations, the Southern Company system could incur substantial costs to clean up affected sites. The traditional electric operating companies and the natural gas distribution utilities conduct studies to determine the extent of any required cleanup and have recognized the estimated costs to clean up known impacted sites in the financial statements. A liability for environmental remediation costs is recognized only when a loss is determined to be probable and reasonably estimable and is reduced as expenditures are incurred. The traditional electric operating companies and the natural gas distribution utilities in Illinois and Georgia have each received authority from their respective state PSCs or other applicable state regulatory agencies to recover approved environmental remediation costs through regulatory mechanisms. Any difference between the liabilities accrued and costs recovered through rates is deferred as a regulatory asset or liability. These regulatory mechanisms are adjusted annually or as necessary within limits approved by the state PSCs or other applicable state regulatory agencies.
Georgia Power has been designated or identified as a potentially responsible party at sites governed by the Georgia Hazardous Site Response Act and/or by the federal Comprehensive Environmental Response, Compensation, and Liability Act, and assessment and potential cleanup of such sites is expected. For 2024, 2023, and 2022, Georgia Power recovered approximately $5 million, $5 million, and $12 million, respectively, through the ECCR tariff for environmental remediation.
Southern Company Gas is subject to environmental remediation liabilities associated with former manufactured gas plant sites. Southern Company Gas' accrued environmental remediation liability at December 31, 2024 and 2023 was based on the estimated cost of environmental investigation and remediation associated with these sites.
At December 31, 2024 and 2023, the environmental remediation liability and the balance of under recovered environmental remediation costs were reflected in the balance sheets of Southern Company, Georgia Power, and Southern Company Gas as shown in the table below. Alabama Power and Mississippi Power did not have environmental remediation liabilities at December 31, 2024 or 2023.
Southern CompanyGeorgia
Power		Southern Company Gas
(in millions)
December 31, 2024:
Environmental remediation liability:
Other current liabilities$37 $13 $24 
Accrued environmental remediation198 — 198 
Under recovered environmental remediation costs:
Other regulatory assets, current$37 $5 $32 
Other regulatory assets, deferred212 11 201 
December 31, 2023:
Environmental remediation liability:
Other current liabilities$44 $14 $30 
Accrued environmental remediation192 — 192 
Under recovered environmental remediation costs:
Other regulatory assets, current$45 $5 $40 
Other regulatory assets, deferred210 15 195 
The ultimate outcome of these matters cannot be determined at this time; however, as a result of the regulatory treatment for environmental remediation expenses described above, the final disposition of these matters is not expected to have a material impact on the financial statements of the applicable Registrants.
Nuclear Fuel Disposal Costs
Acting through the DOE and pursuant to the Nuclear Waste Policy Act of 1982, the U.S. government entered into contracts with Alabama Power and Georgia Power that required the DOE to take title to and dispose of spent nuclear fuel generated at Plants Farley, Hatch, and Vogtle Units 1 and 2 beginning no later than January 31, 1998. The DOE has yet to commence performance of its contractual and statutory obligation to dispose of spent nuclear fuel. Consequently, Alabama Power and Georgia Power pursued and continue to pursue legal remedies against the U.S. government for its partial breach of contract.
In 2014, Alabama Power and Georgia Power filed their third round of lawsuits against the U.S. government in the Court of Federal Claims, seeking damages for the costs of continuing to store spent nuclear fuel at Plants Farley, Hatch, and Vogtle Units 1 and 2 for the period from January 1, 2011 through December 31, 2013. The damage period was subsequently extended to December 31, 2014. In 2019, the Court of Federal Claims granted Alabama Power's and Georgia Power's motion for summary judgment on damages not disputed by the U.S. government, awarding those undisputed damages to Alabama Power and Georgia Power.
In 2017, Alabama Power and Georgia Power filed their fourth round of lawsuits against the U.S. government in the Court of Federal Claims, seeking damages for the costs of continuing to store spent nuclear fuel at Plants Farley, Hatch, and Vogtle Units 1 and 2 for the period from January 1, 2015 through December 31, 2017. In 2020, Alabama Power and Georgia Power filed amended complaints in those fourth-round lawsuits adding damages incurred from January 1, 2018 to December 31, 2019 to the claim period.
On June 7, 2024, and August 15, 2024, the Court of Federal Claims entered final judgments on the remaining damages in the third and fourth round of lawsuits, respectively, awarding Alabama Power a total of approximately $100 million and Georgia Power a total of approximately $121 million (based on its ownership interests), which represent claims for the period from January 1, 2011 through December 31, 2019. This represents recovery on all claims that Alabama Power and Georgia Power have filed against the U.S. government to date.
On December 3, 2024, the Alabama PSC directed Alabama Power to return the award, which was reflected as a regulatory liability at December 31, 2024, to customers through bill credits during the months of January, February, and March 2025. During the third quarter 2024, Georgia Power credited the award to accounts where the original costs were charged, which reduced rate base, fuel, and cost of service for the benefit of customers, as previously authorized by the Georgia PSC. As a result of this regulatory treatment, there will be no material impact on Southern Company's, Alabama Power's, or Georgia Power's net income.
Damages will continue to accumulate until the issue is resolved, the U.S. government disposes of Alabama Power's and Georgia Power's spent nuclear fuel pursuant to its contractual obligations, or alternative storage is otherwise provided. However, Alabama Power and Georgia Power expect to credit any future recoveries for the benefit of customers in accordance with direction from their respective PSC; therefore, no material impact on Southern Company's, Alabama Power's, or Georgia Power's net income is expected.
On-site dry spent fuel storage facilities are operational at all three plants and can be expanded to accommodate spent fuel through the expected life of each plant.
Nuclear Insurance
Under the Price-Anderson Amendments Act (Act), Alabama Power and Georgia Power maintain agreements of indemnity with the NRC that, together with private insurance, cover third-party liability arising from any nuclear incident occurring at the companies' nuclear power plants. The Act provides funds up to $16.3 billion for public liability claims that could arise from a single nuclear incident. Each nuclear plant is insured against this liability to a maximum of $500 million by American Nuclear Insurers (ANI), with the remaining coverage provided by a mandatory program of deferred premiums that could be assessed, after a nuclear incident, against all owners of commercial nuclear reactors. A company could be assessed up to $166 million per incident for each licensed reactor it operates but not more than an aggregate of $25 million per incident to be paid in a calendar year for each reactor. Such maximum assessment, excluding any applicable state premium taxes, for Alabama Power and Georgia Power, based on its ownership and buyback interests in all licensed reactors, is $332 million and $473 million, respectively, per incident, but not more than an aggregate of $49 million and $71 million, respectively, to be paid for each incident in any one year. Both the maximum assessment per reactor and the maximum yearly assessment are adjusted for inflation at least every five years. The next scheduled adjustment is due no later than November 1, 2028. See Note 5 under "Joint Ownership Agreements" for additional information on joint ownership agreements.
Alabama Power and Georgia Power are members of Nuclear Electric Insurance Limited (NEIL), a mutual insurer established to provide property damage insurance in an amount up to $1.5 billion for members' operating nuclear generating facilities. Additionally, both companies have NEIL policies that currently provide decontamination, excess property insurance, and premature decommissioning coverage up to $1.25 billion for nuclear losses and policies providing coverage up to $750 million for non-nuclear losses in excess of the $1.5 billion primary coverage.
NEIL also covers the additional costs that would be incurred in obtaining replacement power during a prolonged accidental outage at a member's nuclear plant. Members can purchase this coverage, subject to a deductible waiting period of up to 26 weeks, with a maximum per occurrence per unit limit of $490 million. After the deductible period, weekly indemnity payments would be received until either the unit is operational or until the limit is exhausted. Alabama Power and Georgia Power each purchase limits based on the projected full cost of replacement power, subject to ownership limitations, and have each elected a 12-week deductible waiting period for each nuclear plant.
Under each of the NEIL policies, members are subject to assessments each year if losses exceed the accumulated funds available to the insurer. The maximum annual assessments for Alabama Power and Georgia Power as of December 31, 2024 under the NEIL policies would be $60 million and $80 million, respectively.
Claims resulting from terrorist acts and cyber events are covered under both the ANI and NEIL policies (subject to normal policy limits). The maximum aggregate that NEIL will pay for all claims resulting from terrorist acts and cyber events in any 12-month period is $3.2 billion each, plus such additional amounts NEIL can recover through reinsurance, indemnity, or other sources.
For all on-site property damage insurance policies for commercial nuclear power plants, the NRC requires that the proceeds of such policies shall be dedicated first for the sole purpose of placing the reactor in a safe and stable condition after an accident. Any remaining proceeds are to be applied next toward the costs of decontamination and debris removal operations ordered by the NRC, and any further remaining proceeds are to be paid either to the applicable company or to its debt trustees as may be appropriate under the policies and applicable trust indentures. In the event of a loss, the amount of insurance available might not be adequate to cover property damage and other expenses incurred. Uninsured losses and other expenses, to the extent not recovered from customers, would be borne by Alabama Power or Georgia Power, as applicable, and could have a material effect on Southern Company's, Alabama Power's, and Georgia Power's financial condition, cash flows, and results of operations.
All retrospective assessments, whether generated for liability, property, or replacement power, may be subject to applicable state premium taxes
Other Matters
Alabama Power
In April 2019, Bellsouth Telecommunications d/b/a AT&T Alabama (AT&T) filed a complaint against Alabama Power with the FCC alleging that the pole rental rate AT&T is required to pay pursuant to the parties' joint use agreement is unjust and unreasonable under federal law. The complaint sought a new rate and refunds of alleged overpayments since 2013. In August 2019, the FCC stayed the case in favor of arbitration, which AT&T did not pursue. On December 31, 2024, Alabama Power and AT&T reached a settlement that resolved several disputes between the parties, including the outstanding FCC complaint. The terms of the settlement are not expected to have a material impact on Alabama Power's or Southern Company's financial statements. The joint use agreement remains in effect.
Mississippi Power
In 2022, 2023, and 2024, Mississippi Power recorded charges to income associated with abandonment and related closure costs and ongoing period costs, net of salvage proceeds, for the mine and gasifier-related assets at the Kemper County energy facility. These charges, including related tax impacts, totaled $15 million pre-tax ($12 million after tax) in 2022, $17 million pre-tax ($12 million after tax) in 2023, and $12 million pre-tax ($9 million after tax) in 2024. The pre-tax charges are included in other operations and maintenance expenses on the statements of income.
Dismantlement of the abandoned gasifier-related assets and site restoration activities are expected to be completed by the end of 2025. Additional pre-tax period costs associated with dismantlement and site restoration activities, including related costs for compliance and safety, ARO accretion, and property taxes, net of salvage, are estimated to total approximately $15 million.
See "General Litigation Matters – Southern Company and Mississippi Power" herein for information regarding litigation associated with the Kemper County energy facility.
Commitments
To supply a portion of the fuel requirements of the Southern Company system's electric generating plants, the Southern Company system has entered into various long-term commitments not recognized on the balance sheets for the procurement and delivery of
fossil fuel and, for Alabama Power and Georgia Power, nuclear fuel. The majority of the Registrants' fuel expense for the periods presented was purchased under long-term commitments. Each Registrant expects that a substantial amount of its future fuel needs will continue to be purchased under long-term commitments.
Georgia Power has commitments, in the form of capacity purchases, regarding a portion of a 5% interest in the original cost of Plant Vogtle Units 1 and 2 owned by MEAG Power that are in effect until the later of the retirement of the plant or the latest stated maturity date of MEAG Power's bonds issued to finance such ownership interest. The payments for capacity are required whether or not any capacity is available. Portions of the capacity payments made to MEAG Power for its Plant Vogtle Units 1 and 2 investment relate to costs in excess of Georgia Power's allowed investment for ratemaking purposes. The present value of these portions at the time of the disallowance was written off. Generally, the cost of such capacity is included in purchased power in Southern Company's statements of income and in purchased power, non-affiliates in Georgia Power's statements of income. Georgia Power's capacity payments related to this commitment totaled $4 million, $3 million, and $4 million in 2024, 2023, and 2022, respectively. At December 31, 2024, Georgia Power's estimated long-term obligations related to this commitment totaled $35 million, consisting of $3 million for 2025, $2 million annually for 2026 through 2029, and $24 million thereafter.
See Note 9 for information regarding PPAs accounted for as leases.
Guarantees
SCS may enter into various types of wholesale energy and natural gas contracts acting as an agent for the traditional electric operating companies and Southern Power. Under these agreements, each of the traditional electric operating companies and Southern Power may be jointly and severally liable. Accordingly, Southern Company has entered into keep-well agreements with each of the traditional electric operating companies to ensure they will not subsidize or be responsible for any costs, losses, liabilities, or damages resulting from the inclusion of Southern Power as a contracting party under these agreements.
Alabama Power has guaranteed a $100 million principal amount long-term bank loan SEGCO entered into in 2018 and subsequently extended and amended. Georgia Power has agreed to reimburse Alabama Power for the portion of such obligation corresponding to Georgia Power's proportionate ownership of SEGCO's stock if Alabama Power is called upon to make such payment under its guarantee. At December 31, 2024, the capitalization of SEGCO consisted of $56 million of equity and $80 million of long-term debt that matures in November 2025, on which the annual interest requirement is derived from a variable rate index. SEGCO had no short-term debt outstanding at December 31, 2024. See Note 7 under "SEGCO" for additional information.
As discussed in Note 9, Alabama Power and Georgia Power have entered into certain residual value guarantees related to railcar leases, with Georgia Power's railcar leases terminating in June 2024.
v3.25.0.1
REVENUE FROM CONTRACTS WITH CUSTOMERS
 12 Months Ended
Dec. 31, 2024
Revenue from Contract with Customer [Abstract]  
REVENUE FROM CONTRACTS WITH CUSTOMERS REVENUE FROM CONTRACTS WITH CUSTOMERS
The Registrants generate revenues from a variety of sources, some of which are not accounted for as revenue from contracts with customers, such as leases, derivatives, and certain cost recovery mechanisms. Included in the wholesale electric revenues of the traditional electric operating companies and Southern Power are revenues associated with affiliate transactions. These revenues are generated through long-term PPAs or short-term energy sales made in accordance with the IIC, as approved by the FERC. Amounts related to these affiliate revenues are eliminated in consolidation for Southern Company. See Note 1 under "Affiliate Transactions" and "Revenues" for additional information. See Notes 9 and 14 for additional information on revenue accounted for under lease and derivative accounting guidance, respectively.
The following table disaggregates revenue from contracts with customers for the periods presented:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
2024
Operating revenues
Retail electric revenues
Residential$8,276 $3,133 $4,835 $308 $— $— 
Commercial6,585 2,042 4,219 324 — — 
Industrial3,892 1,742 1,808 342 — — 
Other124 13 102 9 — — 
Total retail electric revenues18,877 6,930 10,964 983 — — 
Natural gas distribution revenues
Residential1,753 — — — — 1,753 
Commercial417 — — — — 417 
Transportation1,295 — — — — 1,295 
Industrial 34 — — — — 34 
Other316 — — — — 316 
Total natural gas distribution revenues3,815 — — — — 3,815 
Wholesale electric revenues
PPA energy revenues1,059 206 94 4 778 — 
PPA capacity revenues641 108 136 63 400 — 
Non-PPA revenues226 139 5 375 230 — 
Total wholesale electric revenues1,926 453 235 442 1,408 — 
Other natural gas revenues
Gas marketing services507 — — — — 507 
Other
18 — — — — 18 
Total other natural gas revenues
525 — — — — 525 
Other revenues1,621 240 721 52 37 — 
Total revenue from contracts with customers26,764 7,623 11,920 1,477 1,445 4,340 
Other revenue sources(*)
(40)(69)(589)(14)569 116 
Total operating revenues$26,724 $7,554 $11,331 $1,463 $2,014 $4,456 
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
2023
Operating revenues
Retail electric revenues
Residential$7,309 $2,904 $4,105 $300 $— $— 
Commercial5,860 1,928 3,624 308 — — 
Industrial3,613 1,721 1,558 334 — — 
Other112 12 91 9 — — 
Total retail electric revenues16,894 6,565 9,378 951 — — 
Natural gas distribution revenues
Residential1,981 — — — — 1,981 
Commercial505 — — — — 505 
Transportation1,184 — — — — 1,184 
Industrial 45 — — — — 45 
Other324 — — — — 324 
Total natural gas distribution revenues4,039 — — — — 4,039 
Wholesale electric revenues
PPA energy revenues1,107 234 87 20 790 — 
PPA capacity revenues624 156 51 45 376 — 
Non-PPA revenues250 65 35 407 409 — 
Total wholesale electric revenues1,981 455 173 472 1,575 — 
Other natural gas revenues
Gas marketing services528 — — — — 528 
Other
31 — — — — 31 
Total other natural gas revenues559 — — — — 559 
Other revenues1,355 213 578 39 55 — 
Total revenue from contracts with customers24,828 7,233 10,129 1,462 1,630 4,598 
Other revenue sources(*)
425 (183)(11)12 559 104 
Total operating revenues$25,253 $7,050 $10,118 $1,474 $2,189 $4,702 
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
2022
Operating revenues
Retail electric revenues
Residential$6,604 $2,638 $3,664 $302 $— $— 
Commercial5,369 1,685 3,385 299 — — 
Industrial3,764 1,507 1,921 336 — — 
Other102 14 79 9 — — 
Total retail electric revenues15,839 5,844 9,049 946 — — 
Natural gas distribution revenues
Residential2,843 — — — — 2,843 
Commercial763 — — — — 763 
Transportation1,186 — — — — 1,186 
Industrial84 — — — — 84 
Other342 — — — — 342 
Total natural gas distribution revenues5,218 — — — — 5,218 
Wholesale electric revenues
PPA energy revenues2,274 489 130 16 1,673 — 
PPA capacity revenues596 194 47 4 356 — 
Non-PPA revenues250 200 30 690 740 — 
Total wholesale electric revenues3,120 883 207 710 2,769 — 
Other natural gas revenues
Gas marketing services636 — — — — 636 
Other
51 — — — — 51 
Total other natural gas revenues687 — — — — 687 
Other revenues1,077 194 446 47 36 — 
Total revenue from contracts with customers25,941 6,921 9,702 1,703 2,805 5,905 
Other revenue sources(*)
3,338 896 1,882 (9)564 57 
Total operating revenues$29,279 $7,817 $11,584 $1,694 $3,369 $5,962 
(*)Other revenue sources relate to revenues from customers accounted for as derivatives and leases, alternative revenue programs at Southern Company Gas, and cost recovery mechanisms and revenues (including those related to fuel costs) that meet other scope exceptions for revenues from contracts with customers at the traditional electric operating companies.
Contract Balances
The following table reflects the closing balances of receivables, contract assets, and contract liabilities related to revenues from contracts with customers at December 31, 2024 and 2023:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Accounts Receivable
At December 31, 2024$3,048 $783 $1,244 $113 $106 $660 
At December 31, 20232,820 821 1,011 90 122 684 
Contract Assets
At December 31, 2024$323 $3 $184 $— $— $72 
At December 31, 2023271 2 121 — — 56 
Contract Liabilities
At December 31, 2024$140 $11 $34 $— $2 $3 
At December 31, 2023116 — 1 — 4 — 
Contract assets for Georgia Power primarily relate to retail customer fixed bill programs, where the payment is contingent upon Georgia Power's continued performance and the customer's continued participation in the program over a one-year contract term, and unregulated service agreements, where payment is contingent on project completion. Contract liabilities for Georgia Power primarily relate to cash collections recognized in advance of revenue for unregulated service agreements. Southern Company Gas' contract assets relate to work performed on an energy efficiency enhancement and upgrade contract with the U.S. General Services Administration. Southern Company Gas receives cash advances from a third-party financial institution to fund work performed, of which approximately $68 million had been received at December 31, 2024. These advances have been accounted for as long-term debt on the balance sheets. See Note 1 under "Affiliate Transactions" for additional information regarding the construction contract. At December 31, 2024 and 2023, Southern Company's unregulated distributed generation business had contract assets of $67 million and $91 million, respectively, and contract liabilities of $95 million and $115 million, respectively, for outstanding performance obligations, all of which are expected to be satisfied within one year.
Revenues recognized in 2024 and 2023, which were included in contract liabilities at December 31, 2023 and 2022, respectively, were $98 million and $36 million respectively, for Southern Company and immaterial for the other Registrants. Contract liabilities are primarily classified as current on the balance sheets as the corresponding revenues are generally expected to be recognized within one year.
Remaining Performance Obligations
Southern Company's subsidiaries may enter into long-term contracts with customers in which revenues are recognized as performance obligations are satisfied over the contract term. For the traditional electric operating companies and Southern Power, these contracts primarily relate to PPAs whereby electricity and generation capacity are provided to a customer. The revenue recognized for the delivery of electricity is variable; however, certain PPAs include a fixed payment for fixed generation capacity over the term of the contract. For Southern Company Gas, these contracts primarily relate to the U.S. General Services Administration contract described above. Southern Company's unregulated distributed generation business also has partially
satisfied performance obligations related to certain fixed price contracts. Revenues from contracts with customers related to these performance obligations remaining at December 31, 2024 are expected to be recognized as follows:
20252026202720282029Thereafter
(in millions)
Southern Company$937 $427 $371 $343 $309 $2,636 
Alabama Power11 — — — — — 
Georgia Power69 30 15 16 2 27 
Mississippi Power(*)
63 66 69 73 — — 
Southern Power(*)
340 331 340 316 312 2,609 
Southern Company Gas2 — — — — — 
(*)Includes performance obligations related to affiliate PPAs with Georgia Power. See Note 1 under "Affiliate Transactions" for additional information.
v3.25.0.1
PROPERTY, PLANT, AND EQUIPMENT
 12 Months Ended
Dec. 31, 2024
Property, Plant and Equipment [Abstract]  
PROPERTY, PLANT, AND EQUIPMENT PROPERTY, PLANT, AND EQUIPMENT
Property, plant, and equipment is stated at original cost or fair value at acquisition, as appropriate, less any regulatory disallowances and impairments. Original cost may include: materials; labor; minor items of property; appropriate administrative and general costs; payroll-related costs such as taxes, pensions, and other benefits; and the interest capitalized and/or cost of equity funds used during construction.
The Registrants' property, plant, and equipment in service consisted of the following at December 31, 2024 and 2023:
At December 31, 2024:Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Electric utilities:
Generation$61,292 $16,801 $26,089 $2,946 $14,920 $— 
Transmission16,280 6,449 8,800 989 — — 
Distribution28,678 10,373 16,887 1,418 — — 
General/other6,547 2,878 3,260 344 41 — 
Electric utilities' plant in service112,797 36,501 55,036 5,697 14,961 — 
Southern Company Gas:
Natural gas transportation and distribution
18,896 — — — — 18,896 
Storage facilities1,748 — — — — 1,748 
Other1,694 — — — — 1,694 
Southern Company Gas plant in service22,338 — — — — 22,338 
Other plant in service2,008 — — — — — 
Total plant in service$137,143 $36,501 $55,036 $5,697 $14,961 $22,338 
At December 31, 2023:Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Electric utilities:
Generation$57,325 $16,584 $22,587 $2,909 $14,649 $— 
Transmission15,561 6,152 8,402 966 — — 
Distribution26,482 9,775 15,380 1,327 — — 
General/other6,305 2,918 3,001 321 41 — 
Electric utilities' plant in service105,673 35,429 49,370 5,523 14,690 — 
Southern Company Gas:
Natural gas transportation and distribution
17,798 — — — — 17,798 
Storage facilities1,565 — — — — 1,565 
Other1,477 — — — — 1,477 
Southern Company Gas plant in service20,840 — — — — 20,840 
Other plant in service1,915 — — — — — 
Total plant in service$128,428 $35,429 $49,370 $5,523 $14,690 $20,840 
The cost of replacements of property, exclusive of minor items of property, is capitalized. The cost of maintenance, repairs, and replacement of minor items of property is charged to other operations and maintenance expenses as incurred or performed with the exception of nuclear refueling costs and certain maintenance costs including those described below.
In accordance with orders from their respective state PSCs, Alabama Power and Georgia Power defer nuclear refueling outage operations and maintenance expenses to a regulatory asset when the charges are incurred. Alabama Power amortizes the costs over a subsequent 18-month period with Plant Farley's fall outage cost amortization beginning in January of the following year and spring outage cost amortization beginning in July of the same year. Georgia Power amortizes its costs over each unit's operating cycle, or 18 months for Plant Vogtle Units 1 through 4 and 24 months for Plant Hatch Units 1 and 2. Georgia Power's amortization period begins the month the refueling outage starts.
The portion of Southern Company Gas' non-working gas used to maintain the structural integrity of natural gas storage facilities that is considered to be non-recoverable is depreciated, while the recoverable or retained portion is not depreciated.
See Note 9 for information on finance lease right-of-use (ROU) assets, net, which are included in property, plant, and equipment.
The Registrants have deferred certain implementation costs related to cloud hosting arrangements. At December 31, 2024 and 2023, deferred cloud implementation costs, net of amortization, which are generally included in other deferred charges and assets on the Registrants' balance sheets, were as follows:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Deferred cloud implementation costs, net:
At December 31, 2024
$321 $92 $111 $13 $12 $35 
At December 31, 2023
325 85 99 13 15 43 
Once a hosted software is placed into service, the related deferred costs are amortized on a straight-line basis over the remaining expected hosting arrangement term, including any renewal options that are reasonably certain of exercise. The amortization is reflected with the associated cloud hosting fees, which are generally reflected in other operations and maintenance expenses on
the Registrants' statements of income. Amortization of deferred cloud implementation costs recognized in 2024, 2023, and 2022 was immaterial for Mississippi Power, Southern Power, and Southern Company Gas and was as follows for the other Registrants:
Southern Company
Alabama Power
Georgia Power
(in millions)
2024$56 $17 $22 
202346 11 19 
202229 8 12 
See Note 2 under "Regulatory Assets and Liabilities" for information on deferrals of certain other operations and maintenance costs associated with software and cloud computing projects by the traditional electric operating companies and natural gas distribution utilities, as authorized by their respective state PSCs or applicable state regulatory agencies.
Depreciation and Amortization
The traditional electric operating companies' and Southern Company Gas' depreciation of the original cost of utility plant in service is provided primarily by using composite straight-line rates. The approximate rates for 2024, 2023, and 2022 were as follows:
202420232022
Alabama Power4.2 %4.1 %2.7 %
Georgia Power3.4 %3.8 %3.3 %
Mississippi Power3.3 %3.4 %3.4 %
Southern Company Gas2.9 %2.7 %2.7 %
Depreciation studies are conducted periodically to update the composite rates. These studies are filed with the respective state PSC and/or other applicable state and federal regulatory agencies for the traditional electric operating companies and the natural gas distribution utilities. Effective January 1, 2023, Alabama Power's and Georgia Power's depreciation rates were revised. On October 25, 2024, Mississippi Power filed an updated depreciation study with the Mississippi PSC requesting an $11 million increase in total annual depreciation. On February 13, 2025, Mississippi Power entered into a stipulation with the MPUS to include certain modifications to the interim net salvage rates and increases to certain service lives. The stipulation requests an $8 million increase in total annual depreciation. The ultimate outcome of this matter cannot be determined at this time. See Note 2 for additional information.
When property, plant, and equipment subject to composite depreciation is retired or otherwise disposed of in the normal course of business, its original cost, together with the cost of removal, less salvage, is charged to accumulated depreciation. For other property dispositions, the applicable cost and accumulated depreciation are removed from the balance sheet accounts, and a gain or loss is recognized. Minor items of property included in the original cost of the asset are retired when the related property unit is retired.
At December 31, 2024 and 2023, accumulated depreciation for Southern Company and Southern Company Gas consisted of utility plant in service totaling $38.9 billion and $36.6 billion, respectively, for Southern Company and $5.6 billion and $5.3 billion, respectively, for Southern Company Gas, as well as other plant in service totaling $1.2 billion and $1.1 billion, respectively, for Southern Company and $252 million and $210 million, respectively, for Southern Company Gas. Other plant in service includes the non-utility assets of Southern Company Gas, as well as, for Southern Company, certain other non-utility subsidiaries. Depreciation of the original cost of other plant in service is provided primarily on a straight-line basis over estimated useful lives. Useful lives for Southern Company Gas's non-utility assets range from five to 10 years for transportation equipment, five to 40 years for storage facilities, and up to 78 years for other assets. Useful lives for the assets of Southern Company's other non-utility subsidiaries range up to 40 years.
Southern Power
Southern Power applies component depreciation, where depreciation is computed principally by the straight-line method over the estimated useful life of the asset. Certain of Southern Power's generation assets related to natural gas-fired facilities are depreciated on a units-of-production basis, using hours or starts, to better match outage and maintenance costs to the usage of, and
revenues from, these assets. The primary assets in Southern Power's property, plant, and equipment are generating facilities, which generally have estimated useful lives as follows:
Southern Power Generating FacilityUseful life
Natural gas
Up to 50 years
Solar
Up to 35 years
Wind
Up to 35 years
When Southern Power's depreciable property, plant, and equipment is retired, or otherwise disposed of in the normal course of business, the applicable cost and accumulated depreciation is removed and a gain or loss is recognized in the statements of income. Southern Power reviews its estimated useful lives and salvage values on an ongoing basis. The results of these reviews could result in changes which could have a material impact on Southern Power's net income.
Joint Ownership Agreements
At December 31, 2024, the Registrants' percentage ownership and investment (exclusive of nuclear fuel) in jointly-owned facilities in commercial operation were as follows:
Facility (Type)Percent
Ownership		Plant in ServiceAccumulated
Depreciation		CWIP
(in millions)
Alabama Power
Plant Greene County (natural gas) Units 1 and 2
60.0 %
(a)
$192 $140 $1 
Plant Miller (coal) Units 1 and 291.8 
(b)
2,180 829 7 
Georgia Power
Plant Hatch (nuclear) Units 1 and 2
50.1 %
(c)
$1,464 $604 $66 
Plant Vogtle (nuclear) Units 1 and 245.7 
(c)
3,621 2,342 162 
Plant Vogtle (nuclear) Units 3 and 4
45.7 
(c)
7,953 119 45 
Plant Scherer (coal) Units 1 and 28.4 
(c)
289 140 4 
Plant Scherer (coal) Unit 375.0 
(c)
1,316 720 22 
Rocky Mountain (pumped storage)25.4 
(d)
182 160 6 
Mississippi Power
Plant Greene County (natural gas) Units 1 and 2
40.0 %
(a)
$125 $88 $2 
Plant Daniel (coal) Units 1 and 250.0 
(e)
791 286 3 
Southern Company Gas
Dalton Pipeline (natural gas pipeline)50.0 %
(f)
$271 $32 $1 
(a)Jointly owned by Alabama Power and Mississippi Power and operated and maintained by Alabama Power.
(b)Jointly owned with PowerSouth and operated and maintained by Alabama Power.
(c)Georgia Power owns undivided interests in Plants Hatch, Vogtle, and Scherer in varying amounts jointly with one or more of the following entities: OPC, MEAG Power, Dalton, FP&L, and Jacksonville Electric Authority. Georgia Power has been contracted to operate and maintain the plants as agent for the co-owners and is jointly and severally liable for third-party claims related to these plants.
(d)Jointly owned with OPC, which is the operator of the plant.
(e)Jointly owned with FP&L. In accordance with the operating agreement, Mississippi Power acts as FP&L's agent with respect to the operation and maintenance of these units. See Note 2 under "Mississippi Power – Plant Daniel" for information on Mississippi Power's agreement with FP&L to acquire FP&L's 50% ownership interest in Plant Daniel Units 1 and 2.
(f)Jointly owned with The Williams Companies, Inc., the Dalton Pipeline is a 115-mile natural gas pipeline that serves as an extension of the Transcontinental Gas Pipe Line Company, LLC pipeline system into northwest Georgia. Southern Company Gas leases its 50% undivided ownership for approximately $26 million annually through 2042. The lessee is responsible for maintaining the pipeline during the lease term and for providing service to transportation customers under its FERC-regulated tariff.
The Registrants' proportionate share of their jointly-owned facility operating expenses is included in the corresponding operating expenses in the statements of income and each Registrant is responsible for providing its own financing.
Assets Subject to Lien
Mississippi Power provides retail service to its largest retail customer, Chevron Products Company (Chevron), at its refinery in Pascagoula, Mississippi through at least 2038 in accordance with agreements approved by the Mississippi PSC. The agreements grant Chevron a security interest in the co-generation assets located at the refinery and owned by Mississippi Power, with a lease receivable balance of $139 million at December 31, 2024, that is exercisable upon the occurrence of (i) certain bankruptcy events or (ii) other events of default coupled with specific reductions in steam output at the facility and a downgrade of Mississippi Power's credit rating to below investment grade by two of the three rating agencies. See Note 9 under "Lessor" for additional information.
See Note 8 under "Long-term Debt" for information regarding debt secured by certain assets of Georgia Power and Southern Company Gas.
v3.25.0.1
ASSET RETIREMENT OBLIGATIONS
 12 Months Ended
Dec. 31, 2024
Asset Retirement Obligation Disclosure [Abstract]  
ASSET RETIREMENT OBLIGATIONS ASSET RETIREMENT OBLIGATIONS
AROs are computed as the present value of the estimated costs for an asset's future retirement and are recorded in the period in which the liability is incurred. The estimated costs are capitalized as part of the related long-lived asset and depreciated over the asset's useful life. In the absence of quoted market prices, AROs are estimated using present value techniques in which estimates of future cash outlays associated with the asset retirements are discounted using a credit-adjusted risk-free rate. Estimates of the timing and amounts of future cash outlays are based on projections of when and how the assets will be retired and the cost of future removal activities. Each traditional electric operating company and natural gas distribution utility has received accounting guidance from its state PSC or applicable state regulatory agency allowing the continued accrual or recovery of other retirement costs for long-lived assets that it does not have a legal obligation to retire. Accordingly, the accumulated removal costs for these obligations are reflected in the balance sheets as regulatory liabilities and amounts to be recovered are reflected in the balance sheets as regulatory assets.
The ARO liabilities for the traditional electric operating companies primarily relate to facilities that are subject to the CCR Rule and the related state rules, principally surface impoundments. In addition, Alabama Power and Georgia Power have retirement obligations related to the decommissioning of nuclear facilities (Alabama Power's Plant Farley and Georgia Power's ownership interests in Plant Hatch and Plant Vogtle). See "Nuclear Decommissioning" herein for additional information. Other significant AROs include various landfill sites and asbestos removal for Alabama Power, Georgia Power, and Mississippi Power and gypsum cells and mine reclamation for Mississippi Power. The ARO liability for Southern Power primarily relates to its solar and wind facilities, which are located on long-term land leases requiring the restoration of land at the end of the lease.
The traditional electric operating companies and Southern Company Gas also have identified other retirement obligations, such as obligations related to certain electric transmission and distribution facilities, certain asbestos-containing material within long-term assets not subject to ongoing repair and maintenance activities, certain wireless communication towers, the disposal of polychlorinated biphenyls in certain transformers, leasehold improvements, equipment on customer property, and property associated with the Southern Company system's rail lines and natural gas pipelines. However, liabilities for the removal of these assets have not been recorded because the settlement timing for certain retirement obligations related to these assets is indeterminable and, therefore, the fair value of the retirement obligations cannot be reasonably estimated. A liability for these retirement obligations will be recognized when sufficient information becomes available to support a reasonable estimation of the ARO.
Southern Company and the traditional electric operating companies will continue to recognize in their respective statements of income allowed removal costs in accordance with regulatory treatment. Any differences between costs recognized in accordance with accounting standards related to asset retirement and environmental obligations and those reflected in rates are recognized as either a regulatory asset or liability in the balance sheets as ordered by the various state PSCs.
Details of the AROs included in the balance sheets are as follows:
Southern CompanyAlabama PowerGeorgia PowerMississippi Power
Southern Power(*)
(in millions)
Balance at December 31, 2022$10,840 $4,287 $6,034 $179 $144 
Liabilities incurred90 — 90 — — 
Liabilities settled(617)(270)(304)(18)— 
Accretion expense
403 156 230 5 6 
Cash flow revisions(399)(15)(385)2 — 
Balance at December 31, 2023$10,317 $4,158 $5,665 $168 $150 
Liabilities incurred130 8 120 — 2 
Liabilities settled(566)(254)(270)(17)— 
Accretion expense
400 153 232 5 7 
Cash flow revisions(347)(7)(332)(8)— 
Balance at December 31, 2024$9,934 $4,058 $5,415 $148 $159 
(*)Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets.
In June 2023, Alabama Power completed an updated decommissioning cost site study for Plant Farley. The estimated cost of decommissioning based on the study resulted in a decrease in Alabama Power's ARO liability of approximately $15 million. See "Nuclear Decommissioning" herein for additional information.
Following initial criticality for Plant Vogtle Unit 3 and 4 on March 6, 2023 and February 14, 2024, respectively, Georgia Power recorded AROs of approximately $90 million and $118 million, respectively. See "Nuclear Decommissioning" herein and Note 2 under "Georgia Power – Nuclear Construction" for additional information.
In September 2023 and November 2023, Georgia Power recorded net decreases of approximately $175 million and $210 million, respectively, to its AROs related to the CCR Rule and the related state rule resulting from changes in estimates, including lower future inflation rates and the timing of closure activities.
In September 2024, Georgia Power completed updated decommissioning cost site studies for Plants Hatch and Vogtle Units 1 through 4. The estimated cost of decommissioning based on the studies resulted in a decrease in Georgia Power's ARO liability of $389 million. See "Nuclear Decommissioning" herein for additional information.
In November 2024, Georgia Power recorded a net increase of approximately $60 million to its AROs related to the CCR Rule and the related state rule resulting from changes in estimates, including higher future inflation rates and the timing of closure activities.
The cost estimates for AROs related to the disposal of CCR are based on information at December 31, 2024 using various assumptions related to closure and post-closure costs, timing of future cash outlays, inflation and discount rates, and the potential methods for complying with the CCR Rule and the related state rules. The traditional electric operating companies have periodically updated, and expect to continue periodically updating, their related cost estimates and ARO liabilities for each CCR unit as additional information related to these assumptions becomes available. Some of these updates have been, and future updates may be, material. The cost estimates for Alabama Power are based on closure-in-place for all surface impoundments. The cost estimates for Georgia Power and Mississippi Power are based on a combination of closure-in-place for some surface impoundments and closure by removal for others. Additionally, the closure designs and plans in the States of Alabama and Georgia are subject to approval by environmental regulatory agencies. Absent continued recovery of ARO costs through regulated rates, results of operations, cash flows, and financial condition for Southern Company and the traditional electric operating companies could be materially impacted. The ultimate outcome of these matters cannot be determined at this time. See Note 3 under "General Litigation Matters – Alabama Power" for additional information.
Nuclear Decommissioning
The NRC requires licensees of commercial nuclear power reactors to establish a plan for providing reasonable assurance of funds for future decommissioning. Alabama Power and Georgia Power have external trust funds (Funds) to comply with the NRC's regulations. Use of the Funds is restricted to nuclear decommissioning activities. The Funds are managed and invested in accordance with applicable requirements of various regulatory bodies, including the NRC, the FERC, and state PSCs, as well as the IRS. While Alabama Power and Georgia Power are allowed to prescribe an overall investment policy to the Funds' managers,
neither Southern Company nor its subsidiaries or affiliates are allowed to engage in the day-to-day management of the Funds or to mandate individual investment decisions. Day-to-day management of the investments in the Funds is delegated to unrelated third-party managers with oversight by the management of Alabama Power and Georgia Power. The Funds' managers are authorized, within certain investment guidelines, to actively buy and sell securities at their own discretion in order to maximize the return on the Funds' investments. The Funds are invested in a tax-efficient manner in a diversified mix of equity and fixed income securities and are reported as trading securities.
Alabama Power and Georgia Power record the investment securities held in the Funds at fair value, as disclosed in Note 13, as management believes that fair value best represents the nature of the Funds. Gains and losses, whether realized or unrealized, are recorded in the regulatory liability for AROs in the balance sheets and are not included in net income or OCI. Fair value adjustments and realized gains and losses are determined on a specific identification basis.
Investment securities in the Funds at December 31, 2024 and 2023 were as follows:
Southern CompanyAlabama
Power		Georgia
Power
(in millions)
At December 31, 2024:
Equity securities$1,413 $848 $565 
Debt securities976 335 641 
Other securities232 202 30 
Total investment securities in the Funds$2,621 $1,385 $1,236 
At December 31, 2023:
Equity securities$1,288 $796 $492 
Debt securities895 277 618 
Other securities239 186 53 
Total investment securities in the Funds
$2,422 $1,259 $1,163 
These amounts exclude receivables related to investment income and pending investment sales and payables related to pending investment purchases.
The fair value increases (decreases) of the Funds, including unrealized gains (losses) and reinvested interest and dividends and excluding the Funds' expenses, for 2024, 2023, and 2022 are shown in the table below.
Southern CompanyAlabama
Power		Georgia
Power
(in millions)
Fair value increases (decreases)
2024$229 $143 $86 
2023281 157 124 
2022(360)(171)(189)
Unrealized gains (losses)
At December 31, 2024$113 $64 $49 
At December 31, 2023241 119 122 
At December 31, 2022(391)(204)(187)
The investment securities held in the Funds continue to be managed with a long-term focus. Accordingly, all purchases and sales within the Funds are presented separately in the statements of cash flows as investing cash flows, consistent with the nature of the securities and purpose for which the securities were acquired.
For Alabama Power, approximately $12 million and $13 million at December 31, 2024 and 2023, respectively, previously recorded in internal reserves is being transferred into the Funds through 2040 as approved by the Alabama PSC.
The NRC's minimum external funding requirements are based on a generic estimate of the cost to decommission only the radioactive portions of a nuclear unit based on the size and type of reactor. Alabama Power and Georgia Power have filed plans
with the NRC designed to ensure that, over time, the deposits and earnings of the Funds will provide the minimum funding amounts prescribed by the NRC.
At December 31, 2024 and 2023, the accumulated provisions for the external decommissioning trust funds were as follows:
20242023
(in millions)
Alabama Power
Plant Farley$1,385 $1,259 
Georgia Power
Plant Hatch$735 $705 
Plant Vogtle Units 1 and 2460 434 
Plant Vogtle Units 3 and 441 24 
Total$1,236 $1,163 
Site study cost is the estimate to decommission a specific facility as of the site study year. The decommissioning cost estimates are based on removal of the plant from service and prompt dismantlement. The actual decommissioning costs may vary from these estimates because of changes in the assumed date of decommissioning, changes in NRC requirements, or changes in the assumptions used in making these estimates. The estimated costs of decommissioning at December 31, 2024 based on the most current studies were as follows:
Alabama Power
Georgia Power
Plant
Farley
Plant
 Hatch(*)
Plant Vogtle
 Units 1 and 2(*)
Plant Vogtle
 Unit 3 and 4(*)
Most current study year
2023202420242024
Decommissioning periods:
Beginning year2037203420472062
Completion year2087208820922074
(in millions)
Site study costs:
Radiated structures$1,402 $795 $674 $599 
Spent fuel management513 306 255 88 
Non-radiated structures133 77 107 89 
Total site study costs$2,048 $1,178 $1,036 $776 
(*)Based on Georgia Power's ownership interests.
For ratemaking purposes, Alabama Power's decommissioning costs are based on the site study and Georgia Power's decommissioning costs are based on the NRC generic estimate to decommission the radioactive portion of the facilities and the site study estimate for spent fuel management. Significant assumptions used to determine these costs for ratemaking were an estimated inflation rate of 4.5% for Plant Farley, 2.5% for Plants Hatch and Vogtle Units 1 and 2, and 2.3% for Plant Vogtle Units 3 and 4 and an estimated trust earnings rate of 7.0% for Plant Farley, 4.5% for Plants Hatch and Vogtle Units 1 and 2, and 4.3% for Plant Vogtle Units 3 and 4.
Amounts previously contributed to the Funds for Plant Farley are currently projected to be adequate to meet the decommissioning obligations. Alabama Power's site-specific estimates of decommissioning costs for Plant Farley are updated every five years. The next site study for Alabama Power is expected to be completed in 2028. Projections of funds are reviewed with the Alabama PSC to ensure that, over time, the deposits and earnings of the Funds will provide adequate funding to cover the site-specific costs. If necessary, Alabama Power would seek the Alabama PSC's approval to address any changes in a manner consistent with NRC and other applicable requirements.
Under the 2019 ARP, Georgia Power's annual decommissioning cost for ratemaking in 2022 was a total of $4 million for Plant Hatch and Plant Vogtle Units 1 and 2. Effective January 1, 2023, as approved in the 2022 ARP, there is no annual decommissioning cost for ratemaking for Plant Hatch and Plant Vogtle Units 1 and 2. Any funding amount required by the NRC during the period covered by the 2022 ARP will be deferred to a regulatory asset and recovery is expected to be determined in Georgia Power's next base rate case. See Note 2 under "Georgia Power – Rate Plans – 2022 ARP" for additional information.
Effective August 1, 2023, as approved under the Plant Vogtle Unit 3 and Common Facilities rate proceeding, Georgia Power's annual decommissioning cost for ratemaking is $8 million for Plant Vogtle Unit 3. Effective May 1, 2024, as approved under the Prudency Stipulation, Georgia Power's annual decommissioning cost for ratemaking is $8 million for Plant Vogtle Unit 4. See Note 2 under "Georgia Power – Nuclear Construction – Regulatory Matters" for additional information.
v3.25.0.1
CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS
 12 Months Ended
Dec. 31, 2024
Equity Method Investments and Joint Ventures [Abstract]  
CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS
The Registrants may hold ownership interests in a number of business ventures with varying ownership structures. Partnership interests and other variable interests are evaluated to determine if each entity is a VIE. If a venture is a VIE for which a Registrant is the primary beneficiary, the assets, liabilities, and results of operations of the entity are consolidated. The Registrants reassess the conclusion as to whether an entity is a VIE upon certain occurrences, which are deemed reconsideration events.
For entities that are not determined to be VIEs, the Registrants evaluate whether they have control or significant influence over the investee to determine the appropriate consolidation and presentation. Generally, entities under the control of a Registrant are consolidated, and entities over which a Registrant can exert significant influence, but which a Registrant does not control, are accounted for under the equity method of accounting.
Investments accounted for under the equity method are recorded within equity investments in unconsolidated subsidiaries in the balance sheets and, for Southern Company and Southern Company Gas, the equity income is recorded within earnings from equity method investments in the statements of income. See "SEGCO" and "Southern Company Gas" herein for additional information.
Southern Company
At December 31, 2024 and 2023, Southern Holdings had equity method investments totaling $128 million and $126 million, respectively, primarily related to investments in venture capital funds focused on energy and utility investments. Earnings/losses from these investments were immaterial for all periods presented.
SEGCO
Alabama Power and Georgia Power own equally all of the outstanding capital stock of SEGCO, which owns electric generating units at Plant Gaston with a total rated capacity of 1,020 MWs, as well as associated transmission facilities. Retirement of SEGCO's generating units is currently expected to occur by December 31, 2028. However, Alabama Power, in conjunction with Georgia Power, is evaluating extending the operation of Plant Gaston Units 1 through 4 beyond the indicated retirement date. See Note 2 under "Georgia Power – Integrated Resource Plans – 2025 IRP" for additional information. Alabama Power and Georgia Power account for SEGCO using the equity method; Southern Company consolidates SEGCO. The capacity of these units is sold equally to Alabama Power and Georgia Power. Alabama Power and Georgia Power make payments sufficient to provide for the operating expenses, taxes, interest expense, and an ROE. The share of purchased power included in purchased power, affiliates in the statements of income totaled $115 million in 2024, $112 million in 2023, and $124 million in 2022 for Alabama Power and $118 million in 2024, $115 million in 2023, and $127 million in 2022 for Georgia Power.
SEGCO paid dividends of $20 million in 2024, $25 million in 2023, and $14 million in 2022, one half of which were paid to each of Alabama Power and Georgia Power. In addition, Alabama Power and Georgia Power each recognize 50% of SEGCO's net income.
Alabama Power, which owns and operates a generating unit adjacent to the SEGCO generating units, has a joint ownership agreement with SEGCO for the ownership of an associated gas pipeline. Alabama Power owns 14% of the pipeline with the remaining 86% owned by SEGCO.
See Note 3 under "Guarantees" for additional information regarding guarantees of Alabama Power and Georgia Power related to SEGCO.
Southern Power
Variable Interest Entities
Southern Power has certain subsidiaries that are determined to be VIEs. Southern Power is considered the primary beneficiary of these VIEs because it controls the most significant activities of the VIEs, including operating and maintaining the respective assets, and has the obligation to absorb expected losses of these VIEs to the extent of its equity interests.
SP Solar and SP Wind
SP Solar is owned by Southern Power and a limited partner. A wholly-owned subsidiary of Southern Power is the general partner and holds a 1% ownership interest, and another wholly-owned subsidiary of Southern Power owns a 66% ownership interest. The
limited partner holds the remaining 33% noncontrolling interest. SP Solar qualifies as a VIE since the arrangement is structured as a limited partnership and the 33% limited partner does not have substantive kick-out rights against the general partner.
At December 31, 2024 and 2023, SP Solar had total assets of $5.4 billion and $5.6 billion, respectively, total liabilities of $372 million and $399 million, respectively, and noncontrolling interests of $1.0 billion. Cash distributions from SP Solar are allocated 67% to Southern Power and 33% to the limited partner in accordance with their partnership interest percentage. Under the terms of the limited partnership agreement, distributions without limited partner consent are limited to available cash and SP Solar is obligated to distribute all such available cash to its partners each quarter. Available cash includes all cash generated in the quarter subject to the maintenance of appropriate operating reserves.
SP Wind is owned by Southern Power and three financial investors. A wholly-owned subsidiary of Southern Power owns 100% of the Class B membership interests and the three financial investors own 100% of the Class A membership interests. SP Wind qualifies as a VIE since the structure of the arrangement is similar to a limited partnership and the Class A members do not have substantive kick-out rights against Southern Power.
At December 31, 2024 and 2023, SP Wind had total assets of $2.0 billion and $2.1 billion, respectively, total liabilities of $177 million and $187 million, respectively, and noncontrolling interests of $35 million and $38 million, respectively. Under the terms of the limited liability agreement, distributions without Class A member consent are limited to available cash and SP Wind is obligated to distribute all such available cash to its members each quarter. Available cash includes all cash generated in the quarter subject to the maintenance of appropriate operating reserves. Cash distributions from SP Wind are generally allocated 60% to Southern Power and 40% to the three financial investors in accordance with the limited liability agreement.
Southern Power consolidates both SP Solar and SP Wind, as the primary beneficiary, since it controls the most significant activities of each entity, including operating and maintaining their assets. Certain transfers and sales of the assets in the VIEs are subject to partner consent and the liabilities are non-recourse to the general credit of Southern Power. Liabilities consist of customary working capital items and do not include any long-term debt.
Other Variable Interest Entities
Southern Power has other consolidated VIEs that relate to certain subsidiaries that have either sold noncontrolling interests to tax equity investors or acquired less than a 100% interest from facility developers. These entities are considered VIEs because the arrangements are structured similar to a limited partnership and the noncontrolling members do not have substantive kick-out rights.
At December 31, 2024 and 2023, the other VIEs had total assets of $1.6 billion and $1.7 billion, respectively, total liabilities of $224 million and $230 million, respectively, and noncontrolling interests of $691 million and 761 million, respectively. Under the terms of the partnership agreements, distributions of all available cash are required each month or quarter and additional distributions require partner consent.
Equity Method Investments
During 2023 and 2022, Southern Power sold its remaining equity method investments in wind projects and received proceeds totaling $50 million and $38 million, respectively. Earnings (loss) from these investments, including the gains associated with the sales, were immaterial for 2023 and 2022.
Southern Company Gas
The carrying amounts of Southern Company Gas' equity method investments at December 31, 2024 and 2023 were as follows:
Investment BalanceDecember 31, 2024
December 31, 2023
(in millions)
SNG$1,245 $1,202 
Other
34 33 
Total$1,279 $1,235 
The earnings from Southern Company Gas' equity method investment related to SNG were $146 million in 2024, $139 million in 2023, and $146 million in 2022. The earnings from Southern Company Gas' other equity method investments were immaterial for all periods presented.
v3.25.0.1
FINANCING
 12 Months Ended
Dec. 31, 2024
Debt Disclosure [Abstract]  
FINANCING FINANCING
Long-term Debt
Details of long-term debt at December 31, 2024 and 2023 are provided in the following table:
At December 31, 2024
Balance Outstanding at
December 31,
MaturityWeighted Average
Interest Rate		20242023
(in millions)
Southern Company
Senior notes(a)
2025-20744.33%$44,862 $40,235 
Junior subordinated notes2027-20814.32%7,389 8,333 
FFB loans(b)
2025-20442.88%4,703 4,788 
Revenue bonds(c)
2025-20633.15%3,379 3,400 
First mortgage bonds(d)
2025-20643.79%2,775 2,500 
Medium-term notes2026-20277.03%84 84 
Other long-term debt2025-20454.96%209 234 
Finance lease obligations(e)
287 298 
Unamortized fair value adjustment275 302 
Unamortized debt premium (discount), net(58)(198)
Unamortized debt issuance expenses(419)(290)
Total long-term debt63,486 59,686 
Less: Amount due within one year4,718 2,476 
Total long-term debt excluding amount due within one year$58,768 $57,210 
Alabama Power
Senior notes2025-20733.94%$9,875 $9,875 
Revenue bonds(c)
2025-20633.11%1,300 1,321 
Other long-term debt2026-20306.11%61 75 
Finance lease obligations(e)
4 5 
Unamortized debt premium (discount), net(19)(20)
Unamortized debt issuance expenses(67)(73)
Total long-term debt11,154 11,183 
Less: Amount due within one year655 223 
Total long-term debt excluding amount due within one year$10,499 $10,960 
Georgia Power
Senior notes2025-20744.49%$11,292 $9,575 
Junior subordinated notes20775.00%270 270 
FFB loans(b)
2025-20442.88%4,703 4,788 
Revenue bonds(c)
2025-20623.18%1,968 1,968 
Finance lease obligations(e)
261 240 
Unamortized debt premium (discount), net(21)(19)
Unamortized debt issuance expenses(123)(122)
Total long-term debt18,350 16,700 
Less: Amount due within one year966 502 
Total long-term debt excluding amount due within one year$17,384 $16,198 
At December 31, 2024
Balance Outstanding at
December 31,
MaturityWeighted Average
Interest Rate		20242023
(in millions)
Mississippi Power
Senior notes2026-20544.33%$1,575 $1,525 
Revenue bonds(c)
2025-20523.16%111 111 
Finance lease obligations(e)
14 16 
Unamortized debt premium (discount), net2 1 
Unamortized debt issuance expenses(9)(9)
Total long-term debt1,693 1,644 
Less: Amount due within one year12 201 
Total long-term debt excluding amount due within one year$1,681 $1,443 
Southern Power
Senior notes(a)
2025-20464.05%$2,695 $2,728 
Unamortized debt premium (discount), net(4)(4)
Unamortized debt issuance expenses(11)(13)
Total long-term debt2,680 2,711 
Less: Amount due within one year500 — 
Total long-term debt excluding amount due within one year$2,180 $2,711 
Southern Company Gas
Senior notes2025-20514.41%$5,375 $4,930 
First mortgage bonds(d)
2025-20643.79%2,775 2,500 
Medium-term notes2026-20277.03%84 84 
Other long-term debt2025-20453.81%68 59 
Unamortized fair value adjustment275 302 
Unamortized debt premium (discount), net(9)(8)
Unamortized debt issuance expenses(37)(34)
Total long-term debt8,531 7,833 
Less: Amount due within one year302 — 
Total long-term debt excluding amount due within one year$8,229 $7,833 
(a)Includes a fair value gain (loss) of $(45) million and $(12) million at December 31, 2024 and 2023, respectively, related to Southern Power's foreign currency hedge on its euro-denominated senior notes.
(b)Secured by a first priority lien on (i) Georgia Power's undivided ownership interest in Plant Vogtle Units 3 and 4 (primarily the units, the related real property, and any nuclear fuel loaded in the reactor core) and (ii) Georgia Power's rights and obligations under the principal contracts relating to Plant Vogtle Units 3 and 4. See "DOE Loan Guarantee Borrowings" herein for additional information.
(c)Revenue bond obligations represent loans to the traditional electric operating companies from public authorities of funds derived from sales by such authorities of revenue bonds issued to finance pollution control and solid waste disposal and wastewater facilities. In some cases, the revenue bond obligations represent obligations under installment sales agreements with respect to facilities constructed with the proceeds of revenue bonds issued by public authorities. The traditional electric operating companies are required to make payments sufficient for the authorities to meet principal and interest requirements of such bonds. Proceeds from certain issuances are restricted until qualifying expenditures are incurred.
(d)Secured by substantially all of Nicor Gas' properties.
(e)Secured by the underlying lease ROU asset. See Note 9 for additional information.
Maturities of long-term debt for the next five years are as follows:
Southern Company(a)
Alabama Power(b)
Georgia
Power(c)
Mississippi Power
Southern Power(d)
Southern Company
Gas
(in millions)
2025$4,727 $658 $967 $12 $500 $300 
20263,792 47 451 66 964 530 
20274,075 551 1,015 10 — 154 
20282,827 107 868 357 — 150 
20291,990 — 861 1 — 150 
(a)See notes (b), (c), and (d) below.
(b)Alabama Power's 2025 maturities include $200 million aggregate principal amount of Series 2023A Floating Rate Senior Notes due May 15, 2073 that are repayable at the option of the holders at certain dates that began in 2024. As a result, the senior notes are classified as securities due within one year on the balance sheets of Southern Company and Alabama Power at December 31, 2024.
(c)Amounts include principal amortization related to the FFB borrowings; however, the final maturity date is February 20, 2044. See "DOE Loan Guarantee Borrowings" herein for additional information. Georgia Power's 2025 maturities include approximately $117 million aggregate principal amount of Series 2024C Floating Rate Senior Notes due November 15, 2074 that are repayable at the option of the holders at certain dates beginning in 2025. As a result, the senior notes are classified as securities due within one year on the balance sheets of Southern Company and Georgia Power at December 31, 2024.
(d)Southern Power's 2026 maturities include $564 million of euro-denominated debt at the U.S. dollar-denominated hedge settlement amount.
DOE Loan Guarantee Borrowings
Pursuant to the loan guarantee program established under Title XVII of the Energy Policy Act of 2005 (Title XVII Loan Guarantee Program), Georgia Power and the DOE entered into a loan guarantee agreement in 2014 and the Amended and Restated Loan Guarantee Agreement in 2019. Under the Amended and Restated Loan Guarantee Agreement, the DOE agreed to guarantee the obligations of Georgia Power under the FFB Credit Facilities. Under the FFB Credit Facilities, Georgia Power was authorized to make term loan borrowings through the FFB in an amount up to approximately $5.130 billion.
In 2021, Georgia Power made the final borrowings under the FFB Credit Facilities and no further borrowings are permitted. During 2024, Georgia Power made principal amortization payments of $86 million under the FFB Credit Facilities. At December 31, 2024 and 2023, Georgia Power had $4.7 billion and $4.8 billion of borrowings outstanding under the FFB Credit Facilities, respectively.
All borrowings under the FFB Credit Facilities are full recourse to Georgia Power, and Georgia Power is obligated to reimburse the DOE for any payments the DOE is required to make to the FFB under its guarantee. Georgia Power's reimbursement obligations to the DOE are secured by a first priority lien on (i) Georgia Power's undivided ownership interest in Plant Vogtle Units 3 and 4 (primarily the units, the related real property, and any nuclear fuel loaded in the reactor core) and (ii) Georgia Power's rights and obligations under the principal contracts relating to Plant Vogtle Units 3 and 4. There are no restrictions on Georgia Power's ability to grant liens on other property.
The final maturity date for each advance under the FFB Credit Facilities is February 20, 2044. Interest is payable quarterly and principal payments began in 2020. Each borrowing under the FFB Credit Facilities bears interest at a fixed rate equal to the applicable U.S. Treasury rate at the time of the borrowing plus a spread equal to 0.375%.
Under the Amended and Restated Loan Guarantee Agreement, Georgia Power is subject to customary borrower affirmative and negative covenants and events of default. In addition, Georgia Power is subject to project-related reporting requirements and other project-specific covenants and events of default.
In the event certain mandatory prepayment events occur, Georgia Power will be required to prepay the outstanding principal amount of all borrowings under the FFB Credit Facilities over a period of five years (with level principal amortization). Among other things, these mandatory prepayment events include (i) loss of necessary governmental approvals for operation of Plant Vogtle Units 3 and 4; (ii) loss of regulation by the Georgia PSC; (iii) cost disallowances by the Georgia PSC that could have a material adverse effect on Georgia Power's ability to repay the outstanding borrowings under the FFB Credit Facilities; (iv) certain material casualty losses or a governmental taking of Plant Vogtle Units 3 and 4; or (v) loss of access to the intellectual property rights necessary to operate Plant Vogtle Units 3 and 4. Under certain circumstances, insurance proceeds and any proceeds from an event of taking must be applied to immediately prepay outstanding borrowings under the FFB Credit Facilities. Georgia Power also may voluntarily prepay outstanding borrowings under the FFB Credit Facilities. Under the FFB Credit Facilities, any prepayment (whether mandatory or optional) will be made with a make-whole premium or discount, as applicable.
See Note 2 under "Georgia Power – Nuclear Construction" for additional information.
Secured Debt
Each of Southern Company's subsidiaries is organized as a legal entity, separate and apart from Southern Company and its other subsidiaries. There are no agreements or other arrangements among the Southern Company system companies under which the assets of one company have been pledged or otherwise made available to satisfy obligations of Southern Company or any of its other subsidiaries.
As discussed under "Long-term Debt" herein, the Registrants had secured debt outstanding at December 31, 2024 and 2023. Each Registrant's senior notes, junior subordinated notes, revenue bond obligations, bank term loans, credit facility borrowings, and notes payable are effectively subordinated to all secured debt of each respective Registrant.
Equity Units
In May 2022, Southern Company remarketed $862.5 million aggregate principal amount of its Series 2019A Remarketable Junior Subordinated Notes due August 1, 2024 (2019A RSNs) and $862.5 million aggregate principal amount of its Series 2019B Remarketable Junior Subordinated Notes due August 1, 2027 (2019B RSNs), pursuant to the terms of its 2019 Series A Equity Units (Equity Units). In connection with the remarketing, the interest rates on the 2019A RSNs and the 2019B RSNs were reset to 4.475% and 5.113%, respectively, payable on a semi-annual basis. In August 2022, the proceeds were ultimately used to settle the purchase contracts entered into as part of the Equity Units and Southern Company issued approximately 25.2 million shares of common stock and received proceeds of $1.725 billion. In August 2024, Southern Company repaid at maturity the $862.5 million 2019A RSNs. At December 31, 2023, the 2019A RSNs were included on Southern Company's consolidated balance sheet in securities due within one year. At December 31, 2024 and 2023, the 2019B RSNs were included on Southern Company's consolidated balance sheets in long-term debt.
Convertible Senior Notes
In May 2024, Southern Company issued $1.5 billion aggregate principal amount of Series 2024A 4.50% Convertible Senior Notes due June 15, 2027 (Series 2024A Convertible Senior Notes).
In February 2023, Southern Company issued $1.5 billion aggregate principal amount of Series 2023A 3.875% Convertible Senior Notes due December 15, 2025 (Series 2023A Convertible Senior Notes). In March 2023, Southern Company issued an additional $225 million aggregate principal amount of the Series 2023A Convertible Senior Notes upon the exercise by the initial purchasers of their over-allotment option.
Interest on the Series 2024A Convertible Senior Notes and the Series 2023A Convertible Senior Notes is payable semiannually. The Series 2024A Convertible Senior Notes and the Series 2023A Convertible Senior Notes will mature on June 15, 2027 and December 15, 2025, respectively, unless earlier converted or repurchased, but are not redeemable at the option of Southern Company. Both the Series 2024A Convertible Senior Notes and the Series 2023A Convertible Senior Notes are direct, unsecured, and unsubordinated obligations of Southern Company, ranking equally with all of Southern Company's other unsecured and unsubordinated indebtedness from time to time outstanding, and are effectively subordinated to all secured indebtedness of Southern Company.
Under the following circumstances, holders may convert their Series 2024A Convertible Senior Notes and their Series 2023A Convertible Senior Notes at their option prior to the close of business on the business day preceding March 15, 2027 and September 15, 2025, respectively:
•during any calendar quarter (and only during such calendar quarter), if the last reported sale price of Southern Company's common stock for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the applicable conversion price of the Series 2024A Convertible Senior Notes or the Series 2023A Convertible Senior Notes, as the case may be, on each applicable trading day as determined by Southern Company;
•during the five business day period after any 10 consecutive trading day period (Measurement Period) in which the applicable trading price per $1,000 principal amount of Series 2024A Convertible Senior Notes or Series 2023A Convertible Senior Notes, as the case may be, for each trading day of the Measurement Period was less than 98% of the product of the last reported sale price of the common stock and the applicable conversion rate on each such trading day; or
•upon the occurrence of certain corporate events specified in the respective supplemental indentures governing the Series 2024A Convertible Senior Notes and the Series 2023A Convertible Senior Notes.
On or after March 15, 2027, for the Series 2024A Convertible Senior Notes, and September 15, 2025, for the Series 2023A Convertible Senior Notes, a holder may convert all or any portion of its Series 2024A Convertible Senior Notes or its Series 2023A Convertible Senior Notes, as the case may be. at any time prior to the close of business on the second scheduled trading day immediately preceding the applicable maturity date regardless of the foregoing conditions.
Southern Company will settle conversions of the Series 2024A Convertible Senior Notes and the Series 2023A Convertible Senior Notes by paying cash up to the aggregate principal amount of the Series 2024A Convertible Senior Notes and the Series 2023A Convertible Senior Notes to be converted and paying or delivering, as the case may be, cash, shares of common stock, or a combination of cash and shares of common stock, at Southern Company's election, in respect of the remainder, if any, of Southern Company's conversion obligation in excess of the aggregate principal amount of the Series 2024A Convertible Senior Notes and the Series 2023A Convertible Senior Notes being converted. The Series 2024A Convertible Senior Notes are initially convertible at a rate of 10.8166 shares of common stock per $1,000 principal amount converted, which is approximately equal to $92.45 per share of common stock. The Series 2023A Convertible Senior Notes are initially convertible at a rate of 11.8818 shares of common stock per $1,000 principal amount converted, which is approximately equal to $84.16 per share of common stock. These conversion rates will be subject to adjustment upon the occurrence of certain specified events but will not be adjusted for accrued and unpaid interest. In addition, upon the occurrence of a make-whole fundamental change (as defined in the respective supplemental indentures governing the Series 2024A Convertible Senior Notes and the Series 2023A Convertible Senior Notes), Southern Company will, in certain circumstances, increase the applicable conversion rate by a number of additional shares of common stock for conversions in connection with the make-whole fundamental change.
Upon the occurrence of a fundamental change (as defined in the respective supplemental indentures governing the Series 2024A Convertible Senior Notes and the Series 2023A Convertible Senior Notes), holders of the Series 2024A Convertible Senior Notes and the Series 2023A Convertible Senior Notes may require Southern Company to purchase all or a portion of their Series 2024A Convertible Senior Notes and their Series 2023A Convertible Senior Notes, in principal amounts equal to $1,000 or an integral multiple thereof, for cash at a price equal to 100% of the principal amount of the Series 2024A Convertible Senior Notes and the Series 2023A Convertible Senior Notes to be purchased plus any accrued and unpaid interest.
Equity Distribution Agreement
In May 2024, Southern Company established an at-the-market program by entering into an equity distribution agreement pursuant to which it may sell, from time to time, up to an aggregate of 50 million shares of its common stock, including through forward sale contracts. In November 2024, Southern Company entered into separate forward sale contracts with forward purchasers for the sale of:
•1,000,000 shares of common stock with an initial forward price of $86.5645 per share and
•1,000,000 shares of common stock with an initial forward price of $87.9658 per share.
In addition, in December 2024, Southern Company entered into a forward sale contract with a forward purchaser for the sale of 436,614 shares of its common stock, 143,920 of which had been sold by the forward seller as of December 31, 2024, with the remaining 292,694 shares sold subsequent to December 31, 2024, all with an initial forward price of $83.3293 per share.
Each initial forward price is subject to adjustment under certain specified circumstances as specified in the forward sale contracts. Southern Company may settle each of the forward transactions in shares, cash, or net shares on or before December 31, 2025. As of December 31, 2024, no shares had been settled under these forward confirmations.
Bank Credit Arrangements
At December 31, 2024, committed credit arrangements with banks were as follows:
Expires
Company2025202620272029TotalUnused
Expires within
One Year
(in millions)
Southern Company parent(a)
$150 $— $— $1,850 $2,000 $1,998 $150 
Alabama Power(b)
— 665 — 700 1,365 1,364 — 
Georgia Power300 — — 1,750 2,050 2,026 300 
Mississippi Power— — 275 — 275 275 — 
Southern Power(a)(c)
— — — 600 600 600 — 
Southern Company Gas(d)
100 — — 1,500 1,600 1,598 100 
SEGCO30 — — — 30 30 30 
Southern Company$580 $665 $275 $6,400 $7,920 $7,891 $580 
(a)Arrangement expiring in 2029 represents a $2.45 billion combined arrangement for Southern Company and Southern Power allowing for flexible sublimits.
(b)Includes $15 million expiring in 2026 at Alabama Property Company, a wholly-owned subsidiary of Alabama Power, of which $14 million was unused at December 31, 2024. Alabama Power is not party to this arrangement.
(c)Does not include Southern Power Company's $75 million and $100 million continuing letter of credit facilities for standby letters of credit, expiring in 2027 and 2026, respectively, of which $16 million and $11 million, respectively, was unused at December 31, 2024. Southern Power's subsidiaries are not parties to its bank credit arrangements or letter of credit facilities.
(d)Southern Company Gas, as the parent entity, guarantees the obligations of Southern Company Gas Capital, which is the borrower of $800 million of the credit arrangement expiring in 2029. Southern Company Gas' committed credit arrangement expiring in 2029 also includes $700 million for which Nicor Gas is the borrower and which is restricted for working capital needs of Nicor Gas. Pursuant to the multi-year credit arrangement expiring in 2029, the allocations between Southern Company Gas Capital and Nicor Gas may be adjusted. Nicor Gas is also the borrower under a $100 million credit arrangement expiring in 2025. See "Structural Considerations" herein for additional information.
The bank credit arrangements require payment of commitment fees based on the unused portion of the commitments. Commitment fees average less than 1/4 of 1% for the Registrants and Nicor Gas. Subject to applicable market conditions, Southern Company and its subsidiaries expect to renew or replace their bank credit arrangements as needed, prior to expiration. In connection therewith, Southern Company and its subsidiaries may extend the maturity dates and/or increase or decrease the lending commitments thereunder.
These bank credit arrangements, as well as the term loan arrangements of the Registrants, Nicor Gas, and SEGCO, contain covenants that limit debt levels and contain cross-acceleration provisions to other indebtedness (including guarantee obligations) that are restricted only to the indebtedness of the individual company. The cross-acceleration provisions to other indebtedness would trigger an event of default if the applicable borrower defaulted on indebtedness, the payment of which was then accelerated. Southern Company's, Mississippi Power's, Southern Company Gas', and Nicor Gas' credit arrangements contain covenants that limit debt levels to 70% of total capitalization, as defined in the agreements, and the other subsidiaries' bank credit arrangements contain covenants that limit debt levels to 65% of total capitalization, as defined in the agreements. For purposes of these definitions, debt excludes junior subordinated notes and, in certain arrangements, other hybrid securities. Additionally, for Southern Company and Southern Power, for purposes of these definitions, debt excludes any project debt incurred by certain subsidiaries of Southern Power to the extent such debt is non-recourse to Southern Power and capitalization excludes the capital stock or other equity attributable to such subsidiaries. At December 31, 2024, the Registrants, Nicor Gas, and SEGCO were in compliance with all such covenants. None of the bank credit arrangements contain material adverse change clauses at the time of borrowings.
A portion of the unused credit with banks is allocated to provide liquidity support to certain revenue bonds of the traditional electric operating companies and the commercial paper programs of the Registrants, Nicor Gas, and SEGCO. At December 31, 2024, outstanding variable rate demand revenue bonds of the traditional electric operating companies with allocated liquidity support totaled approximately $1.7 billion (comprised of approximately $796 million at Alabama Power, $819 million at Georgia Power, and $69 million at Mississippi Power). In addition, at December 31, 2024, Alabama Power and Georgia Power had approximately $207 million and $157 million, respectively, of fixed rate revenue bonds outstanding that are required to be remarketed within the next 12 months. Alabama Power's $207 million of fixed rate revenue bonds are classified as securities due within one year on its balance sheets as they are not covered by long-term committed credit. All other variable rate demand
revenue bonds and fixed rate revenue bonds required to be remarketed within the next 12 months are classified as long-term debt on the balance sheets as a result of available long-term committed credit.
At both December 31, 2024 and 2023, Southern Power had $106 million of cash collateral posted related to PPA requirements, which is included in other deferred charges and assets on Southern Power's consolidated balance sheets.
Notes Payable
The Registrants, Nicor Gas, and SEGCO make short-term borrowings primarily through commercial paper programs that have the liquidity support of the committed bank credit arrangements described above under "Bank Credit Arrangements." Southern Power's subsidiaries are not parties or obligors to its commercial paper program. Southern Company Gas maintains commercial paper programs at Southern Company Gas Capital and at Nicor Gas. Nicor Gas' commercial paper program supports working capital needs at Nicor Gas as Nicor Gas is not permitted to make money pool loans to affiliates. All of Southern Company Gas' other subsidiaries benefit from Southern Company Gas Capital's commercial paper program. See "Structural Considerations" herein for additional information.
In addition, Southern Company and certain of its subsidiaries have entered into various bank term loan agreements. Unless otherwise stated, the proceeds of these loans were used to repay existing indebtedness and for general corporate purposes, including working capital and, for the subsidiaries, their continuous construction programs.
Commercial paper and short-term bank term loans are included in notes payable in the balance sheets. Details of short-term borrowings for the applicable Registrants were as follows:
Notes Payable at December 31, 2024
Notes Payable at December 31, 2023
Amount
Outstanding		Weighted Average
Interest Rate		Amount
Outstanding		Weighted Average
Interest Rate
(in millions)(in millions)
Southern Company
Commercial paper$1,138 4.7 %$1,794 5.6 %
Short-term bank debt200 5.3 520 6.4 
Total$1,338 4.8 %$2,314 5.7 %
Alabama Power
Commercial paper
$— — %$40 5.5 %
Georgia Power
Commercial paper$— — %$809 5.6 %
Short-term bank debt200 5.3 520 6.4 
Total$200 5.3 %$1,329 5.9 %
Mississippi Power
Commercial paper$14 4.6 %$— — %
Southern Power
Commercial paper$— — %$138 5.5 %
Southern Company Gas
Commercial paper:
Southern Company Gas Capital$283 4.7 %$23 5.5 %
Nicor Gas172 4.6 392 5.5 
Total$455 4.7 %$415 5.5 %
See "Bank Credit Arrangements" herein for information on bank term loan covenants that limit debt levels and cross-acceleration or cross-default provisions.
Outstanding Classes of Capital Stock
Southern Company
Common Stock
Stock Issued
During 2024, Southern Company issued approximately 5.8 million shares of common stock primarily through equity compensation plans.
Shares Reserved
At December 31, 2024, a total of 177 million shares were reserved for issuance pursuant to the Southern Investment Plan, employee savings plans, the Equity and Incentive Compensation Plan (which includes performance share units and restricted stock units as discussed in Note 12), an at-the-market program, and the Series 2024A Convertible Senior Notes and Series 2023A Convertible Senior Notes (as discussed under "Convertible Senior Notes" herein). Of the shares reserved, 25 million shares are available for awards under the Equity and Incentive Compensation Plan at December 31, 2024.
Diluted Earnings Per Share
For Southern Company, the only difference in computing basic and diluted earnings per share (EPS) is attributable to awards outstanding under stock-based compensation plans, the Series 2024A Convertible Senior Notes, the Series 2023A Convertible Senior Notes, and forward sale contracts pursuant to the equity distribution agreement. EPS dilution resulting from stock-based compensation plans and the forward sale contracts is determined using the treasury stock method, and EPS dilution resulting from the Series 2024A Convertible Senior Notes and the Series 2023A Convertible Senior Notes is determined using the net share settlement method. See Note 12 and "Convertible Senior Notes" and "Equity Distribution Agreement" herein for additional information. Shares used to compute diluted EPS were as follows:
 Average Common Stock Shares
 202420232022
 (in millions)
As reported shares1,096 1,092 1,075 
Effect of stock-based compensation6 6 6 
Diluted shares1,102 1,098 1,081 
For all periods presented, an immaterial number of stock-based compensation awards was excluded from the diluted EPS calculation because the awards were anti-dilutive.
For 2024, there was no dilution resulting from the Series 2024A Convertible Senior Notes and the forward sale contracts, and the dilution resulting from the Series 2023A Convertible Senior Notes was immaterial.
Preferred Stock of Subsidiaries
As discussed further under "Alabama Power" herein, during 2022, Alabama Power redeemed all of its preferred stock and Class A preferred stock.
Alabama Power
Alabama Power has preferred stock, Class A preferred stock, preference stock, and common stock authorized, but only common stock outstanding at December 31, 2024.
During 2022, Alabama Power redeemed all of its preferred stock and Class A preferred stock at the redemption prices per share provided in the table below, plus accrued and unpaid dividends to the redemption date.
Preferred Stock Redeemed During 2022Par Value/Stated Capital Per ShareSharesRedemption
Price Per Share
4.92% Preferred Stock
$10080,000 $103.23
4.72% Preferred Stock
$10050,000 $102.18
4.64% Preferred Stock
$10060,000 $103.14
4.60% Preferred Stock
$100100,000 $104.20
4.52% Preferred Stock
$10050,000 $102.93
4.20% Preferred Stock
$100135,115 $105.00
5.00% Class A Preferred Stock
$2510,000,000 
$25.00
Georgia Power
Georgia Power has preferred stock, Class A preferred stock, preference stock, and common stock authorized, but only common stock outstanding.
Mississippi Power
Mississippi Power has preferred stock and common stock authorized, but only common stock outstanding
Dividend Restrictions
The income of Southern Company is derived primarily from equity in earnings of its subsidiaries. At December 31, 2024, consolidated retained earnings included $6.5 billion of undistributed retained earnings of the subsidiaries.
The traditional electric operating companies and Southern Power can only pay dividends to Southern Company out of retained earnings or paid-in-capital.
See Note 7 under "Southern Power" for information regarding the distribution requirements for certain Southern Power subsidiaries.
By regulation, Nicor Gas is restricted, up to its retained earnings balance, in the amount it can dividend or loan to affiliates and is not permitted to make money pool loans to affiliates. At December 31, 2024, the amount of Southern Company Gas' subsidiary retained earnings available for dividend payment totaled $1.6 billion.
Structural Considerations
Since Southern Company and Southern Company Gas are holding companies, the right of Southern Company and Southern Company Gas and, hence, the right of creditors of Southern Company or Southern Company Gas to participate in any distribution of the assets of any respective subsidiary of Southern Company or Southern Company Gas, whether upon liquidation, reorganization or otherwise, is subject to prior claims of creditors and preferred stockholders of such subsidiary.
Southern Company Gas Capital was established to provide for certain of Southern Company Gas' ongoing financing needs through a commercial paper program, the issuance of various debt, hybrid securities, and other financing arrangements. Southern Company Gas fully and unconditionally guarantees all debt issued by Southern Company Gas Capital. Nicor Gas is not permitted by regulation to make loans to affiliates or utilize Southern Company Gas Capital for its financing needs.
Southern Power Company's senior notes, bank term loan, commercial paper, and bank credit arrangement are unsecured senior indebtedness, which rank equally with all other unsecured and unsubordinated debt of Southern Power Company. Southern Power's subsidiaries are not issuers, borrowers, or obligors, as applicable, under any of these unsecured senior debt arrangements, which are effectively subordinated to any future secured debt of Southern Power Company and any potential claims of creditors of Southern Power's subsidiaries.
v3.25.0.1
LEASES
 12 Months Ended
Dec. 31, 2024
Leases [Abstract]  
LEASES LEASES
Lessee
The Registrants recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with ROU assets that will be amortized over the term of each lease.
As lessee, the Registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
At December 31, 2024
Electric generating units(*)
$672 $56 $1,509 $— $— $— 
Real estate/land834 3 45 2 540 20 
Communication towers118 2 4 — — 21 
Railcars64 31 29 4 — — 
Other52 2 2 16 — — 
Total$1,740 $94 $1,589 $22 $540 $41 
At December 31, 2023
Electric generating units(*)
$670 $58 $1,028 $— $— $— 
Real estate/land871 4 54 2 546 28 
Communication towers123 1 4 — — 23 
Railcars64 32 27 5 — — 
Other60 3 2 18 — — 
Total$1,788 $98 $1,115 $25 $546 $51 
(*)Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information.
Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 20 years while the land leases have remaining terms of up to 44 years, including renewal periods.
Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies and Nicor Gas. Communication tower leases have remaining terms of up to 16 years.
Renewal options exist in many of the leases. The expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease unless it is considered reasonably certain that the lease will be extended. Land leases associated with renewable energy facilities at Southern Power and communication tower leases for automated meter infrastructure at Nicor Gas include renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities and the automated meter infrastructure, respectively.
Contracts that Contain a Lease
While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the PPA, which varies between three and 15 years. Georgia Power has several PPAs with Southern Power that Georgia Power accounts for as leases with a lease obligation of $893 million and $416 million at December 31, 2024 and 2023, respectively. The amount paid for energy under these affiliate PPAs reflects a price that would be paid in an arm's-length transaction as reviewed and approved by both the Georgia PSC and the FERC. Amounts related to the affiliate PPAs are eliminated in consolidation for Southern Company.
Short-term Leases
Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Registrants generally recognize lease expense for these leases on a straight-line basis over the lease term.
Residual Value Guarantees
Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power, with Georgia Power's railcar leases terminating in June 2024. The amounts probable of being paid under those guarantees are included in the lease payments. All such amounts were immaterial at December 31, 2024 and 2023.
Lease and Nonlease Components
For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the Registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the ROU asset.
Balance sheet amounts recorded for operating and finance leases are as follows:
Southern CompanyAlabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
At December 31, 2024
Operating Leases
Operating lease ROU assets, net$1,386 $84 $1,331 $8 $484 $38 
Operating lease obligations - current$200 $14 $169 $4 $29 $11 
Operating lease obligations - non-current1,253 76 1,159 4 511 30 
Total operating lease obligations(*)
$1,453 $90 $1,328 $8 $540 $41 
Finance Leases
Finance lease ROU assets, net$254 $4 $227 $14 $— $— 
Finance lease obligations - current$9 $1 $20 $1 $— $— 
Finance lease obligations - non-current278 3 241 13 — — 
Total finance lease obligations $287 $4 $261 $14 $— $— 
At December 31, 2023
Operating Leases
Operating lease ROU assets, net$1,432 $87 $884 $9 $488 $47 
Operating lease obligations - current$183 $12 $135 $3 $29 $11 
Operating lease obligations - non-current1,307 81 740 6 517 40 
Total operating lease obligations(*)
$1,490 $93 $875 $9 $546 $51 
Finance Leases
Finance lease ROU assets, net$272 $5 $203 $15 $— $— 
Finance lease obligations - current$11 $2 $18 $1 $— $— 
Finance lease obligations - non-current287 3 222 15 — — 
Total finance lease obligations$298 $5 $240 $16 $— $— 
(*)Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $567 million, $55 million, and $1.3 billion, respectively, at December 31, 2024 and $566 million, $58 million, and $813 million, respectively, at December 31, 2023.
If not presented separately on the Registrants' balance sheets, amounts related to leases are presented as follows: operating lease ROU assets, net are included in "other deferred charges and assets"; operating lease obligations are included in "other current liabilities" and "other deferred credits and liabilities," as applicable; finance lease ROU assets, net are included in "plant in service"; and finance lease obligations are included in "securities due within one year" and "long-term debt," as applicable.
Lease costs for 2024, 2023, and 2022, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Lease cost
Operating lease cost(*)
$248 $19 $190 $4 $27 $12 
Finance lease cost:
Amortization of ROU assets20 2 23 1 — — 
Interest on lease obligations15 — 15 1 — — 
Total finance lease cost35 2 38 2 — — 
Short-term lease costs 37 15 15 — — — 
Variable lease cost48 (1)77 — 4 — 
Total lease cost $368 $35 $320 $6 $31 $12 
2023
Lease cost
Operating lease cost(*)
$252 $16 $192 $5 $34 $12 
Finance lease cost:
Amortization of ROU assets24 2 19 1 — — 
Interest on lease obligations14 — 17 — — — 
Total finance lease cost38 2 36 1 — — 
Short-term lease costs40 16 16 — — — 
Variable lease cost47 — 74 — 4 — 
Total lease cost$377 $34 $318 $6 $38 $12 
2022
Lease cost
Operating lease cost(*)
$297 $59 $198 $5 $32 $15 
Finance lease cost:
Amortization of ROU assets23 1 15 1 — — 
Interest on lease obligations13 — 17 1 — — 
Total finance lease cost36 1 32 2 — — 
Short-term lease costs64 44 13 — — — 
Variable lease cost125 13 105 — 5 — 
Sublease income(1)— — — — — 
Total lease cost$521 $117 $348 $7 $37 $15 
(*)Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $108 million, $5 million, and $168 million, respectively, in 2024, $112 million, $4 million, and $174 million, respectively, in 2023, and $162 million, $48 million, and $180 million, respectively, in 2022.
Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs, including $45 million, $42 million, and $45 million in 2024, 2023, and 2022, respectively, from finance leases which are included in purchased power on Georgia Power's statements of income, of which $22 million, $21 million, and $21 million was included in purchased power, affiliates in 2024, 2023, and 2022, respectively.
Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$243 $19 $186 $4 $33 $12 
Operating cash flows from finance leases15 — 21 — — — 
Financing cash flows from finance leases11 2 23 1 — — 
ROU assets obtained under operating leases146 11 609 — 10 1 
Reassessment of ROU assets under operating leases(7)— — — (7)— 
ROU assets obtained under finance leases1 — 44 — — — 
2023
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$253 $17 $199 $5 $33 $12 
Operating cash flows from finance leases15 — 22 — — — 
Financing cash flows from finance leases18 2 16 1 — — 
ROU assets obtained under operating leases100 30 26 1 7 7 
ROU assets obtained under finance leases3 3 18 — — — 
2022
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$303 $58 $206 $5 $30 $14 
Operating cash flows from finance leases11 — 20 1 — — 
Financing cash flows from finance leases16 1 10 1 — — 
ROU assets obtained under operating leases56 10 17 9 — 3 
Reassessment of ROU assets under operating leases16 — — — 16 — 
ROU assets obtained under finance leases118 2 116 — — — 
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
At December 31, 2024
Weighted-average remaining lease term in years:
Operating leases16.410.27.94.332.36.8
Finance leases16.02.710.110.9N/AN/A
Weighted-average discount rate:
Operating leases 4.73 %5.04 %4.73 %3.83 %4.88 %3.84 %
Finance leases4.86 %4.05 %5.8 %2.74 %N/AN/A
At December 31, 2023
Weighted-average remaining lease term in years:
Operating leases17.211.17.54.633.17.0
Finance leases16.74.310.611.9N/AN/A
Weighted-average discount rate:
Operating leases4.68 %5.02 %4.58 %3.67 %4.89 %3.80 %
Finance leases4.85 %3.93 %5.95 %2.74 %N/AN/A
Maturities of lease liabilities are as follows:
At December 31, 2024
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
Maturity Analysis
Operating leases:
2025$239 $18 $228 $4 $31 $12 
2026212 15 224 3 29 9 
2027190 12 223 1 29 4 
2028170 9 217 — 29 3 
2029138 7 196 — 30 4 
Thereafter1,255 56 511 1 978 15 
Total2,204 117 1,599 9 1,126 47 
Less: Present value discount 751 27 271 1 586 6 
Operating lease obligations $1,453 $90 $1,328 $8 $540 $41 
Finance leases:
2025$28 $2 $39 $2 $— $— 
202627 1 41 2 — — 
202726 1 41 1 — — 
202825 — 42 1 — — 
202925 — 42 1 — — 
Thereafter290 — 139 9 — — 
Total421 4 344 16 — — 
Less: Present value discount134 — 83 2 — — 
Finance lease obligations$287 $4 $261 $14 $— $— 
Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis.
At December 31, 2024, Georgia Power has two affiliate PPAs with Southern Power that have not yet commenced and will be accounted for as leases. The PPAs each have a term of 10 years and are expected to commence in 2025 and 2028. The estimated total obligations associated with these PPAs is $83 million. Southern Company Gas has executed an 11.5-year building lease agreement that will commence during the first half of 2025. The lease has a total obligation of approximately $105 million.
Lessor
The Registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable Registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to 10 years, after which the contracts renew on a month-to-month basis at the customer's option. For Georgia Power, these arrangements also include PPAs related to electric generating units accounted for as operating leases with remaining terms of up to 15 years. For Mississippi Power, these arrangements also include a tolling arrangement related to an electric generating unit accounted for as a sales-type lease with a remaining term of 14 years. For Southern Power, these arrangements consist of PPAs related to electric generating units accounted for as operating leases with remaining terms of up to 22 years and PPAs related to battery energy storage facilities accounted for as sales-type leases with remaining terms of up to 17 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 18 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with remaining terms of up to 9 years.
Lease income for 2024, 2023, and 2022, is as follows:
Southern
Company		Alabama PowerGeorgia PowerMississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Lease income - interest income on sales-type leases$24 $— $— $15 $9 $— 
Lease income - operating leases136 9 28 3 88 36 
Variable lease income417 1 — — 450 — 
Total lease income$577 $10 $28 $18 $547 $36 
2023
Lease income - interest income on sales-type leases$24 $— $— $14 $10 $— 
Lease income - operating leases164 35 29 2 85 37 
Variable lease income406 1 — — 437 — 
Total lease income$594 $36 $29 $16 $532 $37 
2022
Lease income - interest income on sales-type leases$25 $— $— $15 $10 $— 
Lease income - operating leases208 77 32 2 85 36 
Variable lease income417 1 — — 448 — 
Total lease income$650 $78 $32 $17 $543 $36 
Lease payments received under tolling arrangements and PPAs consist of either scheduled payments or variable payments based on the amount of energy produced by the underlying electric generating units. Lease income related to PPAs is included in wholesale revenues for Alabama Power, Georgia Power, and Southern Power. Scheduled payments to be received under outdoor lighting contracts' initial terms, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses.
The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows:
At December 31, 2024
Southern CompanyMississippi PowerSouthern
Power
 (in millions)
2025$52 $24 $15 
202638 23 15 
202737 22 15 
202836 21 15 
202935 20 15 
Thereafter302 132 170 
Total undiscounted cash flows$500 $242 $245 
Net investment in sales-type lease(*)
297 139 158 
Difference between undiscounted cash flows and discounted cash flows$203 $103 $87 
(*)For Mississippi Power, included in other current assets ($10 million and $10 million at December 31, 2024 and 2023, respectively) and other property and investments ($129 million and $138 million at December 31, 2024 and 2023, respectively) on the balance sheets. For Southern Power, included in other current assets ($15 million and $15 million at December 31, 2024 and 2023, respectively) and net investment in sales-type leases ($143 million and $148 million at December 31, 2024 and 2023, respectively) on the balance sheets.
The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows:
At December 31, 2024
Southern
Company		Alabama
Power		Southern
Power		Southern Company Gas
 (in millions)
2025$117 $6 $142 $35 
2026111 5 148 29 
2027109 4 150 28 
2028109 4 161 28 
2029112 3 164 28 
Thereafter621 31 506 326 
Total$1,179 $53 $1,271 $474 
Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Alabama Power and Southern Power allocate revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under contracts accounted for as operating leases at Georgia Power and Mississippi Power are immaterial.
Southern Company Leveraged Lease
At December 31, 2024, a subsidiary of Southern Holdings had one leveraged lease agreement, which relates to energy generation, with an expected remaining term of seven years. Southern Company receives federal income tax deductions for depreciation and amortization, as well as interest on long-term debt, related to this investment. Southern Company wrote off the related investment balance in 2020 following an evaluation of the recoverability of the lease receivable and the expected residual value of the generation assets at the end of the lease.
In June 2022, the Southern Holdings subsidiary operating the generating plant for the lessee provided notice to the lessee to terminate the related operating and maintenance agreement effective June 30, 2023. Subsequently, the lessee failed to make the semi-annual lease payment due in December 2022. As a result, the Southern Holdings subsidiary was unable to make its corresponding payment to the holders of the underlying non-recourse debt related to the generation assets. The parties to the lease entered into forbearance agreements which suspended the related contractual rights of the parties while they continued restructuring negotiations, during which the termination date for the operating and maintenance agreement was delayed until July 31, 2023. The negotiations were completed in July 2023, resulting in the Southern Holdings subsidiary agreeing to continue operating the plant for the lessee until the lessee's associated power off-take agreement ends in 2032, subject to certain terms and
conditions. The restructuring had no material impact on Southern Company's financial statements. Southern Company will continue to monitor the operational performance of the underlying assets and evaluate the ability of the lessee to continue to meet its obligations, including those associated with a future closure or retirement of the generation assets and associated properties, including the dry ash landfill.
LEASES LEASES
Lessee
The Registrants recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with ROU assets that will be amortized over the term of each lease.
As lessee, the Registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
At December 31, 2024
Electric generating units(*)
$672 $56 $1,509 $— $— $— 
Real estate/land834 3 45 2 540 20 
Communication towers118 2 4 — — 21 
Railcars64 31 29 4 — — 
Other52 2 2 16 — — 
Total$1,740 $94 $1,589 $22 $540 $41 
At December 31, 2023
Electric generating units(*)
$670 $58 $1,028 $— $— $— 
Real estate/land871 4 54 2 546 28 
Communication towers123 1 4 — — 23 
Railcars64 32 27 5 — — 
Other60 3 2 18 — — 
Total$1,788 $98 $1,115 $25 $546 $51 
(*)Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information.
Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 20 years while the land leases have remaining terms of up to 44 years, including renewal periods.
Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies and Nicor Gas. Communication tower leases have remaining terms of up to 16 years.
Renewal options exist in many of the leases. The expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease unless it is considered reasonably certain that the lease will be extended. Land leases associated with renewable energy facilities at Southern Power and communication tower leases for automated meter infrastructure at Nicor Gas include renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities and the automated meter infrastructure, respectively.
Contracts that Contain a Lease
While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the PPA, which varies between three and 15 years. Georgia Power has several PPAs with Southern Power that Georgia Power accounts for as leases with a lease obligation of $893 million and $416 million at December 31, 2024 and 2023, respectively. The amount paid for energy under these affiliate PPAs reflects a price that would be paid in an arm's-length transaction as reviewed and approved by both the Georgia PSC and the FERC. Amounts related to the affiliate PPAs are eliminated in consolidation for Southern Company.
Short-term Leases
Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Registrants generally recognize lease expense for these leases on a straight-line basis over the lease term.
Residual Value Guarantees
Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power, with Georgia Power's railcar leases terminating in June 2024. The amounts probable of being paid under those guarantees are included in the lease payments. All such amounts were immaterial at December 31, 2024 and 2023.
Lease and Nonlease Components
For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the Registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the ROU asset.
Balance sheet amounts recorded for operating and finance leases are as follows:
Southern CompanyAlabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
At December 31, 2024
Operating Leases
Operating lease ROU assets, net$1,386 $84 $1,331 $8 $484 $38 
Operating lease obligations - current$200 $14 $169 $4 $29 $11 
Operating lease obligations - non-current1,253 76 1,159 4 511 30 
Total operating lease obligations(*)
$1,453 $90 $1,328 $8 $540 $41 
Finance Leases
Finance lease ROU assets, net$254 $4 $227 $14 $— $— 
Finance lease obligations - current$9 $1 $20 $1 $— $— 
Finance lease obligations - non-current278 3 241 13 — — 
Total finance lease obligations $287 $4 $261 $14 $— $— 
At December 31, 2023
Operating Leases
Operating lease ROU assets, net$1,432 $87 $884 $9 $488 $47 
Operating lease obligations - current$183 $12 $135 $3 $29 $11 
Operating lease obligations - non-current1,307 81 740 6 517 40 
Total operating lease obligations(*)
$1,490 $93 $875 $9 $546 $51 
Finance Leases
Finance lease ROU assets, net$272 $5 $203 $15 $— $— 
Finance lease obligations - current$11 $2 $18 $1 $— $— 
Finance lease obligations - non-current287 3 222 15 — — 
Total finance lease obligations$298 $5 $240 $16 $— $— 
(*)Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $567 million, $55 million, and $1.3 billion, respectively, at December 31, 2024 and $566 million, $58 million, and $813 million, respectively, at December 31, 2023.
If not presented separately on the Registrants' balance sheets, amounts related to leases are presented as follows: operating lease ROU assets, net are included in "other deferred charges and assets"; operating lease obligations are included in "other current liabilities" and "other deferred credits and liabilities," as applicable; finance lease ROU assets, net are included in "plant in service"; and finance lease obligations are included in "securities due within one year" and "long-term debt," as applicable.
Lease costs for 2024, 2023, and 2022, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Lease cost
Operating lease cost(*)
$248 $19 $190 $4 $27 $12 
Finance lease cost:
Amortization of ROU assets20 2 23 1 — — 
Interest on lease obligations15 — 15 1 — — 
Total finance lease cost35 2 38 2 — — 
Short-term lease costs 37 15 15 — — — 
Variable lease cost48 (1)77 — 4 — 
Total lease cost $368 $35 $320 $6 $31 $12 
2023
Lease cost
Operating lease cost(*)
$252 $16 $192 $5 $34 $12 
Finance lease cost:
Amortization of ROU assets24 2 19 1 — — 
Interest on lease obligations14 — 17 — — — 
Total finance lease cost38 2 36 1 — — 
Short-term lease costs40 16 16 — — — 
Variable lease cost47 — 74 — 4 — 
Total lease cost$377 $34 $318 $6 $38 $12 
2022
Lease cost
Operating lease cost(*)
$297 $59 $198 $5 $32 $15 
Finance lease cost:
Amortization of ROU assets23 1 15 1 — — 
Interest on lease obligations13 — 17 1 — — 
Total finance lease cost36 1 32 2 — — 
Short-term lease costs64 44 13 — — — 
Variable lease cost125 13 105 — 5 — 
Sublease income(1)— — — — — 
Total lease cost$521 $117 $348 $7 $37 $15 
(*)Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $108 million, $5 million, and $168 million, respectively, in 2024, $112 million, $4 million, and $174 million, respectively, in 2023, and $162 million, $48 million, and $180 million, respectively, in 2022.
Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs, including $45 million, $42 million, and $45 million in 2024, 2023, and 2022, respectively, from finance leases which are included in purchased power on Georgia Power's statements of income, of which $22 million, $21 million, and $21 million was included in purchased power, affiliates in 2024, 2023, and 2022, respectively.
Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$243 $19 $186 $4 $33 $12 
Operating cash flows from finance leases15 — 21 — — — 
Financing cash flows from finance leases11 2 23 1 — — 
ROU assets obtained under operating leases146 11 609 — 10 1 
Reassessment of ROU assets under operating leases(7)— — — (7)— 
ROU assets obtained under finance leases1 — 44 — — — 
2023
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$253 $17 $199 $5 $33 $12 
Operating cash flows from finance leases15 — 22 — — — 
Financing cash flows from finance leases18 2 16 1 — — 
ROU assets obtained under operating leases100 30 26 1 7 7 
ROU assets obtained under finance leases3 3 18 — — — 
2022
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$303 $58 $206 $5 $30 $14 
Operating cash flows from finance leases11 — 20 1 — — 
Financing cash flows from finance leases16 1 10 1 — — 
ROU assets obtained under operating leases56 10 17 9 — 3 
Reassessment of ROU assets under operating leases16 — — — 16 — 
ROU assets obtained under finance leases118 2 116 — — — 
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
At December 31, 2024
Weighted-average remaining lease term in years:
Operating leases16.410.27.94.332.36.8
Finance leases16.02.710.110.9N/AN/A
Weighted-average discount rate:
Operating leases 4.73 %5.04 %4.73 %3.83 %4.88 %3.84 %
Finance leases4.86 %4.05 %5.8 %2.74 %N/AN/A
At December 31, 2023
Weighted-average remaining lease term in years:
Operating leases17.211.17.54.633.17.0
Finance leases16.74.310.611.9N/AN/A
Weighted-average discount rate:
Operating leases4.68 %5.02 %4.58 %3.67 %4.89 %3.80 %
Finance leases4.85 %3.93 %5.95 %2.74 %N/AN/A
Maturities of lease liabilities are as follows:
At December 31, 2024
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
Maturity Analysis
Operating leases:
2025$239 $18 $228 $4 $31 $12 
2026212 15 224 3 29 9 
2027190 12 223 1 29 4 
2028170 9 217 — 29 3 
2029138 7 196 — 30 4 
Thereafter1,255 56 511 1 978 15 
Total2,204 117 1,599 9 1,126 47 
Less: Present value discount 751 27 271 1 586 6 
Operating lease obligations $1,453 $90 $1,328 $8 $540 $41 
Finance leases:
2025$28 $2 $39 $2 $— $— 
202627 1 41 2 — — 
202726 1 41 1 — — 
202825 — 42 1 — — 
202925 — 42 1 — — 
Thereafter290 — 139 9 — — 
Total421 4 344 16 — — 
Less: Present value discount134 — 83 2 — — 
Finance lease obligations$287 $4 $261 $14 $— $— 
Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis.
At December 31, 2024, Georgia Power has two affiliate PPAs with Southern Power that have not yet commenced and will be accounted for as leases. The PPAs each have a term of 10 years and are expected to commence in 2025 and 2028. The estimated total obligations associated with these PPAs is $83 million. Southern Company Gas has executed an 11.5-year building lease agreement that will commence during the first half of 2025. The lease has a total obligation of approximately $105 million.
Lessor
The Registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable Registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to 10 years, after which the contracts renew on a month-to-month basis at the customer's option. For Georgia Power, these arrangements also include PPAs related to electric generating units accounted for as operating leases with remaining terms of up to 15 years. For Mississippi Power, these arrangements also include a tolling arrangement related to an electric generating unit accounted for as a sales-type lease with a remaining term of 14 years. For Southern Power, these arrangements consist of PPAs related to electric generating units accounted for as operating leases with remaining terms of up to 22 years and PPAs related to battery energy storage facilities accounted for as sales-type leases with remaining terms of up to 17 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 18 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with remaining terms of up to 9 years.
Lease income for 2024, 2023, and 2022, is as follows:
Southern
Company		Alabama PowerGeorgia PowerMississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Lease income - interest income on sales-type leases$24 $— $— $15 $9 $— 
Lease income - operating leases136 9 28 3 88 36 
Variable lease income417 1 — — 450 — 
Total lease income$577 $10 $28 $18 $547 $36 
2023
Lease income - interest income on sales-type leases$24 $— $— $14 $10 $— 
Lease income - operating leases164 35 29 2 85 37 
Variable lease income406 1 — — 437 — 
Total lease income$594 $36 $29 $16 $532 $37 
2022
Lease income - interest income on sales-type leases$25 $— $— $15 $10 $— 
Lease income - operating leases208 77 32 2 85 36 
Variable lease income417 1 — — 448 — 
Total lease income$650 $78 $32 $17 $543 $36 
Lease payments received under tolling arrangements and PPAs consist of either scheduled payments or variable payments based on the amount of energy produced by the underlying electric generating units. Lease income related to PPAs is included in wholesale revenues for Alabama Power, Georgia Power, and Southern Power. Scheduled payments to be received under outdoor lighting contracts' initial terms, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses.
The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows:
At December 31, 2024
Southern CompanyMississippi PowerSouthern
Power
 (in millions)
2025$52 $24 $15 
202638 23 15 
202737 22 15 
202836 21 15 
202935 20 15 
Thereafter302 132 170 
Total undiscounted cash flows$500 $242 $245 
Net investment in sales-type lease(*)
297 139 158 
Difference between undiscounted cash flows and discounted cash flows$203 $103 $87 
(*)For Mississippi Power, included in other current assets ($10 million and $10 million at December 31, 2024 and 2023, respectively) and other property and investments ($129 million and $138 million at December 31, 2024 and 2023, respectively) on the balance sheets. For Southern Power, included in other current assets ($15 million and $15 million at December 31, 2024 and 2023, respectively) and net investment in sales-type leases ($143 million and $148 million at December 31, 2024 and 2023, respectively) on the balance sheets.
The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows:
At December 31, 2024
Southern
Company		Alabama
Power		Southern
Power		Southern Company Gas
 (in millions)
2025$117 $6 $142 $35 
2026111 5 148 29 
2027109 4 150 28 
2028109 4 161 28 
2029112 3 164 28 
Thereafter621 31 506 326 
Total$1,179 $53 $1,271 $474 
Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Alabama Power and Southern Power allocate revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under contracts accounted for as operating leases at Georgia Power and Mississippi Power are immaterial.
Southern Company Leveraged Lease
At December 31, 2024, a subsidiary of Southern Holdings had one leveraged lease agreement, which relates to energy generation, with an expected remaining term of seven years. Southern Company receives federal income tax deductions for depreciation and amortization, as well as interest on long-term debt, related to this investment. Southern Company wrote off the related investment balance in 2020 following an evaluation of the recoverability of the lease receivable and the expected residual value of the generation assets at the end of the lease.
In June 2022, the Southern Holdings subsidiary operating the generating plant for the lessee provided notice to the lessee to terminate the related operating and maintenance agreement effective June 30, 2023. Subsequently, the lessee failed to make the semi-annual lease payment due in December 2022. As a result, the Southern Holdings subsidiary was unable to make its corresponding payment to the holders of the underlying non-recourse debt related to the generation assets. The parties to the lease entered into forbearance agreements which suspended the related contractual rights of the parties while they continued restructuring negotiations, during which the termination date for the operating and maintenance agreement was delayed until July 31, 2023. The negotiations were completed in July 2023, resulting in the Southern Holdings subsidiary agreeing to continue operating the plant for the lessee until the lessee's associated power off-take agreement ends in 2032, subject to certain terms and
conditions. The restructuring had no material impact on Southern Company's financial statements. Southern Company will continue to monitor the operational performance of the underlying assets and evaluate the ability of the lessee to continue to meet its obligations, including those associated with a future closure or retirement of the generation assets and associated properties, including the dry ash landfill.
LEASES LEASES
Lessee
The Registrants recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with ROU assets that will be amortized over the term of each lease.
As lessee, the Registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
At December 31, 2024
Electric generating units(*)
$672 $56 $1,509 $— $— $— 
Real estate/land834 3 45 2 540 20 
Communication towers118 2 4 — — 21 
Railcars64 31 29 4 — — 
Other52 2 2 16 — — 
Total$1,740 $94 $1,589 $22 $540 $41 
At December 31, 2023
Electric generating units(*)
$670 $58 $1,028 $— $— $— 
Real estate/land871 4 54 2 546 28 
Communication towers123 1 4 — — 23 
Railcars64 32 27 5 — — 
Other60 3 2 18 — — 
Total$1,788 $98 $1,115 $25 $546 $51 
(*)Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information.
Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 20 years while the land leases have remaining terms of up to 44 years, including renewal periods.
Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies and Nicor Gas. Communication tower leases have remaining terms of up to 16 years.
Renewal options exist in many of the leases. The expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease unless it is considered reasonably certain that the lease will be extended. Land leases associated with renewable energy facilities at Southern Power and communication tower leases for automated meter infrastructure at Nicor Gas include renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities and the automated meter infrastructure, respectively.
Contracts that Contain a Lease
While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the PPA, which varies between three and 15 years. Georgia Power has several PPAs with Southern Power that Georgia Power accounts for as leases with a lease obligation of $893 million and $416 million at December 31, 2024 and 2023, respectively. The amount paid for energy under these affiliate PPAs reflects a price that would be paid in an arm's-length transaction as reviewed and approved by both the Georgia PSC and the FERC. Amounts related to the affiliate PPAs are eliminated in consolidation for Southern Company.
Short-term Leases
Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Registrants generally recognize lease expense for these leases on a straight-line basis over the lease term.
Residual Value Guarantees
Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power, with Georgia Power's railcar leases terminating in June 2024. The amounts probable of being paid under those guarantees are included in the lease payments. All such amounts were immaterial at December 31, 2024 and 2023.
Lease and Nonlease Components
For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the Registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the ROU asset.
Balance sheet amounts recorded for operating and finance leases are as follows:
Southern CompanyAlabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
At December 31, 2024
Operating Leases
Operating lease ROU assets, net$1,386 $84 $1,331 $8 $484 $38 
Operating lease obligations - current$200 $14 $169 $4 $29 $11 
Operating lease obligations - non-current1,253 76 1,159 4 511 30 
Total operating lease obligations(*)
$1,453 $90 $1,328 $8 $540 $41 
Finance Leases
Finance lease ROU assets, net$254 $4 $227 $14 $— $— 
Finance lease obligations - current$9 $1 $20 $1 $— $— 
Finance lease obligations - non-current278 3 241 13 — — 
Total finance lease obligations $287 $4 $261 $14 $— $— 
At December 31, 2023
Operating Leases
Operating lease ROU assets, net$1,432 $87 $884 $9 $488 $47 
Operating lease obligations - current$183 $12 $135 $3 $29 $11 
Operating lease obligations - non-current1,307 81 740 6 517 40 
Total operating lease obligations(*)
$1,490 $93 $875 $9 $546 $51 
Finance Leases
Finance lease ROU assets, net$272 $5 $203 $15 $— $— 
Finance lease obligations - current$11 $2 $18 $1 $— $— 
Finance lease obligations - non-current287 3 222 15 — — 
Total finance lease obligations$298 $5 $240 $16 $— $— 
(*)Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $567 million, $55 million, and $1.3 billion, respectively, at December 31, 2024 and $566 million, $58 million, and $813 million, respectively, at December 31, 2023.
If not presented separately on the Registrants' balance sheets, amounts related to leases are presented as follows: operating lease ROU assets, net are included in "other deferred charges and assets"; operating lease obligations are included in "other current liabilities" and "other deferred credits and liabilities," as applicable; finance lease ROU assets, net are included in "plant in service"; and finance lease obligations are included in "securities due within one year" and "long-term debt," as applicable.
Lease costs for 2024, 2023, and 2022, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Lease cost
Operating lease cost(*)
$248 $19 $190 $4 $27 $12 
Finance lease cost:
Amortization of ROU assets20 2 23 1 — — 
Interest on lease obligations15 — 15 1 — — 
Total finance lease cost35 2 38 2 — — 
Short-term lease costs 37 15 15 — — — 
Variable lease cost48 (1)77 — 4 — 
Total lease cost $368 $35 $320 $6 $31 $12 
2023
Lease cost
Operating lease cost(*)
$252 $16 $192 $5 $34 $12 
Finance lease cost:
Amortization of ROU assets24 2 19 1 — — 
Interest on lease obligations14 — 17 — — — 
Total finance lease cost38 2 36 1 — — 
Short-term lease costs40 16 16 — — — 
Variable lease cost47 — 74 — 4 — 
Total lease cost$377 $34 $318 $6 $38 $12 
2022
Lease cost
Operating lease cost(*)
$297 $59 $198 $5 $32 $15 
Finance lease cost:
Amortization of ROU assets23 1 15 1 — — 
Interest on lease obligations13 — 17 1 — — 
Total finance lease cost36 1 32 2 — — 
Short-term lease costs64 44 13 — — — 
Variable lease cost125 13 105 — 5 — 
Sublease income(1)— — — — — 
Total lease cost$521 $117 $348 $7 $37 $15 
(*)Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $108 million, $5 million, and $168 million, respectively, in 2024, $112 million, $4 million, and $174 million, respectively, in 2023, and $162 million, $48 million, and $180 million, respectively, in 2022.
Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs, including $45 million, $42 million, and $45 million in 2024, 2023, and 2022, respectively, from finance leases which are included in purchased power on Georgia Power's statements of income, of which $22 million, $21 million, and $21 million was included in purchased power, affiliates in 2024, 2023, and 2022, respectively.
Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$243 $19 $186 $4 $33 $12 
Operating cash flows from finance leases15 — 21 — — — 
Financing cash flows from finance leases11 2 23 1 — — 
ROU assets obtained under operating leases146 11 609 — 10 1 
Reassessment of ROU assets under operating leases(7)— — — (7)— 
ROU assets obtained under finance leases1 — 44 — — — 
2023
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$253 $17 $199 $5 $33 $12 
Operating cash flows from finance leases15 — 22 — — — 
Financing cash flows from finance leases18 2 16 1 — — 
ROU assets obtained under operating leases100 30 26 1 7 7 
ROU assets obtained under finance leases3 3 18 — — — 
2022
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$303 $58 $206 $5 $30 $14 
Operating cash flows from finance leases11 — 20 1 — — 
Financing cash flows from finance leases16 1 10 1 — — 
ROU assets obtained under operating leases56 10 17 9 — 3 
Reassessment of ROU assets under operating leases16 — — — 16 — 
ROU assets obtained under finance leases118 2 116 — — — 
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
At December 31, 2024
Weighted-average remaining lease term in years:
Operating leases16.410.27.94.332.36.8
Finance leases16.02.710.110.9N/AN/A
Weighted-average discount rate:
Operating leases 4.73 %5.04 %4.73 %3.83 %4.88 %3.84 %
Finance leases4.86 %4.05 %5.8 %2.74 %N/AN/A
At December 31, 2023
Weighted-average remaining lease term in years:
Operating leases17.211.17.54.633.17.0
Finance leases16.74.310.611.9N/AN/A
Weighted-average discount rate:
Operating leases4.68 %5.02 %4.58 %3.67 %4.89 %3.80 %
Finance leases4.85 %3.93 %5.95 %2.74 %N/AN/A
Maturities of lease liabilities are as follows:
At December 31, 2024
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
Maturity Analysis
Operating leases:
2025$239 $18 $228 $4 $31 $12 
2026212 15 224 3 29 9 
2027190 12 223 1 29 4 
2028170 9 217 — 29 3 
2029138 7 196 — 30 4 
Thereafter1,255 56 511 1 978 15 
Total2,204 117 1,599 9 1,126 47 
Less: Present value discount 751 27 271 1 586 6 
Operating lease obligations $1,453 $90 $1,328 $8 $540 $41 
Finance leases:
2025$28 $2 $39 $2 $— $— 
202627 1 41 2 — — 
202726 1 41 1 — — 
202825 — 42 1 — — 
202925 — 42 1 — — 
Thereafter290 — 139 9 — — 
Total421 4 344 16 — — 
Less: Present value discount134 — 83 2 — — 
Finance lease obligations$287 $4 $261 $14 $— $— 
Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis.
At December 31, 2024, Georgia Power has two affiliate PPAs with Southern Power that have not yet commenced and will be accounted for as leases. The PPAs each have a term of 10 years and are expected to commence in 2025 and 2028. The estimated total obligations associated with these PPAs is $83 million. Southern Company Gas has executed an 11.5-year building lease agreement that will commence during the first half of 2025. The lease has a total obligation of approximately $105 million.
Lessor
The Registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable Registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to 10 years, after which the contracts renew on a month-to-month basis at the customer's option. For Georgia Power, these arrangements also include PPAs related to electric generating units accounted for as operating leases with remaining terms of up to 15 years. For Mississippi Power, these arrangements also include a tolling arrangement related to an electric generating unit accounted for as a sales-type lease with a remaining term of 14 years. For Southern Power, these arrangements consist of PPAs related to electric generating units accounted for as operating leases with remaining terms of up to 22 years and PPAs related to battery energy storage facilities accounted for as sales-type leases with remaining terms of up to 17 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 18 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with remaining terms of up to 9 years.
Lease income for 2024, 2023, and 2022, is as follows:
Southern
Company		Alabama PowerGeorgia PowerMississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Lease income - interest income on sales-type leases$24 $— $— $15 $9 $— 
Lease income - operating leases136 9 28 3 88 36 
Variable lease income417 1 — — 450 — 
Total lease income$577 $10 $28 $18 $547 $36 
2023
Lease income - interest income on sales-type leases$24 $— $— $14 $10 $— 
Lease income - operating leases164 35 29 2 85 37 
Variable lease income406 1 — — 437 — 
Total lease income$594 $36 $29 $16 $532 $37 
2022
Lease income - interest income on sales-type leases$25 $— $— $15 $10 $— 
Lease income - operating leases208 77 32 2 85 36 
Variable lease income417 1 — — 448 — 
Total lease income$650 $78 $32 $17 $543 $36 
Lease payments received under tolling arrangements and PPAs consist of either scheduled payments or variable payments based on the amount of energy produced by the underlying electric generating units. Lease income related to PPAs is included in wholesale revenues for Alabama Power, Georgia Power, and Southern Power. Scheduled payments to be received under outdoor lighting contracts' initial terms, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses.
The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows:
At December 31, 2024
Southern CompanyMississippi PowerSouthern
Power
 (in millions)
2025$52 $24 $15 
202638 23 15 
202737 22 15 
202836 21 15 
202935 20 15 
Thereafter302 132 170 
Total undiscounted cash flows$500 $242 $245 
Net investment in sales-type lease(*)
297 139 158 
Difference between undiscounted cash flows and discounted cash flows$203 $103 $87 
(*)For Mississippi Power, included in other current assets ($10 million and $10 million at December 31, 2024 and 2023, respectively) and other property and investments ($129 million and $138 million at December 31, 2024 and 2023, respectively) on the balance sheets. For Southern Power, included in other current assets ($15 million and $15 million at December 31, 2024 and 2023, respectively) and net investment in sales-type leases ($143 million and $148 million at December 31, 2024 and 2023, respectively) on the balance sheets.
The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows:
At December 31, 2024
Southern
Company		Alabama
Power		Southern
Power		Southern Company Gas
 (in millions)
2025$117 $6 $142 $35 
2026111 5 148 29 
2027109 4 150 28 
2028109 4 161 28 
2029112 3 164 28 
Thereafter621 31 506 326 
Total$1,179 $53 $1,271 $474 
Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Alabama Power and Southern Power allocate revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under contracts accounted for as operating leases at Georgia Power and Mississippi Power are immaterial.
Southern Company Leveraged Lease
At December 31, 2024, a subsidiary of Southern Holdings had one leveraged lease agreement, which relates to energy generation, with an expected remaining term of seven years. Southern Company receives federal income tax deductions for depreciation and amortization, as well as interest on long-term debt, related to this investment. Southern Company wrote off the related investment balance in 2020 following an evaluation of the recoverability of the lease receivable and the expected residual value of the generation assets at the end of the lease.
In June 2022, the Southern Holdings subsidiary operating the generating plant for the lessee provided notice to the lessee to terminate the related operating and maintenance agreement effective June 30, 2023. Subsequently, the lessee failed to make the semi-annual lease payment due in December 2022. As a result, the Southern Holdings subsidiary was unable to make its corresponding payment to the holders of the underlying non-recourse debt related to the generation assets. The parties to the lease entered into forbearance agreements which suspended the related contractual rights of the parties while they continued restructuring negotiations, during which the termination date for the operating and maintenance agreement was delayed until July 31, 2023. The negotiations were completed in July 2023, resulting in the Southern Holdings subsidiary agreeing to continue operating the plant for the lessee until the lessee's associated power off-take agreement ends in 2032, subject to certain terms and
conditions. The restructuring had no material impact on Southern Company's financial statements. Southern Company will continue to monitor the operational performance of the underlying assets and evaluate the ability of the lessee to continue to meet its obligations, including those associated with a future closure or retirement of the generation assets and associated properties, including the dry ash landfill.
LEASES LEASES
Lessee
The Registrants recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with ROU assets that will be amortized over the term of each lease.
As lessee, the Registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
At December 31, 2024
Electric generating units(*)
$672 $56 $1,509 $— $— $— 
Real estate/land834 3 45 2 540 20 
Communication towers118 2 4 — — 21 
Railcars64 31 29 4 — — 
Other52 2 2 16 — — 
Total$1,740 $94 $1,589 $22 $540 $41 
At December 31, 2023
Electric generating units(*)
$670 $58 $1,028 $— $— $— 
Real estate/land871 4 54 2 546 28 
Communication towers123 1 4 — — 23 
Railcars64 32 27 5 — — 
Other60 3 2 18 — — 
Total$1,788 $98 $1,115 $25 $546 $51 
(*)Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information.
Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 20 years while the land leases have remaining terms of up to 44 years, including renewal periods.
Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies and Nicor Gas. Communication tower leases have remaining terms of up to 16 years.
Renewal options exist in many of the leases. The expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease unless it is considered reasonably certain that the lease will be extended. Land leases associated with renewable energy facilities at Southern Power and communication tower leases for automated meter infrastructure at Nicor Gas include renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities and the automated meter infrastructure, respectively.
Contracts that Contain a Lease
While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the PPA, which varies between three and 15 years. Georgia Power has several PPAs with Southern Power that Georgia Power accounts for as leases with a lease obligation of $893 million and $416 million at December 31, 2024 and 2023, respectively. The amount paid for energy under these affiliate PPAs reflects a price that would be paid in an arm's-length transaction as reviewed and approved by both the Georgia PSC and the FERC. Amounts related to the affiliate PPAs are eliminated in consolidation for Southern Company.
Short-term Leases
Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Registrants generally recognize lease expense for these leases on a straight-line basis over the lease term.
Residual Value Guarantees
Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power, with Georgia Power's railcar leases terminating in June 2024. The amounts probable of being paid under those guarantees are included in the lease payments. All such amounts were immaterial at December 31, 2024 and 2023.
Lease and Nonlease Components
For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the Registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the ROU asset.
Balance sheet amounts recorded for operating and finance leases are as follows:
Southern CompanyAlabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
At December 31, 2024
Operating Leases
Operating lease ROU assets, net$1,386 $84 $1,331 $8 $484 $38 
Operating lease obligations - current$200 $14 $169 $4 $29 $11 
Operating lease obligations - non-current1,253 76 1,159 4 511 30 
Total operating lease obligations(*)
$1,453 $90 $1,328 $8 $540 $41 
Finance Leases
Finance lease ROU assets, net$254 $4 $227 $14 $— $— 
Finance lease obligations - current$9 $1 $20 $1 $— $— 
Finance lease obligations - non-current278 3 241 13 — — 
Total finance lease obligations $287 $4 $261 $14 $— $— 
At December 31, 2023
Operating Leases
Operating lease ROU assets, net$1,432 $87 $884 $9 $488 $47 
Operating lease obligations - current$183 $12 $135 $3 $29 $11 
Operating lease obligations - non-current1,307 81 740 6 517 40 
Total operating lease obligations(*)
$1,490 $93 $875 $9 $546 $51 
Finance Leases
Finance lease ROU assets, net$272 $5 $203 $15 $— $— 
Finance lease obligations - current$11 $2 $18 $1 $— $— 
Finance lease obligations - non-current287 3 222 15 — — 
Total finance lease obligations$298 $5 $240 $16 $— $— 
(*)Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $567 million, $55 million, and $1.3 billion, respectively, at December 31, 2024 and $566 million, $58 million, and $813 million, respectively, at December 31, 2023.
If not presented separately on the Registrants' balance sheets, amounts related to leases are presented as follows: operating lease ROU assets, net are included in "other deferred charges and assets"; operating lease obligations are included in "other current liabilities" and "other deferred credits and liabilities," as applicable; finance lease ROU assets, net are included in "plant in service"; and finance lease obligations are included in "securities due within one year" and "long-term debt," as applicable.
Lease costs for 2024, 2023, and 2022, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Lease cost
Operating lease cost(*)
$248 $19 $190 $4 $27 $12 
Finance lease cost:
Amortization of ROU assets20 2 23 1 — — 
Interest on lease obligations15 — 15 1 — — 
Total finance lease cost35 2 38 2 — — 
Short-term lease costs 37 15 15 — — — 
Variable lease cost48 (1)77 — 4 — 
Total lease cost $368 $35 $320 $6 $31 $12 
2023
Lease cost
Operating lease cost(*)
$252 $16 $192 $5 $34 $12 
Finance lease cost:
Amortization of ROU assets24 2 19 1 — — 
Interest on lease obligations14 — 17 — — — 
Total finance lease cost38 2 36 1 — — 
Short-term lease costs40 16 16 — — — 
Variable lease cost47 — 74 — 4 — 
Total lease cost$377 $34 $318 $6 $38 $12 
2022
Lease cost
Operating lease cost(*)
$297 $59 $198 $5 $32 $15 
Finance lease cost:
Amortization of ROU assets23 1 15 1 — — 
Interest on lease obligations13 — 17 1 — — 
Total finance lease cost36 1 32 2 — — 
Short-term lease costs64 44 13 — — — 
Variable lease cost125 13 105 — 5 — 
Sublease income(1)— — — — — 
Total lease cost$521 $117 $348 $7 $37 $15 
(*)Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $108 million, $5 million, and $168 million, respectively, in 2024, $112 million, $4 million, and $174 million, respectively, in 2023, and $162 million, $48 million, and $180 million, respectively, in 2022.
Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs, including $45 million, $42 million, and $45 million in 2024, 2023, and 2022, respectively, from finance leases which are included in purchased power on Georgia Power's statements of income, of which $22 million, $21 million, and $21 million was included in purchased power, affiliates in 2024, 2023, and 2022, respectively.
Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$243 $19 $186 $4 $33 $12 
Operating cash flows from finance leases15 — 21 — — — 
Financing cash flows from finance leases11 2 23 1 — — 
ROU assets obtained under operating leases146 11 609 — 10 1 
Reassessment of ROU assets under operating leases(7)— — — (7)— 
ROU assets obtained under finance leases1 — 44 — — — 
2023
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$253 $17 $199 $5 $33 $12 
Operating cash flows from finance leases15 — 22 — — — 
Financing cash flows from finance leases18 2 16 1 — — 
ROU assets obtained under operating leases100 30 26 1 7 7 
ROU assets obtained under finance leases3 3 18 — — — 
2022
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$303 $58 $206 $5 $30 $14 
Operating cash flows from finance leases11 — 20 1 — — 
Financing cash flows from finance leases16 1 10 1 — — 
ROU assets obtained under operating leases56 10 17 9 — 3 
Reassessment of ROU assets under operating leases16 — — — 16 — 
ROU assets obtained under finance leases118 2 116 — — — 
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
At December 31, 2024
Weighted-average remaining lease term in years:
Operating leases16.410.27.94.332.36.8
Finance leases16.02.710.110.9N/AN/A
Weighted-average discount rate:
Operating leases 4.73 %5.04 %4.73 %3.83 %4.88 %3.84 %
Finance leases4.86 %4.05 %5.8 %2.74 %N/AN/A
At December 31, 2023
Weighted-average remaining lease term in years:
Operating leases17.211.17.54.633.17.0
Finance leases16.74.310.611.9N/AN/A
Weighted-average discount rate:
Operating leases4.68 %5.02 %4.58 %3.67 %4.89 %3.80 %
Finance leases4.85 %3.93 %5.95 %2.74 %N/AN/A
Maturities of lease liabilities are as follows:
At December 31, 2024
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
Maturity Analysis
Operating leases:
2025$239 $18 $228 $4 $31 $12 
2026212 15 224 3 29 9 
2027190 12 223 1 29 4 
2028170 9 217 — 29 3 
2029138 7 196 — 30 4 
Thereafter1,255 56 511 1 978 15 
Total2,204 117 1,599 9 1,126 47 
Less: Present value discount 751 27 271 1 586 6 
Operating lease obligations $1,453 $90 $1,328 $8 $540 $41 
Finance leases:
2025$28 $2 $39 $2 $— $— 
202627 1 41 2 — — 
202726 1 41 1 — — 
202825 — 42 1 — — 
202925 — 42 1 — — 
Thereafter290 — 139 9 — — 
Total421 4 344 16 — — 
Less: Present value discount134 — 83 2 — — 
Finance lease obligations$287 $4 $261 $14 $— $— 
Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis.
At December 31, 2024, Georgia Power has two affiliate PPAs with Southern Power that have not yet commenced and will be accounted for as leases. The PPAs each have a term of 10 years and are expected to commence in 2025 and 2028. The estimated total obligations associated with these PPAs is $83 million. Southern Company Gas has executed an 11.5-year building lease agreement that will commence during the first half of 2025. The lease has a total obligation of approximately $105 million.
Lessor
The Registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable Registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to 10 years, after which the contracts renew on a month-to-month basis at the customer's option. For Georgia Power, these arrangements also include PPAs related to electric generating units accounted for as operating leases with remaining terms of up to 15 years. For Mississippi Power, these arrangements also include a tolling arrangement related to an electric generating unit accounted for as a sales-type lease with a remaining term of 14 years. For Southern Power, these arrangements consist of PPAs related to electric generating units accounted for as operating leases with remaining terms of up to 22 years and PPAs related to battery energy storage facilities accounted for as sales-type leases with remaining terms of up to 17 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 18 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with remaining terms of up to 9 years.
Lease income for 2024, 2023, and 2022, is as follows:
Southern
Company		Alabama PowerGeorgia PowerMississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Lease income - interest income on sales-type leases$24 $— $— $15 $9 $— 
Lease income - operating leases136 9 28 3 88 36 
Variable lease income417 1 — — 450 — 
Total lease income$577 $10 $28 $18 $547 $36 
2023
Lease income - interest income on sales-type leases$24 $— $— $14 $10 $— 
Lease income - operating leases164 35 29 2 85 37 
Variable lease income406 1 — — 437 — 
Total lease income$594 $36 $29 $16 $532 $37 
2022
Lease income - interest income on sales-type leases$25 $— $— $15 $10 $— 
Lease income - operating leases208 77 32 2 85 36 
Variable lease income417 1 — — 448 — 
Total lease income$650 $78 $32 $17 $543 $36 
Lease payments received under tolling arrangements and PPAs consist of either scheduled payments or variable payments based on the amount of energy produced by the underlying electric generating units. Lease income related to PPAs is included in wholesale revenues for Alabama Power, Georgia Power, and Southern Power. Scheduled payments to be received under outdoor lighting contracts' initial terms, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses.
The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows:
At December 31, 2024
Southern CompanyMississippi PowerSouthern
Power
 (in millions)
2025$52 $24 $15 
202638 23 15 
202737 22 15 
202836 21 15 
202935 20 15 
Thereafter302 132 170 
Total undiscounted cash flows$500 $242 $245 
Net investment in sales-type lease(*)
297 139 158 
Difference between undiscounted cash flows and discounted cash flows$203 $103 $87 
(*)For Mississippi Power, included in other current assets ($10 million and $10 million at December 31, 2024 and 2023, respectively) and other property and investments ($129 million and $138 million at December 31, 2024 and 2023, respectively) on the balance sheets. For Southern Power, included in other current assets ($15 million and $15 million at December 31, 2024 and 2023, respectively) and net investment in sales-type leases ($143 million and $148 million at December 31, 2024 and 2023, respectively) on the balance sheets.
The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows:
At December 31, 2024
Southern
Company		Alabama
Power		Southern
Power		Southern Company Gas
 (in millions)
2025$117 $6 $142 $35 
2026111 5 148 29 
2027109 4 150 28 
2028109 4 161 28 
2029112 3 164 28 
Thereafter621 31 506 326 
Total$1,179 $53 $1,271 $474 
Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Alabama Power and Southern Power allocate revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under contracts accounted for as operating leases at Georgia Power and Mississippi Power are immaterial.
Southern Company Leveraged Lease
At December 31, 2024, a subsidiary of Southern Holdings had one leveraged lease agreement, which relates to energy generation, with an expected remaining term of seven years. Southern Company receives federal income tax deductions for depreciation and amortization, as well as interest on long-term debt, related to this investment. Southern Company wrote off the related investment balance in 2020 following an evaluation of the recoverability of the lease receivable and the expected residual value of the generation assets at the end of the lease.
In June 2022, the Southern Holdings subsidiary operating the generating plant for the lessee provided notice to the lessee to terminate the related operating and maintenance agreement effective June 30, 2023. Subsequently, the lessee failed to make the semi-annual lease payment due in December 2022. As a result, the Southern Holdings subsidiary was unable to make its corresponding payment to the holders of the underlying non-recourse debt related to the generation assets. The parties to the lease entered into forbearance agreements which suspended the related contractual rights of the parties while they continued restructuring negotiations, during which the termination date for the operating and maintenance agreement was delayed until July 31, 2023. The negotiations were completed in July 2023, resulting in the Southern Holdings subsidiary agreeing to continue operating the plant for the lessee until the lessee's associated power off-take agreement ends in 2032, subject to certain terms and
conditions. The restructuring had no material impact on Southern Company's financial statements. Southern Company will continue to monitor the operational performance of the underlying assets and evaluate the ability of the lessee to continue to meet its obligations, including those associated with a future closure or retirement of the generation assets and associated properties, including the dry ash landfill.
v3.25.0.1
INCOME TAXES
 12 Months Ended
Dec. 31, 2024
Income Tax Disclosure [Abstract]  
INCOME TAXES INCOME TAXES
Southern Company files a consolidated federal income tax return and the Registrants file various state income tax returns, some of which are combined or unitary. Under a joint consolidated income tax allocation agreement, each Southern Company subsidiary's current and deferred tax expense is computed on a stand-alone basis, and each subsidiary is allocated an amount of tax similar to that which would be paid if it filed a separate income tax return except for certain credit utilization and state apportionment results. In accordance with IRS regulations, each company is jointly and severally liable for the federal tax liability.
Current and Deferred Income Taxes
Details of income tax provisions are as follows:
2024
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern Power Southern Company Gas
(in millions)
Federal —
Current$221 $357 $200 $32 $(112)$84 
Deferred387 (111)211 2 106 86 
Total federal
608 246 411 34 (6)170 
State —
Current152 103 52 (1)6 42 
Deferred209 11 140 14 (13)46 
Total state
361 114 192 13 (7)88 
Total$969 $360 $603 $47 $(13)$258 
2023
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Federal —
Current$54 $242 $205 $49 $(320)$62 
Deferred299 (257)195 (26)334 68 
Total federal
353 (15)400 23 14 130 
State —
Current41 82 37 1 (1)24 
Deferred102 14 11 12 (1)57 
Total state
143 96 48 13 (2)81 
Total$496 $81 $448 $36 $12 $211 
2022
Southern CompanyAlabama PowerGeorgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
(in millions)
Federal —
Current$10 $54 $38 $42 $(43)$122 
Deferred455 259 152 (16)56 (3)
Total federal
465 313 190 26 13 119 
State —
Current27 14 (21)— 2 42 
Deferred303 96 201 11 5 19 
Total state
330 110 180 11 7 61 
Total$795 $423 $370 $37 $20 $180 
Southern Company's and Southern Power's ITCs and PTCs generated in the current tax year and carried forward from prior tax years that cannot be utilized or transferred in the current tax year are reclassified from current to deferred taxes in federal income tax expense in the tables above. Southern Power's ITCs and PTCs reclassified in this manner were immaterial in 2024 and 2023 and $17 million in 2022. Southern Power received $71 million, $332 million, and $49 million of cash related to federal ITCs under renewable energy initiatives in 2024, 2023, and 2022, respectively. See "Deferred Tax Assets and Liabilities" herein for additional information.
In accordance with regulatory requirements, deferred federal ITCs for the traditional electric operating companies are amortized over the average life of the related property, with such amortization normally applied as a credit to reduce depreciation and amortization in the statements of income. Southern Power's and the natural gas distribution utilities' deferred federal ITCs, as well as certain state ITCs for Nicor Gas, are amortized to income tax expense over the life of the respective asset. ITCs amortized in 2024, 2023, and 2022 were immaterial for the traditional electric operating companies and Southern Company Gas and were as follows for Southern Company and Southern Power:
Southern CompanySouthern Power
(in millions)
2024$109 $58 
202384 58 
202283 58 
When Southern Power recognizes tax credits, the tax basis of the asset is reduced by 50% of the ITCs received, which, together with the deferred credit, results in a net deferred tax asset. Southern Power has elected to recognize the tax benefit of this basis difference as a reduction to income tax expense in the year in which the plant reaches commercial operation.
State ITCs and other state credits, which are recognized in the period in which the credits are generated, reduced Georgia Power's income tax expense by $44 million in 2024, $49 million in 2023, and $53 million in 2022.
Southern Power's federal and state PTCs, which are recognized in the period in which the credits are generated, reduced Southern Power's income tax expense by $32 million in 2024, $26 million in 2023, and $27 million in 2022.
In 2024, Alabama Power, Georgia Power, and Southern Power entered into transferability agreements with non-affiliated parties to sell ITCs and PTCs at a discount to the generated credit value in 2024, 2025, and 2026. Georgia Power and Southern Power received cash of $11 million and $24 million, respectively, from credits transferred during the year. The discount will be recorded as a reduction in tax credits recognized in the financial statements. The Southern Company system continues to explore the ability to efficiently monetize its tax credits through third-party transferability agreements.
Pursuant to the Vogtle Joint Ownership Agreements, Georgia Power paid $131 million in 2024 and $39 million in 2023 to the other Vogtle Owners for advanced nuclear PTCs for Plant Vogtle Unit 3 and 4, which were utilized and not reflected as a reduction to current income tax expense. The gains recognized in both periods were recorded in income tax benefit and were immaterial.
Effective Tax Rate
Southern Company's effective tax rate is typically lower than the statutory rate due to employee stock plans' dividend deduction, non-taxable AFUDC equity at the traditional electric operating companies, flowback of excess deferred income taxes at the regulated utilities, and federal income tax benefits from ITCs and PTCs primarily at Southern Power, Georgia Power, and Alabama Power.
A reconciliation of the federal statutory income tax rate to the effective income tax (benefit) rate is as follows:
2024
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
Federal statutory rate21.0 %21.0 %21.0 %21.0 %21.0 %21.0 %
State income tax, net of federal deduction3.6 5.0 1.7 4.4 (2.3)7.0 
Changes in valuation allowance, net of federal benefit
1.9 — 3.1 — — — 
Employee stock plans' dividend deduction(0.4)— — — — — 
Non-deductible book depreciation0.6 0.6 0.7 0.3 — — 
Flowback of excess deferred income taxes(3.9)(5.3)(2.2)(6.5)— (2.2)
AFUDC-Equity(0.8)(0.7)(1.0)— — — 
Federal PTCs(2.8)(0.1)(3.7)— (17.2)— 
ITC amortization(1.2)(0.1)(0.2)— (26.4)— 
Noncontrolling interests0.6 — — — 17.1 — 
Other(0.1)— (0.2)— 0.2 — 
Effective income tax (benefit) rate18.5 %20.4 %19.2 %19.2 %(7.6)%25.8 %
2023
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
Federal statutory rate21.0 %21.0 %21.0 %21.0 %21.0 %21.0 %
State income tax, net of federal deduction2.9 5.2 2.1 4.9 (0.7)7.8 
Changes in valuation allowance, net of federal benefit
(0.3)— (0.6)— — — 
Employee stock plans' dividend deduction(0.5)— — — — — 
Non-deductible book depreciation0.7 0.7 0.8 0.4 — — 
Flowback of excess deferred income taxes(9.2)(19.8)(2.6)(10.2)— (2.6)
AFUDC-Equity(1.1)(1.2)(1.2)— — — 
Federal PTCs(1.2)— (1.4)— (7.4)— 
ITC amortization(1.3)(0.1)(0.1)— (19.0)— 
Noncontrolling interests0.6 — — — 11.1 — 
Other(0.2)(0.2)(0.3)0.1 0.1 (0.6)
Effective income tax rate11.4 %5.6 %17.7 %16.2 %5.1 %25.6 %
2022
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
Federal statutory rate21.0 %21.0 %21.0 %21.0 %21.0 %21.0 %
State income tax, net of federal deduction7.8 4.8 3.3 4.4 1.9 6.4 
Changes in valuation allowance, net of federal benefit
(1.6)— 3.2 — — — 
Employee stock plans' dividend deduction(0.5)— — — — — 
Non-deductible book depreciation0.6 0.5 0.6 0.3 — — 
Flowback of excess deferred income taxes(6.6)(1.9)(9.6)(7.8)— (2.5)
AFUDC-Equity(1.1)(0.8)(1.5)— — — 
Federal PTCs— — — — (6.6)— 
ITC amortization(1.3)(0.1)(0.1)— (17.2)(0.1)
Noncontrolling interests0.5 — — — 8.4 — 
Other— 0.3 — 0.3 (0.1)(0.9)
Effective income tax rate18.8 %23.8 %16.9 %18.2 %7.4 %23.9 %
Deferred Tax Assets and Liabilities
The tax effects of temporary differences between the carrying amounts of assets and liabilities in the financial statements of the Registrants and their respective tax bases, which give rise to deferred tax assets and liabilities, are as follows:
December 31, 2024
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Deferred tax liabilities —
Accelerated depreciation$9,828 $2,583 $3,810 $344 $1,309 $1,575 
Property basis differences3,025 1,497 918 192 — 412 
Employee benefit obligations1,067 362 470 54 13 60 
AROs727 458 221 — — — 
Under recovered fuel and natural gas costs 318 13 305 — — — 
Regulatory assets –
AROs1,886 658 1,193 35 — — 
Employee benefit obligations746 191 237 35 — 35 
Remaining book value of retired assets360 168 187 5 — — 
Storm damage reserves
216 — 216 — — — 
Premium on reacquired debt57 8 48 1 — — 
Other678 171 187 61 1 201 
Total deferred income tax liabilities18,908 6,109 7,792 727 1,323 2,283 
Deferred tax assets —
AROs2,613 1,116 1,414 35 — — 
CAMT carryforwards
40 — 18 — — 104 
ITC and PTC carryforwards1,380 48 719 — 384 — 
Employee benefit obligations897 196 279 49 16 87 
Estimated loss on plants under construction773 — 773 — — — 
Estimated loss on regulatory disallowance20 — — — — 20 
Other state deferred tax attributes366 — 26 224 49 16 
Federal effect of net state deferred tax liabilities402 197 100 — 23 107 
Other property basis differences176 — 75 — 85 — 
State effect of federal deferred taxes126 126 — — — — 
Other partnership basis differences60 — — — 60 — 
Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)18 18 — — — — 
Long-term debt fair value adjustment73 — — — — 73 
Other comprehensive losses48 3 — — 1 — 
Other601 227 160 50 20 86 
Total deferred income tax assets7,593 1,931 3,564 358 638 493 
Valuation allowance(333)— (157)(41)(27)(6)
Net deferred income tax assets7,260 1,931 3,407 317 611 487 
Net deferred income taxes (assets)/liabilities$11,648 $4,178 $4,385 $410 $712 $1,796 
Recognized in the balance sheets:
Accumulated deferred income taxes – assets$(82)$— $— $(82)$— $— 
Accumulated deferred income taxes – liabilities$11,730 $4,178 $4,385 $492 $712 $1,796 
December 31, 2023
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Deferred tax liabilities —
Accelerated depreciation$9,683 $2,566 $3,628 $339 $1,346 $1,576 
Property basis differences2,647 1,444 812 188 — 189 
Employee benefit obligations979 321 446 49 12 74 
AROs833 476 314 — — — 
Under recovered fuel and natural gas costs601 80 508 13 — — 
Regulatory assets –
AROs1,902 667 1,196 39 — — 
Employee benefit obligations797 213 260 37 — 11 
Remaining book value of retired assets369 143 221 5 — — 
Premium on reacquired debt63 9 53 1 — — 
Other700 182 223 43 2 191 
Total deferred income tax liabilities18,574 6,101 7,661 714 1,360 2,041 
Deferred tax assets —
AROs2,735 1,143 1,510 39 — — 
ITC and PTC carryforwards1,387 12 691 — 481 — 
Employee benefit obligations985 224 316 52 10 89 
Estimated loss on plants under construction857 — 857 — — — 
Estimated loss on regulatory disallowance
26 — — — — 26 
Other state deferred tax attributes363 — 13 231 49 8 
Federal effect of net state deferred tax liabilities418 215 92 — 27 101 
Other property basis differences197 — 83 — 97 — 
State effect of federal deferred taxes115 115 — — — — 
Other partnership basis differences85 — — — 85 — 
Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)34 30 — 3 — — 
Long-term debt fair value adjustment79 — — — — 79 
Other comprehensive losses67 4 4 — 6 — 
Other538 188 152 57 18 74 
Total deferred income tax assets7,886 1,931 3,718 382 773 377 
Valuation allowance(206)— (75)(41)(27)(7)
Net deferred income tax assets7,680 1,931 3,643 341 746 370 
Net deferred income taxes (assets)/liabilities$10,894 $4,170 $4,018 $373 $614 $1,671 
Recognized in the balance sheets:
Accumulated deferred income taxes – assets$(96)$— $— $(96)$— $— 
Accumulated deferred income taxes – liabilities$10,990 $4,170 $4,018 $469 $614 $1,671 
The traditional electric operating companies and the natural gas distribution utilities have tax-related regulatory assets (deferred income tax charges) and regulatory liabilities (deferred income tax credits). The regulatory assets are primarily attributable to tax benefits flowed through to customers in prior years, deferred taxes previously recognized at rates lower than the current enacted tax law, and taxes applicable to capitalized interest. The regulatory liabilities are primarily attributable to deferred taxes previously recognized at rates higher than the current enacted tax law and to unamortized ITCs. See Note 2 for each Registrant's related balances at December 31, 2024 and 2023.
Tax Credit Carryforwards
Federal ITC/PTC carryforwards at December 31, 2024 were as follows:
Southern CompanyAlabama
Power		Georgia
Power		Southern
Power
(in millions)
Federal ITC/PTC carryforwards$765 $48 $147 $384 
Tax year in which federal ITC/PTC carryforwards begin expiring2031203220312035
Year by which federal ITC/PTC carryforwards are expected to be utilized2028202820282028
The estimated tax credit utilization reflects the various transactions described in Note 15 and could be impacted by numerous factors, including the acquisition or construction of additional renewable projects, changes in taxable income projections, transfer of eligible credits, potential income tax rate changes, and remaining final guidance on the IRA. In the third quarter 2023 and the second quarter 2024, Georgia Power started generating advanced nuclear PTCs for Plant Vogtle Units 3 and 4, respectively, beginning on each unit's respective in-service date. In addition, pursuant to the Vogtle Joint Ownership Agreements, Georgia Power is purchasing advanced nuclear PTCs for Plant Vogtle Unit 3 and 4 from the other Vogtle Owners. See Note 2 under "Georgia Power – Nuclear Construction" for additional information on Plant Vogtle Units 3 and 4.
At December 31, 2024, Southern Company and Georgia Power also had approximately $515 million and $472 million, respectively, in net state investment and other net state tax credit carryforwards for the State of Georgia that will expire between tax years 2024 and 2033 and are not expected to be fully utilized. Southern Company and Georgia Power have a net state valuation allowance of $161 million and $124 million, respectively, associated with these carryforwards, which increased during 2024 by $101 million and $64 million, respectively.
At December 31, 2024, Southern Company and certain subsidiaries also had approximately $40 million in net CAMT carryforwards that have an indefinite carryforward period and are expected to be fully utilized by 2031.
The ultimate outcome of these matters cannot be determined at this time.
Net Operating Loss Carryforwards
At December 31, 2024, the net state income tax benefit of state and local NOL carryforwards and associated valuation allowances for Southern Company's subsidiaries were as follows:
Company/JurisdictionApproximate Net State Income Tax Benefit of NOL CarryforwardsTax Year NOL
Begins Expiring
Net State Valuation Allowance for NOL Carryforwards
(in millions)(in millions)
Mississippi Power
Mississippi $178 2032$(32)
Southern Power
Oklahoma$26 2035$(11)
Florida10 2034(10)
Other states2 
2034
— 
Southern Power Total$38 $(21)
Other(*)
New York$11 2036$(11)
New York City14 2036(14)
Other states24 
2025
(4)
Southern Company Total$265 $(82)
(*)Represents other non-registrant Southern Company subsidiaries. Alabama Power, Georgia Power, and Southern Company Gas did not have material state or local NOL carryforwards at December 31, 2024.
Certain state NOLs are not expected to be fully utilized prior to expiration. The ultimate outcome of these matters cannot be determined at this time.
Unrecognized Tax Benefits
Changes in unrecognized tax benefits for the periods presented were as follows:
Southern
Company
Georgia
Power
Southern
Company Gas
(in millions)
Unrecognized tax benefits at December 31, 2021$47 $— $— 
Tax positions changes —
Increase from prior periods33 — 32 
Unrecognized tax benefits at December 31, 202280 — 32 
Tax positions changes —
Increase from prior periods88 86 2 
Statute of limitations expiration(52)(9)— 
Unrecognized tax benefits at December 31, 2023
116 77 34 
Tax positions changes —
Increase from prior periods10 — 10 
Decrease from prior periods
(44)(43)— 
Unrecognized tax benefits at December 31, 2024
$82 $34 $44 
The unrecognized tax positions increase from prior periods for 2022 is primarily related to the amendment of certain 2018 state tax filing positions related to Southern Company Gas dispositions. If accepted by the states, these positions would decrease Southern Company's and Southern Company Gas' annual effective tax rates. The ultimate outcome of these unrecognized tax benefits is dependent on acceptance by each state and is not expected to be resolved within the next 12 months.
The unrecognized tax positions increase from prior periods for 2023 is primarily related to the amendment of certain 2019 through 2021 state tax filing positions related to tax credit utilization, a portion of which decreased in the fourth quarter 2023 due to a statute of limitations expiration. If effective settlement of the positions is favorable, these positions would decrease Southern Company's and Georgia Power's annual effective tax rates. The ultimate outcome of this unrecognized tax benefit, which is expected to be resolved within the next 12 months, is dependent on acceptance by the state or expiration of related statute of limitations.
The unrecognized tax positions reductions due to statute of limitations expiration for 2023 primarily relate to a 2019 state tax filing position to exclude certain gains from 2019 dispositions from taxation in a certain unitary state. This tax position and related interest was recognized in the fourth quarter 2023 and decreased Southern Company's annual effective tax rate.
The unrecognized tax positions increase from prior periods for 2024 is primarily related to a certain state tax filing position at Southern Company Gas. If effective settlement of this position is favorable, this position would decrease Southern Company's and Southern Company Gas' annual effective tax rates. The ultimate outcome is dependent on acceptance by the state.
The unrecognized tax positions decrease from prior periods for 2024 is primarily related to the 2019 and 2020 amended state filing positions related to tax credit utilization at Georgia Power.
All of the Registrants classify interest on tax uncertainties as interest expense. Accrued interest for all tax positions was immaterial for all years presented. None of the Registrants accrued any penalties on uncertain tax positions.
The IRS has finalized its audits of Southern Company's consolidated federal income tax returns through 2023. Southern Company is a participant in the Compliance Assurance Process of the IRS. The IRS selected six Southern Power partnership returns for exam for the 2020 and 2021 tax years. One audit for 2021 is still under review, and the remaining audits have been closed with no change. The ultimate outcome of this matter cannot be determined at this time. The audits for the Registrants' state income tax returns have either been concluded, or the statute of limitations has expired, for years prior to 2018.
v3.25.0.1
RETIREMENT BENEFITS
 12 Months Ended
Dec. 31, 2024
Retirement Benefits [Abstract]  
RETIREMENT BENEFITS RETIREMENT BENEFITS
The Southern Company system has a qualified defined benefit, trusteed pension plan covering substantially all employees, with the exception of PowerSecure employees. The qualified pension plan is funded in accordance with requirements of the Employee Retirement Income Security Act of 1974, as amended (ERISA). No contributions to the qualified pension plan were made for the year ended December 31, 2024 and no mandatory contributions to the qualified pension plan are anticipated for the year ending December 31, 2025. The Southern Company system also provides certain non-qualified defined benefits for a select group of management and highly compensated employees, which are funded on a cash basis. In addition, the Southern Company system
provides certain medical care and life insurance benefits for retired employees through other postretirement benefit plans. The traditional electric operating companies fund other postretirement trusts to the extent required by their respective regulatory commissions. Southern Company Gas has a separate unfunded supplemental retirement health care plan that provides medical care and life insurance benefits to employees of discontinued businesses. For the year ending December 31, 2025, no contributions to any other postretirement trusts are expected.
Actuarial Assumptions
The weighted average rates assumed in the actuarial calculations used to determine both the net periodic costs for the pension and other postretirement benefit plans for the following year and the benefit obligations as of the measurement date are presented below.
2024
Assumptions used to determine net
periodic costs:		Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
Pension plans
Discount rate – benefit obligations5.07 %5.08 %5.06 %5.06 %5.14 %5.05 %
Discount rate – interest costs4.94 4.94 4.94 4.93 5.01 4.93 
Discount rate – service costs5.19 5.20 5.21 5.19 5.20 5.13 
Expected long-term return on plan assets8.30 8.30 8.30 8.30 8.30 8.30 
Annual salary increase4.60 4.60 4.60 4.60 4.60 4.60 
Other postretirement benefit plans
Discount rate – benefit obligations4.99 %5.01 %4.98 %4.98 %5.06 %4.98 %
Discount rate – interest costs4.90 4.90 4.89 4.90 4.94 4.89 
Discount rate – service costs5.16 5.17 5.16 5.16 5.14 5.16 
Expected long-term return on plan assets7.67 7.97 7.59 7.43 — 6.36 
Annual salary increase4.60 4.60 4.60 4.60 4.60 4.60 
2023
Assumptions used to determine net
periodic costs:		Southern CompanyAlabama
Power		Georgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
Pension plans
Discount rate – benefit obligations5.25 %5.26 %5.25 %5.25 %5.31 %5.24 %
Discount rate – interest costs5.13 5.14 5.12 5.12 5.19 5.12 
Discount rate – service costs5.36 5.38 5.38 5.37 5.37 5.31 
Expected long-term return on plan assets8.40 8.40 8.40 8.40 8.40 8.40 
Annual salary increase4.80 4.80 4.80 4.80 4.80 4.80 
Other postretirement benefit plans
Discount rate – benefit obligations5.18 %5.20 %5.17 %5.17 %5.24 %5.16 %
Discount rate – interest costs5.08 5.09 5.07 5.08 5.12 5.07 
Discount rate – service costs5.34 5.35 5.34 5.33 5.33 5.33 
Expected long-term return on plan assets7.67 7.95 7.49 7.43 — 6.59 
Annual salary increase4.80 4.80 4.80 4.80 4.80 4.80 
2022
Assumptions used to determine net periodic costs:Southern CompanyAlabama
Power		Georgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
Pension plans
Discount rate – benefit obligations3.09 %3.12 %3.07 %3.07 %3.21 %3.04 %
Discount rate – interest costs2.55 2.58 2.51 2.54 2.79 2.53 
Discount rate – service costs3.34 3.36 3.37 3.35 3.36 3.21 
Expected long-term return on plan assets8.25 8.25 8.25 8.25 8.25 8.25 
Annual salary increase4.80 4.80 4.80 4.80 4.80 4.80 
Other postretirement benefit plans
Discount rate – benefit obligations2.90 %2.95 %2.87 %2.88 %3.07 %2.82 %
Discount rate – interest costs2.32 2.38 2.30 2.27 2.55 2.17 
Discount rate – service costs3.26 3.30 3.27 3.26 3.25 3.22 
Expected long-term return on plan assets7.21 7.54 6.88 7.22 — 6.08 
Annual salary increase4.80 4.80 4.80 4.80 4.80 4.80 
2024
Assumptions used to determine benefit obligations:Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
Pension plans
Discount rate5.76 %5.78 %5.75 %5.76 %5.84 %5.73 %
Annual salary increase4.60 4.60 4.60 4.60 4.60 4.60 
Other postretirement benefit plans
Discount rate5.64 %5.67 %5.61 %5.63 %5.73 %5.62 %
Annual salary increase4.60 4.60 4.60 4.60 4.60 4.60 
2023
Assumptions used to determine benefit obligations:Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
Pension plans
Discount rate5.07 %5.08 %5.06 %5.06 %5.14 %5.05 %
Annual salary increase4.60 4.60 4.60 4.60 4.60 4.60 
Other postretirement benefit plans
Discount rate4.99 %5.01 %4.98 %4.98 %5.06 %4.98 %
Annual salary increase4.60 4.60 4.60 4.60 4.60 4.60 
The Registrants estimate the expected rate of return on pension plan and other postretirement benefit plan assets using a financial model to project the expected return on each current investment portfolio. The analysis projects an expected rate of return on each of the different asset classes in order to arrive at the expected return on the entire portfolio relying on each trust's target asset allocation and reasonable capital market assumptions. The financial model is based on four key inputs: anticipated returns by asset class (based in part on historical returns), each trust's target asset allocation, an anticipated inflation rate, and the projected impact of a periodic rebalancing of each trust's portfolio. The Registrants set the expected rate of return assumption using an arithmetic mean which represents the expected simple average return to be earned by the pension plan assets over any one year. The Registrants believe the use of the arithmetic mean is more compatible with the expected rate of return's function of estimating a single year's investment return.
An additional assumption used in measuring the accumulated other postretirement benefit obligations (APBO) was a weighted average medical care cost trend rate. The weighted average medical care cost trend rates used in measuring the APBO for the Registrants at December 31, 2024 were as follows:
Initial Cost Trend RateUltimate Cost Trend RateYear That Ultimate Rate is Reached
Pre-658.00 %4.50 %2033
Post-65 medical5.50 4.50 2033
Post-65 prescription11.00 4.50 2033
Pension Plans
The total accumulated benefit obligation for the pension plans at December 31, 2024 and 2023 was as follows:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
December 31, 2024$11,437 $2,617 $3,438 $519 $140 $779 
December 31, 202311,991 2,746 3,674 546 145 808 
An actuarial gain of $887 million and an actuarial loss of $493 million were recorded for the annual remeasurement of the Southern Company system pension plans at December 31, 2024 and 2023, respectively, primarily due to an increase of 69 basis points and a decrease of 18 basis points, respectively, in the overall discount rate used to calculate the benefit obligation as a result of higher market interest rates.
Changes in the projected benefit obligations and the fair value of plan assets during the plan years ended December 31, 2024 and 2023 were as follows:
2024
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Change in benefit obligation
Benefit obligation at beginning of year$13,252 $3,076 $4,009 $599 $177 $882 
Service cost292 68 70 12 7 28 
Interest cost635 148 191 29 9 42 
Benefits paid(728)(162)(239)(33)(6)(46)
Actuarial gain(887)(222)(298)(40)(20)(64)
Balance at end of year12,564 2,908 3,733 567 167 842 
Change in plan assets
Fair value of plan assets at beginning of year14,618 3,544 4,571 669 185 980 
Actual return on plan assets604 148 152 23 7 39 
Employer contributions65 9 35 5 2 5 
Benefits paid(728)(162)(239)(33)(6)(46)
Fair value of plan assets at end of year14,559 3,539 4,519 664 188 978 
Accrued asset$1,995 $631 $786 $97 $21 $136 
2023
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Change in benefit obligation
Benefit obligation at beginning of year$12,602 $2,906 $3,851 $569 $163 $868 
Service cost275 64 68 11 6 24 
Interest cost626 145 191 28 8 42 
Benefits paid(744)(155)(224)(32)(6)(104)
Actuarial loss493 116 123 23 6 52 
Balance at end of year13,252 3,076 4,009 599 177 882 
Change in plan assets
Fair value of plan assets at beginning of year14,218 3,427 4,456 649 178 1,002 
Actual return on plan assets1,092 260 331 50 12 79 
Employer contributions52 11 9 2 2 3 
Benefits paid(744)(154)(225)(32)(7)(104)
Fair value of plan assets at end of year14,618 3,544 4,571 669 185 980 
Accrued asset$1,366 $468 $562 $70 $8 $98 
The projected benefit obligations for the qualified and non-qualified pension plans at December 31, 2024 are shown in the following table. All pension plan assets are related to the qualified pension plan.
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Projected benefit obligations:
Qualified pension plan$11,886 $2,794 $3,622 $540 $146 $788 
Non-qualified pension plan678 114 111 27 21 54 
Amounts recognized in the balance sheets at December 31, 2024 and 2023 related to the Registrants' pension plans consist of the following:
Southern
Company		Alabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
December 31, 2024:
Prepaid pension costs(a)
$2,674 $746 $897 $124 $41 $191 
Other regulatory assets, deferred(b)
2,708 741 973 144 — 126 
Other current liabilities(68)(13)(13)(2)(2)(4)
Employee benefit obligations(c)
(611)(102)(98)(25)(18)(51)
Other regulatory liabilities, deferred(50)— — — — — 
AOCI52 — — — 11 (54)
December 31, 2023:
Prepaid pension costs(a)
$2,079 $585 $706 $99 $31 $158 
Other regulatory assets, deferred(b)
2,960 821 1,051 152 — 143 
Other current liabilities(64)(11)(13)(2)(2)(3)
Employee benefit obligations(c)
(649)(106)(131)(27)(21)(58)
Other regulatory liabilities, deferred(47)— — — — — 
AOCI79 — — — 20 (45)
(a)Included in prepaid pension and other postretirement benefit costs on Alabama Power's balance sheet and other deferred charges and assets on Southern Power's consolidated balance sheet.
(b)Amounts for Southern Company exclude regulatory assets of $155 million and $173 million at December 31, 2024 and 2023, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company.
(c)Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets.
Presented below are the amounts included in regulatory assets at December 31, 2024 and 2023 related to the portion of the defined benefit pension plan attributable to Southern Company, the traditional electric operating companies, and Southern Company Gas that had not yet been recognized in net periodic pension cost.
Southern
Company		Alabama PowerGeorgia
Power		Mississippi PowerSouthern Company Gas
(in millions)
Balance at December 31, 2024
Regulatory assets:
Prior service cost$8 $3 $5 $1 $(4)
Net loss2,650 738 968 143 91 
Regulatory amortization— — — — 39 
Total regulatory assets(*)
$2,658 $741 $973 $144 $126 
Balance at December 31, 2023
Regulatory assets:
Prior service cost$9 $4 $6 $1 $(7)
Net loss2,904 817 1,045 151 100 
Regulatory amortization— — — — 50 
Total regulatory assets(*)
$2,913 $821 $1,051 $152 $143 
(*)Amounts for Southern Company exclude regulatory assets of $155 million and $173 million at December 31, 2024 and 2023, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company.
The changes in the balance of regulatory assets related to the portion of the defined benefit pension plan attributable to Southern Company, the traditional electric operating companies, and Southern Company Gas for the years ended December 31, 2024 and 2023 are presented in the following table:
Southern
Company		Alabama PowerGeorgia
Power		Mississippi PowerSouthern Company Gas
(in millions)
Regulatory assets (liabilities):(*)
Balance at December 31, 2022$2,371 $679 $887 $123 $111 
Net loss576 153 178 31 34 
Reclassification adjustments:
Amortization of prior service costs(1)(1)(1)— 2 
Amortization of net loss(33)(10)(13)(2)— 
Amortization of regulatory assets(*)
— — — — (4)
Total reclassification adjustments(34)(11)(14)(2)(2)
Total change542 142 164 29 32 
Balance at December 31, 2023$2,913 $821 $1,051 $152 $143 
Net gain(199)(63)(58)(5)(7)
Reclassification adjustments:
Amortization of prior service costs(1)(1)(1)— 2 
Amortization of net loss(55)(16)(19)(3)(1)
Amortization of regulatory assets(*)
— — — — (11)
Total reclassification adjustments(56)(17)(20)(3)(10)
Total change(255)(80)(78)(8)(17)
Balance at December 31, 2024$2,658 $741 $973 $144 $126 
(*)Amounts for Southern Company exclude regulatory assets of $155 million and $173 million at December 31, 2024 and 2023, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company.
Presented below are the amounts included in AOCI at December 31, 2024 and 2023 related to the portion of the defined benefit pension plan attributable to Southern Company, Southern Power, and Southern Company Gas that had not yet been recognized in net periodic pension cost.
Southern
Company		Southern
Power		Southern Company
Gas
(in millions)
Balance at December 31, 2024
AOCI:
Prior service cost$(1)$— $(1)
Net (gain) loss53 11 (53)
Total AOCI$52 $11 $(54)
Balance at December 31, 2023
AOCI:
Prior service cost$(1)$— $(2)
Net (gain) loss80 20 (43)
Total AOCI$79 $20 $(45)
The components of OCI related to the portion of the defined benefit pension plan attributable to Southern Company, Southern Power, and Southern Company Gas for the years ended December 31, 2024 and 2023 are presented in the following table:
Southern CompanySouthern
Power		Southern Company
Gas
(in millions)
AOCI:
Balance at December 31, 2022$24 $11 $(75)
Net loss62 9 29 
Reclassification adjustments:
Amortization of prior service costs1 — 1 
Amortization of net loss(8)— — 
Total reclassification adjustments(7)— 1 
Total change55 9 30 
Balance at December 31, 2023$79 $20 $(45)
Net gain(29)(9)(11)
Reclassification adjustments:
Amortization of prior service costs1 — 2 
Amortization of net gain1 — — 
Total reclassification adjustments2 — 2 
Total change(27)(9)(9)
Balance at December 31, 2024$52 $11 $(54)
Components of net periodic pension cost for the Registrants were as follows:
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
2024
Service cost$292 $68 $70 $12 $7 $28 
Interest cost635 148 191 29 9 42 
Expected return on plan assets(1,263)(307)(393)(58)(17)(85)
Recognized net loss(*)
55 16 19 3 — — 
Net amortization(*)
— 1 1 — — 15 
Prior service cost(*)
— — — — — (3)
Net periodic pension income$(281)$(74)$(112)$(14)$(1)$(3)
2023
Service cost$275 $64 $68 $11 $6 $24 
Interest cost626 145 191 28 8 42 
Expected return on plan assets(1,229)(297)(385)(56)(15)(85)
Recognized net (gain) loss(*)
32 9 13 2 — (5)
Net amortization(*)
— 1 1 — — 15 
Prior service cost(*)
— — — — — (3)
Net periodic pension income$(296)$(78)$(112)$(15)$(1)$(12)
2022
Service cost$412 $99 $103 $17 $9 $34 
Interest cost408 96 123 18 6 28 
Expected return on plan assets(1,265)(306)(399)(57)(15)(91)
Recognized net loss(*)
240 62 75 11 2 8 
Net amortization(*)
— 1 1 — — 15 
Prior service cost(*)
— — — — — (3)
Net periodic pension cost (income)$(205)$(48)$(97)$(11)$2 $(9)
(*)For Southern Company, excludes amounts related to net periodic pension cost of $20 million, $17 million, and $21 million for the years ended December 31, 2024, 2023, and 2022, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company.
The service cost component of net periodic pension cost is included in operations and maintenance expenses and all other components of net periodic pension cost are included in other income (expense), net in the Registrants' statements of income.
Net periodic pension cost is the sum of service cost, interest cost, and other costs netted against the expected return on plan assets. The expected return on plan assets is determined by multiplying the expected rate of return on plan assets and the market-related value of plan assets. In determining the market-related value of plan assets, the Registrants have elected to amortize changes in the market value of return-seeking plan assets over five years and to recognize the changes in the market value of liability-hedging plan assets immediately. Given the significant concentration in return-seeking plan assets, the accounting value of plan assets that is used to calculate the expected return on plan assets differs from the current fair value of the plan assets.
Future benefit payments reflect expected future service and are estimated based on assumptions used to measure the projected benefit obligation for the pension plans. At December 31, 2024, estimated benefit payments were as follows:
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Benefit Payments:
2025$773 $170 $245 $34 $7 $58 
2026801 177 250 36 8 60 
2027823 183 254 37 8 62 
2028842 187 258 38 7 64 
2029862 192 262 38 8 66 
2030 to 20344,529 1,013 1,333 204 51 346 
Other Postretirement Benefits
Changes in the APBO and the fair value of the Registrants' plan assets during the plan years ended December 31, 2024 and 2023 were as follows:
2024
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Change in benefit obligation
Benefit obligation at beginning of year$1,386 $329 $489 $57 $9 $172 
Service cost15 4 4 1 — 1 
Interest cost65 16 23 3 — 8 
Benefits paid(105)(25)(37)(4)(1)(12)
Actuarial (gain) loss(2)2 9 (2)1 (13)
Balance at end of year1,359 326 488 55 9 156 
Change in plan assets
Fair value of plan assets at beginning of year1,095 403 410 25 — 128 
Actual return on plan assets96 37 34 — — 18 
Employer contributions55 6 13 3 1 7 
Benefits paid(105)(25)(37)(4)(1)(12)
Fair value of plan assets at end of year1,141 421 420 24 — 141 
Accrued asset (liability)$(218)$95 $(68)$(31)$(9)$(15)
2023
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Change in benefit obligation
Benefit obligation at beginning of year$1,441 $344 $514 $59 $9 $179 
Service cost15 4 4 1 — 1 
Interest cost70 17 25 3 — 9 
Benefits paid(107)(24)(36)(4)(1)(18)
Actuarial (gain) loss(33)(12)(18)(2)1 1 
Balance at end of year1,386 329 489 57 9 172 
Change in plan assets
Fair value of plan assets at beginning of year998 372 368 24 — 113 
Actual return on plan assets131 52 51 2 — 19 
Employer contributions73 3 27 3 1 14 
Benefits paid(107)(24)(36)(4)(1)(18)
Fair value of plan assets at end of year1,095 403 410 25 — 128 
Accrued asset (liability)$(291)$74 $(79)$(32)$(9)$(44)
Amounts recognized in the balance sheets at December 31, 2024 and 2023 related to the Registrants' other postretirement benefit plans consist of the following:
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern
Power		Southern Company Gas
(in millions)
December 31, 2024:
Prepaid other postretirement benefit costs(a)
$— $95 $— $— $— $— 
Other regulatory assets, deferred(b)
24 — 3 — — — 
Other current liabilities(6)— — — (1)— 
Employee benefit obligations(c)
(212)— (68)(31)(8)(15)
Other regulatory liabilities, deferred(213)(45)(67)(9)— (84)
AOCI(14)— — — — (15)
December 31, 2023:
Prepaid other postretirement benefit costs(a)
$— $74 $— $— $— $— 
Other regulatory assets, deferred(b)
23 — 11 — — — 
Other current liabilities(6)— — — (1)— 
Employee benefit obligations(c)
(285)— (79)(32)(8)(44)
Other regulatory liabilities, deferred(231)(48)(85)(10)— (68)
AOCI(9)— — — 1 (10)
(a)Included in prepaid pension and other postretirement benefit costs on Alabama Power's balance sheet.
(b)Amounts for Southern Company exclude regulatory assets of $16 million and $24 million at December 31, 2024 and 2023, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company.
(c)Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets.
Presented below are the amounts included in net regulatory assets (liabilities) at December 31, 2024 and 2023 related to the other postretirement benefit plans of Southern Company, the traditional electric operating companies, and Southern Company Gas that had not yet been recognized in net periodic other postretirement benefit cost.
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern Company Gas
(in millions)
Balance at December 31, 2024:
Regulatory assets (liabilities):
Prior service cost$11 $3 $4 $1 $— 
Net gain(200)(48)(68)(10)(71)
Regulatory amortization— — — — (13)
Total regulatory assets (liabilities)(*)
$(189)$(45)$(64)$(9)$(84)
Balance at December 31, 2023:
Regulatory assets (liabilities):
Prior service cost$13 $4 $5 $1 $— 
Net gain(216)(52)(79)(11)(64)
Regulatory amortization— — — — (4)
Total regulatory assets (liabilities)(*)
$(203)$(48)$(74)$(10)$(68)
(*)Amounts for Southern Company exclude regulatory assets of $16 million and $24 million at December 31, 2024 and 2023, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company.
The changes in the balance of net regulatory assets (liabilities) related to the other postretirement benefit plans for the plan years ended December 31, 2024 and 2023 are presented in the following table:
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern Company Gas
(in millions)
Net regulatory assets (liabilities):(*)
Balance at December 31, 2022$(136)$(21)$(39)$(9)$(58)
Net gain(77)(30)(38)(1)— 
Reclassification adjustments:
Amortization of prior service costs(1)— (1)— — 
Amortization of net gain6 3 4 — — 
Amortization of regulatory assets(*)
— — — — (10)
Total reclassification adjustments5 3 3 — (10)
Total change(72)(27)(35)(1)(10)
Balance at December 31, 2023$(208)$(48)$(74)$(10)$(68)
Net (gain) loss8 1 6 1 (12)
Reclassification adjustments:
Amortization of prior service costs(2)(1)(1)— — 
Amortization of net gain13 3 5 — 5 
Amortization of regulatory assets(*)
— — — — (9)
Total reclassification adjustments11 2 4 — (4)
Total change19 3 10 1 (16)
Balance at December 31, 2024$(189)$(45)$(64)$(9)$(84)
(*)Amounts for Southern Company exclude regulatory assets of $16 million and $24 million at December 31, 2024 and 2023, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company.
Presented below are the amounts included in AOCI at December 31, 2024 and 2023 related to the other postretirement benefit plans of Southern Company, Southern Power, and Southern Company Gas that had not yet been recognized in net periodic other postretirement benefit cost.
Southern
Company		Southern
Power		Southern Company
Gas
(in millions)
Balance at December 31, 2024
AOCI:
Net (gain) loss$(14)$— $(15)
Balance at December 31, 2023
AOCI:
Prior service cost$1 $— $— 
Net (gain) loss(10)1 (10)
Total AOCI$(9)$1 $(10)
The components of OCI related to the other postretirement benefit plans for the plan years ended December 31, 2024 and 2023 are presented in the following table:
Southern CompanySouthern
Power		Southern Company Gas
(in millions)
AOCI:
Balance at December 31, 2022$(4)$— $(2)
Net (gain) loss(12)1 — 
Reclassification adjustments:
Amortization of net gain (loss)7 — (8)
Total change(5)1 (8)
Balance at December 31, 2023$(9)$1 $(10)
Net gain(8)(1)(5)
Reclassification adjustments:
Amortization of net gain (loss)3 — — 
Total change(5)(1)(5)
Balance at December 31, 2024$(14)$— $(15)
Components of the other postretirement benefit plans' net periodic cost for the Registrants were as follows:
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
2024
Service cost$15 $4 $4 $1 $— $1 
Interest cost65 16 23 3 — 8 
Expected return on plan assets(89)(35)(32)(3)1 (13)
Net amortization(*)
(13)(3)(4)— — 6 
Net periodic other postretirement benefit cost (income)$(22)$(18)$(9)$1 $1 $2 
2023
Service cost$15 $4 $4 $1 $— $1 
Interest cost70 17 25 3 — 9 
Expected return on plan assets(83)(33)(29)(3)1 (10)
Net amortization(*)
(11)(3)(3)— — 6 
Net periodic other postretirement benefit cost (income)$(9)$(15)$(3)$1 $1 $6 
2022
Service cost$23 $6 $6 $1 $— $1 
Interest cost42 10 15 2 — 5 
Expected return on plan assets(80)(32)(28)(2)1 (9)
Net amortization(*)
(1)— 2 — — 6 
Net periodic other postretirement benefit cost (income)$(16)$(16)$(5)$1 $1 $3 
(*)For Southern Company, excludes amounts related to net periodic other postretirement benefit cost of $8 million for all years presented associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company.
The service cost component of net periodic other postretirement benefit cost is included in operations and maintenance expenses and all other components of net periodic other postretirement benefit cost are included in other income (expense), net in the Registrants' statements of income.
The Registrants' future benefit payments, including prescription drug benefits, are provided in the table below. These amounts reflect expected future service and are estimated based on assumptions used to measure the APBO for the other postretirement benefit plans.
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Benefit payments:
2025$112 $24 $40 $5 $1 $16 
2026112 25 40 5 1 16 
2027113 26 41 5 1 15 
2028114 26 41 5 1 15 
2029114 27 42 5 1 14 
2030 to 2034558 133 205 22 1 61 
Benefit Plan Assets
Pension plan and other postretirement benefit plan assets are managed and invested in accordance with all applicable requirements, including ERISA and the Internal Revenue Code. The Registrants' investment policies for both the pension plans and the other postretirement benefit plans cover a diversified mix of assets as described below. Derivative instruments may be used to gain efficient exposure to the various asset classes and as hedging tools. Additionally, the Registrants minimize the risk of large losses primarily through diversification but also monitor and manage other aspects of risk.
The investment strategy for plan assets related to the Southern Company system's qualified pension plan is to be broadly diversified across major asset classes. The asset allocation is established after consideration of various factors that affect the assets and liabilities of the pension plan including, but not limited to, historical and expected returns and interest rates, volatility, correlations of asset classes, the current level of assets and liabilities, and the assumed growth in assets and liabilities. Because a significant portion of the liability of the pension plan is long-term in nature, the assets are invested consistent with long-term investment expectations for return and risk. To manage the actual asset class exposures relative to the target asset allocation, the Southern Company system employs a formal rebalancing program. As additional risk management, external investment managers and service providers are subject to written guidelines to ensure appropriate and prudent investment practices. Management believes the portfolio is well-diversified with no significant concentrations of risk.
Investment Strategies and Benefit Plan Asset Fair Values
A description of the major asset classes that the pension and other postretirement benefit plans are comprised of, along with the valuation methods used for fair value measurement, is provided below:
DescriptionValuation Methodology
Domestic equity: A mix of large and small capitalization stocks with generally an equal distribution of value and growth attributes, managed both actively and through passive index approaches.

International equity: A mix of large and small capitalization growth and value stocks with developed and emerging markets exposure, managed both actively and through fundamental indexing approaches.
Domestic and international equities such as common stocks, American depositary receipts, and real estate investment trusts that trade on public exchanges are classified as Level 1 investments and are valued at the closing price in the active market. Equity funds with unpublished prices that are comprised of publicly traded securities (such as commingled/pooled funds) are also valued at the closing price in the active market but are classified as Level 2.
Fixed income: A mix of domestic and international bonds.
Investments in fixed income securities, including fixed income pooled funds, are generally classified as Level 2 investments and are valued based on prices reported in the market place. Additionally, the value of fixed income securities takes into consideration certain items such as broker quotes, spreads, yield curves, interest rates, and discount rates that apply to the term of a specific instrument.
Trust-owned life insurance (TOLI): Investments of taxable trusts aimed at minimizing the impact of taxes on the portfolio.
Investments in TOLI policies are classified as Level 2 investments and are valued based on the underlying investments held in the policy's separate accounts. The underlying assets are equity and fixed income pooled funds that are comprised of Level 1 and Level 2 securities.
Real estate: Investments in equity or debt of real properties and in publicly traded real estate securities.

Special situations: Investments in opportunistic strategies with the objective of diversifying and enhancing returns and exploiting short-term inefficiencies, as well as investments in promising new strategies of a longer-term nature.

Private equity: Investments in private or public securities typically through privately-negotiated and/or structured transactions, including leveraged buyouts, venture capital, and distressed debt.

Private credit: Investments focused on debt instruments, of which returns are driven by income rather than capital appreciation.

Infrastructure: Investments in real assets, typically with long-term, predictable, and stable cash flows and a meaningful income component.
Investments in real estate, special situations, private equity, private credit, and infrastructure are typically invested in private partnerships and/or other pooled vehicles (Investment Funds) which are generally classified as Net Asset Value as a Practical Expedient, since the Investment Funds and underlying assets are not publicly traded and/or often have liquidity restrictions. The managers of the Investment Funds value the assets using various inputs and techniques depending on the nature of the underlying investments. Techniques may include purchase multiples for comparable transactions, comparable public company trading multiples, discounted cash flow analysis, prevailing market capitalization rates, recent sales of comparable investments, and independent third-party appraisals. The total market value of each of the Investment Funds is determined by aggregating the value of the underlying assets less liabilities.
For purposes of determining the fair value of the pension plan and other postretirement benefit plan assets and the appropriate level designation, management relies on information provided by the plan's trustee. This information is reviewed and evaluated by management with changes made to the trustee information as appropriate. The fair values presented herein exclude cash, receivables related to investment income and pending investment sales, and payables related to pending investment purchases.
The fair values, and actual allocations relative to the target allocations, of the Southern Company system's pension plans at December 31, 2024 and 2023 are presented below.
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)Total
(in millions)
Southern Company
Assets:
Equity:41 %41 %
Domestic equity$2,095 $835 $— $2,930 
International equity1,959 1,032 — 2,991 
Fixed income:30 31 
U.S. Treasury, government, and agency bonds— 1,780 — 1,780 
Mortgage- and asset-backed securities— 48 — 48 
Corporate bonds— 1,715 — 1,715 
Pooled funds— 792 — 792 
Cash equivalents and other255 — — 255 
Real estate investments361 — 1,563 1,924 12 13 
Special situations— — 237 237 3 2 
Private equity— — 1,797 1,797 9 12 
Private credit
— — 152 152 3 1 
Infrastructure
— — — — 2 — 
Total$4,670 $6,202 $3,749 $14,621 100 %100 %
Liabilities:
Derivatives$— $(33)$— $(33)
Total$4,670 $6,169 $3,749 $14,588 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)Total
(in millions)
Alabama Power
Assets:
Equity:41 %41 %
Domestic equity$509 $203 $— $712 
International equity476 251 — 727 
Fixed income:30 31 
U.S. Treasury, government, and agency bonds— 433 — 433 
Mortgage- and asset-backed securities— 12 — 12 
Corporate bonds— 417 — 417 
Pooled funds— 193 — 193 
Cash equivalents and other62 — — 62 
Real estate investments88 — 380 468 12 13 
Special situations— — 57 57 3 2 
Private equity— — 437 437 9 12 
Private credit
— — 37 37 3 1 
Infrastructure
— — — — 2 — 
Total$1,135 $1,509 $911 $3,555 100 %100 %
Liabilities:
Derivatives$— $(8)$— $(8)
Total$1,135 $1,501 $911 $3,547 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)Total
(in millions)
Georgia Power
Assets:
Equity:41 %41 %
Domestic equity$652 $259 $— $911 
International equity608 320 — 928 
Fixed income:30 31 
U.S. Treasury, government, and agency bonds— 552 — 552 
Mortgage- and asset-backed securities— 15 — 15 
Corporate bonds— 532 — 532 
Pooled funds— 246 — 246 
Cash equivalents and other79 — — 79 
Real estate investments112 — 485 597 12 13 
Special situations— — 73 73 3 2 
Private equity— — 558 558 9 12 
Private credit
— — 47 47 3 1 
Infrastructure
— — — — 2 — 
Total$1,451 $1,924 $1,163 $4,538 100 %100 %
Liabilities:
Derivatives$— $(10)$— $(10)
Total$1,451 $1,914 $1,163 $4,528 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)Total
(in millions)
Mississippi Power
Assets:
Equity:41 %41 %
Domestic equity$97 $38 $— $135 
International equity89 47 — 136 
Fixed income:30 31 
U.S. Treasury, government, and agency bonds— 81 — 81 
Mortgage- and asset-backed securities— 2 — 2 
Corporate bonds— 78 — 78 
Pooled funds— 36 — 36 
Cash equivalents and other12 — — 12 
Real estate investments16 — 71 87 12 13 
Special situations— — 11 11 3 2 
Private equity— — 82 82 9 12 
Private credit
— — 7 7 3 1 
Infrastructure
— — — — 2 — 
Total$214 $282 $171 $667 100 %100 %
Liabilities:
Derivatives$— $(2)$— $(2)
Total$214 $280 $171 $665 100 %100 %
Southern Power
Assets:
Equity:41 %41 %
Domestic equity$27 $11 $— $38 
International equity25 13 — 38 
Fixed income:30 31 
U.S. Treasury, government, and agency bonds— 23 — 23 
Mortgage- and asset-backed securities— 1 — 1 
Corporate bonds— 22 — 22 
Pooled funds— 10 — 10 
Cash equivalents and other3 — — 3 
Real estate investments5 — 20 25 12 13 
Special situations— — 3 3 3 2 
Private equity— — 23 23 9 12 
Private credit
— — 2 2 3 1 
Infrastructure
— — — — 2 — 
Total$60 $80 $48 $188 100%100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)Total
(in millions)
Southern Company Gas
Assets:
Equity:41 %41 %
Domestic equity$142 $56 $— $198 
International equity132 69 — 201 
Fixed income:30 31 
U.S. Treasury, government, and agency bonds— 120 — 120 
Mortgage- and asset-backed securities— 3 — 3 
Corporate bonds— 115 — 115 
Pooled funds— 53 — 53 
Cash equivalents and other17 — — 17 
Real estate investments24 — 105 129 12 13 
Special situations— — 16 16 3 2 
Private equity— — 121 121 9 12 
Private credit
— — 10 10 3 1 
Infrastructure
— — — — 2 — 
Total$315 $416 $252 $983 100 %100 %
Liabilities:
Derivatives$— $(2)$— $(2)
Total$315 $414 $252 $981 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2023:(Level 1)(Level 2)(NAV)Total
(in millions)
Southern Company
Assets:
Equity:41 %40 %
Domestic equity$1,959 $771 $— $2,730 
International equity1,947 1,052 — 2,999 
Fixed income:30 32 
U.S. Treasury, government, and agency bonds— 1,973 — 1,973 
Mortgage- and asset-backed securities— 44 — 44 
Corporate bonds— 1,724 — 1,724 
Pooled funds— 777 — 777 
Cash equivalents and other371 58 — 429 
Real estate investments369 — 1,684 2,053 12 14 
Special situations— — 245 245 3 2 
Private equity— — 1,761 1,761 9 12 
Private Credit— — 25 25 3 — 
Infrastructure— — — — 2 — 
Total$4,646 $6,399 $3,715 $14,760 100 %100 %
Alabama Power
Assets:
Equity:41 %40 %
Domestic equity$476 $187 $— $663 
International equity472 255 — 727 
Fixed income:30 32 
U.S. Treasury, government, and agency bonds— 479 — 479 
Mortgage- and asset-backed securities— 11 — 11 
Corporate bonds— 418 — 418 
Pooled funds— 188 — 188 
Cash equivalents and other90 14 — 104 
Real estate investments89 — 408 497 12 14 
Special situations— — 59 59 3 2 
Private equity— — 427 427 9 12 
Private credit
— — 6 6 3 — 
Infrastructure
— — — — 2 — 
Total$1,127 $1,552 $900 $3,579 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2023:(Level 1)(Level 2)(NAV)Total
(in millions)
Georgia Power
Assets:
Equity:41 %40 %
Domestic equity$611 $241 $— $852 
International equity609 329 — 938 
Fixed income:30 32 
U.S. Treasury, government, and agency bonds— 617 — 617 
Mortgage- and asset-backed securities— 14 — 14 
Corporate bonds— 539 — 539 
Pooled funds— 243 — 243 
Cash equivalents and other116 18 — 134 
Real estate investments115 — 527 642 12 14 
Special situations— — 77 77 3 2 
Private equity— — 551 551 9 12 
Private credit
— — 8 8 3 — 
Infrastructure
— — — — 2 — 
Total$1,451 $2,001 $1,163 $4,615 100 %100 %
Mississippi Power
Assets:
Equity:41 %40 %
Domestic equity$89 $35 $— $124 
International equity89 48 — 137 
Fixed income:30 32 
U.S. Treasury, government, and agency bonds— 90 — 90 
Mortgage- and asset-backed securities— 2 — 2 
Corporate bonds— 79 — 79 
Pooled funds— 36 — 36 
Cash equivalents and other17 3 — 20 
Real estate investments17 — 77 94 12 14 
Special situations— — 11 11 3 2 
Private equity— — 81 81 9 12 
Private credit
— — 1 1 3 — 
Infrastructure
— — — — 2 — 
Total$212 $293 $170 $675 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2023:(Level 1)(Level 2)(NAV)Total
(in millions)
Southern Power
Assets:
Equity:41 %40 %
Domestic equity$24 $10 $— $34 
International equity25 13 — 38 
Fixed income:30 32 
U.S. Treasury, government, and agency bonds— 25 — 25 
Mortgage - and asset backed securities
— 1 — 1 
Corporate bonds— 22 — 22 
Pooled funds— 10 — 10 
Cash equivalents and other5 1 — 6 
Real estate investments5 — 21 26 12 14 
Special situations— — 3 3 3 2 
Private equity— — 22 22 9 12 
Private credit
— — — — 3 — 
Infrastructure
— — — — 2 — 
Total$59 $82 $46 $187 100 %100 %
Southern Company Gas
Assets:
Equity:41 %40 %
Domestic equity$130 $52 $— $182 
International equity130 71 — 201 
Fixed income:30 32 
U.S. Treasury, government, and agency bonds— 132 — 132 
Mortgage- and asset-backed securities— 3 — 3 
Corporate bonds— 116 — 116 
Pooled funds— 52 — 52 
Cash equivalents and other25 4 — 29 
Real estate investments25 — 113 138 12 14 
Special situations— — 16 16 3 2 
Private equity— — 118 118 9 12 
Private credit
— — 2 2 3 — 
Infrastructure
— — — — 2 — 
Total$310 $430 $249 $989 100 %100 %
The fair values, and actual allocations relative to the target allocations, of the applicable Registrants' other postretirement benefit plan assets at December 31, 2024 and 2023 are presented below.
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTotalTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)
(in millions)
Southern Company
Assets:
Equity:61 %62 %
Domestic equity$94 $98 $— $192 
International equity54 83 — 137 
Fixed income:29 28 
U.S. Treasury, government, and agency bonds— 54 — 54 
Mortgage- and asset-backed securities— 1 — 1 
Corporate bonds— 48 — 48 
Pooled funds— 99 — 99 
Cash equivalents and other16 — — 16 
Trust-owned life insurance— 478 — 478 
Real estate investments11 — 43 54 4 5 
Special situations— — 6 6 1 1 
Private equity— — 50 50 3 4 
Private credit
— — 4 4 1 — 
Infrastructure
— — — — 1 — 
Total$175 $861 $103 $1,139 100 %100 %
Liabilities:
Derivatives$— $(1)$— $(1)
Total$175 $860 $103 $1,138 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTotalTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)
(in millions)
Alabama Power
Assets:
Equity:68 %68 %
Domestic equity$17 $7 $— $24 
International equity16 9 — 25 
Fixed income:23 24 
U.S. Treasury, government, and agency bonds— 14 — 14 
Corporate bonds— 14 — 14 
Pooled funds— 11 — 11 
Cash equivalents and other2 — — 2 
Trust-owned life insurance— 294 — 294 
Real estate investments3 — 13 16 3 4 
Special situations— — 2 2 1 1 
Private equity— — 15 15 3 3 
Private credit
— — 1 1 1 — 
Infrastructure
— — — — 1 — 
Total$38 $349 $31 $418 100 %100 %
Georgia Power
Assets:
Equity:59 %59 %
Domestic equity$52 $7 $— $59 
International equity16 41 — 57 
Fixed income:35 33 
U.S. Treasury, government, and agency bonds— 14 — 14 
Corporate bonds— 14 — 14 
Pooled funds— 48 — 48 
Cash equivalents and other10 — — 10 
Trust-owned life insurance— 184 — 184 
Real estate investments4 — 13 17 3 4 
Special situations— — 2 2 1 1 
Private equity— — 15 15 2 3 
Total$82 $308 $30 $420 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTotalTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)
(in millions)
Mississippi Power
Assets:
Equity:34 %32 %
Domestic equity$3 $1 $— $4 
International equity3 1 — 4 
Fixed income:43 44 
U.S. Treasury, government, and agency bonds— 7 — 7 
Corporate bonds— 2 — 2 
Pooled funds— 1 — 1 
Cash equivalents and other1 — — 1 
Real estate investments— — 2 2 10 11 
Special situations— — — — 2 2 
Private equity— — 2 2 7 10 
Private credit
— — — — 3 1 
Infrastructure
— — — — 1 — 
Total$7 $12 $4 $23 100 %100 %
Southern Company Gas
Assets:
Equity:72 %73 %
Domestic equity$1 $76 $— $77 
International equity1 23 — 24 
Fixed income:26 25 
U.S. Treasury, government, and agency bonds— 1 — 1 
Corporate bonds— 1 — 1 
Pooled funds— 32 — 32 
Cash equivalents and other1 — — 1 
Real estate investments— — 1 1 1 1 
Private equity— — 1 1 1 1 
Total$3 $133 $2 $138 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2023:(Level 1)(Level 2)(NAV)Total
(in millions)
Southern Company
Assets:
Equity:60 %61 %
Domestic equity$85 $87 $— $172 
International equity53 82 — 135 
Fixed income:30 28 
U.S. Treasury, government, and agency bonds— 57 — 57 
Mortgage- and asset-backed securities— 2 — 2 
Corporate bonds— 47 — 47 
Pooled funds— 92 — 92 
Cash equivalents and other21 2 — 23 
Trust-owned life insurance— 456 — 456 
Real estate investments11 — 46 57 4 6 
Special situations— — 6 6 1 1 
Private equity— — 48 48 3 4 
Private credit
— — 1 1 1 — 
Infrastructure
— — — — 1 — 
Total$170 $825 $101 $1,096 100 %100 %
Alabama Power
Assets:
Equity:67 %66 %
Domestic equity$16 $6 $— $22 
International equity16 9 — 25 
Fixed income:23 23 
U.S. Treasury, government, and agency bonds— 16 — 16 
Corporate bonds— 14 — 14 
Pooled funds— 8 — 8 
Cash equivalents and other3 — — 3 
Trust-owned life insurance— 280 — 280 
Real estate investments3 — 14 17 4 6 
Special situations— — 2 2 1 1 
Private equity— — 15 15 3 4 
Private credit
— — — — 1 — 
Infrastructure
— — — — 1 — 
Total$38 $333 $31 $402 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2023:(Level 1)(Level 2)(NAV)Total
(in millions)
Georgia Power
Assets:
Equity:58 %57 %
Domestic equity$47 $6 $— $53 
International equity16 40 — 56 
Fixed income:35 35 
U.S. Treasury, government, and agency bonds— 16 — 16 
Corporate bonds— 14 — 14 
Pooled funds— 47 — 47 
Cash equivalents and other13 — — 13 
Trust-owned life insurance— 176 — 176 
Real estate investments4 — 14 18 3 4 
Special situations— — 2 2 1 1 
Private equity— — 14 14 2 3 
Private credit
— — — — 1 — 
Total$80 $299 $30 $409 100 %100 %
Mississippi Power
Assets:
Equity:34 %33 %
Domestic equity$3 $1 $— $4 
International equity3 1 — 4 
Fixed income:43 44 
U.S. Treasury, government, and agency bonds— 7 — 7 
Corporate bonds— 2 — 2 
Pooled funds— 1 — 1 
Cash equivalents and other1 — — 1 
Real estate investments1 — 2 3 10 11 
Special situations— — — — 2 2 
Private equity— — 2 2 7 10 
Private credit
— — — — 3 — 
Infrastructure
— — — — 1 — 
Total$8 $12 $4 $24 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2023:(Level 1)(Level 2)(NAV)Total
(in millions)
Southern Company Gas
Assets:
Equity:72 %72 %
Domestic equity$2 $67 $— $69 
International equity2 22 — 24 
Fixed income:26 26 
U.S. Treasury, government, and agency bonds— 1 — 1 
Corporate bonds— 1 — 1 
Pooled funds— 29 — 29 
Cash equivalents and other1 — — 1 
Real estate investments— — 1 1 1 1 
Private equity— — 1 1 1 1 
Total$5 $120 $2 $127 100 %100 %
Employee Savings Plan
Southern Company and its subsidiaries also sponsor 401(k) defined contribution plans covering substantially all employees and provide matching contributions up to specified percentages of an employee's eligible pay. Total matching contributions made to the plans for 2024, 2023, and 2022 were as follows:
Southern CompanyAlabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern Company Gas
(in millions)
2024$137 $29 $31 $5 $3 $20 
2023131 28 31 5 3 18 
2022124 26 29 5 3 17 
v3.25.0.1
STOCK COMPENSATION
 12 Months Ended
Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]  
STOCK COMPENSATION STOCK COMPENSATION
Stock-based compensation in the form of Southern Company performance share units (PSU) and restricted stock units (RSU) may be granted through the Equity and Incentive Compensation Plan to eligible Southern Company system employees.
At December 31, 2024, the number of current and former employees participating in stock-based compensation programs for the Registrants was as follows:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
Number of employees1,154 158 161 36 36 183 
The majority of PSUs and RSUs awarded contain terms where employees become immediately vested in PSUs and RSUs upon retirement. As a result, compensation expense for employees that are retirement eligible at the grant date is recognized immediately, while compensation expense for employees that are expected to become retirement eligible during the vesting period is recognized over the period from grant date to the date of retirement eligibility. In addition, the Registrants recognize forfeitures as they occur.
All unvested PSUs and RSUs vest immediately upon a change in control where Southern Company is not the surviving corporation. Stock-based compensation activity is immaterial for the Subsidiary Registrants.
Performance Share Units
PSUs granted to employees vest at the end of a three-year performance period. Shares of Southern Company common stock are delivered to employees at the end of the performance period with the number of shares issued ranging from 0% to 200% of the target number of PSUs granted, based on achievement of the performance goals established by the Compensation Committee of the Southern Company Board of Directors.
Southern Company has issued two types of PSUs, each with a unique performance goal. These types of PSUs include total shareholder return (TSR) awards based on the TSR for Southern Company common stock during the three-year performance period as compared to a group of industry peers and ROE awards based on Southern Company's equity-weighted return over the performance period.
The fair value of TSR awards is determined as of the grant date using a Monte Carlo simulation model. In determining the fair value of the TSR awards issued to employees, the expected volatility is based on the historical volatility of Southern Company's stock over a period equal to the performance period. The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant that covers the performance period of the awards. The following table shows the assumptions used in the pricing model and the weighted average grant-date fair value of TSR awards granted:
Year Ended December 31202420232022
Expected volatility19.1%30.0%29.6%
Interest rate4.0%3.8%1.7%
Weighted average grant-date fair value$80.99$76.83$79.69
The Registrants recognize TSR award compensation expense on a straight-line basis over the three-year performance period without remeasurement.
The fair values of ROE awards are based on the closing stock price of Southern Company common stock on the date of the grant. The weighted average grant-date fair value of the ROE awards granted during 2024, 2023, and 2022 was $69.67, $68.93, and $66.87, respectively. Compensation expense for ROE awards is generally recognized ratably over the three-year performance period adjusted for expected changes in ROE performance. Total compensation cost recognized for vested ROE awards reflects final performance metrics.
Southern Company had 2.4 million unvested PSUs outstanding at December 31, 2023. In February 2024, the PSUs that vested for the three-year performance period ended December 31, 2023 were converted into 2.3 million shares outstanding at a share price of $66.95. During 2024, Southern Company granted 1.1 million PSUs and 1.2 million PSUs were vested or forfeited, resulting in 2.3 million unvested PSUs outstanding at December 31, 2024. In February 2025, the PSUs that vested for the three-year performance period ended December 31, 2024 were converted into 2.0 million shares outstanding at a weighted average share price of $83.87.
Southern Company's total PSU compensation cost and the related tax benefit recognized in income for the years ended December 31, 2024, 2023, and 2022 were as follows:
202420232022
(in millions)
Compensation cost recognized in income$102 $107 $101 
Tax benefit of compensation cost recognized in income27 28 26 
The compensation cost related to the grant of Southern Company PSUs to the employees of each Subsidiary Registrant is recognized in each Subsidiary Registrant's financial statements with a corresponding credit to equity representing a capital contribution from Southern Company.
At December 31, 2024, Southern Company's total unrecognized compensation cost related to PSUs was $33 million and is expected to be recognized over a weighted-average period of approximately 19 months.
Restricted Stock Units
The fair value of RSUs is based on the closing stock price of Southern Company common stock on the date of the grant. The weighted average grant-date fair values of RSUs granted during 2024, 2023, and 2022 were $70.49, $68.95, and $67.20, respectively. For most RSU awards, one-third of the RSUs vest each year throughout a three-year service period and
compensation cost for RSUs is generally recognized over the corresponding one-, two-, or three-year vesting period. Shares of Southern Company common stock are delivered to employees at the end of each vesting period.
Southern Company had 0.9 million RSUs outstanding at December 31, 2023. During 2024, Southern Company granted 0.5 million RSUs and 0.5 million RSUs were vested or forfeited, resulting in 0.9 million unvested RSUs outstanding at December 31, 2024, including RSUs related to employee retention agreements.
Southern Company's total RSU compensation cost and the related tax benefit recognized in income for the years ended December 31, 2024, 2023, and 2022 were as follows:
202420232022
(in millions)
Compensation cost recognized in income$30 $30 $26 
Tax benefit of compensation cost recognized in income8 8 7 
Total unrecognized compensation cost related to RSUs at December 31, 2024, which is being recognized over a weighted-average period of approximately 19 months, was immaterial for Southern Company.
The compensation cost related to the grant of Southern Company RSUs to the employees of each Subsidiary Registrant is recognized in such Subsidiary Registrant's financial statements with a corresponding credit to equity representing a capital contribution from Southern Company.
Stock Options
In 2015, Southern Company discontinued granting stock options. As of December 31, 2017, all stock option awards were vested and compensation cost fully recognized and the last exercise occurred in November 2024.
Southern Company's cash receipts from issuances related to stock options exercised under the share-based payment arrangements for the years ended December 31, 2024, 2023, and 2022 were $14 million, $28 million, and $75 million, respectively.
Southern Company's total intrinsic value of options exercised and the related tax benefit for the years ended December 31, 2024, 2023, and 2022 were as follows:
202420232022
(in millions)
Intrinsic value of options exercised$10 $18 $49 
Tax benefit of options exercised2 4 12 
v3.25.0.1
FAIR VALUE MEASUREMENTS
 12 Months Ended
Dec. 31, 2024
Fair Value Disclosures [Abstract]  
FAIR VALUE MEASUREMENTS FAIR VALUE MEASUREMENTS
Fair value measurements are based on inputs of observable and unobservable market data that a market participant would use in pricing the asset or liability. The use of observable inputs is maximized where available and the use of unobservable inputs is minimized for fair value measurement and reflects a three-tier fair value hierarchy that prioritizes inputs to valuation techniques used for fair value measurement.
•Level 1 consists of observable market data in an active market for identical assets or liabilities.
•Level 2 consists of observable market data, other than that included in Level 1, that is either directly or indirectly observable.
•Level 3 consists of unobservable market data. The input may reflect the assumptions of each Registrant of what a market participant would use in pricing an asset or liability. If there is little available market data, then each Registrant's own assumptions are the best available information.
In the case of multiple inputs being used in a fair value measurement, the lowest level input that is significant to the fair value measurement represents the level in the fair value hierarchy in which the fair value measurement is reported.
Net asset value as a practical expedient is the classification used for assets that do not have readily determined fair values. Fund managers value the assets using various inputs and techniques depending on the nature of the underlying investments.
At December 31, 2024, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows:
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical Assets Significant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2024:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Southern Company
Assets:
Energy-related derivatives(a)
$12 $77 $— $— $89 
Investments in trusts:(b)
Domestic equity849 250 — — 1,099 
Foreign equity148 175 — — 323 
U.S. Treasury and government agency securities— 371 — — 371 
Municipal bonds— 47 — — 47 
Pooled funds – fixed income— 7 — — 7 
Corporate bonds— 452 — — 452 
Mortgage and asset backed securities— 106 — — 106 
Private equity— — — 181 181 
Cash and cash equivalents1 — — — 1 
Other39 3 — 9 51 
Investments, available for sale:
U.S. Treasury and government agency securities2 7 — — 9 
Corporate bonds1 2 — — 3 
Mortgage and asset backed securities
— 10 — — 10 
Cash equivalents and restricted cash
533 19 — — 552 
Other investments9 31 8 — 48 
Total$1,594 $1,557 $8 $190 $3,349 
Liabilities:
Energy-related derivatives(a)
$5 $124 $— $— $129 
Interest rate derivatives— 269 — — 269 
Foreign currency derivatives— 218 — — 218 
Contingent consideration3 — 16 — 19 
Other— 13 11 — 24 
Total$8 $624 $27 $— $659 
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical Assets Significant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2024:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Alabama Power
Assets:
Energy-related derivatives
$— $26 $— $— $26 
Nuclear decommissioning trusts:(b)
Domestic equity459 241 — — 700 
Foreign equity148 — — — 148 
U.S. Treasury and government agency securities— 16 — — 16 
Municipal bonds— 1 — — 1 
Corporate bonds— 287 — — 287 
Mortgage and asset backed securities— 31 — — 31 
Private equity — — — 181 181 
Other11 1 — 9 21 
Cash equivalents and restricted cash
334 19 — — 353 
Other investments— 31 — — 31 
Total$952 $653 $— $190 $1,795 
Liabilities:
Energy-related derivatives$— $42 $— $— $42 
Georgia Power
Assets:
Energy-related derivatives$— $19 $— $— $19 
Nuclear decommissioning trusts:(b)
Domestic equity390 1 — — 391 
Foreign equity— 174 — — 174 
U.S. Treasury and government agency securities— 355 — — 355 
Municipal bonds— 46 — — 46 
Corporate bonds— 165 — — 165 
Mortgage and asset backed securities— 75 — — 75 
Other28 2 — — 30 
Cash equivalents35 — — — 35 
Total$453 $837 $— $— $1,290 
Liabilities:
Energy-related derivatives$— $42 $— $— $42 
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical Assets Significant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2024:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Mississippi Power
Assets:
Energy-related derivatives$— $19 $— $— $19 
Liabilities:
Energy-related derivatives$— $34 $— $— $34 
Southern Power
Assets:
Energy-related derivatives$— $4 $— $— $4 
Cash equivalents51 — — — 51 
Total$51 $4 $— $— $55 
Liabilities:
Foreign currency derivatives$— $51 $— $— $51 
Contingent consideration3 — 16 — 19 
Other— 13 11 — 24 
Total$3 $64 $27 $— $94 
Southern Company Gas
Assets:
Energy-related derivatives(a)
$12 $9 $— $— $21 
Non-qualified deferred compensation trusts:
Domestic equity— 8 — — 8 
Foreign equity— 1 — — 1 
Pooled funds - fixed income— 7 — — 7 
Cash and cash equivalents1 — — — 1 
Investments, available for sale:
U.S. Treasury and government agency securities2 7 — — 9 
Corporate bonds1 2 — — 3 
Mortgage and asset backed securities
— 10 — — 10 
Cash equivalents22 — — — 22 
Total$38 $44 $— $— $82 
Liabilities:
Energy-related derivatives(a)
$5 $6 $— $— $11 
Interest rate derivatives— 84 — — 84 
Total$5 $90 $— $— $95 
(a)Excludes cash collateral of $17 million.
(b)Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information.
At December 31, 2023, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows:
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2023:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Southern Company
Assets:
Energy-related derivatives(a)
$6 $49 $— $— $55 
Investments in trusts:(b)
Domestic equity764 216 — — 980 
Foreign equity145 171 — — 316 
U.S. Treasury and government agency securities— 369 — — 369 
Municipal bonds— 48 — — 48 
Pooled funds – fixed income— 6 — — 6 
Corporate bonds— 389 — — 389 
Mortgage and asset backed securities— 89 — — 89 
Private equity— — — 169 169 
Cash and cash equivalents3 — — — 3 
Other58 3 — 9 70 
Cash equivalents and restricted cash
253 15 — — 268 
Other investments9 27 8 — 44 
Total$1,238 $1,382 $8 $178 $2,806 
Liabilities:
Energy-related derivatives(a)
$46 $312 $— $— $358 
Interest rate derivatives— 264 — — 264 
Foreign currency derivatives— 122 — — 122 
Contingent consideration3 — 16 — 19 
Other— 13 — — 13 
Total$49 $711 $16 $— $776 
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2023:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Alabama Power
Assets:
Energy-related derivatives
$— $15 $— $— $15 
Nuclear decommissioning trusts:(b)
Domestic equity443 208 — — 651 
Foreign equity145 — — — 145 
U.S. Treasury and government agency securities— 20 — — 20 
Municipal bonds— 1 — — 1 
Corporate bonds— 231 — — 231 
Mortgage and asset backed securities— 25 — — 25 
Private equity — — — 169 169 
Other8 — — 9 17 
Cash equivalents and restricted cash
119 15 — — 134 
Other investments— 27 — — 27 
Total$715 $542 $— $178 $1,435 
Liabilities:
Energy-related derivatives$— $110 $— $— $110 
Georgia Power
Assets:
Energy-related derivatives$— $13 $— $— $13 
Nuclear decommissioning trusts:(b)
Domestic equity321 1 — — 322 
Foreign equity— 170 — — 170 
U.S. Treasury and government agency securities— 349 — — 349 
Municipal bonds— 47 — — 47 
Corporate bonds— 158 — — 158 
Mortgage and asset backed securities— 64 — — 64 
Other50 3 — — 53 
Total$371 $805 $— $— $1,176 
Liabilities:
Energy-related derivatives$— $124 $— $— $124 
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2023:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Mississippi Power
Assets:
Energy-related derivatives$— $15 $— $— $15 
Cash equivalents17 — — — 17 
Total$17 $15 $— $— $32 
Liabilities:
Energy-related derivatives$— $61 $— $— $61 
Southern Power
Assets:
Energy-related derivatives$— $3 $— $— $3 
Liabilities:
Energy-related derivatives$— $5 $— $— $5 
Foreign currency derivatives— 22 — — 22 
Contingent consideration3 — 16 — 19 
Other— 13 — — 13 
Total$3 $40 $16 $— $59 
Southern Company Gas
Assets:
Energy-related derivatives(a)
$6 $3 $— $— $9 
Non-qualified deferred compensation trusts:
Domestic equity— 7 — — 7 
Foreign equity— 1 — — 1 
Pooled funds - fixed income— 6 — — 6 
Cash and cash equivalents
3 — — — 3 
Total$9 $17 $— $— $26 
Liabilities:
Energy-related derivatives(a)
$46 $12 $— $— $58 
Interest rate derivatives— 79 — — 79 
Total$46 $91 $— $— $137 
(a)Excludes cash collateral of $62 million.
(b)Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information.
Valuation Methodologies
The energy-related derivatives primarily consist of exchange-traded and OTC financial products for natural gas and physical power products, including, from time to time, basis swaps. These are standard products used within the energy industry and are valued using the market approach. The inputs used are mainly from observable market sources, such as forward natural gas prices, power prices, implied volatility, and overnight index swap interest rates. Interest rate derivatives are also standard OTC products that are valued using observable market data and assumptions commonly used by market participants. The fair value of interest rate derivatives reflects the net present value of expected payments and receipts under the swap agreement based on the market's
expectation of future interest rates. Additional inputs to the net present value calculation may include the contract terms, counterparty credit risk, and, occasionally, implied volatility of interest rate options. The fair value of cross-currency swaps reflects the net present value of expected payments and receipts under the swap agreement based on the market's expectation of future foreign currency exchange rates. Additional inputs to the net present value calculation may include the contract terms, counterparty credit risk, and discount rates. The interest rate derivatives and cross-currency swaps are categorized as Level 2 under Fair Value Measurements as these inputs are based on observable data and valuations of similar instruments. See Note 14 for additional information on how these derivatives are used.
For fair value measurements of the investments within the nuclear decommissioning trusts and the non-qualified deferred compensation trusts, external pricing vendors are designated for each asset class with each security specifically assigned a primary pricing source. For investments held within commingled funds, fair value is determined at the end of each business day through the net asset value, which is established by obtaining the underlying securities' individual prices from the primary pricing source. A market price secured from the primary source vendor is then evaluated by management in its valuation of the assets within the trusts. As a general approach, fixed income market pricing vendors gather market data (including indices and market research reports) and integrate relative credit information, observed market movements, and sector news into proprietary pricing models, pricing systems, and mathematical tools. Dealer quotes and other market information, including live trading levels and pricing analysts' judgments, are also obtained when available.
The NRC requires licensees of commissioned nuclear power reactors to establish a plan for providing reasonable assurance of funds for future decommissioning. See Note 6 under "Nuclear Decommissioning" for additional information.
Southern Power has contingent payment obligations related to two of its acquisitions whereby it is primarily obligated to make generation-based payments to the seller, commencing at the commercial operation of each facility and continuing through 2026 and 2036, respectively. The obligations are primarily categorized as Level 3 under Fair Value Measurements as the fair value is determined using significant unobservable inputs for the forecasted facility's generation in MW-hours, as well as other inputs such as a fixed dollar amount per MW-hour, and a discount rate. The fair value of the obligations reflects the net present value of expected payments and any periodic change arising from forecasted generation is expected to be immaterial.
Southern Power also has payment obligations through 2040 whereby it must reimburse the transmission owners for interconnection facilities and network upgrades constructed to support connection of a Southern Power generating facility to the transmission system. The obligations are categorized as Level 2 under Fair Value Measurements as the fair value is determined using observable inputs for the contracted amounts and reimbursement period, as well as a discount rate. The fair value of the obligations reflects the net present value of expected payments.
"Other investments" primarily includes investments traded in the open market that have maturities greater than 90 days, which are categorized as Level 2 under Fair Value Measurements and are comprised of corporate bonds, bank certificates of deposit, treasury bonds, and/or agency bonds.
The fair value measurements of private market investments held in Alabama Power's nuclear decommissioning trusts that are calculated at net asset value per share (or its equivalent) as a practical expedient totaled $190 million and $178 million at December 31, 2024 and 2023, respectively. Unfunded commitments related to the private market investments totaled $78 million and $87 million at December 31, 2024 and 2023, respectively. Private market investments include high-quality private equity funds across several market sectors, funds that invest in real estate assets, and a private credit fund. Private market funds do not have redemption rights. Distributions from these funds will be received as the underlying investments in the funds are liquidated.
Southern Company Gas' investments, available for sale relate to a wholly-owned subsidiary that insures various risk exposures of Southern Company Gas and its subsidiaries. Corporate and municipal bonds, government agency securities, and commercial paper are valued using pricing models maximizing the use of observable inputs for similar securities, including basing value on yields currently available on comparable securities of issues with similar credit ratings. Mortgage and asset backed securities are valued through an analysis of the underlying assets and a review of the documentation, including financials, the manager's valuation methodology in valuing their underlying assets, the types of assets and risks involved, and the investor's exit and termination parameters.
At December 31, 2024 and 2023, other financial instruments for which the carrying amount did not equal fair value were as follows:
Southern
  Company(*)
Alabama PowerGeorgia PowerMississippi PowerSouthern Power
Southern Company
 Gas(*)
(in billions)
At December 31, 2024:
Long-term debt, including securities due within one year:
Carrying amount$63.2 $11.2 $18.1 $1.7 $2.7 $8.5 
Fair value57.7 9.8 16.2 1.5 2.6 7.4 
At December 31, 2023:
Long-term debt, including securities due within one year:
Carrying amount$59.4 $11.2 $16.5 $1.6 $2.7 $7.8 
Fair value55.0 10.1 15.1 1.4 2.6 6.8 
(*)The carrying amount of Southern Company Gas' long-term debt includes fair value adjustments from the effective date of the 2016 merger with Southern Company. Southern Company Gas amortizes the fair value adjustments over the remaining lives of the respective bonds, the latest being through 2043.
The fair values are determined using Level 2 measurements and are based on quoted market prices for the same or similar issues or on the current rates available to the Registrants.
v3.25.0.1
DERIVATIVES
 12 Months Ended
Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
DERIVATIVES DERIVATIVES
The Registrants are exposed to market risks, including commodity price risk, interest rate risk, weather risk, and occasionally foreign currency exchange rate risk. To manage the volatility attributable to these exposures, each company nets its exposures, where possible, to take advantage of natural offsets and enters into various derivative transactions for the remaining exposures pursuant to each company's policies in areas such as counterparty exposure and risk management practices. Each company's policy is that derivatives are to be used primarily for hedging purposes and mandates strict adherence to all applicable risk management policies. Derivative positions are monitored using techniques including, but not limited to, market valuation, value at risk, stress testing, and sensitivity analysis. Derivative instruments are recognized at fair value in the balance sheets as either assets or liabilities and are presented on a net basis. See Note 13 for additional fair value information. In the statements of cash flows, any cash impacts of settled energy-related and interest rate derivatives are recorded as operating activities. Any cash impacts of settled foreign currency derivatives are classified as operating or financing activities to correspond with the classification of the hedged interest or principal, respectively. See Note 1 under "Financial Instruments" for additional information.
Energy-Related Derivatives
The Subsidiary Registrants enter into energy-related derivatives to hedge exposures to electricity, natural gas, and other fuel price changes. However, due to cost-based rate regulations and other various cost recovery mechanisms, the traditional electric operating companies and the natural gas distribution utilities have limited exposure to market volatility in energy-related commodity prices. Each of the traditional electric operating companies and certain of the natural gas distribution utilities of Southern Company Gas manage fuel-hedging programs, implemented per the guidelines of their respective state PSCs or other applicable state regulatory agencies, through the use of financial derivative contracts, which are expected to continue to mitigate price volatility. The traditional electric operating companies (with respect to wholesale generating capacity) and Southern Power have limited exposure to market volatility in energy-related commodity prices because their long-term sales contracts shift substantially all fuel cost responsibility to the purchaser. However, the traditional electric operating companies and Southern Power may be exposed to market volatility in energy-related commodity prices to the extent any uncontracted capacity is used to sell electricity. Southern Company Gas retains exposure to price changes that can, in a volatile energy market, be material and can adversely affect its results of operations.
Southern Company Gas also enters into weather derivative contracts as economic hedges in the event of warmer-than-normal weather. Exchange-traded options are carried at fair value, with changes reflected in natural gas revenues. Non-exchange-traded options are accounted for using the intrinsic value method. Changes in the intrinsic value for non-exchange-traded contracts are reflected in natural gas revenues.
Energy-related derivative contracts are accounted for under one of three methods:
•Regulatory Hedges – Energy-related derivative contracts designated as regulatory hedges relate primarily to the traditional electric operating companies' and the natural gas distribution utilities' fuel-hedging programs, where gains and losses are initially recorded as regulatory liabilities and assets, respectively, and then are included in fuel expense as the underlying fuel is used in operations and ultimately recovered through an approved cost recovery mechanism.
•Cash Flow Hedges – Gains and losses on energy-related derivatives designated as cash flow hedges (which are mainly used to hedge anticipated purchases and sales) are initially deferred in AOCI before being recognized in the statements of income in the same period and in the same income statement line item as the earnings effect of the hedged transactions.
•Not Designated – Gains and losses on energy-related derivative contracts that are not designated or fail to qualify as hedges are recognized in the statements of income as incurred.
Some energy-related derivative contracts require physical delivery as opposed to financial settlement, and this type of derivative is both common and prevalent within the electric and natural gas industries. When an energy-related derivative contract is settled physically, any cumulative unrealized gain or loss is reversed and the contract price is recognized in the respective line item representing the actual price of the underlying goods being delivered.
At December 31, 2024, the net volume of energy-related derivative contracts for natural gas positions, together with the longest hedge date over which the respective entity is hedging its exposure to the variability in future cash flows for forecasted transactions and the longest non-hedge date for derivatives not designated as hedges, were as follows:
Net
Purchased
mmBtu		Longest
Hedge
Date		Longest
Non-Hedge
Date
(in millions)
Southern Company(*)
43120302028
Alabama Power1232027—
Georgia Power1162027—
Mississippi Power1032028—
Southern Power620302025
Southern Company Gas(*)
8320272028
(*)Southern Company Gas' derivative instruments include both long and short natural gas positions. A long position is a contract to purchase natural gas and a short position is a contract to sell natural gas. Southern Company Gas' volume represents the net of long natural gas positions of 90 million mmBtu and short natural gas positions of 7 million mmBtu at December 31, 2024, which is also included in Southern Company's total volume.
In addition to the volumes discussed above, the traditional electric operating companies and Southern Power enter into physical natural gas supply contracts that provide the option to sell back excess natural gas due to operational constraints. The maximum expected volume of natural gas subject to such a feature is 15 million mmBtu for Southern Company, which includes 4 million mmBtu for Alabama Power, 6 million mmBtu for Georgia Power, 2 million mmBtu for Mississippi Power, and 3 million mmBtu for Southern Power.
For cash flow hedges of energy-related derivatives, the estimated pre-tax gains (losses) expected to be reclassified from AOCI to earnings for the year ending December 31, 2025 are immaterial for Southern Company, Southern Power, and Southern Company Gas.
Interest Rate Derivatives
Southern Company and certain subsidiaries may enter into interest rate derivatives to hedge exposure to changes in interest rates. Derivatives related to existing variable rate securities or forecasted transactions are accounted for as cash flow hedges where the derivatives' fair value gains or losses are recorded in OCI and are reclassified into earnings at the same time and presented on the same income statement line item as the earnings effect of the hedged transactions. Derivatives related to existing fixed rate securities are accounted for as fair value hedges, where the derivatives' fair value gains or losses and hedged items' fair value gains or losses are both recorded directly to earnings on the same income statement line item. Fair value gains or losses on derivatives that are not designated or fail to qualify as hedges are recognized in the statements of income as incurred.
At December 31, 2024, the following interest rate derivatives were outstanding:
Notional
Amount		Weighted Average Interest Rate PaidInterest
Rate
Received		Hedge
Maturity
Date		Fair Value
Gain (Loss) December 31, 2024
(in millions)(in millions)
Fair Value Hedges of Existing Debt
Southern Company parent$400 
1-month SOFR + 0.80%
1.75%March 2028$(42)
Southern Company parent1,000 
1-month SOFR + 2.48%
3.70%April 2030(143)
Southern Company Gas500 
1-month SOFR + 0.49%
1.75%January 2031(84)
Southern Company$1,900 $(269)
For cash flow hedges of interest rate derivatives, the estimated pre-tax gains (losses) expected to be reclassified from AOCI to interest expense for the year ending December 31, 2025 are $(13) million for Southern Company and immaterial for the traditional electric operating companies and Southern Company Gas. Deferred gains and losses related to interest rate derivatives are expected to be amortized into earnings through 2054 for Southern Company, Georgia Power, and Mississippi Power, 2052 for Alabama Power, and 2046 for Southern Company Gas.
Foreign Currency Derivatives
Southern Company and certain subsidiaries, including Southern Power, may enter into foreign currency derivatives to hedge exposure to changes in foreign currency exchange rates, such as that arising from the issuance of debt denominated in a currency other than U.S. dollars. Derivatives related to forecasted transactions are accounted for as cash flow hedges where the derivatives' fair value gains or losses are recorded in OCI and are reclassified into earnings at the same time and on the same income statement line as the earnings effect of the hedged transactions, including foreign currency gains or losses arising from changes in the U.S. currency exchange rates. Derivatives related to existing fixed rate securities are accounted for as fair value hedges, where the derivatives' fair value gains or losses and hedged items' fair value gains or losses are both recorded directly to earnings on the same income statement line item, including foreign currency gains or losses arising from changes in the U.S. currency exchange rates. Southern Company has elected to exclude the cross-currency basis spread from the assessment of effectiveness in the fair value hedges of its foreign currency risk and record any difference between the change in the fair value of the excluded components and the amounts recognized in earnings as a component of OCI.
At December 31, 2024, the following foreign currency derivatives were outstanding:
Pay NotionalPay RateReceive NotionalReceive RateHedge
Maturity Date		Fair Value
Gain (Loss) December 31, 2024
(in millions)(in millions) (in millions)
Cash Flow Hedges of Existing Debt
Southern Power$564 3.78%€500 1.85%June 2026$(51)
Fair Value Hedges of Existing Debt
Southern Company parent1,476 3.39%1,250 1.88%September 2027(167)
Southern Company$2,040 €1,750 $(218)
For cash flow hedges of foreign currency derivatives, the estimated pre-tax losses expected to be reclassified from AOCI to earnings for the year ending December 31, 2025 are $25 million for Southern Power.
Derivative Financial Statement Presentation and Amounts
The Registrants enter into derivative contracts that may contain certain provisions that permit intra-contract netting of derivative receivables and payables for routine billing and offsets related to events of default and settlements. Southern Company and certain subsidiaries also utilize master netting agreements to mitigate exposure to counterparty credit risk. These agreements may contain provisions that permit netting across product lines and against cash collateral. The fair value amounts of derivative assets and liabilities on the balance sheets are presented net to the extent that there are netting arrangements or similar agreements with the counterparties.
The fair value of energy-related derivatives, interest rate derivatives, and foreign currency derivatives was reflected as either assets or liabilities in the balance sheets (included in "Other" or shown separately as "Risk Management Activities") as follows:
20242023
Derivative Category and Balance Sheet LocationAssetsLiabilitiesAssetsLiabilities
(in millions)
Southern Company
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$33 $82 $12 $198 
Non-current
42 40 31 117 
Total derivatives designated as hedging instruments for regulatory purposes75 122 43 315 
Derivatives designated as hedging instruments in cash flow and fair value hedges
Energy-related derivatives:
Current
4 3 — 29 
Non-current
4 — 3 4 
Interest rate derivatives:
Current
— 61 — 74 
Non-current
— 208 — 190 
Foreign currency derivatives:
Current
— 36 — 34 
Non-current
— 182 — 88 
Total derivatives designated as hedging instruments in cash flow and fair value hedges8 490 3 419 
Energy-related derivatives not designated as hedging instruments
Current
5 3 8 8 
Non-current
1 — 1 2 
Total derivatives not designated as hedging instruments6 3 9 10 
Gross amounts recognized 89 615 55 744 
Gross amounts offset(a)
(44)(61)(23)(85)
Net amounts recognized in the Balance Sheets(b)
$45 $554 $32 $659 
Alabama Power
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$11 $30 $6 $69 
Non-current
15 12 9 41 
Total derivatives designated as hedging instruments for regulatory purposes26 42 15 110 
Gross amounts offset(19)(19)(10)(10)
Net amounts recognized in the Balance Sheets$7 $23 $5 $100 
20242023
Derivative Category and Balance Sheet LocationAssetsLiabilitiesAssetsLiabilities
(in millions)
Georgia Power
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$6 $32 $2 $82 
Non-current
13 9 10 42 
Total derivatives designated as hedging instruments for regulatory purposes19 41 12 124 
Energy-related derivatives not designated as hedging instruments
Current
— 1 — — 
Non-current
— — 1 — 
Total derivatives not designated as hedging instruments— 1 1 — 
Gross amounts recognized19 42 13 124 
Gross amounts offset(15)(15)(11)(11)
Net amounts recognized in the Balance Sheets$4 $27 $2 $113 
Mississippi Power
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$5 $15 $3 $27 
Non-current
14 19 12 34 
Total derivatives designated as hedging instruments for regulatory purposes19 34 15 61 
Gross amounts offset(17)(17)(14)(14)
Net amounts recognized in the Balance Sheets$2 $17 $1 $47 
Southern Power
Derivatives designated as hedging instruments in cash flow hedges
Energy-related derivatives:
Current
$1 $— $— $5 
Non-current
3 — 3 — 
Foreign currency derivatives:
Current
— 11 — 11 
Non-current
— 40 — 11 
Total derivatives designated as hedging instruments in cash flow hedges
4 51 3 27 
Net amounts recognized in the Balance Sheets$4 $51 $3 $27 
20242023
Derivative Category and Balance Sheet LocationAssetsLiabilitiesAssetsLiabilities
(in millions)
Southern Company Gas
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$11 $5 $1 $20 
Derivatives designated as hedging instruments in cash flow and fair value hedges
Energy-related derivatives:
Current
3 3 — 24 
Non-current
1 — — 4 
Interest rate derivatives:
Current
— 17 — 20 
Non-current
— 67 — 59 
Total derivatives designated as hedging instruments in cash flow and fair value hedges4 87 — 107 
Energy-related derivatives not designated as hedging instruments
Current
5 2 7 8 
Non-current
1 — 1 2 
Total derivatives not designated as hedging instruments6 2 8 10 
Gross amounts recognized21 94 9 137 
Gross amounts offset(a)
7 (10)12 (50)
Net amounts recognized in the Balance Sheets(b)
$28 $84 $21 $87 
(a)Gross amounts offset includes cash collateral held on deposit in broker margin accounts of $17 million and $62 million at December 31, 2024 and 2023, respectively.
(b)Net amounts of derivative instruments outstanding exclude immaterial premium and intrinsic value associated with weather derivatives for all periods presented.
At December 31, 2024 and 2023, the pre-tax effects of unrealized derivative gains (losses) arising from energy-related derivative instruments designated as regulatory hedging instruments and deferred were as follows:
Regulatory Hedge Unrealized Gain (Loss) Recognized in the Balance Sheets
Derivative Category and Balance Sheet
Location		Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern Company Gas
 (in millions)
At December 31, 2024:
Energy-related derivatives:
Other regulatory assets, current$(61)$(23)$(26)$(11)$(1)
Other regulatory assets, deferred(5)— — (5)— 
Other regulatory liabilities, current8 4 — — 4 
Other regulatory liabilities, deferred8 3 4 1 — 
Total energy-related derivative gains (losses)$(50)$(16)$(22)$(15)$3 
At December 31, 2023:
Energy-related derivatives:
Other regulatory assets, current$(180)$(67)$(80)$(25)$(8)
Other regulatory assets, deferred(87)(32)(33)(22)— 
Other regulatory liabilities, current9 4 — 1 4 
Other regulatory liabilities, deferred1 — 1 — — 
Total energy-related derivative gains (losses)$(257)$(95)$(112)$(46)$(4)
For the years ended December 31, 2024, 2023, and 2022, the pre-tax effects of cash flow and fair value hedge accounting on AOCI for the applicable Registrants were as follows:
Gain (Loss) From Derivatives Recognized in OCI202420232022
(in millions)
Southern Company
Cash flow hedges:
Energy-related derivatives$(7)$(81)$3 
Interest rate derivatives23 (12)46 
Foreign currency derivatives(40)14 (105)
Fair value hedges(*):
Foreign currency derivatives16 21 (24)
Total$(8)$(58)$(80)
Georgia Power
Cash flow hedges:
Interest rate derivatives$24 $(2)$31 
Mississippi Power
Cash flow hedges:
Interest rate derivatives$7 $— $— 
Southern Power
Cash flow hedges:
Energy-related derivatives$(1)$(18)$(15)
Foreign currency derivatives(40)14 (105)
Total$(41)$(4)$(120)
Southern Company Gas
Cash flow hedges:
Energy-related derivatives$(6)$(63)$18 
Interest rate derivatives(5)— — 
Total$(11)$(63)$18 
(*)Represents amounts excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI.
The pre-tax effects of interest rate derivatives designated as cash flow hedging instruments on AOCI were immaterial for Alabama Power for the years ended December 31, 2023 and 2022.
The pre-tax effects of cash flow and fair value hedge accounting on income for the years ended December 31, 2024, 2023, and 2022 were as follows:
Gain (Loss)
Statements of Income Location
Derivative Category
202420232022
(in millions)
Southern Company
Cost of natural gas
Energy-related cash flow hedges
$(40)$(44)$37 
Other operations and maintenance
Energy-related cash flow hedges
(2)(2)— 
Depreciation and amortization
Energy-related cash flow hedges
(6)(23)(5)
Interest expense, net of amounts capitalized
Interest rate cash flow hedges
(16)(35)(25)
Foreign currency cash flow hedges
(12)(11)(19)
Interest rate fair value hedges
(4)37 (291)
Other income (expense), net
Foreign currency cash flow hedges
(33)19 (83)
Foreign currency fair value hedges
2 69 (106)
Amount excluded from effectiveness testing recognized in earnings
(16)(21)24 
Southern Power
Depreciation and amortization
Energy-related cash flow hedges
$(6)$(23)$(5)
Interest expense, net of amounts capitalized
Foreign currency cash flow hedges
(12)(11)(19)
Other income (expense), net
Foreign currency cash flow hedges
(33)19 (83)
Southern Company Gas
Cost of natural gas
Energy-related cash flow hedges
$(40)$(44)$37 
Other operations and maintenance
Energy-related cash flow hedges
(2)(2)— 
Interest expense, net of amounts capitalized
Interest rate cash flow hedges
(1)(19)(4)
Interest rate fair value hedges
(5)6 (86)
The pre-tax effects of cash flow hedge accounting on income for interest rate derivatives were immaterial for the traditional electric operating companies for all years presented.
At December 31, 2024 and 2023, the following amounts were recorded on the balance sheets related to cumulative basis adjustments for fair value hedges:
Carrying Amount of
the Hedged Item		Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item
Balance Sheet Location of Hedged ItemsAt December 31, 2024At December 31, 2023At December 31, 2024At December 31, 2023
(in millions)(in millions)
Southern Company
Long-term debt$(2,936)$(3,024)$242 $235 
Southern Company Gas
Long-term debt$(422)$(427)$75 $70 
The pre-tax effects of energy-related derivatives not designated as hedging instruments on the statements of income of Southern Company and Southern Company Gas for the years ended December 31, 2024, 2023, and 2022 were as follows:
Gain (Loss)
Derivatives in Non-Designated Hedging RelationshipsStatements of Income Location202420232022
(in millions)
Energy-related derivatives
Natural gas revenues(*)
$— $— $(11)
Cost of natural gas94 59 (65)
Total derivatives in non-designated hedging relationships$94 $59 $(76)
(*)Excludes the impact of weather derivatives recorded in natural gas revenues of $12 million, $15 million, and $(7) million for 2024, 2023 and 2022, respectively, as they are accounted for based on intrinsic value rather than fair value.
The pre-tax effects of energy-related derivatives not designated as hedging instruments were immaterial for all other Registrants for all years presented.
Contingent Features
The Registrants do not have any credit arrangements that would require material changes in payment schedules or terminations as a result of a credit rating downgrade. There are certain derivatives that could require collateral, but not accelerated payment, in the event of various credit rating changes of certain Southern Company subsidiaries. Generally, collateral may be provided by a Southern Company guaranty, letter of credit, or cash. At December 31, 2024, the Registrants had no collateral posted with derivative counterparties to satisfy these arrangements.
For Southern Company, the fair value of foreign currency derivative liabilities and interest rate derivative liabilities with contingent features, and the maximum potential collateral requirements arising from the credit-risk-related contingent features at a rating below BBB- and/or Baa3, was $72 million at December 31, 2024. For Southern Power, the fair value of foreign currency derivative liabilities with contingent features, and the maximum potential collateral requirements arising from the credit-risk-related contingent features at a rating below BBB- and/or Baa3, was $24 million at December 31, 2024. For the traditional electric operating companies and Southern Power, energy-related derivative liabilities with contingent features and the maximum potential collateral requirements arising from the credit-risk-related contingent features, at a rating below BBB- and/or Baa3, were immaterial at December 31, 2024. The maximum potential collateral requirements arising from the credit-risk-related contingent features for the traditional electric operating companies and Southern Power include certain agreements that could require collateral in the event that one or more Southern Company power pool participants has a credit rating change to below investment grade.
Alabama Power and Southern Power maintain accounts with certain regional transmission organizations to facilitate financial derivative transactions, and they may be required to post collateral based on the value of the positions in these accounts and the associated margin requirements. At December 31, 2024, cash collateral posted in these accounts was immaterial for Alabama Power and Southern Power. Southern Company Gas maintains accounts with brokers or the clearing houses of certain exchanges to facilitate financial derivative transactions. Based on the value of the positions in these accounts and the associated margin requirements, Southern Company Gas may be required to deposit cash into these accounts. At December 31, 2024, cash collateral held on deposit in broker margin accounts was $17 million.
The Registrants are exposed to losses related to financial instruments in the event of counterparties' nonperformance. The Registrants generally enter into agreements and material transactions with counterparties that have investment grade credit ratings by Moody's, S&P, or Fitch or with counterparties who have posted collateral to cover potential credit exposure. The Registrants have also established risk management policies and controls to determine and monitor the creditworthiness of counterparties in order to mitigate their exposure to counterparty credit risk.
Southern Company Gas uses established credit policies to determine and monitor the creditworthiness of counterparties, including requirements to post collateral or other credit security, as well as the quality of pledged collateral. Collateral or credit security is most often in the form of cash or letters of credit from an investment-grade financial institution, but may also include cash or U.S. government securities held by a trustee. Prior to entering a physical transaction, Southern Company Gas assigns its counterparties an internal credit rating and credit limit based on the counterparties' Moody's, S&P, and Fitch ratings, commercially available credit reports, and audited financial statements. Southern Company Gas may require counterparties to pledge additional collateral when deemed necessary.
Southern Company Gas utilizes netting agreements whenever possible to mitigate exposure to counterparty credit risk. Netting agreements enable Southern Company Gas to net certain assets and liabilities by counterparty across product lines and against
cash collateral, provided the netting and cash collateral agreements include such provisions. While the amounts due from, or owed to, counterparties are settled net, they are recorded on a gross basis on the balance sheet as energy marketing receivables and energy marketing payables.
The Registrants do not anticipate a material adverse effect on their respective financial statements as a result of counterparty nonperformance.
v3.25.0.1
ACQUISITIONS AND DISPOSITIONS
 12 Months Ended
Dec. 31, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]  
ACQUISITIONS AND DISPOSITIONS ACQUISITIONS AND DISPOSITIONS
Alabama Power
In 2022, Alabama Power completed its acquisition of the Calhoun Generating Station, which was accounted for as an asset acquisition. The total purchase price was $179 million, of which $171 million was related to net assets recorded within property, plant, and equipment on the balance sheet and reflected in property additions within the investing section of the statement of cash flows. The remainder primarily related to fossil fuel stock and materials and supplies. See Note 2 under "Alabama Power – Rate CNP New Plant" for additional information.
On October 24, 2024, Alabama Power entered into an agreement to acquire all of the equity interests in Tenaska Alabama Partners, L.P., which owns and operates the Lindsay Hill Generating Station. See Note 2 under "Alabama Power – Petition for Certificate of Convenience and Necessity" for additional information.
Mississippi Power
On November 8, 2024, Mississippi Power entered into an agreement with FP&L to acquire FP&L's 50% ownership interest in Plant Daniel Units 1 and 2. See Note 2 under "Mississippi Power – Plant Daniel" for additional information.
Southern Power
Southern Power's acquisition-related costs for the projects discussed under "Asset Acquisitions" and "Construction Projects" were not material for any of the years presented.
Asset Acquisitions
During 2023, Southern Power acquired the Millers Branch and South Cheyenne projects, as discussed further under "Construction Projects" below, with an aggregate purchase price of $193 million. There were no asset acquisitions during 2024 and 2022.
Construction Projects
During 2024, Southern Power completed construction of and placed in service the 150-MW South Cheyenne solar facility. In addition, Southern Power continued construction of the 200-MW first phase and began construction of the 180-MW second phase and the 132-MW third phase of the Millers Branch solar facility. At December 31, 2024, the total cost of construction incurred for the Millers Branch project was $292 million, which is primarily included in CWIP.
Project
Facility		Resource
Approximate Nameplate Capacity (MW)
Location
Actual/Projected COD
PPA Contract Period
Projects Under Construction at December 31, 2024
Millers Branch
Phase I
Solar
200
Haskell County, TX
Fourth quarter 2025
20 years
Phase II
Solar
180Haskell County, TX
Second quarter 2026
15 years
Phase III
Solar
132Haskell County, TX
Fourth quarter 2026
15 years
Projects Completed During 2024
South Cheyenne
Solar
150
Laramie County, WY
April 2024
20 years
Projects Completed During 2022
Garland Solar Storage(a)
Battery energy storage88Kern County, CA
September 2021 through February 2022(b)
20 years
Tranquillity Solar Storage(a)
Battery energy storage72Fresno County, CA
November 2021 through
March 2022(c)
20 years
(a)Southern Power consolidates each project's operating results in its financial statements and the tax equity partner and two other partners each own a noncontrolling interest. See Note 9 under "Lessor" for additional information.
(b)The facility has a total capacity of 88 MWs, of which 73 MWs were placed in service in 2021 and 15 MWs were placed in service in 2022.
(c)The facility has a total capacity of 72 MWs, of which 32 MWs were placed in service in 2021 and 40 MWs were placed in service in 2022.
Development Projects
In November 2024, Southern Power committed to a development project to repower 200 MWs of the 299-MW Kay Wind facility located in Kay County, Oklahoma. The output of the project is contracted under an amended 20-year PPA with commercial operation projected to occur in the third quarter 2026.
Southern Company Gas
In September 2022, certain affiliates of Southern Company Gas entered into agreements to sell two natural gas storage facilities located in California and Texas for an aggregate purchase price of $186 million, plus working capital and certain other adjustments. The sale of the Texas facility was completed in November 2022 and the sale of the California facility was completed in September 2023. Both sales resulted in an immaterial loss. Completion of the sale of the Texas facility was subject to release of a Southern Company Gas parent guarantee, which was executed in October 2022 and, as a result, Southern Company Gas recorded pre-tax impairment charges totaling approximately $131 million ($99 million after tax) in the fourth quarter 2022.
Neither of these dispositions, both individually and combined, represented a strategic shift in operations for Southern Company Gas that has, or is expected to have, a major effect on its operations and financial results; therefore, none of the assets related to the sales were classified as discontinued operations for the applicable periods presented.
v3.25.0.1
SEGMENT AND RELATED INFORMATION
 12 Months Ended
Dec. 31, 2024
Segment Reporting [Abstract]  
SEGMENT AND RELATED INFORMATION SEGMENT AND RELATED INFORMATION
The Registrants adopted ASU 2023-07 and applied the guidance retrospectively effective for the fiscal year beginning January 1, 2024. See Note 1 under "Recently Adopted Accounting Standards" for additional information.
The CODM at Southern Company, the traditional electric operating companies, and Southern Company Gas is the chairman, president, and chief executive officer of such Registrant. Southern Power's CODM consists of the chairman and chief executive officer and the president. The CODMs assess segment performance using net income that is reflected on the Registrants' respective statements of income as net income attributable to the registrant, net income after dividends on preferred stock, or net income, as applicable. The CODMs use net income in the annual budget and forecasting process and consider budget versus actual results on a monthly basis when making decisions about the allocation of resources. Unless noted below, the CODMs do not utilize segment asset information.
Southern Company
Southern Company's reportable business segments are the sale of electricity by the traditional electric operating companies, the sale of electricity in the competitive wholesale market by Southern Power, and the sale of natural gas and other complementary products and services by Southern Company Gas. While the traditional electric operating companies represent three separate operating segments, they are vertically integrated utilities providing electric service to retail customers, as well as wholesale customers, in the Southeast and have been aggregated into one reportable segment. Revenues from sales by Southern Power to the traditional electric operating companies were $371 million, $537 million, and $875 million in 2024, 2023, and 2022, respectively. Revenues from sales of natural gas from Southern Company Gas to the traditional electric operating companies and Southern Power were immaterial for all periods presented. The "All Other" column includes the Southern Company parent entity, which does not allocate operating expenses to business segments. Also, this category includes segments below the quantitative threshold for separate disclosure. These segments include providing distributed energy and resilience solutions and deploying microgrids for commercial, industrial, governmental, and utility customers, as well as investments in telecommunications. All other inter-segment revenues are not material.
Southern Company's CODM utilizes segment net income, including variances to budget and forecasts, to assess performance and is not provided with segment expense information. To achieve the consolidated net income goal, Southern Company's CODM sets net income expectations for each operating segment, which is expected to monitor its expenses in order to achieve its assigned net income target. Therefore, Southern Company has no reportable significant segment expenses.
Financial data for business segments and products and services for the years ended December 31, 2024, 2023, and 2022 was as follows:
Electric Utilities
Traditional
Electric
Operating
Companies		Southern
Power		EliminationsTotalSouthern Company Gas
Total Reportable Segments
All
Other		EliminationsConsolidated
(in millions)
2024
Operating revenues$19,977 $2,014 $(388)$21,603 $4,456 $26,059 $843 $(178)$26,724 
Other segment items(a)(b)(c)(d)
10,057 1,060 (388)10,729 2,613 13,342 802 (149)13,995 
Depreciation and amortization(e)
3,512 522 — 4,034 650 4,684 71 — 4,755 
Earnings from equity method investments8 — — 8 146 154 (17)2 139 
Interest expense1,255 117 — 1,372 341 1,713 1,030 — 2,743 
Income taxes (benefit)1,016 (13)— 1,003 258 1,261 (292)— 969 
Segment net income (loss)(b)(c)(d)(e)(f)
$4,145 $328 $— $4,473 $740 $5,213 $(785)$(27)$4,401 
Goodwill$— $2 $— $2 $5,015 $5,017 $144 $— $5,161 
Total assets105,577 12,653 (1,025)117,205 26,177 143,382 2,371 (573)145,180 
2023
Operating revenues$18,358 $2,189 $(549)$19,998 $4,702 $24,700 $718 $(165)$25,253 
Other segment items(a)(c)(g)(h)
9,643 1,187 (549)10,281 3,124 13,405 699 (150)13,954 
Depreciation and amortization3,361 504 — 3,865 582 4,447 78 — 4,525 
Earnings from equity method investments(1)— — (1)140 139 5 — 144 
Interest expense1,145 129 — 1,274 310 1,584 879 (17)2,446 
Income taxes (benefit)571 12 — 583 211 794 (298)— 496 
Segment net income (loss)(c)(f)(g)(h)
$3,637 $357 $— $3,994 $615 $4,609 $(635)$2 $3,976 
Goodwill$— $2 $— $2 $5,015 $5,017 $144 $— $5,161 
Total assets100,429 12,761 (545)112,645 25,083 137,728 2,446 (843)139,331 
2022
Operating revenues$20,408 $3,369 $(904)$22,873 $5,962 $28,835 $593 $(149)$29,279 
Other segment items(a)(c)(i)(j)
12,820 2,341 (904)14,257 4,536 18,793 771 (138)19,426 
Depreciation and amortization2,513 516 — 3,029 559 3,588 75 — 3,663 
Earnings from equity method investments— — — — 148 148 3 — 151 
Interest expense929 138 — 1,067 263 1,330 694 (2)2,022 
Income taxes (benefit)828 20 — 848 180 1,028 (233)— 795 
Segment net income (loss)(c)(f)(i)(j)
$3,318 $354 $— $3,672 $572 $4,244 $(711)$(9)$3,524 
Goodwill$— $2 $— $2 $5,015 $5,017 $144 $— $5,161 
Total assets95,861 13,081 (659)108,283 24,621 132,904 2,665 (678)134,891 
(a)Primarily consists of fuel, purchased power, cost of natural gas, cost of other sales, other operations and maintenance, taxes other than income taxes, charges (credits) to income for estimated probable losses, losses (gains) on asset dispositions, impairment charges, AFUDC equity, non-service cost-related retirement benefits income, and net income (loss) attributable to noncontrolling interests.
(b)For the traditional electric operating companies, includes a pre-tax impairment loss at Alabama Power of $36 million ($27 million after tax) related to Alabama Power discontinuing the development of a multi-use commercial facility. See Note 1 under "Impairment of Long-Lived Assets" for additional information.
(c)For the traditional electric operating companies, includes pre-tax charges (credits) to income at Georgia Power for the estimated probable loss associated with the construction and completion of Plant Vogtle Units 3 and 4 of $(21) million ($(16) million after tax) in 2024, $(68) million ($(50) million after tax) in 2023, and $183 million ($137 million after tax) in 2022. See Note 2 under "Georgia Power – Nuclear Construction" for additional information.
(d)For the traditional electric operating companies, includes a pre-tax gain at Georgia power of approximately $114 million ($84 million after tax) related to the sale of transmission line assets under the integrated transmission system agreement. See Note 2 under "Georgia Power – Transmission Asset Sales" for additional information.
(e)For Southern Power, includes pre-tax accelerated depreciation of $9 million ($7 million after tax) related to the commitment to repower 200 MWs of the Kay Wind facility. See Note 15 under "Southern Power – Development Projects" for additional information.
(f)Attributable to Southern Company.
(g)For Southern Power, includes an $18 million pre-tax loss recovery ($9 million after tax and partnership allocations) related to an arbitration award and a $16 million pre-tax gain ($12 million after tax) on the sale of spare parts. See Note 3 under "General Litigation Matters – Southern Power" for additional information.
(h)For Southern Company Gas, includes pre-tax charges totaling approximately $96 million ($72 million after tax) associated with the disallowance of certain capital investments at Nicor Gas. See Note 2 under "Southern Company Gas" for additional information.
(i)For Southern Company Gas, includes pre-tax impairment charges totaling approximately $131 million ($99 million after tax) related to the sale of natural gas storage facilities. See Note 15 under "Southern Company Gas" for additional information.
(j)For the "All Other" column, includes a $119 million goodwill impairment loss (pre-tax and after tax) at PowerSecure. See Note 1 under "Goodwill and Other Intangible Assets" for additional information.
Products and Services
Electric Utilities' Revenues
YearRetailWholesaleOtherTotal
(in millions)
2024$17,790 $2,431 $1,382 $21,603 
202316,343 2,467 1,188 19,998 
202218,197 3,641 1,035 22,873 
Southern Company Gas' Revenues
YearGas
Distribution
Operations		Gas
Marketing
Services		All OtherTotal
(in millions)
2024$3,899 $516 $41 $4,456 
20234,090 548 64 4,702 
20225,240 638 84 5,962 
Traditional Electric Operating Companies
Each of the traditional electric operating companies' single reportable business segment is the sale of electricity. Revenues from products and services of the traditional electric operating companies are segregated into retail, wholesale, and other as reflected on their statements of income.
Alabama Power and Georgia Power have identified utility operations and maintenance expenses as significant segment expenses provided to their CODMs. Utility operations and maintenance expenses is calculated as other operations and maintenance, as reflected on the statements of income, less expenses from unregulated products and services, losses (gains) on asset dispositions, impairment charges, and amortization of cloud software. Alabama Power's utility operations and maintenance expenses are disaggregated into expenses related to Rate RSE and Rate CNP Compliance, which are not applicable to Georgia Power. See Note 2 under "Alabama Power" for additional information.
Financial data for Alabama Power's and Georgia Power's significant segment expenses and other segment information for the years ended December 31, 2024, 2023, and 2022 was as follows:
202420232022
(in millions)
Alabama Power
Operating revenues$7,554 $7,050 $7,817 
Utility operations and maintenance
Rate RSE expenses1,480 1,421 1,645 
Rate CNP Compliance expenses279 254 237 
Total utility operations and maintenance1,759 1,675 1,882 
Other segment items(a)(b)
2,125 2,098 2,915 
Depreciation and amortization1,459 1,401 875 
Interest expense448 425 382 
Income taxes360 81 423 
Segment net income(b)
$1,403 $1,370 $1,340 
Capital expenditures$2,114 $2,159 $2,206 
Georgia Power
Operating revenues$11,331 $10,118 $11,584 
Utility operations and maintenance2,210 1,901 2,237 
Other segment items(a)(c)(d)
3,476 3,382 5,249 
Depreciation and amortization1,774 1,681 1,430 
Interest expense725 626 485 
Income taxes603 448 370 
Segment net income(c)(d)
$2,543 $2,080 $1,813 
Capital expenditures$5,355 $5,394 $4,219 
(a)Primarily consists of fuel, purchased power, expenses from unregulated products and services, losses (gains) on asset dispositions, impairment charges, amortization of cloud software, taxes other than income taxes, charges (credits) to income for estimated probable losses, AFUDC equity, and non-service cost-related retirement benefits income. Also includes earnings from equity method investments, which were immaterial for all periods presented.
(b)For 2024, includes a pre-tax impairment loss of $36 million ($27 million after tax) related to Alabama Power discontinuing the development of a multi-use commercial facility. See Note 1 under "Impairment of Long-Lived Assets" for additional information.
(c)Includes pre-tax charges (credits) to income for the estimated probable loss associated with the construction and completion of Plant Vogtle Units 3 and 4 of $(21) million ($(16) million after tax) in 2024, $(68) million ($(50) million after tax) in 2023, and $183 million ($137 million after tax) in 2022. See Note 2 under "Georgia Power – Nuclear Construction" for additional information.
(d)For 2024, includes a pre-tax gain of approximately $114 million ($84 million after tax) related to the sale of transmission line assets under the integrated transmission system agreement. See Note 2 under "Georgia Power – Transmission Asset Sales" for additional information.
Mississippi Power's CODM utilizes segment expense information in the form of variances to budget to assess performance; therefore, Mississippi Power has no reportable significant segment expenses. Mississippi Power's segment information for revenues, depreciation and amortization, interest expense, and income taxes is reflected on its statements of income. Mississippi Power's earnings from equity method investments are included in other income (expense), net on its statements of income and were immaterial for all periods presented. Other segment items primarily consist of fuel and purchased power, other operations and maintenance, taxes other than income taxes, and non-service cost-related retirement benefits income and totaled $0.9 billion, $1.0 billion, and $1.3 billion for the years ended December 31, 2024, 2023, and 2022, respectively.
Southern Power
Southern Power's single reportable business segment is the sale of electricity in the competitive wholesale market. Substantially all of Southern Power's revenues from products and services are reflected as wholesale on its consolidated statements of income. Southern Power's CODM utilizes segment expense information in the form of variances to budget to assess performance; therefore, Southern Power has no reportable significant segment expenses. Southern Power's segment information for revenues, depreciation and amortization, interest expense, and income taxes (benefit) is reflected on its consolidated statements of income. Southern Power had no earnings from equity method investments for any period presented. Other segment items primarily consist of fuel, purchased power, other operations and maintenance, taxes other than income taxes, losses (gains) on asset dispositions,
and net income (loss) attributable to noncontrolling interests and totaled $1.1 billion, $1.2 billion, and $2.3 billion for the years ended December 31, 2024, 2023, and 2022, respectively.
Southern Company Gas
Southern Company Gas manages its business through three reportable segments – gas distribution operations, gas pipeline investments, and gas marketing services. The non-reportable segments are combined and presented as all other. See Note 15 under "Southern Company Gas" for additional information on the disposition activities described herein.
The gas distribution operations segment is the largest component of Southern Company Gas' business and includes natural gas local distribution utilities that construct, manage, and maintain intrastate natural gas pipelines and gas distribution facilities in four states.
The gas pipeline investments segment consists of joint ventures in natural gas pipeline investments including a 50% interest in SNG and a 50% joint ownership interest in the Dalton Pipeline. These natural gas pipelines enable the provision of diverse sources of natural gas supplies to the customers of Southern Company Gas. See Notes 5 and 7 for additional information.
The gas marketing services segment provides natural gas marketing to end-use customers primarily in Georgia and Illinois through SouthStar.
The "All Other" column includes segments and subsidiaries that fall below the quantitative threshold for separate disclosure, including storage and fuels operations. The "All Other" column included a natural gas storage facility in Texas through its sale in November 2022 and a natural gas storage facility in California through its sale in September 2023.
Southern Company Gas' CODM utilizes segment expense information in the form of variances to budget to assess performance; therefore, Southern Company Gas has no reportable significant segment expenses.
Financial data for business segments for the years ended December 31, 2024, 2023, and 2022 was as follows:
Gas Distribution OperationsGas Pipeline InvestmentsGas Marketing Services
Total Reportable Segments
All OtherEliminationsConsolidated
(in millions)
2024
Operating revenues$3,899 $32 $516 $4,447 $23 $(14)$4,456 
Other segment items(a)
2,236 6 356 2,598 29 (14)2,613 
Depreciation and amortization630 5 14 649 1 — 650 
Earnings from equity method investments— 146 — 146 — — 146 
Interest expense311 35 3 349 (8)— 341 
Income taxes172 31 41 244 14 — 258 
Segment net income (loss)
$550 $101 $102 $753 $(13)$— $740 
Total assets$24,067 $1,573 $1,696 $27,336 $10,047 $(11,206)$26,177 
2023
Operating revenues$4,105 $32 $548 $4,685 $36 $(19)$4,702 
Other segment items(a)(b)
2,702 5 402 3,109 34 (19)3,124 
Depreciation and amortization561 5 15 581 1 — 582 
Earnings from equity method investments— 140 — 140 — — 140 
Interest expense275 32 3 310 — — 310 
Income taxes126 32 37 195 16 — 211 
Segment net income (loss)(b)
$441 $98 $91 $630 $(15)$— $615 
Total assets$22,906 $1,534 $1,615 $26,055 $9,675 $(10,647)$25,083 
2022
Operating revenues$5,267 $32 $638 $5,937 $55 $(30)$5,962 
Other segment items(a)(c)
3,907 6 488 4,401 165 (30)4,536 
Depreciation and amortization516 5 16 537 22 — 559 
Earnings from equity method investments— 148 — 148 — — 148 
Interest expense229 27 3 259 4 — 263 
Income taxes (benefit)145 35 37 217 (37)— 180 
Segment net income (loss)(c)
$470 $107 $94 $671 $(99)$— $572 
Total assets$22,040 $1,577 $1,616 $25,233 $8,943 $(9,555)$24,621 
(a)Primarily consists of cost of natural gas, other operations and maintenance, taxes other than income taxes, impairment charges, estimated loss on regulatory disallowance, AFUDC equity, and non-service cost-related retirement benefits income.
(b)For gas distribution operations, includes pre-tax charges totaling approximately $96 million ($72 million after tax) associated with the disallowance of certain capital investments at Nicor Gas. See Note 2 under "Southern Company Gas" for additional information.
(c)For the "All Other" column, includes pre-tax impairment charges totaling approximately $131 million ($99 million after tax) related to the sale of natural gas storage facilities. See Note 15 under "Southern Company Gas" for additional information.
v3.25.0.1
VALUATION AND QUALIFYING ACCOUNTS
 12 Months Ended
Dec. 31, 2024
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]  
VALUATION AND QUALIFYING ACCOUNTS
SCHEDULE II — VALUATION AND QUALIFYING ACCOUNTS
FOR THE YEARS ENDED DECEMBER 31, 2024, 2023, AND 2022

Additions
DescriptionBalance at Beginning of PeriodCharged to IncomeCharged to Other Accounts
Deductions(*)
Balance at End of Period
(in millions)
Provision for uncollectible accounts:
Southern Company
2024$68 $119 $(1)$112 $74 
202371 87 3 93 68 
202278 71 (1)77 71 
Alabama Power
2024$16 $26 $— $20 $22 
202314 16 — 14 16 
202214 10 — 10 14 
Georgia Power
2024$4 $51 $— $40 $15 
20233 26 — 25 4 
20222 21 — 20 3 
Mississippi Power
2024$1 $2 $— $2 $1 
20231 2 — 2 1 
20221 1 1 2 1 
Southern Power
2024$1 $(1)$— $— $— 
20231 — — — 1 
20225 (2)— 2 1 
Southern Company Gas
2024$44 $39 $(1)$49 $33 
202350 43 3 52 44 
202239 55 — 44 50 
(*)Deductions represent write-offs of accounts considered to be uncollectible, less recoveries of amounts previously written off.
SCHEDULE II — VALUATION AND QUALIFYING ACCOUNTS (CONTINUED)
FOR THE YEARS ENDED DECEMBER 31, 2024, 2023, AND 2022

Additions
DescriptionBalance at Beginning of PeriodCharged to IncomeCharged to Other AccountsDeductionsBalance at End of Period
(in millions)
Tax valuation allowance (net state):
Southern Company(a)(b)(c)
2024$168 $97 $3 $— $268 
2023207 (14)(25)— 168 
2022169 68 (30)— 207 
Georgia Power(b)
2024$60 $97 $(33)$— $124 
202398 (15)(23)— 60 
202258 70 (30)— 98 
Mississippi Power(c)
2024$32 $— $— $— $32 
202332 — — — 32 
202232 — — — 32 
Southern Power(c)
2024$21 $— $— $— $21 
202321 — — — 21 
202221 — — — 21 
Southern Company Gas(c)
2024$5 $— $(1)$— $4 
20237 — (2)— 5 
20227 — — — 7 
(a)In 2024, Southern Company established a valuation allowance for certain Georgia state tax credits expected to expire prior to being fully utilized.
(b)In 2018, Georgia Power established a valuation allowance for certain Georgia state tax credits expected to expire prior to being fully utilized, which has been adjusted in subsequent years as a result of changes in projected state taxable income.
(c)Associated with a state net operating loss carryforward expected to expire prior to being fully utilized.
See Note 10 to the financial statements in Item 8 herein for additional information.
v3.25.0.1
Insider Trading Arrangements
 3 Months Ended
Dec. 31, 2024
shares
Trading Arrangements, by Individual  
Non-Rule 10b5-1 Arrangement Adopted false
Rule 10b5-1 Arrangement Terminated false
Non-Rule 10b5-1 Arrangement Terminated false
Kimberly S. Greene [Member]  
Trading Arrangements, by Individual  
Name Kimberly S. Greene
Title Chairman, President, and Chief Executive Officer, Georgia Power
Rule 10b5-1 Arrangement Adopted true
Adoption Date November 4, 2024
Expiration Date March 3, 2026
Arrangement Duration 484 days
Aggregate Available 45,348
Stanley W. Connally, Jr. [Member]  
Trading Arrangements, by Individual  
Name Stanley W. Connally, Jr.
Title Executive Vice President and Chief Operating Officer
Rule 10b5-1 Arrangement Adopted true
Adoption Date November 12, 2024
Expiration Date March 17, 2026
Arrangement Duration 490 days
Aggregate Available 12,500
v3.25.0.1
Insider Trading Policies and Procedures
 12 Months Ended
Dec. 31, 2024
Insider Trading Policies and Procedures [Line Items]  
Insider Trading Policies and Procedures Adopted true
v3.25.0.1
Cybersecurity Risk Management and Strategy Disclosure
 12 Months Ended
Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]  
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]
Risk Management and Strategy
Although many of the networks are segmented, overall network security is a centralized shared service across the Southern Company system, led by the TSO and the CISO. Recognizing that no single technology, process, or business control can effectively prevent or mitigate all risks related to cyber threats, multiple technologies, processes, and controls, all working independently but as part of a cohesive strategy, are employed to reduce risk. Southern Company system exposure and defenses are regularly tested through auditing, penetration testing, vulnerability testing, and other exercises designed to assess effectiveness.
The Southern Company system emphasizes both security and resiliency through business assurance and incident response plans designed to identify, evaluate, and remediate incidents when they occur. A 24/7 security operations center is also utilized, which facilitates real-time situational awareness across the cyber-threat environment, and a robust insider threat protection program that leverages cross-function information sharing to assess insider threat activity is employed. The Southern Company system regularly reviews and updates its plans, policies, and technologies and conducts regular training exercises and crisis management preparedness activities to test their effectiveness. In addition, a security awareness program for the Southern
Company system's employees has also been implemented, which is designed to educate and train employees at least annually, or more often as needed, about risks inherent to human interaction with information and operational technology.
The Southern Company system's cybersecurity program is increasingly leveraging intelligence-sharing capabilities about emerging threats within the energy industry, across other industries, with specialized vendors, and through public-private partnerships with U.S. government intelligence agencies. By engaging with both the Electricity Information Sharing and Analysis Center and the Downstream Natural Gas Information Sharing and Analysis Center, the Southern Company system benefits from quality analysis and rapid sharing of security information across the energy sector. Such intelligence helps to allow for better detection and prevention of emerging cyber threats before they materialize. Just as it tests its policies and plans internally, the Southern Company system also engages in external exercises such as the bi-annual GridEx Security Exercise to evaluate and address the preparedness of the industry as a whole.
Many cybersecurity policies and standards across the Southern Company system are governed by multiple regulatory requirements. Portions of these policies and standards are audited by the FERC, the Transportation Security Administration, and the NRC, as appropriate, and are periodically evaluated by third parties such as cybersecurity insurance carriers. Certain members of senior management have high-level security clearances to facilitate access to critical information, and the Southern Company system participates in pilot programs with industry and the U.S. government to share additional information and strengthen cybersecurity and business resiliency.
The Southern Company system also employs systems and processes designed to oversee, identify, and reduce the potential impact of a security incident at a third-party vendor, service provider, or customer or otherwise implicating the third-party technology and systems used. Among other things, the Southern Company system has established a Vendor Security Incident Working Group to address such third-party security incidents, including following up with the third party as appropriate and taking steps to mitigate any impact to systems. The Vendor Security Incident Working Group includes members of the internal cybersecurity teams to address any incidents that may invoke the CIRP. Additionally, the Southern Company system typically imposes contractual obligations on vendors and other third-party business partners related to privacy, confidentiality, and data security based on their access to the Southern Company system's data and systems. The Southern Company system also maintains insurance coverage for cyber incidents; the scope of coverage and fitness of coverage is evaluated each year.
Incident Response
The Southern Company system has adopted a CIRP that applies in the event of certain cybersecurity threats or incidents to provide a standardized guide for responding to security incidents. The CIRP sets out a coordinated approach to investigating, containing, documenting, and mitigating incidents, including reporting findings and keeping senior management and other key stakeholders informed and involved as appropriate. In general, the incident response process follows the National Institute of Standards and Technology guidance and focuses on four phases: preparation; detection and analysis; containment, eradication, and recovery; and post-incident remediation. The CIRP is reviewed periodically to help ensure its applicability to any changing needs or circumstances and to provide users a tactical tool to effectively respond to incidents. The CIRP applies to all Southern Company system personnel (including third-party contractors, vendors, and partners) that perform functions or services requiring access to secure Southern Company system information and to all devices and network services that are owned or managed by the Southern Company system. A full tabletop exercise is performed at least annually, including stakeholders from business units beyond technology security, such as power delivery, legal, compliance, risk management, and corporate communications. In addition, the Southern Company system participates in sector-level and cross-sector exercises led by industry or the U.S. government. In the event of an incident, the technology security organization, the legal organization, and other stakeholders frequently review lessons learned after an incident has been remediated.
Cybersecurity Risk Management Processes Integrated [Flag] true
Cybersecurity Risk Management Processes Integrated [Text Block]
Although many of the networks are segmented, overall network security is a centralized shared service across the Southern Company system, led by the TSO and the CISO. Recognizing that no single technology, process, or business control can effectively prevent or mitigate all risks related to cyber threats, multiple technologies, processes, and controls, all working independently but as part of a cohesive strategy, are employed to reduce risk. Southern Company system exposure and defenses are regularly tested through auditing, penetration testing, vulnerability testing, and other exercises designed to assess effectiveness.
Cybersecurity Risk Management Third Party Engaged [Flag] true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag] true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag] false
Cybersecurity Risk Board of Directors Oversight [Text Block]
Board of Directors
The Southern Company Board of Directors (Board), along with certain committees (primarily the Audit Committee of the Board) oversees the Southern Company system's enterprise risk management process. The Board devotes significant time and attention to overseeing cybersecurity risk, and the Southern Company system's approach to cybersecurity governance establishes oversight throughout the enterprise. The Board has delegated the primary responsibility to oversee cybersecurity matters to the Business Security and Resiliency Committee (BSRC) of the Board. Having a committee like the BSRC, focused on and dedicated to security, is a strong governance practice. Comprised solely of independent members of the Board, the BSRC is charged with oversight of risks related to cybersecurity, physical security, and operational resiliency. The BSRC includes directors with an understanding of cyber issues. The BSRC meets at every regular Board meeting and when needed in
the event of a specific threat or emerging issue. The Chair of the BSRC regularly reports to the Board in connection with key matters the BSRC considered. The BSRC routinely receives presentations on a range of topics, including the threat environment and vulnerabilities and risks, policies, practices, technology trends, and regulatory developments, from the Chief Information Security Officer (CISO) and the legal organization and, as needed, the Chief Information Officer (CIO). The CISO reports to the BSRC at each regular committee meeting. Protocols have been established by which certain cybersecurity incidents are escalated internally and, where appropriate, reported to the BSRC, and ongoing updates regarding any such incident are provided until it has been resolved. See "Incident Response" herein.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block] The Southern Company Board of Directors (Board), along with certain committees (primarily the Audit Committee of the Board) oversees the Southern Company system's enterprise risk management process.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block] Briefings to the Board on cybersecurity matters include annual briefings to the Audit Committee and the Operations, Environmental, and Safety Committee in addition to briefings to the BSRC at each of its regular meetings (at least five times annually).
Cybersecurity Risk Role of Management [Text Block]
The TSO, led by the CISO, is responsible for the implementation, monitoring, and maintenance of the cybersecurity and data protection practices across the Southern Company system. The Southern Company system also relies on a Data Privacy and Protection team in the compliance organization, as well as the internal audit organization, to work with the TSO on data protection policies and practices. Multiple experienced information security leaders with internal and external security experience responsible for various parts of the business report to the CISO, each of whom is supported by a team of trained cybersecurity professionals. In addition to these internal cybersecurity capabilities, external auditors and security companies are regularly engaged to assist with assessing, testing, identifying, and managing cybersecurity, including through penetration testing, vulnerability testing, and other technical evaluations.
Cybersecurity Risk Management Positions or Committees Responsible [Flag] true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]
Board of Directors
The Southern Company Board of Directors (Board), along with certain committees (primarily the Audit Committee of the Board) oversees the Southern Company system's enterprise risk management process. The Board devotes significant time and attention to overseeing cybersecurity risk, and the Southern Company system's approach to cybersecurity governance establishes oversight throughout the enterprise. The Board has delegated the primary responsibility to oversee cybersecurity matters to the Business Security and Resiliency Committee (BSRC) of the Board. Having a committee like the BSRC, focused on and dedicated to security, is a strong governance practice. Comprised solely of independent members of the Board, the BSRC is charged with oversight of risks related to cybersecurity, physical security, and operational resiliency. The BSRC includes directors with an understanding of cyber issues. The BSRC meets at every regular Board meeting and when needed in
the event of a specific threat or emerging issue. The Chair of the BSRC regularly reports to the Board in connection with key matters the BSRC considered. The BSRC routinely receives presentations on a range of topics, including the threat environment and vulnerabilities and risks, policies, practices, technology trends, and regulatory developments, from the Chief Information Security Officer (CISO) and the legal organization and, as needed, the Chief Information Officer (CIO). The CISO reports to the BSRC at each regular committee meeting. Protocols have been established by which certain cybersecurity incidents are escalated internally and, where appropriate, reported to the BSRC, and ongoing updates regarding any such incident are provided until it has been resolved. See "Incident Response" herein.
Management
The Southern Company system has implemented a cross-functional, risk-based, "defense-in-depth" approach to preventing, detecting, identifying, mitigating, responding to, and recovering from cybersecurity threats and incidents, while also implementing controls and procedures that provide for the prompt escalation of certain cybersecurity incidents so that decisions regarding the public disclosure and reporting of such incidents can be made by management in a timely manner. Overall network efforts are led by the CISO and the Technology Security Organization (TSO), the organization responsible for implementing, monitoring, and maintaining cybersecurity practices across the Southern Company system, and aided by the Executive Vice President of Operations and the Energy Management System and Generation organization. The CISO meets regularly with the CIO and the Chief Executive Officer and reports regularly to committees of the Board to discuss risk management measures implemented to identify and mitigate data protection and cybersecurity risks. Security and resiliency are emphasized through business assurance, enterprise risk management, and incident response plans designed to identify, evaluate, and remediate incidents when they occur. Among other things, the Cybersecurity Incident Response Plan (CIRP) establishes a team comprised of the CISO, the Deputy CISO, the Director of the Digital Defense Center, and members of the legal and compliance organizations to evaluate emerging cyber threats and escalate to executive management and business units as appropriate. Plans, policies, and technologies are regularly updated and training exercises and crisis management preparedness activities are conducted to test effectiveness.
The CISO works closely with the legal and compliance organizations, as well as the relevant business units, to help ensure broad oversight of and compliance with legal, regulatory, and contractual cybersecurity requirements. The CISO has extensive cybersecurity knowledge and skills gained from over 30 years of work experience within the Southern Company system. The CISO receives reports on cybersecurity threats from a variety of sources both internally and externally on an ongoing basis and regularly reviews risk management measures implemented to identify and mitigate cybersecurity risks. Briefings to the Board on cybersecurity matters include annual briefings to the Audit Committee and the Operations, Environmental, and Safety Committee in addition to briefings to the BSRC at each of its regular meetings (at least five times annually).
Internal Cybersecurity Team
The TSO, led by the CISO, is responsible for the implementation, monitoring, and maintenance of the cybersecurity and data protection practices across the Southern Company system. The Southern Company system also relies on a Data Privacy and Protection team in the compliance organization, as well as the internal audit organization, to work with the TSO on data protection policies and practices. Multiple experienced information security leaders with internal and external security experience responsible for various parts of the business report to the CISO, each of whom is supported by a team of trained cybersecurity professionals. In addition to these internal cybersecurity capabilities, external auditors and security companies are regularly engaged to assist with assessing, testing, identifying, and managing cybersecurity, including through penetration testing, vulnerability testing, and other technical evaluations.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block] The CISO has extensive cybersecurity knowledge and skills gained from over 30 years of work experience within the Southern Company system.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]
The CISO works closely with the legal and compliance organizations, as well as the relevant business units, to help ensure broad oversight of and compliance with legal, regulatory, and contractual cybersecurity requirements. The CISO has extensive cybersecurity knowledge and skills gained from over 30 years of work experience within the Southern Company system. The CISO receives reports on cybersecurity threats from a variety of sources both internally and externally on an ongoing basis and regularly reviews risk management measures implemented to identify and mitigate cybersecurity risks. Briefings to the Board on cybersecurity matters include annual briefings to the Audit Committee and the Operations, Environmental, and Safety Committee in addition to briefings to the BSRC at each of its regular meetings (at least five times annually).
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag] true
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)
 12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]  
General
General
Southern Company is the parent company of three traditional electric operating companies, as well as Southern Power, Southern Company Gas, SCS, Southern Linc, Southern Holdings, Southern Nuclear, PowerSecure, and other direct and indirect subsidiaries. The traditional electric operating companies – Alabama Power, Georgia Power, and Mississippi Power – are vertically integrated utilities providing electric service in three Southeastern states. Southern Power develops, constructs, acquires, owns, operates, and manages power generation assets, including renewable energy projects, and sells electricity at market-based rates in the wholesale market. Southern Company Gas distributes natural gas through natural gas distribution utilities, including Nicor Gas (Illinois), Atlanta Gas Light (Georgia), Virginia Natural Gas, and Chattanooga Gas (Tennessee). Southern Company Gas is also involved in several other complementary businesses including gas pipeline investments and gas marketing services. SCS, the system service company, provides, at cost, specialized services to Southern Company and its subsidiary companies. Southern Linc provides digital wireless communications for use by Southern Company and its subsidiary companies and also markets these services to the public and provides fiber optics services within the Southeast. Southern Holdings is an intermediate holding company subsidiary. Southern Nuclear operates and provides services to the Southern Company system's nuclear power plants, including Alabama Power's Plant Farley and Georgia Power's Plants Hatch and Vogtle. PowerSecure develops distributed energy and resilience solutions and deploys microgrids for commercial, industrial, governmental, and utility customers.
The Registrants' financial statements reflect investments in subsidiaries on a consolidated basis. Intercompany transactions have been eliminated in consolidation. The equity method is used for investments in entities in which a Registrant has significant influence but does not have control and for VIEs where a Registrant has an equity investment but is not the primary beneficiary. Southern Power has controlling ownership in certain legal entities for which the contractual provisions represent profit-sharing arrangements because the allocations of cash distributions and tax benefits are not based on fixed ownership percentages. For these arrangements, the noncontrolling interest is accounted for under a balance sheet approach utilizing the HLBV method. The HLBV method calculates each partner's share of income based on the change in net equity the partner can legally claim in an HLBV at the end of the period compared to the beginning of the period. See "Variable Interest Entities" herein and Note 7 for additional information.
The traditional electric operating companies, Southern Power, certain subsidiaries of Southern Company Gas, and certain other subsidiaries are subject to regulation by the FERC, and the traditional electric operating companies and the natural gas distribution utilities are also subject to regulation by their respective state PSCs or other applicable state regulatory agencies. As such, the respective financial statements of the applicable Registrants reflect the effects of rate regulation in accordance with GAAP and comply with the accounting policies and practices prescribed by relevant state PSCs or other applicable state regulatory agencies.
The preparation of financial statements in conformity with GAAP requires the use of estimates, and the actual results may differ from those estimates. Certain prior years' data presented in the financial statements have been reclassified to conform to the current year presentation. These reclassifications had no impact on the Registrants' results of operations, financial position, or cash flows.
Recently Adopted Accounting Standards
Recently Adopted Accounting Standards
In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (ASU 2023-07), which requires entities to disclose significant segment expenses, other segment items, the title and position of the CODM, and information related to how the CODM assesses segment performance and allocates resources, among certain other required disclosures. Additionally, previous annual disclosures will be required in interim periods. The Registrants adopted ASU 2023-07 and applied the guidance retrospectively effective for the fiscal year beginning January 1, 2024. ASU 2023-07 will be applied retrospectively for the interim periods beginning January 1, 2025. See Note 16 for additional information and related disclosures.
Affiliate Transactions
Affiliate Transactions
The traditional electric operating companies, Southern Power, and Southern Company Gas have agreements with SCS under which certain of the following services are rendered to them at direct or allocated cost: general executive and advisory, general and design engineering, operations, purchasing, accounting, finance, treasury, legal, tax, information technology, marketing, auditing, insurance and pension administration, human resources, systems and procedures, digital wireless communications, cellular tower space, and other services with respect to business and operations, construction management, and Southern
Company power pool transactions. These costs are primarily included in other operations and maintenance expenses or capitalized to property, plant, and equipment.
Regulatory Assets and Liabilities
Regulatory Assets and Liabilities
The traditional electric operating companies and the natural gas distribution utilities are subject to accounting requirements for the effects of rate regulation. Regulatory assets represent probable future revenues associated with certain costs that are expected to be recovered from customers through the ratemaking process. Regulatory liabilities represent costs recovered that are expected to be incurred in the future or probable future reductions in revenues associated with amounts that are expected to be credited to customers through the ratemaking process.
In the event that a portion of a traditional electric operating company's or a natural gas distribution utility's operations is no longer subject to applicable accounting rules for rate regulation, such company would be required to write off to income or reclassify to AOCI related regulatory assets and liabilities that are not specifically recoverable through regulated rates. In addition, the traditional electric operating company or the natural gas distribution utility would be required to determine if any impairment to other assets, including plant, exists and write down the assets, if impaired, to their fair values. All regulatory assets and liabilities are to be reflected in rates. See Note 2 for additional information including details of regulatory assets and liabilities reflected in the balance sheets for Southern Company, the traditional electric operating companies, and Southern Company Gas.
Revenues
Revenues
The Registrants generate revenues from a variety of sources which are accounted for under various revenue accounting guidance, including revenue from contracts with customers, lease, derivative, and regulatory accounting. See Notes 4, 9, and 14 for additional information.
Traditional Electric Operating Companies
The majority of the revenues of the traditional electric operating companies are generated from contracts with retail electric customers. These revenues, generated from the integrated service to deliver electricity when and if called upon by the customer, are recognized as a single performance obligation satisfied over time, at a tariff rate, and as electricity is delivered to the customer during the month. Unbilled revenues related to retail sales are recognized for estimated deliveries of electricity not yet billed to these customers from the last bill date to the end of the accounting period. Retail rates may include provisions to adjust revenues for fluctuations in fuel costs, fuel hedging, the energy component of purchased power costs, and certain other costs. Revenues are adjusted for differences between these actual costs and amounts billed in current regulated rates. Under or over recovered regulatory clause revenues are recorded in the balance sheets and are recovered from or returned to customers, respectively, through adjustments to the billing factors. See Note 2 for additional information regarding regulatory matters of the traditional electric operating companies.
Wholesale capacity revenues from PPAs are recognized in amounts billable under the contract terms. Energy and other revenues are generally recognized as services are provided. The contracts for capacity and energy in a wholesale PPA have multiple performance obligations where the contract's total transaction price is allocated to each performance obligation based on the standalone selling price. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, the traditional electric operating companies recognize revenue as the performance obligations are satisfied over time as electricity is delivered to the customer or as generation capacity is available to the customer.
For both retail and wholesale revenues, the traditional electric operating companies have elected to recognize revenue for their sales of electricity and capacity using the invoice practical expedient as they generally have a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and that may be invoiced. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of the Registrants' performance obligation.
Southern Power
Southern Power sells capacity and energy at rates specified under contractual terms in long-term PPAs. These PPAs are accounted for as leases, normal sale derivatives, or contracts with customers. Capacity revenues from PPAs classified as operating leases are recognized on a straight-line basis over the term of the agreement. Energy revenues are recognized in the period the energy is delivered. Capacity revenues from PPAs classified as sales-type leases are recognized by accounting for interest income on the net investment in the lease.
Southern Power's non-lease contracts commonly include capacity and energy which are considered separate performance obligations. In these contracts, the total transaction price is allocated to each performance obligation based on the standalone selling price. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, Southern Power recognizes revenue as the performance obligations are satisfied over time, as electricity is delivered to the customer or as generation capacity is made available to the customer.
Southern Power generally has a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and may recognize revenue in the amount to which the entity has a right to invoice. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of Southern Power's performance obligation.
When multiple contracts exist with the same counterparty, the revenues from each contract are accounted for as separate arrangements.
Southern Power may also enter into contracts to sell short-term capacity in the wholesale electricity markets. These sales are generally classified as mark-to-market derivatives and net unrealized gains and losses on such contracts are recorded in wholesale revenues. See Note 14 and "Financial Instruments" herein for additional information.
Southern Company Gas
Southern Company Gas records revenues when goods or services are provided to customers. Those revenues are based on rates approved by the state regulatory agencies of the natural gas distribution utilities.The majority of the revenues of Southern Company Gas are generated from contracts with natural gas distribution customers. Revenues from this integrated service to deliver gas when and if called upon by the customer are recognized as a single performance obligation satisfied over time and are recognized at a tariff rate as gas is delivered to the customer during the month.
Revenues from sales and transportation services are recognized in the same period in which the related volumes are delivered to customers. Revenues from residential and certain commercial and industrial customers are recognized on the basis of scheduled meter readings. Additionally, unbilled revenues are recognized for estimated deliveries of gas not yet billed to these customers, from the last bill date to the end of the accounting period. For other commercial and industrial customers, revenues are based on actual deliveries through the end of the period.
Southern Company Gas has elected to recognize revenue for sales of gas using the invoice practical expedient as it generally has a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and that may be invoiced. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of Southern Company Gas' performance obligation.
Gas Distribution Operations
Atlanta Gas Light operates in a deregulated natural gas market whereby Marketers, rather than a traditional utility, sell natural gas to end-use customers in Georgia and handle customer billing functions. As required by the Georgia PSC, Atlanta Gas Light bills Marketers in equal monthly installments for each residential, commercial, and industrial end-use customer's distribution costs as well as for capacity costs utilizing a seasonal rate design for the calculation of each residential end-use customer's annual straight-fixed-variable charge, which reflects the historic volumetric usage pattern for the entire residential class. With the exception of Atlanta Gas Light, the natural gas distribution utilities have rate structures that include volumetric rate designs that allow the opportunity to recover certain costs based on gas usage.
The tariffs for the natural gas distribution utilities include provisions which allow for the recognition of certain revenues prior to the time such revenues are billed to customers. These provisions are referred to as alternative revenue programs and provide for the recognition of certain revenues prior to billing, as long as the amounts recognized will be collected from customers within 24 months of recognition. Revenue related to alternative revenue programs was $43 million, $20 million, and $(5) million in 2024, 2023, and 2022, respectively. These programs primarily consist of:
•Weather normalization adjustments – reduce customer bills when winter weather is colder than normal and increase customer bills when weather is warmer than normal and are included in the tariffs for Virginia Natural Gas and Chattanooga Gas;
•Revenue normalization mechanisms – mitigate the impact of conservation and declining customer usage and are contained in the tariffs for Virginia Natural Gas and Nicor Gas; and
•Revenue true-up adjustment – included within the provisions of the GRAM program in which Atlanta Gas Light participates as a short-term alternative to formal rate case filings, the revenue true-up feature provides for a positive (or negative) adjustment to record revenue in the amount of any variance to budgeted revenues, which are submitted and approved annually as a requirement of GRAM. Such adjustments are reflected in customer billings in a subsequent program year.
Gas Marketing Services
Gas marketing services is comprised of several choice-based natural gas marketers operating in various deregulated jurisdictions. While gas marketing services follows the same general approach to revenue recognition described for Southern Company Gas above, it recognizes revenues on certain 12-month utility-bill management contracts as the lesser of cumulative earned or cumulative billed amounts.
Concentration of Revenue
Southern Company, Alabama Power, Georgia Power, Mississippi Power (with the exception of its full requirements cost-based MRA electric tariffs described below), Southern Power, and Southern Company Gas each have a diversified base of customers and no single customer comprises 10% or more of each company's revenues.
Mississippi Power provides service under long-term contracts with rural electric cooperative associations and a municipality located in southeastern Mississippi under requirements cost-based MRA electric tariffs which are subject to regulation by the FERC. The contracts with these wholesale customers represented 13.9% of Mississippi Power's total operating revenues in 2024.
Fuel Costs
Fuel Costs
Fuel costs for the traditional electric operating companies and Southern Power are expensed as the fuel is used. Fuel expense generally includes fuel transportation costs and the cost of purchased emissions allowances as they are used. For Alabama Power and Georgia Power, fuel expense also includes the amortization of the cost of nuclear fuel. For the traditional electric operating companies, fuel costs also include gains and/or losses from fuel-hedging programs as approved by their respective state PSCs.
Cost of Natural Gas
Cost of Natural Gas
Excluding Atlanta Gas Light, which does not sell natural gas to end-use customers, Southern Company Gas charges its utility customers for natural gas consumed using natural gas cost recovery mechanisms set by the applicable state regulatory agencies. Under these mechanisms, all prudently-incurred natural gas costs are passed through to customers without markup, subject to regulatory review. Southern Company Gas defers or accrues the difference between the actual cost of natural gas and the amount of commodity revenue earned in a given period such that no operating income is recognized related to these costs. The deferred or accrued amount is either billed or refunded to customers prospectively through adjustments to the commodity rate. Deferred and accrued natural gas costs are included in the balance sheets as regulatory assets and regulatory liabilities, respectively.
Southern Company Gas' gas marketing services' customers are charged for actual or estimated natural gas consumed. Within cost of natural gas, Southern Company Gas also includes costs of lost and unaccounted for gas and gains and losses associated with certain derivatives.
Income Taxes and Other Taxes
Income Taxes
The Registrants use the liability method of accounting for deferred income taxes and provide deferred income taxes for all significant income tax temporary differences. In accordance with regulatory requirements, deferred federal ITCs for the traditional electric operating companies are amortized over the average life of the related property, with such amortization normally applied as a credit to reduce depreciation and amortization in the statements of income. Southern Power's and the natural gas distribution utilities' deferred federal ITCs, as well as certain state ITCs for Nicor Gas, are amortized to income tax expense over the life of the respective asset.
Under current tax law, certain projects at Southern Power related to the construction of renewable facilities are eligible for federal ITCs. Southern Power estimates eligible costs which, as they relate to acquisitions, may not be finalized until the allocation of the purchase price to assets has been finalized. Southern Power applies the deferred method to ITCs, whereby the ITCs are recorded as a deferred credit and amortized to income tax expense over the life of the respective asset. Furthermore, the tax basis of the asset is reduced by 50% of the ITCs received, which, together with the deferred credit, results in a net deferred tax asset. Southern Power has elected to recognize the tax benefit of this basis difference as a reduction to income tax expense in the year in which the plant reaches commercial operation. State ITCs are recognized as an income tax benefit in the period in which the credits are generated. In addition, certain projects are eligible for federal and state PTCs, which are recognized as an income tax benefit based on KWH production.
Federal ITCs and PTCs, as well as state ITCs and other state tax credits available to reduce income taxes payable, were not fully utilized in 2024 and will be carried forward and utilized in future years. In addition, Southern Company is expected to have various state net operating loss (NOL) carryforwards for certain of its subsidiaries, including Mississippi Power and Southern Power, which would result in income tax benefits in the future, if utilized. See Note 10 under "Deferred Tax Assets and Liabilities – Tax Credit Carryforwards" and " – Net Operating Loss Carryforwards" for additional information.
In April 2024, the IRS issued final regulations related to the transferability of certain tax credits under the IRA. Southern Company and certain subsidiaries have tax credits that are eligible to be transferred at a discount to the generated credit value. The discount will be recorded as a reduction in tax credits recognized in the financial statements. See Note 10 under "Current and Deferred Income Taxes" for additional information.
Under current tax law, Georgia Power is eligible to generate advanced nuclear PTCs for Plant Vogtle Units 3 and 4, which are recognized as an income tax benefit based on KWH production and are eligible to be transferred. Pursuant to the Vogtle Joint Ownership Agreements (as defined in Note 2 under "Georgia Power – Nuclear Construction – Cost and Schedule"), Georgia Power is purchasing advanced nuclear PTCs for Plant Vogtle Units 3 and 4 from the other Vogtle Owners. The gain recognized on the purchase of the joint owner PTCs is recognized as an income tax benefit.
The Registrants recognize tax positions that are "more likely than not" of being sustained upon examination by the appropriate taxing authorities. See Note 10 under "Unrecognized Tax Benefits" for additional information.
Other Taxes
Taxes imposed on and collected from customers on behalf of governmental agencies are presented net on the Registrants' statements of income and are excluded from the transaction price in determining the revenue related to contracts with a customer.
Southern Company Gas is taxed on its gas revenues by various governmental authorities, but is allowed to recover these taxes from its customers. Revenue taxes imposed on the natural gas distribution utilities are recorded at the amount charged to customers, which may include a small administrative fee, as operating revenues, and the related taxes imposed on Southern Company Gas are recorded as operating expenses on the statements of income. Revenue taxes included in operating expenses were $112 million, $129 million, and $158 million in 2024, 2023, and 2022, respectively.
Allowance for Funds Used During Construction and Interest Capitalized
Allowance for Funds Used During Construction and Interest Capitalized
The traditional electric operating companies and the natural gas distribution utilities record AFUDC, which represents the estimated debt and equity costs of capital funds that are necessary to finance the construction of new regulated facilities. While cash is not realized currently, AFUDC increases the revenue requirement and is recovered over the service life of the asset through a higher rate base and higher depreciation. The equity component of AFUDC is not taxable.
Interest related to financing the construction of new facilities at Southern Power and new facilities not included in the traditional electric operating companies' and Southern Company Gas' regulated rates is capitalized in accordance with standard interest capitalization requirements.
Impairment of Long-Lived Assets
Impairment of Long-Lived Assets
The Registrants evaluate long-lived assets for impairment when events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. The determination of whether an impairment has occurred is based on either a specific regulatory disallowance, a sales transaction price that is less than the asset group's carrying amount, or an estimate of undiscounted future cash flows attributable to the asset group, as compared with the carrying amount of the assets. If an impairment has occurred, the amount of the impairment loss recognized is determined by either the amount of regulatory disallowance or by the amount the carrying amount exceeds the estimated fair value of the assets. For assets identified as held for sale, the carrying amount is compared to the estimated fair value less the cost to sell in order to determine if an impairment loss is required. Until the assets are disposed of, their estimated fair value is re-evaluated when circumstances or events change.
Goodwill and Other Intangible Assets
Goodwill and Other Intangible Assets
Goodwill and other intangible assets not subject to amortization are evaluated for impairment on an annual basis and when events or changes in circumstances necessitate an evaluation for impairment. Other intangible assets subject to amortization are
evaluated for impairment when events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable.
Southern Power's intangible assets consist primarily of certain PPAs acquired, which are amortized over the term of the respective PPA. Southern Company Gas' goodwill and other intangible assets primarily relate to its 2016 acquisition by Southern Company. In addition to these items, Southern Company's goodwill and other intangible assets also relate to its 2016 acquisition of PowerSecure.
For its 2024 annual goodwill impairment test, Southern Company Gas management performed the quantitative assessment, which resulted in the fair value of its reporting units with goodwill exceeding their carrying amounts. For its 2023 and 2022 annual goodwill impairment tests, Southern Company Gas management performed the qualitative assessment and determined that it was more likely than not that the fair value of its reporting units with goodwill exceeded their carrying amounts, and therefore no quantitative assessment was required.
For its 2024 annual goodwill impairment test, PowerSecure management performed the qualitative assessment and determined that it was more likely than not that the fair value of PowerSecure exceeded its carrying amount, and therefore no quantitative assessment was required. For its 2023 annual goodwill impairment test, PowerSecure management performed the quantitative assessment, which resulted in the fair value of PowerSecure exceeding its carrying amount. For its 2022 annual goodwill impairment test, PowerSecure management performed the quantitative assessment, which resulted in the fair value of PowerSecure being lower than its carrying amount. The fair value was estimated using a discounted cash flow analysis. The decline in fair value primarily resulted from declining macroeconomic conditions, reducing sales growth and estimated cash flows.
Acquisition Accounting
Acquisition Accounting
At the time of an acquisition, management will assess whether acquired assets and activities meet the definition of a business. Acquisitions that meet the definition of a business are accounted for under the acquisition method, and operating results from the date of acquisition are included in the acquiring entity's financial statements. Identifiable assets acquired, liabilities assumed, and
any noncontrolling interests (including any intangible assets) are recognized and measured at fair value. Assets acquired that do not meet the definition of a business are accounted for as an asset acquisition. The purchase price of each asset acquisition is allocated based on the relative fair value of assets acquired. See Note 15 for additional information, including recent and proposed acquisitions.
Determining the fair value of assets acquired and liabilities assumed requires management judgment and management may engage independent valuation experts to assist in this process. Fair values are determined by using market participant assumptions and typically include the timing and amounts of future cash flows, incurred construction costs, the nature of acquired contracts, discount rates, power market prices, and expected asset lives. For potential or successful acquisitions that meet the definition of a business, any due diligence or transaction costs incurred are expensed as incurred. If the acquisition is accounted for as an asset acquisition, direct and incremental transaction costs can be capitalized as a component of the cost of the assets acquired.
Historically, any contingent consideration relates to fixed amounts due to the seller once an acquired construction project is placed in service. For contingent consideration with variable payments, management fair values the arrangement with any changes recorded in the statements of income. See Note 13 for additional fair value information.
Development Costs
Development Costs
For Southern Power, development costs are capitalized once a project is probable of completion, primarily based on a review of its economics and operational feasibility, as well as the status of power off-take agreements and regulatory approvals, if applicable. Southern Power's capitalized development costs are included in CWIP on the balance sheets. All of Southern Power's development costs incurred prior to the determination that a project is probable of completion are expensed as incurred and included in other operations and maintenance expense in the statements of income. If it is determined that a project is no longer probable of completion, any of Southern Power's capitalized development costs are expensed and included in other operations and maintenance expense in the statements of income.
Long-Term Service Agreements
Long-Term Service Agreements
The traditional electric operating companies and Southern Power have entered into LTSAs for the purpose of securing maintenance support for certain of their generating facilities. The LTSAs cover all planned inspections on the covered equipment, which generally includes the cost of all labor and materials. The LTSAs also obligate the counterparties to cover the costs of unplanned maintenance on the covered equipment subject to limits and scope specified in each contract.
Payments made under the LTSAs for the performance of any planned inspections or unplanned capital maintenance are recorded in the statements of cash flows as investing activities. Receipts of major parts into materials and supplies inventory prior to planned inspections are treated as noncash transactions in the statements of cash flows. Any payments made prior to the work being performed are recorded as prepayments in other current assets and non-current assets on the balance sheets or reduce existing payables for LTSA-related work already completed. At the time work is performed, an appropriate amount is accrued for future payments or transferred from the prepayment and recorded as property, plant, and equipment or expensed.
Transmission Receivables/Prepayments
Transmission Receivables/Prepayments
As a result of Southern Power's acquisition and construction of generating facilities, Southern Power has transmission receivables and/or prepayments representing the portion of interconnection network and transmission upgrades that will be reimbursed to Southern Power. Upon completion of the related project, transmission costs are generally reimbursed by the interconnection provider within a five-year period and the receivable/prepayments are reduced as payments or services are received.
Cash, Cash Equivalents, and Restricted Cash
Cash, Cash Equivalents, and Restricted Cash
For purposes of the financial statements, temporary cash investments are considered cash equivalents. Temporary cash investments are securities with original maturities of 90 days or less.
Storm Damage and Reliability Reserves
Storm Damage and Reliability Reserves
In accordance with their respective state PSC orders, the traditional electric operating companies accrue certain amounts annually related to storm damage recovery. Each traditional electric operating company maintains a reserve to cover or is allowed to defer and recover the cost of damages from major storms to its transmission and distribution facilities and, for Mississippi Power, the cost of uninsured damages to its generation facilities and other property. Alabama Power and Mississippi Power also have authority from the Alabama PSC and the Mississippi PSC, respectively, to accrue certain additional amounts as circumstances warrant. Alabama Power recorded an additional accrual of $21 million in 2024, which is included in the table below.
Materials and Supplies
Materials and Supplies
Materials and supplies for the traditional electric operating companies generally includes the average cost of transmission, distribution, and generating plant materials. Materials and supplies for Southern Company Gas generally includes the average cost of propane gas inventory, liquefied natural gas inventory, fleet fuel, and other materials and supplies. Materials and supplies for Southern Power generally includes the average cost of generating plant materials.
Materials are recorded to inventory when purchased and then expensed or capitalized to property, plant, and equipment, as appropriate, at weighted average cost when installed. In addition, certain major parts are recorded as inventory when acquired and then capitalized at cost when installed to property, plant, and equipment.
Fuel Inventory
Fuel Inventory
Fuel inventory for the traditional electric operating companies includes the average cost of coal, natural gas, oil, transportation, and emissions allowances. Fuel inventory for Southern Power, which is included in other current assets, includes the average cost of oil, natural gas, and emissions allowances. Fuel is recorded to inventory when purchased and then expensed, at weighted average cost, as used. Emissions allowances granted by the EPA are included in inventory at zero cost. The traditional electric operating companies recover fuel expense through fuel cost recovery rates approved by each state PSC or, for wholesale rates, the FERC.
Natural Gas for Sale
Natural Gas for Sale
With the exception of Nicor Gas, Southern Company Gas records natural gas inventories on a weighted average cost of gas basis. In Georgia's deregulated, competitive environment, Marketers sell natural gas to firm end-use customers at market-based prices. On a monthly basis, Atlanta Gas Light assigns to Marketers the majority of the pipeline storage services that it has under contract, along with a corresponding amount of inventory. Atlanta Gas Light retains and manages a portion of its pipeline storage assets and related natural gas inventories for system balancing and to serve system demand.
Nicor Gas' natural gas inventory is carried at cost on a LIFO basis. Inventory decrements occurring during the year that are restored prior to year-end are charged to cost of natural gas at the estimated annual replacement cost. Inventory decrements that are not restored prior to year-end are charged to cost of natural gas at the actual LIFO cost of the inventory layers liquidated. The cost of natural gas, including inventory costs, is recovered from customers under a purchased gas recovery mechanism adjusted for differences between actual costs and amounts billed; therefore, LIFO liquidations have no impact on Southern Company's or Southern Company Gas' net income. At December 31, 2024, the Nicor Gas LIFO inventory balance was $188 million. Based on the average cost of gas purchased in December 2024, the estimated replacement cost of Nicor Gas' inventory at December 31, 2024 was $326 million.
Provision for Uncollectible Accounts
Provision for Uncollectible Accounts
The customers of the traditional electric operating companies and the natural gas distribution utilities are billed monthly. For the majority of receivables, a provision for uncollectible accounts is established based on historical collection experience and other factors. For the remaining receivables, if the company is aware of a specific customer's inability to pay, a provision for
uncollectible accounts is recorded to reduce the receivable balance to the amount reasonably expected to be collected. If circumstances change, the estimate of the recoverability of accounts receivable could change as well. Circumstances that could affect this estimate include, but are not limited to, customer credit issues, customer deposits, and general economic conditions. Customers' accounts are written off once they are deemed to be uncollectible. For all periods presented, uncollectible accounts averaged less than 1% of revenues for each Registrant.
Credit risk exposure at Nicor Gas is mitigated by a bad debt rider approved by the Illinois Commission. The bad debt rider provides for the recovery from (or refund to) customers of the difference between Nicor Gas' actual bad debt experience on an annual basis and the benchmark bad debt expense used to establish its base rates for the respective year.
Concentration of Credit Risk
Concentration of Credit Risk
Concentration of credit risk occurs at Atlanta Gas Light for amounts billed for services and other costs to its customers, which consist of 14 Marketers in Georgia (including SouthStar). The credit risk exposure to the Marketers varies seasonally, with the lowest exposure in the non-peak summer months and the highest exposure in the peak winter months. Marketers are responsible for the retail sale of natural gas to end-use customers in Georgia. The functions of the retail sale of gas include the purchase and sale of natural gas, customer service, billings, and collections. The provisions of Atlanta Gas Light's tariff allow Atlanta Gas Light to obtain credit security support in an amount equal to a minimum of two times a Marketer's highest month's estimated bill from Atlanta Gas Light.
Financial Instruments
Financial Instruments
The traditional electric operating companies and Southern Power use derivative financial instruments to limit exposure to fluctuations in interest rates, the prices of certain fuel purchases, electricity purchases and sales, and occasionally foreign currency exchange rates. Southern Company Gas uses derivative financial instruments to limit exposure to fluctuations in natural gas prices, weather, and interest rates. All derivative financial instruments are recognized as either assets or liabilities on the balance sheets (included in "Other" or shown separately as "Risk Management Activities") and are measured at fair value. See Note 13 for additional information regarding fair value. Substantially all of the traditional electric operating companies', Southern Power's, and Southern Company Gas' bulk energy purchases and sales contracts that meet the definition of a derivative are excluded from fair value accounting requirements because they qualify for the "normal" scope exception and are accounted for under the accrual method. Derivative contracts that qualify as cash flow hedges of anticipated transactions or are recoverable through the traditional electric operating companies' and the natural gas distribution utilities' fuel-hedging programs result in the deferral of related gains and losses in AOCI or regulatory assets and liabilities, respectively, until the hedged transactions occur. Other derivative contracts that qualify as fair value hedges are marked to market through current period income and are recorded on a net basis in the statements of income. Cash flows from derivatives are classified on the statements of cash flows in the same category as the hedged item. See Note 14 for additional information regarding derivatives.
The Registrants offset fair value amounts recognized for multiple derivative instruments executed with the same counterparty under netting arrangements. The Registrants had no outstanding collateral repayment obligations or rights to reclaim collateral arising from derivative instruments recognized at December 31, 2024.
The Registrants are exposed to potential losses related to financial instruments in the event of counterparties' nonperformance. The Registrants have established risk management policies and controls to determine and monitor the creditworthiness of counterparties in order to mitigate their exposure to counterparty credit risk.
Southern Company Gas
Southern Company Gas enters into weather derivative contracts as economic hedges of natural gas revenues in the event of warmer-than-normal weather in the Heating Season. Exchange-traded options are carried at fair value, with changes reflected in natural gas revenues. Non-exchange-traded options are accounted for using the intrinsic value method. Changes in the intrinsic value for non-exchange-traded contracts are also reflected in natural gas revenues in the statements of income.
Southern Company Gas enters into transactions to secure transportation capacity between delivery points in order to serve its customers and various markets. NYMEX futures and OTC contracts are used to capture the price differential or spread between the locations served by the capacity to substantially protect the natural gas revenues that will ultimately be realized when the physical flow of natural gas between delivery points occurs. These contracts generally meet the definition of derivatives and are carried at fair value on the balance sheets, with changes in fair value included in earnings in the period of change. These contracts are not designated as hedges for accounting purposes.
The purchase, transportation, storage, and sale of natural gas are accounted for on a weighted average cost or accrual basis, as appropriate, rather than on the fair value basis utilized for the derivatives used to mitigate the natural gas price risk associated with the storage and transportation portfolio. Monthly demand charges are incurred for the contracted storage and transportation
capacity and payments associated with asset management agreements, and these demand charges and payments are recognized on the statements of income in the period they are incurred. This difference in accounting methods can result in volatility in reported earnings, even though the economic margin is substantially unchanged from the dates the transactions were consummated.
DERIVATIVES
The Registrants are exposed to market risks, including commodity price risk, interest rate risk, weather risk, and occasionally foreign currency exchange rate risk. To manage the volatility attributable to these exposures, each company nets its exposures, where possible, to take advantage of natural offsets and enters into various derivative transactions for the remaining exposures pursuant to each company's policies in areas such as counterparty exposure and risk management practices. Each company's policy is that derivatives are to be used primarily for hedging purposes and mandates strict adherence to all applicable risk management policies. Derivative positions are monitored using techniques including, but not limited to, market valuation, value at risk, stress testing, and sensitivity analysis. Derivative instruments are recognized at fair value in the balance sheets as either assets or liabilities and are presented on a net basis. See Note 13 for additional fair value information. In the statements of cash flows, any cash impacts of settled energy-related and interest rate derivatives are recorded as operating activities. Any cash impacts of settled foreign currency derivatives are classified as operating or financing activities to correspond with the classification of the hedged interest or principal, respectively. See Note 1 under "Financial Instruments" for additional information.
Energy-Related Derivatives
The Subsidiary Registrants enter into energy-related derivatives to hedge exposures to electricity, natural gas, and other fuel price changes. However, due to cost-based rate regulations and other various cost recovery mechanisms, the traditional electric operating companies and the natural gas distribution utilities have limited exposure to market volatility in energy-related commodity prices. Each of the traditional electric operating companies and certain of the natural gas distribution utilities of Southern Company Gas manage fuel-hedging programs, implemented per the guidelines of their respective state PSCs or other applicable state regulatory agencies, through the use of financial derivative contracts, which are expected to continue to mitigate price volatility. The traditional electric operating companies (with respect to wholesale generating capacity) and Southern Power have limited exposure to market volatility in energy-related commodity prices because their long-term sales contracts shift substantially all fuel cost responsibility to the purchaser. However, the traditional electric operating companies and Southern Power may be exposed to market volatility in energy-related commodity prices to the extent any uncontracted capacity is used to sell electricity. Southern Company Gas retains exposure to price changes that can, in a volatile energy market, be material and can adversely affect its results of operations.
Southern Company Gas also enters into weather derivative contracts as economic hedges in the event of warmer-than-normal weather. Exchange-traded options are carried at fair value, with changes reflected in natural gas revenues. Non-exchange-traded options are accounted for using the intrinsic value method. Changes in the intrinsic value for non-exchange-traded contracts are reflected in natural gas revenues.
Energy-related derivative contracts are accounted for under one of three methods:
•Regulatory Hedges – Energy-related derivative contracts designated as regulatory hedges relate primarily to the traditional electric operating companies' and the natural gas distribution utilities' fuel-hedging programs, where gains and losses are initially recorded as regulatory liabilities and assets, respectively, and then are included in fuel expense as the underlying fuel is used in operations and ultimately recovered through an approved cost recovery mechanism.
•Cash Flow Hedges – Gains and losses on energy-related derivatives designated as cash flow hedges (which are mainly used to hedge anticipated purchases and sales) are initially deferred in AOCI before being recognized in the statements of income in the same period and in the same income statement line item as the earnings effect of the hedged transactions.
•Not Designated – Gains and losses on energy-related derivative contracts that are not designated or fail to qualify as hedges are recognized in the statements of income as incurred.
Some energy-related derivative contracts require physical delivery as opposed to financial settlement, and this type of derivative is both common and prevalent within the electric and natural gas industries. When an energy-related derivative contract is settled physically, any cumulative unrealized gain or loss is reversed and the contract price is recognized in the respective line item representing the actual price of the underlying goods being delivered.
Interest Rate Derivatives
Southern Company and certain subsidiaries may enter into interest rate derivatives to hedge exposure to changes in interest rates. Derivatives related to existing variable rate securities or forecasted transactions are accounted for as cash flow hedges where the derivatives' fair value gains or losses are recorded in OCI and are reclassified into earnings at the same time and presented on the same income statement line item as the earnings effect of the hedged transactions. Derivatives related to existing fixed rate securities are accounted for as fair value hedges, where the derivatives' fair value gains or losses and hedged items' fair value gains or losses are both recorded directly to earnings on the same income statement line item. Fair value gains or losses on derivatives that are not designated or fail to qualify as hedges are recognized in the statements of income as incurred.
Foreign Currency Derivatives
Southern Company and certain subsidiaries, including Southern Power, may enter into foreign currency derivatives to hedge exposure to changes in foreign currency exchange rates, such as that arising from the issuance of debt denominated in a currency other than U.S. dollars. Derivatives related to forecasted transactions are accounted for as cash flow hedges where the derivatives' fair value gains or losses are recorded in OCI and are reclassified into earnings at the same time and on the same income statement line as the earnings effect of the hedged transactions, including foreign currency gains or losses arising from changes in the U.S. currency exchange rates. Derivatives related to existing fixed rate securities are accounted for as fair value hedges, where the derivatives' fair value gains or losses and hedged items' fair value gains or losses are both recorded directly to earnings on the same income statement line item, including foreign currency gains or losses arising from changes in the U.S. currency exchange rates. Southern Company has elected to exclude the cross-currency basis spread from the assessment of effectiveness in the fair value hedges of its foreign currency risk and record any difference between the change in the fair value of the excluded components and the amounts recognized in earnings as a component of OCI.
Comprehensive Income
Comprehensive Income
The objective of comprehensive income is to report a measure of all changes in common stock equity of an enterprise that result from transactions and other economic events of the period other than transactions with owners. Comprehensive income consists of net income attributable to the Registrant, changes in the fair value of qualifying cash flow hedges, and reclassifications for amounts included in net income. Comprehensive income also consists of certain changes in pension and other postretirement benefit plans for Southern Company, Southern Power, and Southern Company Gas.
Variable Interest Entities
Variable Interest Entities
The Registrants may hold ownership interests in a number of business ventures with varying ownership structures. Partnership interests and other variable interests are evaluated to determine if each entity is a VIE. The primary beneficiary of a VIE is required to consolidate the VIE when it has both the power to direct the activities of the VIE that most significantly impact the VIE's economic performance and the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE. See Note 7 for additional information regarding VIEs.
Asset Retirement Obligations
AROs are computed as the present value of the estimated costs for an asset's future retirement and are recorded in the period in which the liability is incurred. The estimated costs are capitalized as part of the related long-lived asset and depreciated over the asset's useful life. In the absence of quoted market prices, AROs are estimated using present value techniques in which estimates of future cash outlays associated with the asset retirements are discounted using a credit-adjusted risk-free rate. Estimates of the timing and amounts of future cash outlays are based on projections of when and how the assets will be retired and the cost of future removal activities. Each traditional electric operating company and natural gas distribution utility has received accounting guidance from its state PSC or applicable state regulatory agency allowing the continued accrual or recovery of other retirement costs for long-lived assets that it does not have a legal obligation to retire. Accordingly, the accumulated removal costs for these obligations are reflected in the balance sheets as regulatory liabilities and amounts to be recovered are reflected in the balance sheets as regulatory assets.
The ARO liabilities for the traditional electric operating companies primarily relate to facilities that are subject to the CCR Rule and the related state rules, principally surface impoundments. In addition, Alabama Power and Georgia Power have retirement obligations related to the decommissioning of nuclear facilities (Alabama Power's Plant Farley and Georgia Power's ownership interests in Plant Hatch and Plant Vogtle). See "Nuclear Decommissioning" herein for additional information. Other significant AROs include various landfill sites and asbestos removal for Alabama Power, Georgia Power, and Mississippi Power and gypsum cells and mine reclamation for Mississippi Power. The ARO liability for Southern Power primarily relates to its solar and wind facilities, which are located on long-term land leases requiring the restoration of land at the end of the lease.
The traditional electric operating companies and Southern Company Gas also have identified other retirement obligations, such as obligations related to certain electric transmission and distribution facilities, certain asbestos-containing material within long-term assets not subject to ongoing repair and maintenance activities, certain wireless communication towers, the disposal of polychlorinated biphenyls in certain transformers, leasehold improvements, equipment on customer property, and property associated with the Southern Company system's rail lines and natural gas pipelines. However, liabilities for the removal of these assets have not been recorded because the settlement timing for certain retirement obligations related to these assets is indeterminable and, therefore, the fair value of the retirement obligations cannot be reasonably estimated. A liability for these retirement obligations will be recognized when sufficient information becomes available to support a reasonable estimation of the ARO.
Southern Company and the traditional electric operating companies will continue to recognize in their respective statements of income allowed removal costs in accordance with regulatory treatment. Any differences between costs recognized in accordance with accounting standards related to asset retirement and environmental obligations and those reflected in rates are recognized as either a regulatory asset or liability in the balance sheets as ordered by the various state PSCs.
Nuclear Decommissioning
Nuclear Decommissioning
The NRC requires licensees of commercial nuclear power reactors to establish a plan for providing reasonable assurance of funds for future decommissioning. Alabama Power and Georgia Power have external trust funds (Funds) to comply with the NRC's regulations. Use of the Funds is restricted to nuclear decommissioning activities. The Funds are managed and invested in accordance with applicable requirements of various regulatory bodies, including the NRC, the FERC, and state PSCs, as well as the IRS. While Alabama Power and Georgia Power are allowed to prescribe an overall investment policy to the Funds' managers,
neither Southern Company nor its subsidiaries or affiliates are allowed to engage in the day-to-day management of the Funds or to mandate individual investment decisions. Day-to-day management of the investments in the Funds is delegated to unrelated third-party managers with oversight by the management of Alabama Power and Georgia Power. The Funds' managers are authorized, within certain investment guidelines, to actively buy and sell securities at their own discretion in order to maximize the return on the Funds' investments. The Funds are invested in a tax-efficient manner in a diversified mix of equity and fixed income securities and are reported as trading securities.
Alabama Power and Georgia Power record the investment securities held in the Funds at fair value, as disclosed in Note 13, as management believes that fair value best represents the nature of the Funds. Gains and losses, whether realized or unrealized, are recorded in the regulatory liability for AROs in the balance sheets and are not included in net income or OCI. Fair value adjustments and realized gains and losses are determined on a specific identification basis.
Fair Value Measurement
Fair value measurements are based on inputs of observable and unobservable market data that a market participant would use in pricing the asset or liability. The use of observable inputs is maximized where available and the use of unobservable inputs is minimized for fair value measurement and reflects a three-tier fair value hierarchy that prioritizes inputs to valuation techniques used for fair value measurement.
•Level 1 consists of observable market data in an active market for identical assets or liabilities.
•Level 2 consists of observable market data, other than that included in Level 1, that is either directly or indirectly observable.
•Level 3 consists of unobservable market data. The input may reflect the assumptions of each Registrant of what a market participant would use in pricing an asset or liability. If there is little available market data, then each Registrant's own assumptions are the best available information.
In the case of multiple inputs being used in a fair value measurement, the lowest level input that is significant to the fair value measurement represents the level in the fair value hierarchy in which the fair value measurement is reported.
Valuation Methodologies
The energy-related derivatives primarily consist of exchange-traded and OTC financial products for natural gas and physical power products, including, from time to time, basis swaps. These are standard products used within the energy industry and are valued using the market approach. The inputs used are mainly from observable market sources, such as forward natural gas prices, power prices, implied volatility, and overnight index swap interest rates. Interest rate derivatives are also standard OTC products that are valued using observable market data and assumptions commonly used by market participants. The fair value of interest rate derivatives reflects the net present value of expected payments and receipts under the swap agreement based on the market's
expectation of future interest rates. Additional inputs to the net present value calculation may include the contract terms, counterparty credit risk, and, occasionally, implied volatility of interest rate options. The fair value of cross-currency swaps reflects the net present value of expected payments and receipts under the swap agreement based on the market's expectation of future foreign currency exchange rates. Additional inputs to the net present value calculation may include the contract terms, counterparty credit risk, and discount rates. The interest rate derivatives and cross-currency swaps are categorized as Level 2 under Fair Value Measurements as these inputs are based on observable data and valuations of similar instruments. See Note 14 for additional information on how these derivatives are used.
For fair value measurements of the investments within the nuclear decommissioning trusts and the non-qualified deferred compensation trusts, external pricing vendors are designated for each asset class with each security specifically assigned a primary pricing source. For investments held within commingled funds, fair value is determined at the end of each business day through the net asset value, which is established by obtaining the underlying securities' individual prices from the primary pricing source. A market price secured from the primary source vendor is then evaluated by management in its valuation of the assets within the trusts. As a general approach, fixed income market pricing vendors gather market data (including indices and market research reports) and integrate relative credit information, observed market movements, and sector news into proprietary pricing models, pricing systems, and mathematical tools. Dealer quotes and other market information, including live trading levels and pricing analysts' judgments, are also obtained when available.
The NRC requires licensees of commissioned nuclear power reactors to establish a plan for providing reasonable assurance of funds for future decommissioning. See Note 6 under "Nuclear Decommissioning" for additional information.
Southern Power has contingent payment obligations related to two of its acquisitions whereby it is primarily obligated to make generation-based payments to the seller, commencing at the commercial operation of each facility and continuing through 2026 and 2036, respectively. The obligations are primarily categorized as Level 3 under Fair Value Measurements as the fair value is determined using significant unobservable inputs for the forecasted facility's generation in MW-hours, as well as other inputs such as a fixed dollar amount per MW-hour, and a discount rate. The fair value of the obligations reflects the net present value of expected payments and any periodic change arising from forecasted generation is expected to be immaterial.
Southern Power also has payment obligations through 2040 whereby it must reimburse the transmission owners for interconnection facilities and network upgrades constructed to support connection of a Southern Power generating facility to the transmission system. The obligations are categorized as Level 2 under Fair Value Measurements as the fair value is determined using observable inputs for the contracted amounts and reimbursement period, as well as a discount rate. The fair value of the obligations reflects the net present value of expected payments.
"Other investments" primarily includes investments traded in the open market that have maturities greater than 90 days, which are categorized as Level 2 under Fair Value Measurements and are comprised of corporate bonds, bank certificates of deposit, treasury bonds, and/or agency bonds.
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)
 12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]  
Schedule of costs for affiliate transactions Costs for these services from SCS in 2024, 2023, and 2022 were as follows:
Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern Company Gas
(in millions)
2024$813 $1,197 $130 $93 $290 
2023611 857 113 86 261 
2022549 762 115 86 262 
Mississippi Power's and Southern Power's power purchases from affiliates through the Southern Company power pool are included in purchased power on their respective statements of income and were as follows:
Mississippi
Power		Southern
Power
(in millions)
2024$8 $17 
20234 13 
20224 29 
Transportation costs under these agreements in 2024, 2023, and 2022 were as follows:
Alabama
Power		Georgia
Power		Southern
Power		Southern Company Gas
(in millions)
2024$13 $103 $35 $28 
202312 101 34 28 
202218 99 37 27 
The approximate rates for 2024, 2023, and 2022 were as follows:
202420232022
Alabama Power4.2 %4.1 %2.7 %
Georgia Power3.4 %3.8 %3.3 %
Mississippi Power3.3 %3.4 %3.4 %
Southern Company Gas2.9 %2.7 %2.7 %
Schedule of total AFUDC and interest capitalized
Total AFUDC and interest capitalized for the applicable Registrants in 2024, 2023, and 2022 was as follows:
Southern CompanyAlabama
Power
Georgia
Power(*)
Southern
Power		Southern Company Gas
(in millions)
2024$339 $76 $209 $7 $47 
2023400 109 251 3 37 
2022327 90 213 — 24 
(*)See Note 2 under "Georgia Power – Nuclear Construction" for information on the inclusion of a portion of construction costs related to Plant Vogtle Units 3 and 4 in Georgia Power's rate base through each unit's respective in-service date.
Schedule of average AFUDC composite rates
The average AFUDC composite rates for 2024, 2023, and 2022 for the traditional electric operating companies and the natural gas distribution utilities were as follows:
202420232022
Alabama Power8.1 %8.1 %7.9 %
Georgia Power(a)
7.7 %7.6 %7.3 %
Mississippi Power(b)
— %— %5.3 %
Southern Company Gas:
Atlanta Gas Light7.7 %7.4 %7.6 %
Chattanooga Gas7.1 %7.1 %7.1 %
Nicor Gas5.6 %4.6 %2.0 %
(a)Excludes AFUDC related to the construction of Plant Vogtle Units 3 and 4 in 2022 and 2023 and Plant Vogtle Unit 4 in 2024. See Note 2 under "Georgia Power – Nuclear Construction" for additional information.
(b)Mississippi Power's AFUDC was immaterial in 2024 and 2023.
Schedule of goodwill balances
At December 31, 2024 and 2023, goodwill was as follows:
At December 31, 2024At December 31, 2023
(in millions)
Southern Company$5,161 $5,161 
Southern Company Gas:
Gas distribution operations$4,034 $4,034 
Gas marketing services981 981 
Southern Company Gas total$5,015 $5,015 
Schedule of intangible assets subject to amortization
At December 31, 2024 and 2023, other intangible assets were as follows:
At December 31, 2024At December 31, 2023
Gross Carrying AmountAccumulated AmortizationOther
Intangible Assets, Net		Gross Carrying AmountAccumulated AmortizationOther
Intangible Assets, Net
(in millions)(in millions)
Southern Company
Subject to amortization:
Customer relationships$212 $(182)$30 $212 $(172)$40 
Trade names64 (59)5 64 (53)11 
PPA fair value adjustments390 (168)222 390 (148)242 
Other3 (3)— 3 (3)— 
Total subject to amortization$669 $(412)$257 $669 $(376)$293 
Not subject to amortization:
FCC licenses75 — 75 75 — 75 
Total other intangible assets$744 $(412)$332 $744 $(376)$368 
Southern Power(*)
PPA fair value adjustments$390 $(168)$222 $390 $(148)$242 
Southern Company Gas(*)
Gas marketing services
Customer relationships$156 $(150)$6 $156 $(145)$11 
Trade names26 (23)3 26 (21)5 
Total other intangible assets$182 $(173)$9 $182 $(166)$16 
(*)All subject to amortization.
Schedule of intangible assets not subject to amortization
At December 31, 2024 and 2023, other intangible assets were as follows:
At December 31, 2024At December 31, 2023
Gross Carrying AmountAccumulated AmortizationOther
Intangible Assets, Net		Gross Carrying AmountAccumulated AmortizationOther
Intangible Assets, Net
(in millions)(in millions)
Southern Company
Subject to amortization:
Customer relationships$212 $(182)$30 $212 $(172)$40 
Trade names64 (59)5 64 (53)11 
PPA fair value adjustments390 (168)222 390 (148)242 
Other3 (3)— 3 (3)— 
Total subject to amortization$669 $(412)$257 $669 $(376)$293 
Not subject to amortization:
FCC licenses75 — 75 75 — 75 
Total other intangible assets$744 $(412)$332 $744 $(376)$368 
Southern Power(*)
PPA fair value adjustments$390 $(168)$222 $390 $(148)$242 
Southern Company Gas(*)
Gas marketing services
Customer relationships$156 $(150)$6 $156 $(145)$11 
Trade names26 (23)3 26 (21)5 
Total other intangible assets$182 $(173)$9 $182 $(166)$16 
(*)All subject to amortization.
Schedule of amortization associated with other intangible assets
Amortization associated with other intangible assets in 2024, 2023, and 2022 was as follows:
202420232022
(in millions)
Southern Company(a)
$35 $38 $39 
Southern Power(b)
20 20 20 
Southern Company Gas
Gas marketing services7 10 11 
(a)Includes $20 million annually recorded as a reduction to operating revenues.
(b)Recorded as a reduction to operating revenues.
Schedule of estimated future amortization of other intangible assets
At December 31, 2024, the estimated amortization associated with other intangible assets for the next five years is as follows:
20252026202720282029
(in millions)
Southern Company$32 $27 $23 $23 $23 
Southern Power20 20 20 20 19 
Southern Company Gas
Gas marketing services6 3 — — — 
Schedule of cash, cash equivalents, and restricted cash
The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets that total to the amount shown in the statements of cash flows for the applicable Registrants:
Southern
Company
Alabama Power
Georgia
Power		Southern
Power		Southern
Company Gas
(in millions)
At December 31, 2024
Cash and cash equivalents$1,070 $585 $97 $159 $43 
Restricted cash(a):
Other current assets31 — 21 9 1 
Total cash, cash equivalents, and restricted cash(b)
$1,101 $585 $118 $168 $44 
At December 31, 2023
Cash and cash equivalents$748 $324 $9 $124 $33 
Restricted cash(a):
Other current assets141 85 37 17 2 
Other deferred charges and assets31 — 29 3 — 
Total cash, cash equivalents, and restricted cash(b)
$921 $409 $75 $144 $35 
(a)For Alabama Power and Georgia Power, reflects proceeds from the issuance of solid waste disposal facility revenue bonds in 2023 and 2022, respectively. See Note 8 under "Long-term Debt" for additional information. For Southern Power, reflects $9 million and $17 million at December 31, 2024 and 2023, respectively, resulting from an arbitration award held to fund future replacement costs and $3 million at December 31, 2023 held to fund estimated construction completion costs at the Deuel Harvest wind facility. For Southern Company Gas, reflects collateral for workers' compensation, life insurance, and long-term disability insurance.
(b)Total may not add due to rounding.
Reconciliation of restricted cash and cash equivalents
The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets that total to the amount shown in the statements of cash flows for the applicable Registrants:
Southern
Company
Alabama Power
Georgia
Power		Southern
Power		Southern
Company Gas
(in millions)
At December 31, 2024
Cash and cash equivalents$1,070 $585 $97 $159 $43 
Restricted cash(a):
Other current assets31 — 21 9 1 
Total cash, cash equivalents, and restricted cash(b)
$1,101 $585 $118 $168 $44 
At December 31, 2023
Cash and cash equivalents$748 $324 $9 $124 $33 
Restricted cash(a):
Other current assets141 85 37 17 2 
Other deferred charges and assets31 — 29 3 — 
Total cash, cash equivalents, and restricted cash(b)
$921 $409 $75 $144 $35 
(a)For Alabama Power and Georgia Power, reflects proceeds from the issuance of solid waste disposal facility revenue bonds in 2023 and 2022, respectively. See Note 8 under "Long-term Debt" for additional information. For Southern Power, reflects $9 million and $17 million at December 31, 2024 and 2023, respectively, resulting from an arbitration award held to fund future replacement costs and $3 million at December 31, 2023 held to fund estimated construction completion costs at the Deuel Harvest wind facility. For Southern Company Gas, reflects collateral for workers' compensation, life insurance, and long-term disability insurance.
(b)Total may not add due to rounding.
Schedule of regulatory assets
Storm damage reserve activity for the traditional electric operating companies during 2023 and 2024 was as follows:
Southern
Company
Alabama Power
Georgia Power
Mississippi
Power
 (in millions)
Balance at December 31, 2022$216 $97 $83 $36 
Accrual61 18 31 12 
Weather-related damages
(211)(39)(168)(4)
Balance at December 31, 2023$66 $76 $(54)$44 
Accrual79 34 31 14 
Weather-related damages
(850)(40)(804)(6)
Balance at December 31, 2024$(705)$70 $(827)$52 
The traditional electric operating companies accrued the following amounts related to storm damage recovery in 2022:
Southern
Company
Alabama
Power
Georgia
Power
Mississippi
Power
(in millions)
2022$239 $19 $213 $7 
During 2024, 2023, and 2022, Alabama Power and Mississippi Power accrued the following amounts to their reliability reserves:
Southern
Company		Alabama
Power		Mississippi
Power
(in millions)
2024$84 $63 $21 
202363 52 11 
2022191 166 25 
Details of regulatory assets and (liabilities) reflected in the balance sheets at December 31, 2024 and 2023 are provided in the following tables:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2024
AROs(*)
$5,810 $1,906 $3,658 $248 $— 
Retiree benefit plans(*)
2,605 680 892 134 44 
Remaining net book value of retired assets
1,198 454 729 15 — 
Deferred income tax charges
927 264 634 27 — 
Storm damage
859 — 827 32 — 
Deferred depreciation
535 286 249 — — 
Environmental remediation(*)
249 — 16 — 233 
Vacation pay(*)
224 85 112 12 15 
Loss on reacquired debt
219 32 183 4 — 
Software and cloud computing costs
200 76 116 4 4 
Under recovered regulatory clause revenues
167 119 — 17 31 
Regulatory clauses
162 82 — — 80 
Nuclear outage
92 39 53 — — 
Fuel-hedging (realized and unrealized) losses
69 23 29 17 — 
Qualifying repairs of natural gas distribution systems
53 — — — 53 
Long-term debt fair value adjustment
52 — — — 52 
Plant Daniel Units 3 and 4
23 — — 23 — 
Other regulatory assets
184 42 40 30 72 
Deferred income tax credits
(4,536)(1,398)(2,149)(219)(755)
Other cost of removal obligations
(1,176)24 816 (170)(1,846)
Over recovered regulatory clause revenues
(285)(29)(52)— (204)
Reliability reserves
(188)(131)— (57)— 
Storm/property damage reserves
(122)(70)— (52)— 
Nuclear fuel disposal cost recovery
(100)(100)— — — 
Other regulatory liabilities
(180)(28)(14)(6)(31)
Total regulatory assets (liabilities), net$7,041 $2,356 $6,139 $59 $(2,252)
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2023
AROs(*)
$5,733 $1,936 $3,505 $247 $— 
Retiree benefit plans(*)
3,011 815 976 140 146 
Remaining net book value of retired assets
1,357 499 841 17 — 
Deferred income tax charges
897 262 605 28 — 
Under recovered regulatory clause revenues
413 381 — 12 20 
Fuel-hedging (realized and unrealized) losses
270 100 121 49 — 
Deferred depreciation
270 143 127 — — 
Environmental remediation(*)
255 — 20 — 235 
Loss on reacquired debt
238 35 197 5 1 
Vacation pay(*)
217 83 107 11 16 
Software and cloud computing costs
150 59 84 2 5 
Regulatory clauses
140 112 — — 28 
Storm damage
92 — 54 38 — 
Nuclear outage
83 50 33 — — 
Long-term debt fair value adjustment
60 — — — 60 
Qualifying repairs of natural gas distribution systems
40 — — — 40 
Plant Daniel Units 3 and 4
25 — — 25 — 
Other regulatory assets
189 39 33 25 93 
Deferred income tax credits
(4,686)(1,506)(2,161)(241)(759)
Other cost of removal obligations
(1,312)28 617 (186)(1,771)
Over recovered regulatory clause revenues
(287)(3)(46)— (238)
Reliability reserves
(179)(143)— (36)— 
Storm/property damage reserves
(120)(76)— (44)— 
Other regulatory liabilities
(333)(94)(23)(2)(101)
Total regulatory assets (liabilities), net$6,523 $2,720 $5,090 $90 $(2,225)
(*)Generally not earning a return as they are excluded from rate base or are offset in rate base by a corresponding asset or liability.
Unless otherwise noted, the following recovery and amortization periods for these regulatory assets and (liabilities) have been approved by the respective state PSC or regulatory agency:
AROs and other cost of removal obligations – Generally recorded over the related property lives, which may range up to 64 years for Alabama Power, 54 years for Georgia Power, 67 years for Mississippi Power, and 85 years for Southern Company Gas. AROs and other cost of removal obligations are settled and trued up following completion of the related activities. Alabama Power is recovering CCR ARO expenditures over a 38-year period ending in 2054 through Rate CNP Compliance. Effective January 1, 2023, Georgia Power is recovering CCR ARO expenditures over four-year periods through its ECCR tariff. Prior to 2023, expenditures were recovered over three-year periods. See "Georgia Power – Rate Plans" herein and Note 6 for additional information.
Retiree benefit plans – Recovered and amortized over the average remaining service period, which may range up to 14 years for Alabama Power, Georgia Power, Mississippi Power, and Southern Company Gas. Southern Company's balances also include amounts at SCS and Southern Nuclear that are allocated to the applicable regulated utilities. See Note 11 for additional information.
Remaining net book value of retired assets –
Alabama Power: Primarily represents the net book value of Plant Gorgas Unit 10 ($419 million at December 31, 2024) being amortized over 13 years (through 2037) and Plant Barry Unit 4 ($35 million at December 31, 2024) being amortized over 10 years (through 2034). See "Alabama Power – Environmental Accounting Order" herein for additional information.
Georgia Power: Net book values of Plant Wansley Units 1 and 2 and Plant Hammond Units 3 and 4 (totaling $418 million and $302 million, respectively, at December 31, 2024) are being amortized over remaining periods between one and 11 years (between 2025 and 2035). Balance also includes unusable materials and supplies inventories, for which the Georgia PSC will determine a recovery period in a future base rate case.
Mississippi Power: Represents net book value of certain environmental compliance assets at Plant Watson and Plant Greene County. The retail portion is being amortized over 10 years (through 2033) and the wholesale portion is being amortized over 10 years (through 2034). See "Mississippi Power – Environmental Compliance Overview Plan" herein for additional information.
Deferred income tax charges and credits – Charges are recovered and credits are primarily amortized over the related property lives, which may range up to 64 years for Alabama Power, 54 years for Georgia Power, 67 years for Mississippi Power, and 85 years for Southern Company Gas. See Note 10 for additional information. These accounts include certain deferred income tax assets and liabilities not subject to normalization, as described further below:
Alabama Power: Related amounts at December 31, 2024 include excess federal deferred income tax liabilities that are available for the benefit of customers in 2025, as discussed under "Alabama Power – Excess Accumulated Deferred Income Tax Accounting Order" herein. Remaining amounts are being recovered and amortized ratably over the related property lives.
Georgia Power: Related amounts at December 31, 2024 include $135 million of deferred income tax assets related to construction costs for Plant Vogtle Units 3 and 4 being recovered over 10 years (through 2034) and $102 million of excess state deferred income tax liabilities that will be returned to customers in 2025. See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4.
Southern Company Gas: Related amounts at December 31, 2024 include $24 million of deferred income tax liabilities being amortized over periods generally not exceeding five years, primarily related to excess state deferred income tax liabilities. See "Southern Company Gas – Rate Proceedings" herein for additional information.
Storm damage – See "Georgia Power – Storm Damage Recovery" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. Mississippi Power's balance represents deferred storm costs associated with Hurricanes Ida and Zeta being recovered through PEP over seven years (through 2029).
Deferred depreciation –
Alabama Power: Represents deferred depreciation for Plant Barry Unit 5 ($114 million at December 31, 2024) and Plant Barry common coal assets ($48 million at December 31, 2024) to be amortized until 2036 beginning when Plant Barry Unit 5 is retired and Plant Gaston Unit 5 coal assets ($124 million at December 31, 2024) to be amortized until 2039 beginning when the assets are retired.
Georgia Power: Represents deferred depreciation for Plant Scherer Units 1 through 3 ($139 million at December 31, 2024) to be amortized over six years beginning in 2029 and Plant Bowen Units 1 and 2 ($80 million at December 31, 2024) to be amortized over four years beginning in 2031, both as approved under Georgia Power's 2022 ARP, and Plant Vogtle Unit 3 and common facilities ($29 million at December 31, 2024) being amortized over 10 years (through 2034). See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4.
Environmental remediation – Effective January 1, 2023, Georgia Power is recovering $5 million annually for environmental remediation under the 2022 ARP. Southern Company Gas' costs are recovered through environmental cost recovery mechanisms when the remediation work is performed. See Note 3 under "Environmental Remediation" for additional information.
Vacation pay – Recorded as earned by employees and recovered as paid, generally within one year. Includes both vacation and banked holiday pay, if applicable.
Loss on reacquired debt – Recovered over either the remaining life of the original issue or, if refinanced, over the remaining life of the new issue. At December 31, 2024, the remaining amortization periods do not exceed 23 years for Alabama Power, 28 years for Georgia Power, 17 years for Mississippi Power, and three years for Southern Company Gas.
Software and cloud computing costs – Represents certain deferred operations and maintenance costs associated with software and cloud computing projects. For Alabama Power, costs are amortized ratably over the life of the related software, which ranges up to 10 years (through 2034). For Georgia Power, costs incurred through 2022 are being amortized over five years (through 2027), and the recovery period for costs incurred after 2022 will be determined in its next base rate case. For Mississippi Power, the recovery period will be determined in Mississippi Power's annual PEP filing process following the completion of the projects and is expected to begin no earlier than 2026. For Southern Company Gas, costs are being amortized ratably over the life of the related software, which ranges up to 10 years (through 2034).
Under and over recovered regulatory clause revenues –
Alabama Power: Balances are recorded monthly and expected to be recovered over periods of up to six years, with the majority expected to be recovered within one year. See "Alabama Power – Rate CNP PPA," " – Rate CNP Compliance," and " – Rate ECR" herein for additional information.
Georgia Power: Balances are recorded monthly and expected to be recovered or returned within two years. See "Georgia Power – Rate Plans" herein for additional information.
Mississippi Power: At December 31, 2024, $17 million is expected to be recovered through various rate recovery mechanisms over a period to be determined in future rate filings. See "Mississippi Power – Ad Valorem Tax Adjustment" herein for additional information.
Southern Company Gas: Balances are recorded and recovered or amortized over periods generally not exceeding five years. In addition to natural gas cost recovery mechanisms, the natural gas distribution utilities have various other cost recovery mechanisms for the recovery of costs, including those related to infrastructure replacement programs.
Regulatory clauses –
Alabama Power: Effective January 1, 2023, balance is being amortized through Rate RSE over a five-year period ending in 2027.
Southern Company Gas: Represents amounts related to Nicor Gas' volume balancing adjustment rider expected to be recovered over a period of less than two years.
Nuclear outage – Costs are deferred to a regulatory asset when incurred and amortized over a subsequent period of 18 months for Alabama Power and up to 24 months for Georgia Power. See Note 5 for additional information.
Fuel-hedging (realized and unrealized) losses and gains – Assets and liabilities are recorded over the life of the underlying hedged purchase contracts. Upon final settlement, actual costs incurred are recovered through the applicable traditional electric operating company's fuel cost recovery mechanism. Purchase contracts generally do not exceed three and a half years for Alabama Power, three years for Georgia Power, and four years for Mississippi Power. Immaterial amounts for fuel-hedging gains at December 31, 2024 and 2023 are included in other regulatory liabilities.
Qualifying repairs of natural gas distribution systems – Represents deferred costs of certain repairs at Atlanta Gas Light being amortized over 20 years.
Long-term debt fair value adjustment – Recovered over the remaining lives of the original debt issuances at acquisition, which range up to 14 years at December 31, 2024.
Plant Daniel Units 3 and 4 – Represents the difference between Mississippi Power's revenue requirement for Plant Daniel Units 3 and 4 under purchase accounting and operating lease accounting. At December 31, 2024, consists of the $16 million retail portion being amortized through 2039 over the remaining life of the related property and the $8 million wholesale portion being amortized over 10 years (through 2034).
Other regulatory assets – Comprised of numerous immaterial components with remaining amortization periods at December 31, 2024 generally not exceeding 19 years for Alabama Power, 10 years for Georgia Power, 10 years for Mississippi Power, and 15 years for Southern Company Gas.
Reliability reserves and storm/property damage reserves – Utilized as related expenses are incurred. See "Alabama Power – Rate NDR" and " – Reliability Reserve Accounting Order," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" and " – Reliability Reserve Accounting Order" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information.
Nuclear fuel disposal cost recovery – Represents award resulting from litigation related to nuclear fuel disposal costs. See Note 3 under "Nuclear Fuel Disposal Costs" for additional information.
Other regulatory liabilities – Comprised of numerous immaterial components with remaining amortization periods at December 31, 2024 generally not exceeding one year for Alabama Power, three years for Georgia Power, one year for Mississippi Power, and 20 years for Southern Company Gas.
The following table illustrates Southern Company Gas' authorized ratemaking amounts that are not recognized on its balance sheets. These amounts are primarily comprised of an allowed equity rate of return on assets associated with certain regulatory infrastructure programs. These amounts will be recognized as revenues in Southern Company Gas' financial statements in the periods they are billable to customers, the majority of which will be recovered by 2025.
December 31, 2024December 31, 2023
(in millions)
Atlanta Gas Light$11 $23 
Virginia Natural Gas10 10 
Chattanooga Gas7 7 
Nicor Gas— 3 
Total$28 $43 
Schedule of AOCI (loss) balances, net of tax effects
AOCI (loss) balances, net of tax effects, for Southern Company, Southern Power, and Southern Company Gas were as follows:
Qualifying
Hedges		Pension and Other
Postretirement
Benefit Plans
Accumulated Other
Comprehensive
Income (Loss)(*)
(in millions)
Southern Company
Balance at December 31, 2021$(162)$(76)$(237)
Current period change13 58 71 
Balance at December 31, 2022(149)(18)(167)
Current period change28 (38)(10)
Balance at December 31, 2023(121)(56)(177)
Current period change75 24 99 
Balance at December 31, 2024$(46)$(32)$(78)
Southern Power
Balance at December 31, 2021$1 $(29)$(27)
Current period change(10)20 10 
Balance at December 31, 2022(9)(9)(18)
Current period change8 (7)1 
Balance at December 31, 2023(1)(16)(17)
Current period change8 7 15 
Balance at December 31, 2024$7 $(9)$(2)
Southern Company Gas
Balance at December 31, 2021$(14)$38 $24 
Current period change(11)18 7 
Balance at December 31, 2022(25)56 31 
Current period change1 (16)(15)
Balance at December 31, 2023(24)40 16 
Current period change21 11 32 
Balance at December 31, 2024$(3)$51 $48 
(*)May not add due to rounding.
v3.25.0.1
REGULATORY MATTERS (Tables)
 12 Months Ended
Dec. 31, 2024
Regulated Operations [Abstract]  
Schedule of regulatory assets
Storm damage reserve activity for the traditional electric operating companies during 2023 and 2024 was as follows:
Southern
Company
Alabama Power
Georgia Power
Mississippi
Power
 (in millions)
Balance at December 31, 2022$216 $97 $83 $36 
Accrual61 18 31 12 
Weather-related damages
(211)(39)(168)(4)
Balance at December 31, 2023$66 $76 $(54)$44 
Accrual79 34 31 14 
Weather-related damages
(850)(40)(804)(6)
Balance at December 31, 2024$(705)$70 $(827)$52 
The traditional electric operating companies accrued the following amounts related to storm damage recovery in 2022:
Southern
Company
Alabama
Power
Georgia
Power
Mississippi
Power
(in millions)
2022$239 $19 $213 $7 
During 2024, 2023, and 2022, Alabama Power and Mississippi Power accrued the following amounts to their reliability reserves:
Southern
Company		Alabama
Power		Mississippi
Power
(in millions)
2024$84 $63 $21 
202363 52 11 
2022191 166 25 
Details of regulatory assets and (liabilities) reflected in the balance sheets at December 31, 2024 and 2023 are provided in the following tables:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2024
AROs(*)
$5,810 $1,906 $3,658 $248 $— 
Retiree benefit plans(*)
2,605 680 892 134 44 
Remaining net book value of retired assets
1,198 454 729 15 — 
Deferred income tax charges
927 264 634 27 — 
Storm damage
859 — 827 32 — 
Deferred depreciation
535 286 249 — — 
Environmental remediation(*)
249 — 16 — 233 
Vacation pay(*)
224 85 112 12 15 
Loss on reacquired debt
219 32 183 4 — 
Software and cloud computing costs
200 76 116 4 4 
Under recovered regulatory clause revenues
167 119 — 17 31 
Regulatory clauses
162 82 — — 80 
Nuclear outage
92 39 53 — — 
Fuel-hedging (realized and unrealized) losses
69 23 29 17 — 
Qualifying repairs of natural gas distribution systems
53 — — — 53 
Long-term debt fair value adjustment
52 — — — 52 
Plant Daniel Units 3 and 4
23 — — 23 — 
Other regulatory assets
184 42 40 30 72 
Deferred income tax credits
(4,536)(1,398)(2,149)(219)(755)
Other cost of removal obligations
(1,176)24 816 (170)(1,846)
Over recovered regulatory clause revenues
(285)(29)(52)— (204)
Reliability reserves
(188)(131)— (57)— 
Storm/property damage reserves
(122)(70)— (52)— 
Nuclear fuel disposal cost recovery
(100)(100)— — — 
Other regulatory liabilities
(180)(28)(14)(6)(31)
Total regulatory assets (liabilities), net$7,041 $2,356 $6,139 $59 $(2,252)
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2023
AROs(*)
$5,733 $1,936 $3,505 $247 $— 
Retiree benefit plans(*)
3,011 815 976 140 146 
Remaining net book value of retired assets
1,357 499 841 17 — 
Deferred income tax charges
897 262 605 28 — 
Under recovered regulatory clause revenues
413 381 — 12 20 
Fuel-hedging (realized and unrealized) losses
270 100 121 49 — 
Deferred depreciation
270 143 127 — — 
Environmental remediation(*)
255 — 20 — 235 
Loss on reacquired debt
238 35 197 5 1 
Vacation pay(*)
217 83 107 11 16 
Software and cloud computing costs
150 59 84 2 5 
Regulatory clauses
140 112 — — 28 
Storm damage
92 — 54 38 — 
Nuclear outage
83 50 33 — — 
Long-term debt fair value adjustment
60 — — — 60 
Qualifying repairs of natural gas distribution systems
40 — — — 40 
Plant Daniel Units 3 and 4
25 — — 25 — 
Other regulatory assets
189 39 33 25 93 
Deferred income tax credits
(4,686)(1,506)(2,161)(241)(759)
Other cost of removal obligations
(1,312)28 617 (186)(1,771)
Over recovered regulatory clause revenues
(287)(3)(46)— (238)
Reliability reserves
(179)(143)— (36)— 
Storm/property damage reserves
(120)(76)— (44)— 
Other regulatory liabilities
(333)(94)(23)(2)(101)
Total regulatory assets (liabilities), net$6,523 $2,720 $5,090 $90 $(2,225)
(*)Generally not earning a return as they are excluded from rate base or are offset in rate base by a corresponding asset or liability.
Unless otherwise noted, the following recovery and amortization periods for these regulatory assets and (liabilities) have been approved by the respective state PSC or regulatory agency:
AROs and other cost of removal obligations – Generally recorded over the related property lives, which may range up to 64 years for Alabama Power, 54 years for Georgia Power, 67 years for Mississippi Power, and 85 years for Southern Company Gas. AROs and other cost of removal obligations are settled and trued up following completion of the related activities. Alabama Power is recovering CCR ARO expenditures over a 38-year period ending in 2054 through Rate CNP Compliance. Effective January 1, 2023, Georgia Power is recovering CCR ARO expenditures over four-year periods through its ECCR tariff. Prior to 2023, expenditures were recovered over three-year periods. See "Georgia Power – Rate Plans" herein and Note 6 for additional information.
Retiree benefit plans – Recovered and amortized over the average remaining service period, which may range up to 14 years for Alabama Power, Georgia Power, Mississippi Power, and Southern Company Gas. Southern Company's balances also include amounts at SCS and Southern Nuclear that are allocated to the applicable regulated utilities. See Note 11 for additional information.
Remaining net book value of retired assets –
Alabama Power: Primarily represents the net book value of Plant Gorgas Unit 10 ($419 million at December 31, 2024) being amortized over 13 years (through 2037) and Plant Barry Unit 4 ($35 million at December 31, 2024) being amortized over 10 years (through 2034). See "Alabama Power – Environmental Accounting Order" herein for additional information.
Georgia Power: Net book values of Plant Wansley Units 1 and 2 and Plant Hammond Units 3 and 4 (totaling $418 million and $302 million, respectively, at December 31, 2024) are being amortized over remaining periods between one and 11 years (between 2025 and 2035). Balance also includes unusable materials and supplies inventories, for which the Georgia PSC will determine a recovery period in a future base rate case.
Mississippi Power: Represents net book value of certain environmental compliance assets at Plant Watson and Plant Greene County. The retail portion is being amortized over 10 years (through 2033) and the wholesale portion is being amortized over 10 years (through 2034). See "Mississippi Power – Environmental Compliance Overview Plan" herein for additional information.
Deferred income tax charges and credits – Charges are recovered and credits are primarily amortized over the related property lives, which may range up to 64 years for Alabama Power, 54 years for Georgia Power, 67 years for Mississippi Power, and 85 years for Southern Company Gas. See Note 10 for additional information. These accounts include certain deferred income tax assets and liabilities not subject to normalization, as described further below:
Alabama Power: Related amounts at December 31, 2024 include excess federal deferred income tax liabilities that are available for the benefit of customers in 2025, as discussed under "Alabama Power – Excess Accumulated Deferred Income Tax Accounting Order" herein. Remaining amounts are being recovered and amortized ratably over the related property lives.
Georgia Power: Related amounts at December 31, 2024 include $135 million of deferred income tax assets related to construction costs for Plant Vogtle Units 3 and 4 being recovered over 10 years (through 2034) and $102 million of excess state deferred income tax liabilities that will be returned to customers in 2025. See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4.
Southern Company Gas: Related amounts at December 31, 2024 include $24 million of deferred income tax liabilities being amortized over periods generally not exceeding five years, primarily related to excess state deferred income tax liabilities. See "Southern Company Gas – Rate Proceedings" herein for additional information.
Storm damage – See "Georgia Power – Storm Damage Recovery" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. Mississippi Power's balance represents deferred storm costs associated with Hurricanes Ida and Zeta being recovered through PEP over seven years (through 2029).
Deferred depreciation –
Alabama Power: Represents deferred depreciation for Plant Barry Unit 5 ($114 million at December 31, 2024) and Plant Barry common coal assets ($48 million at December 31, 2024) to be amortized until 2036 beginning when Plant Barry Unit 5 is retired and Plant Gaston Unit 5 coal assets ($124 million at December 31, 2024) to be amortized until 2039 beginning when the assets are retired.
Georgia Power: Represents deferred depreciation for Plant Scherer Units 1 through 3 ($139 million at December 31, 2024) to be amortized over six years beginning in 2029 and Plant Bowen Units 1 and 2 ($80 million at December 31, 2024) to be amortized over four years beginning in 2031, both as approved under Georgia Power's 2022 ARP, and Plant Vogtle Unit 3 and common facilities ($29 million at December 31, 2024) being amortized over 10 years (through 2034). See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4.
Environmental remediation – Effective January 1, 2023, Georgia Power is recovering $5 million annually for environmental remediation under the 2022 ARP. Southern Company Gas' costs are recovered through environmental cost recovery mechanisms when the remediation work is performed. See Note 3 under "Environmental Remediation" for additional information.
Vacation pay – Recorded as earned by employees and recovered as paid, generally within one year. Includes both vacation and banked holiday pay, if applicable.
Loss on reacquired debt – Recovered over either the remaining life of the original issue or, if refinanced, over the remaining life of the new issue. At December 31, 2024, the remaining amortization periods do not exceed 23 years for Alabama Power, 28 years for Georgia Power, 17 years for Mississippi Power, and three years for Southern Company Gas.
Software and cloud computing costs – Represents certain deferred operations and maintenance costs associated with software and cloud computing projects. For Alabama Power, costs are amortized ratably over the life of the related software, which ranges up to 10 years (through 2034). For Georgia Power, costs incurred through 2022 are being amortized over five years (through 2027), and the recovery period for costs incurred after 2022 will be determined in its next base rate case. For Mississippi Power, the recovery period will be determined in Mississippi Power's annual PEP filing process following the completion of the projects and is expected to begin no earlier than 2026. For Southern Company Gas, costs are being amortized ratably over the life of the related software, which ranges up to 10 years (through 2034).
Under and over recovered regulatory clause revenues –
Alabama Power: Balances are recorded monthly and expected to be recovered over periods of up to six years, with the majority expected to be recovered within one year. See "Alabama Power – Rate CNP PPA," " – Rate CNP Compliance," and " – Rate ECR" herein for additional information.
Georgia Power: Balances are recorded monthly and expected to be recovered or returned within two years. See "Georgia Power – Rate Plans" herein for additional information.
Mississippi Power: At December 31, 2024, $17 million is expected to be recovered through various rate recovery mechanisms over a period to be determined in future rate filings. See "Mississippi Power – Ad Valorem Tax Adjustment" herein for additional information.
Southern Company Gas: Balances are recorded and recovered or amortized over periods generally not exceeding five years. In addition to natural gas cost recovery mechanisms, the natural gas distribution utilities have various other cost recovery mechanisms for the recovery of costs, including those related to infrastructure replacement programs.
Regulatory clauses –
Alabama Power: Effective January 1, 2023, balance is being amortized through Rate RSE over a five-year period ending in 2027.
Southern Company Gas: Represents amounts related to Nicor Gas' volume balancing adjustment rider expected to be recovered over a period of less than two years.
Nuclear outage – Costs are deferred to a regulatory asset when incurred and amortized over a subsequent period of 18 months for Alabama Power and up to 24 months for Georgia Power. See Note 5 for additional information.
Fuel-hedging (realized and unrealized) losses and gains – Assets and liabilities are recorded over the life of the underlying hedged purchase contracts. Upon final settlement, actual costs incurred are recovered through the applicable traditional electric operating company's fuel cost recovery mechanism. Purchase contracts generally do not exceed three and a half years for Alabama Power, three years for Georgia Power, and four years for Mississippi Power. Immaterial amounts for fuel-hedging gains at December 31, 2024 and 2023 are included in other regulatory liabilities.
Qualifying repairs of natural gas distribution systems – Represents deferred costs of certain repairs at Atlanta Gas Light being amortized over 20 years.
Long-term debt fair value adjustment – Recovered over the remaining lives of the original debt issuances at acquisition, which range up to 14 years at December 31, 2024.
Plant Daniel Units 3 and 4 – Represents the difference between Mississippi Power's revenue requirement for Plant Daniel Units 3 and 4 under purchase accounting and operating lease accounting. At December 31, 2024, consists of the $16 million retail portion being amortized through 2039 over the remaining life of the related property and the $8 million wholesale portion being amortized over 10 years (through 2034).
Other regulatory assets – Comprised of numerous immaterial components with remaining amortization periods at December 31, 2024 generally not exceeding 19 years for Alabama Power, 10 years for Georgia Power, 10 years for Mississippi Power, and 15 years for Southern Company Gas.
Reliability reserves and storm/property damage reserves – Utilized as related expenses are incurred. See "Alabama Power – Rate NDR" and " – Reliability Reserve Accounting Order," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" and " – Reliability Reserve Accounting Order" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information.
Nuclear fuel disposal cost recovery – Represents award resulting from litigation related to nuclear fuel disposal costs. See Note 3 under "Nuclear Fuel Disposal Costs" for additional information.
Other regulatory liabilities – Comprised of numerous immaterial components with remaining amortization periods at December 31, 2024 generally not exceeding one year for Alabama Power, three years for Georgia Power, one year for Mississippi Power, and 20 years for Southern Company Gas.
The following table illustrates Southern Company Gas' authorized ratemaking amounts that are not recognized on its balance sheets. These amounts are primarily comprised of an allowed equity rate of return on assets associated with certain regulatory infrastructure programs. These amounts will be recognized as revenues in Southern Company Gas' financial statements in the periods they are billable to customers, the majority of which will be recovered by 2025.
December 31, 2024December 31, 2023
(in millions)
Atlanta Gas Light$11 $23 
Virginia Natural Gas10 10 
Chattanooga Gas7 7 
Nicor Gas— 3 
Total$28 $43 
Schedule of regulatory liabilities
Details of regulatory assets and (liabilities) reflected in the balance sheets at December 31, 2024 and 2023 are provided in the following tables:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2024
AROs(*)
$5,810 $1,906 $3,658 $248 $— 
Retiree benefit plans(*)
2,605 680 892 134 44 
Remaining net book value of retired assets
1,198 454 729 15 — 
Deferred income tax charges
927 264 634 27 — 
Storm damage
859 — 827 32 — 
Deferred depreciation
535 286 249 — — 
Environmental remediation(*)
249 — 16 — 233 
Vacation pay(*)
224 85 112 12 15 
Loss on reacquired debt
219 32 183 4 — 
Software and cloud computing costs
200 76 116 4 4 
Under recovered regulatory clause revenues
167 119 — 17 31 
Regulatory clauses
162 82 — — 80 
Nuclear outage
92 39 53 — — 
Fuel-hedging (realized and unrealized) losses
69 23 29 17 — 
Qualifying repairs of natural gas distribution systems
53 — — — 53 
Long-term debt fair value adjustment
52 — — — 52 
Plant Daniel Units 3 and 4
23 — — 23 — 
Other regulatory assets
184 42 40 30 72 
Deferred income tax credits
(4,536)(1,398)(2,149)(219)(755)
Other cost of removal obligations
(1,176)24 816 (170)(1,846)
Over recovered regulatory clause revenues
(285)(29)(52)— (204)
Reliability reserves
(188)(131)— (57)— 
Storm/property damage reserves
(122)(70)— (52)— 
Nuclear fuel disposal cost recovery
(100)(100)— — — 
Other regulatory liabilities
(180)(28)(14)(6)(31)
Total regulatory assets (liabilities), net$7,041 $2,356 $6,139 $59 $(2,252)
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2023
AROs(*)
$5,733 $1,936 $3,505 $247 $— 
Retiree benefit plans(*)
3,011 815 976 140 146 
Remaining net book value of retired assets
1,357 499 841 17 — 
Deferred income tax charges
897 262 605 28 — 
Under recovered regulatory clause revenues
413 381 — 12 20 
Fuel-hedging (realized and unrealized) losses
270 100 121 49 — 
Deferred depreciation
270 143 127 — — 
Environmental remediation(*)
255 — 20 — 235 
Loss on reacquired debt
238 35 197 5 1 
Vacation pay(*)
217 83 107 11 16 
Software and cloud computing costs
150 59 84 2 5 
Regulatory clauses
140 112 — — 28 
Storm damage
92 — 54 38 — 
Nuclear outage
83 50 33 — — 
Long-term debt fair value adjustment
60 — — — 60 
Qualifying repairs of natural gas distribution systems
40 — — — 40 
Plant Daniel Units 3 and 4
25 — — 25 — 
Other regulatory assets
189 39 33 25 93 
Deferred income tax credits
(4,686)(1,506)(2,161)(241)(759)
Other cost of removal obligations
(1,312)28 617 (186)(1,771)
Over recovered regulatory clause revenues
(287)(3)(46)— (238)
Reliability reserves
(179)(143)— (36)— 
Storm/property damage reserves
(120)(76)— (44)— 
Other regulatory liabilities
(333)(94)(23)(2)(101)
Total regulatory assets (liabilities), net$6,523 $2,720 $5,090 $90 $(2,225)
(*)Generally not earning a return as they are excluded from rate base or are offset in rate base by a corresponding asset or liability.
Unless otherwise noted, the following recovery and amortization periods for these regulatory assets and (liabilities) have been approved by the respective state PSC or regulatory agency:
AROs and other cost of removal obligations – Generally recorded over the related property lives, which may range up to 64 years for Alabama Power, 54 years for Georgia Power, 67 years for Mississippi Power, and 85 years for Southern Company Gas. AROs and other cost of removal obligations are settled and trued up following completion of the related activities. Alabama Power is recovering CCR ARO expenditures over a 38-year period ending in 2054 through Rate CNP Compliance. Effective January 1, 2023, Georgia Power is recovering CCR ARO expenditures over four-year periods through its ECCR tariff. Prior to 2023, expenditures were recovered over three-year periods. See "Georgia Power – Rate Plans" herein and Note 6 for additional information.
Retiree benefit plans – Recovered and amortized over the average remaining service period, which may range up to 14 years for Alabama Power, Georgia Power, Mississippi Power, and Southern Company Gas. Southern Company's balances also include amounts at SCS and Southern Nuclear that are allocated to the applicable regulated utilities. See Note 11 for additional information.
Remaining net book value of retired assets –
Alabama Power: Primarily represents the net book value of Plant Gorgas Unit 10 ($419 million at December 31, 2024) being amortized over 13 years (through 2037) and Plant Barry Unit 4 ($35 million at December 31, 2024) being amortized over 10 years (through 2034). See "Alabama Power – Environmental Accounting Order" herein for additional information.
Georgia Power: Net book values of Plant Wansley Units 1 and 2 and Plant Hammond Units 3 and 4 (totaling $418 million and $302 million, respectively, at December 31, 2024) are being amortized over remaining periods between one and 11 years (between 2025 and 2035). Balance also includes unusable materials and supplies inventories, for which the Georgia PSC will determine a recovery period in a future base rate case.
Mississippi Power: Represents net book value of certain environmental compliance assets at Plant Watson and Plant Greene County. The retail portion is being amortized over 10 years (through 2033) and the wholesale portion is being amortized over 10 years (through 2034). See "Mississippi Power – Environmental Compliance Overview Plan" herein for additional information.
Deferred income tax charges and credits – Charges are recovered and credits are primarily amortized over the related property lives, which may range up to 64 years for Alabama Power, 54 years for Georgia Power, 67 years for Mississippi Power, and 85 years for Southern Company Gas. See Note 10 for additional information. These accounts include certain deferred income tax assets and liabilities not subject to normalization, as described further below:
Alabama Power: Related amounts at December 31, 2024 include excess federal deferred income tax liabilities that are available for the benefit of customers in 2025, as discussed under "Alabama Power – Excess Accumulated Deferred Income Tax Accounting Order" herein. Remaining amounts are being recovered and amortized ratably over the related property lives.
Georgia Power: Related amounts at December 31, 2024 include $135 million of deferred income tax assets related to construction costs for Plant Vogtle Units 3 and 4 being recovered over 10 years (through 2034) and $102 million of excess state deferred income tax liabilities that will be returned to customers in 2025. See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4.
Southern Company Gas: Related amounts at December 31, 2024 include $24 million of deferred income tax liabilities being amortized over periods generally not exceeding five years, primarily related to excess state deferred income tax liabilities. See "Southern Company Gas – Rate Proceedings" herein for additional information.
Storm damage – See "Georgia Power – Storm Damage Recovery" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. Mississippi Power's balance represents deferred storm costs associated with Hurricanes Ida and Zeta being recovered through PEP over seven years (through 2029).
Deferred depreciation –
Alabama Power: Represents deferred depreciation for Plant Barry Unit 5 ($114 million at December 31, 2024) and Plant Barry common coal assets ($48 million at December 31, 2024) to be amortized until 2036 beginning when Plant Barry Unit 5 is retired and Plant Gaston Unit 5 coal assets ($124 million at December 31, 2024) to be amortized until 2039 beginning when the assets are retired.
Georgia Power: Represents deferred depreciation for Plant Scherer Units 1 through 3 ($139 million at December 31, 2024) to be amortized over six years beginning in 2029 and Plant Bowen Units 1 and 2 ($80 million at December 31, 2024) to be amortized over four years beginning in 2031, both as approved under Georgia Power's 2022 ARP, and Plant Vogtle Unit 3 and common facilities ($29 million at December 31, 2024) being amortized over 10 years (through 2034). See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4.
Environmental remediation – Effective January 1, 2023, Georgia Power is recovering $5 million annually for environmental remediation under the 2022 ARP. Southern Company Gas' costs are recovered through environmental cost recovery mechanisms when the remediation work is performed. See Note 3 under "Environmental Remediation" for additional information.
Vacation pay – Recorded as earned by employees and recovered as paid, generally within one year. Includes both vacation and banked holiday pay, if applicable.
Loss on reacquired debt – Recovered over either the remaining life of the original issue or, if refinanced, over the remaining life of the new issue. At December 31, 2024, the remaining amortization periods do not exceed 23 years for Alabama Power, 28 years for Georgia Power, 17 years for Mississippi Power, and three years for Southern Company Gas.
Software and cloud computing costs – Represents certain deferred operations and maintenance costs associated with software and cloud computing projects. For Alabama Power, costs are amortized ratably over the life of the related software, which ranges up to 10 years (through 2034). For Georgia Power, costs incurred through 2022 are being amortized over five years (through 2027), and the recovery period for costs incurred after 2022 will be determined in its next base rate case. For Mississippi Power, the recovery period will be determined in Mississippi Power's annual PEP filing process following the completion of the projects and is expected to begin no earlier than 2026. For Southern Company Gas, costs are being amortized ratably over the life of the related software, which ranges up to 10 years (through 2034).
Under and over recovered regulatory clause revenues –
Alabama Power: Balances are recorded monthly and expected to be recovered over periods of up to six years, with the majority expected to be recovered within one year. See "Alabama Power – Rate CNP PPA," " – Rate CNP Compliance," and " – Rate ECR" herein for additional information.
Georgia Power: Balances are recorded monthly and expected to be recovered or returned within two years. See "Georgia Power – Rate Plans" herein for additional information.
Mississippi Power: At December 31, 2024, $17 million is expected to be recovered through various rate recovery mechanisms over a period to be determined in future rate filings. See "Mississippi Power – Ad Valorem Tax Adjustment" herein for additional information.
Southern Company Gas: Balances are recorded and recovered or amortized over periods generally not exceeding five years. In addition to natural gas cost recovery mechanisms, the natural gas distribution utilities have various other cost recovery mechanisms for the recovery of costs, including those related to infrastructure replacement programs.
Regulatory clauses –
Alabama Power: Effective January 1, 2023, balance is being amortized through Rate RSE over a five-year period ending in 2027.
Southern Company Gas: Represents amounts related to Nicor Gas' volume balancing adjustment rider expected to be recovered over a period of less than two years.
Nuclear outage – Costs are deferred to a regulatory asset when incurred and amortized over a subsequent period of 18 months for Alabama Power and up to 24 months for Georgia Power. See Note 5 for additional information.
Fuel-hedging (realized and unrealized) losses and gains – Assets and liabilities are recorded over the life of the underlying hedged purchase contracts. Upon final settlement, actual costs incurred are recovered through the applicable traditional electric operating company's fuel cost recovery mechanism. Purchase contracts generally do not exceed three and a half years for Alabama Power, three years for Georgia Power, and four years for Mississippi Power. Immaterial amounts for fuel-hedging gains at December 31, 2024 and 2023 are included in other regulatory liabilities.
Qualifying repairs of natural gas distribution systems – Represents deferred costs of certain repairs at Atlanta Gas Light being amortized over 20 years.
Long-term debt fair value adjustment – Recovered over the remaining lives of the original debt issuances at acquisition, which range up to 14 years at December 31, 2024.
Plant Daniel Units 3 and 4 – Represents the difference between Mississippi Power's revenue requirement for Plant Daniel Units 3 and 4 under purchase accounting and operating lease accounting. At December 31, 2024, consists of the $16 million retail portion being amortized through 2039 over the remaining life of the related property and the $8 million wholesale portion being amortized over 10 years (through 2034).
Other regulatory assets – Comprised of numerous immaterial components with remaining amortization periods at December 31, 2024 generally not exceeding 19 years for Alabama Power, 10 years for Georgia Power, 10 years for Mississippi Power, and 15 years for Southern Company Gas.
Reliability reserves and storm/property damage reserves – Utilized as related expenses are incurred. See "Alabama Power – Rate NDR" and " – Reliability Reserve Accounting Order," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" and " – Reliability Reserve Accounting Order" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information.
Nuclear fuel disposal cost recovery – Represents award resulting from litigation related to nuclear fuel disposal costs. See Note 3 under "Nuclear Fuel Disposal Costs" for additional information.
Other regulatory liabilities – Comprised of numerous immaterial components with remaining amortization periods at December 31, 2024 generally not exceeding one year for Alabama Power, three years for Georgia Power, one year for Mississippi Power, and 20 years for Southern Company Gas.
At December 31, 2024 and 2023, the environmental remediation liability and the balance of under recovered environmental remediation costs were reflected in the balance sheets of Southern Company, Georgia Power, and Southern Company Gas as shown in the table below. Alabama Power and Mississippi Power did not have environmental remediation liabilities at December 31, 2024 or 2023.
Southern CompanyGeorgia
Power		Southern Company Gas
(in millions)
December 31, 2024:
Environmental remediation liability:
Other current liabilities$37 $13 $24 
Accrued environmental remediation198 — 198 
Under recovered environmental remediation costs:
Other regulatory assets, current$37 $5 $32 
Other regulatory assets, deferred212 11 201 
December 31, 2023:
Environmental remediation liability:
Other current liabilities$44 $14 $30 
Accrued environmental remediation192 — 192 
Under recovered environmental remediation costs:
Other regulatory assets, current$45 $5 $40 
Other regulatory assets, deferred210 15 195 
Public utilities general disclosures Details of tariff adjustments are provided in the following table:
Tariff202320242025
(in millions)
Traditional base(a)
$194 $275 $194 
ECCR(21)(99)126 
DSM37 10 (22)
MFF6 5 9 
Total(b)
$216 $191 $306 
(a)For 2025, net of $122 million related to the Georgia state tax rate reduction.
(b)Totals may not add due to rounding.
The following table provides regulatory information for Southern Company Gas' natural gas distribution utilities:
Nicor
Gas
Atlanta Gas
Light
Virginia
Natural Gas
Chattanooga
Gas
Authorized ROE at December 31, 2024
9.51%10.25%9.70%9.80%
Weather normalization mechanisms(a)
üü
Decoupled, including straight-fixed-variable rates(b)
üüü
Regulatory infrastructure program rate(c)
üüü
Bad debt rider(d)
üüü
Energy efficiency plan(e)
üü
Annual base rate adjustment mechanism(f)
üü
Year of last base rate case decision2023201920232018
(a)Designed to help stabilize operating results by allowing recovery of costs in the event of unseasonal weather, but are not direct offsets to the potential impacts on earnings of weather and customer consumption.
(b)Allows for recovery of fixed residential customer service costs separately from assumed natural gas volumes used by customers and provides a benchmark level of revenue for recovery.
(c)See "Infrastructure Replacement Programs and Capital Projects" herein for additional information. Chattanooga Gas' pipeline replacement program costs are recovered through its annual base rate review mechanism.
(d)The recovery (refund) of bad debt expense over (under) an established benchmark expense. The gas portion of bad debt expense is recovered through purchased gas adjustment mechanisms. Nicor Gas also has a rider to recover the non-gas portion of bad debt expense.
(e)Recovery of costs associated with plans to achieve specified energy savings goals.
(f)Regulatory mechanism allowing annual adjustments to base rates up or down based on authorized ROE and/or ROE range.
The following table and discussions provide updates on the infrastructure replacement programs and capital projects at the natural gas distribution utilities at December 31, 2024. These programs are risk-based and designed to update and replace cast iron, bare steel, and mid-vintage plastic materials or expand Southern Company Gas' distribution systems to improve reliability and meet operational flexibility and growth.
UtilityProgramRecovery
Capital Expenditures in 2024
Capital Expenditures Since Project Inception
Pipe
Installed Since
Project Inception		Scope of
Program		Program DurationLast
Year of Program
(in millions)(miles)(miles)(years)
Virginia Natural Gas
SAVE
Rider$75 $561 598 938 182029
Atlanta Gas LightSystem Reinforcement RiderRider99 279 29 N/A62027
Chattanooga GasPipeline Replacement ProgramRate Base12 28 24 73 72027
Total$186 $868 651 1,011 
The following table provides a summary of QIP capital investments during the nine-year program:
Year Status of QIP Annual Review Proceeding
Capital Investments
DisallowedMonth of Disallowance
(in millions)
2015 – 2018Complete$1,246 $— 
2019
Complete(a)
415 32 June 2023
2020
Filed March 2021
402 
(b)
2021
Filed March 2022
392 
(b)
2022
Filed March 2023
408 
(b)
6 
(c)(d)
November 2023
2023
Filed March 2024
365 
(b)
25 
(c)(d)
November 2023
$3,228 $63 
(a)Petition for leave to appeal filed to the Illinois Supreme Court for $14 million.
(b)Capital investments are subject to the required QIP annual review proceeding; years 2020 through 2023 are pending with the Illinois Commission.
(c)Appealed to the Illinois Appellate Court.
(d)Disallowed in Nicor Gas' 2023 general base rate case proceeding. See "Rate Proceedings – Nicor Gas" herein for additional information regarding the Illinois Commission's disallowance of certain capital investments.
Schedule of revised cost and schedule
Georgia Power's net capital costs incurred through December 31, 2024 in connection with Plant Vogtle Units 3 and 4, and its approximate proportionate share of additional capital costs to be incurred after December 31, 2024, including completion of site demobilization and remaining contractor obligations, is as follows:
(in millions)
Total project capital cost forecast(a)(b)
$10,732 
Net investment at December 31, 2024(b)
(10,663)
Remaining estimate to complete$69 
(a)Includes approximately $1.2 billion of costs that are not shared with the other Vogtle Owners. Excludes financing costs capitalized through AFUDC of approximately $440 million accrued through Unit 4's in-service date.
(b)Net of $1.7 billion received from Toshiba under the Guarantee Settlement Agreement and approximately $188 million in related customer refunds.
v3.25.0.1
CONTINGENCIES, COMMITMENTS, AND GUARANTEES (Tables)
 12 Months Ended
Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]  
Schedule of regulatory liabilities
Details of regulatory assets and (liabilities) reflected in the balance sheets at December 31, 2024 and 2023 are provided in the following tables:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2024
AROs(*)
$5,810 $1,906 $3,658 $248 $— 
Retiree benefit plans(*)
2,605 680 892 134 44 
Remaining net book value of retired assets
1,198 454 729 15 — 
Deferred income tax charges
927 264 634 27 — 
Storm damage
859 — 827 32 — 
Deferred depreciation
535 286 249 — — 
Environmental remediation(*)
249 — 16 — 233 
Vacation pay(*)
224 85 112 12 15 
Loss on reacquired debt
219 32 183 4 — 
Software and cloud computing costs
200 76 116 4 4 
Under recovered regulatory clause revenues
167 119 — 17 31 
Regulatory clauses
162 82 — — 80 
Nuclear outage
92 39 53 — — 
Fuel-hedging (realized and unrealized) losses
69 23 29 17 — 
Qualifying repairs of natural gas distribution systems
53 — — — 53 
Long-term debt fair value adjustment
52 — — — 52 
Plant Daniel Units 3 and 4
23 — — 23 — 
Other regulatory assets
184 42 40 30 72 
Deferred income tax credits
(4,536)(1,398)(2,149)(219)(755)
Other cost of removal obligations
(1,176)24 816 (170)(1,846)
Over recovered regulatory clause revenues
(285)(29)(52)— (204)
Reliability reserves
(188)(131)— (57)— 
Storm/property damage reserves
(122)(70)— (52)— 
Nuclear fuel disposal cost recovery
(100)(100)— — — 
Other regulatory liabilities
(180)(28)(14)(6)(31)
Total regulatory assets (liabilities), net$7,041 $2,356 $6,139 $59 $(2,252)
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2023
AROs(*)
$5,733 $1,936 $3,505 $247 $— 
Retiree benefit plans(*)
3,011 815 976 140 146 
Remaining net book value of retired assets
1,357 499 841 17 — 
Deferred income tax charges
897 262 605 28 — 
Under recovered regulatory clause revenues
413 381 — 12 20 
Fuel-hedging (realized and unrealized) losses
270 100 121 49 — 
Deferred depreciation
270 143 127 — — 
Environmental remediation(*)
255 — 20 — 235 
Loss on reacquired debt
238 35 197 5 1 
Vacation pay(*)
217 83 107 11 16 
Software and cloud computing costs
150 59 84 2 5 
Regulatory clauses
140 112 — — 28 
Storm damage
92 — 54 38 — 
Nuclear outage
83 50 33 — — 
Long-term debt fair value adjustment
60 — — — 60 
Qualifying repairs of natural gas distribution systems
40 — — — 40 
Plant Daniel Units 3 and 4
25 — — 25 — 
Other regulatory assets
189 39 33 25 93 
Deferred income tax credits
(4,686)(1,506)(2,161)(241)(759)
Other cost of removal obligations
(1,312)28 617 (186)(1,771)
Over recovered regulatory clause revenues
(287)(3)(46)— (238)
Reliability reserves
(179)(143)— (36)— 
Storm/property damage reserves
(120)(76)— (44)— 
Other regulatory liabilities
(333)(94)(23)(2)(101)
Total regulatory assets (liabilities), net$6,523 $2,720 $5,090 $90 $(2,225)
(*)Generally not earning a return as they are excluded from rate base or are offset in rate base by a corresponding asset or liability.
Unless otherwise noted, the following recovery and amortization periods for these regulatory assets and (liabilities) have been approved by the respective state PSC or regulatory agency:
AROs and other cost of removal obligations – Generally recorded over the related property lives, which may range up to 64 years for Alabama Power, 54 years for Georgia Power, 67 years for Mississippi Power, and 85 years for Southern Company Gas. AROs and other cost of removal obligations are settled and trued up following completion of the related activities. Alabama Power is recovering CCR ARO expenditures over a 38-year period ending in 2054 through Rate CNP Compliance. Effective January 1, 2023, Georgia Power is recovering CCR ARO expenditures over four-year periods through its ECCR tariff. Prior to 2023, expenditures were recovered over three-year periods. See "Georgia Power – Rate Plans" herein and Note 6 for additional information.
Retiree benefit plans – Recovered and amortized over the average remaining service period, which may range up to 14 years for Alabama Power, Georgia Power, Mississippi Power, and Southern Company Gas. Southern Company's balances also include amounts at SCS and Southern Nuclear that are allocated to the applicable regulated utilities. See Note 11 for additional information.
Remaining net book value of retired assets –
Alabama Power: Primarily represents the net book value of Plant Gorgas Unit 10 ($419 million at December 31, 2024) being amortized over 13 years (through 2037) and Plant Barry Unit 4 ($35 million at December 31, 2024) being amortized over 10 years (through 2034). See "Alabama Power – Environmental Accounting Order" herein for additional information.
Georgia Power: Net book values of Plant Wansley Units 1 and 2 and Plant Hammond Units 3 and 4 (totaling $418 million and $302 million, respectively, at December 31, 2024) are being amortized over remaining periods between one and 11 years (between 2025 and 2035). Balance also includes unusable materials and supplies inventories, for which the Georgia PSC will determine a recovery period in a future base rate case.
Mississippi Power: Represents net book value of certain environmental compliance assets at Plant Watson and Plant Greene County. The retail portion is being amortized over 10 years (through 2033) and the wholesale portion is being amortized over 10 years (through 2034). See "Mississippi Power – Environmental Compliance Overview Plan" herein for additional information.
Deferred income tax charges and credits – Charges are recovered and credits are primarily amortized over the related property lives, which may range up to 64 years for Alabama Power, 54 years for Georgia Power, 67 years for Mississippi Power, and 85 years for Southern Company Gas. See Note 10 for additional information. These accounts include certain deferred income tax assets and liabilities not subject to normalization, as described further below:
Alabama Power: Related amounts at December 31, 2024 include excess federal deferred income tax liabilities that are available for the benefit of customers in 2025, as discussed under "Alabama Power – Excess Accumulated Deferred Income Tax Accounting Order" herein. Remaining amounts are being recovered and amortized ratably over the related property lives.
Georgia Power: Related amounts at December 31, 2024 include $135 million of deferred income tax assets related to construction costs for Plant Vogtle Units 3 and 4 being recovered over 10 years (through 2034) and $102 million of excess state deferred income tax liabilities that will be returned to customers in 2025. See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4.
Southern Company Gas: Related amounts at December 31, 2024 include $24 million of deferred income tax liabilities being amortized over periods generally not exceeding five years, primarily related to excess state deferred income tax liabilities. See "Southern Company Gas – Rate Proceedings" herein for additional information.
Storm damage – See "Georgia Power – Storm Damage Recovery" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. Mississippi Power's balance represents deferred storm costs associated with Hurricanes Ida and Zeta being recovered through PEP over seven years (through 2029).
Deferred depreciation –
Alabama Power: Represents deferred depreciation for Plant Barry Unit 5 ($114 million at December 31, 2024) and Plant Barry common coal assets ($48 million at December 31, 2024) to be amortized until 2036 beginning when Plant Barry Unit 5 is retired and Plant Gaston Unit 5 coal assets ($124 million at December 31, 2024) to be amortized until 2039 beginning when the assets are retired.
Georgia Power: Represents deferred depreciation for Plant Scherer Units 1 through 3 ($139 million at December 31, 2024) to be amortized over six years beginning in 2029 and Plant Bowen Units 1 and 2 ($80 million at December 31, 2024) to be amortized over four years beginning in 2031, both as approved under Georgia Power's 2022 ARP, and Plant Vogtle Unit 3 and common facilities ($29 million at December 31, 2024) being amortized over 10 years (through 2034). See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4.
Environmental remediation – Effective January 1, 2023, Georgia Power is recovering $5 million annually for environmental remediation under the 2022 ARP. Southern Company Gas' costs are recovered through environmental cost recovery mechanisms when the remediation work is performed. See Note 3 under "Environmental Remediation" for additional information.
Vacation pay – Recorded as earned by employees and recovered as paid, generally within one year. Includes both vacation and banked holiday pay, if applicable.
Loss on reacquired debt – Recovered over either the remaining life of the original issue or, if refinanced, over the remaining life of the new issue. At December 31, 2024, the remaining amortization periods do not exceed 23 years for Alabama Power, 28 years for Georgia Power, 17 years for Mississippi Power, and three years for Southern Company Gas.
Software and cloud computing costs – Represents certain deferred operations and maintenance costs associated with software and cloud computing projects. For Alabama Power, costs are amortized ratably over the life of the related software, which ranges up to 10 years (through 2034). For Georgia Power, costs incurred through 2022 are being amortized over five years (through 2027), and the recovery period for costs incurred after 2022 will be determined in its next base rate case. For Mississippi Power, the recovery period will be determined in Mississippi Power's annual PEP filing process following the completion of the projects and is expected to begin no earlier than 2026. For Southern Company Gas, costs are being amortized ratably over the life of the related software, which ranges up to 10 years (through 2034).
Under and over recovered regulatory clause revenues –
Alabama Power: Balances are recorded monthly and expected to be recovered over periods of up to six years, with the majority expected to be recovered within one year. See "Alabama Power – Rate CNP PPA," " – Rate CNP Compliance," and " – Rate ECR" herein for additional information.
Georgia Power: Balances are recorded monthly and expected to be recovered or returned within two years. See "Georgia Power – Rate Plans" herein for additional information.
Mississippi Power: At December 31, 2024, $17 million is expected to be recovered through various rate recovery mechanisms over a period to be determined in future rate filings. See "Mississippi Power – Ad Valorem Tax Adjustment" herein for additional information.
Southern Company Gas: Balances are recorded and recovered or amortized over periods generally not exceeding five years. In addition to natural gas cost recovery mechanisms, the natural gas distribution utilities have various other cost recovery mechanisms for the recovery of costs, including those related to infrastructure replacement programs.
Regulatory clauses –
Alabama Power: Effective January 1, 2023, balance is being amortized through Rate RSE over a five-year period ending in 2027.
Southern Company Gas: Represents amounts related to Nicor Gas' volume balancing adjustment rider expected to be recovered over a period of less than two years.
Nuclear outage – Costs are deferred to a regulatory asset when incurred and amortized over a subsequent period of 18 months for Alabama Power and up to 24 months for Georgia Power. See Note 5 for additional information.
Fuel-hedging (realized and unrealized) losses and gains – Assets and liabilities are recorded over the life of the underlying hedged purchase contracts. Upon final settlement, actual costs incurred are recovered through the applicable traditional electric operating company's fuel cost recovery mechanism. Purchase contracts generally do not exceed three and a half years for Alabama Power, three years for Georgia Power, and four years for Mississippi Power. Immaterial amounts for fuel-hedging gains at December 31, 2024 and 2023 are included in other regulatory liabilities.
Qualifying repairs of natural gas distribution systems – Represents deferred costs of certain repairs at Atlanta Gas Light being amortized over 20 years.
Long-term debt fair value adjustment – Recovered over the remaining lives of the original debt issuances at acquisition, which range up to 14 years at December 31, 2024.
Plant Daniel Units 3 and 4 – Represents the difference between Mississippi Power's revenue requirement for Plant Daniel Units 3 and 4 under purchase accounting and operating lease accounting. At December 31, 2024, consists of the $16 million retail portion being amortized through 2039 over the remaining life of the related property and the $8 million wholesale portion being amortized over 10 years (through 2034).
Other regulatory assets – Comprised of numerous immaterial components with remaining amortization periods at December 31, 2024 generally not exceeding 19 years for Alabama Power, 10 years for Georgia Power, 10 years for Mississippi Power, and 15 years for Southern Company Gas.
Reliability reserves and storm/property damage reserves – Utilized as related expenses are incurred. See "Alabama Power – Rate NDR" and " – Reliability Reserve Accounting Order," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" and " – Reliability Reserve Accounting Order" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information.
Nuclear fuel disposal cost recovery – Represents award resulting from litigation related to nuclear fuel disposal costs. See Note 3 under "Nuclear Fuel Disposal Costs" for additional information.
Other regulatory liabilities – Comprised of numerous immaterial components with remaining amortization periods at December 31, 2024 generally not exceeding one year for Alabama Power, three years for Georgia Power, one year for Mississippi Power, and 20 years for Southern Company Gas.
At December 31, 2024 and 2023, the environmental remediation liability and the balance of under recovered environmental remediation costs were reflected in the balance sheets of Southern Company, Georgia Power, and Southern Company Gas as shown in the table below. Alabama Power and Mississippi Power did not have environmental remediation liabilities at December 31, 2024 or 2023.
Southern CompanyGeorgia
Power		Southern Company Gas
(in millions)
December 31, 2024:
Environmental remediation liability:
Other current liabilities$37 $13 $24 
Accrued environmental remediation198 — 198 
Under recovered environmental remediation costs:
Other regulatory assets, current$37 $5 $32 
Other regulatory assets, deferred212 11 201 
December 31, 2023:
Environmental remediation liability:
Other current liabilities$44 $14 $30 
Accrued environmental remediation192 — 192 
Under recovered environmental remediation costs:
Other regulatory assets, current$45 $5 $40 
Other regulatory assets, deferred210 15 195 
v3.25.0.1
REVENUE FROM CONTRACTS WITH CUSTOMERS (Tables)
 12 Months Ended
Dec. 31, 2024
Revenue from Contract with Customer [Abstract]  
Disaggregation of revenue
The following table disaggregates revenue from contracts with customers for the periods presented:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
2024
Operating revenues
Retail electric revenues
Residential$8,276 $3,133 $4,835 $308 $— $— 
Commercial6,585 2,042 4,219 324 — — 
Industrial3,892 1,742 1,808 342 — — 
Other124 13 102 9 — — 
Total retail electric revenues18,877 6,930 10,964 983 — — 
Natural gas distribution revenues
Residential1,753 — — — — 1,753 
Commercial417 — — — — 417 
Transportation1,295 — — — — 1,295 
Industrial 34 — — — — 34 
Other316 — — — — 316 
Total natural gas distribution revenues3,815 — — — — 3,815 
Wholesale electric revenues
PPA energy revenues1,059 206 94 4 778 — 
PPA capacity revenues641 108 136 63 400 — 
Non-PPA revenues226 139 5 375 230 — 
Total wholesale electric revenues1,926 453 235 442 1,408 — 
Other natural gas revenues
Gas marketing services507 — — — — 507 
Other
18 — — — — 18 
Total other natural gas revenues
525 — — — — 525 
Other revenues1,621 240 721 52 37 — 
Total revenue from contracts with customers26,764 7,623 11,920 1,477 1,445 4,340 
Other revenue sources(*)
(40)(69)(589)(14)569 116 
Total operating revenues$26,724 $7,554 $11,331 $1,463 $2,014 $4,456 
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
2023
Operating revenues
Retail electric revenues
Residential$7,309 $2,904 $4,105 $300 $— $— 
Commercial5,860 1,928 3,624 308 — — 
Industrial3,613 1,721 1,558 334 — — 
Other112 12 91 9 — — 
Total retail electric revenues16,894 6,565 9,378 951 — — 
Natural gas distribution revenues
Residential1,981 — — — — 1,981 
Commercial505 — — — — 505 
Transportation1,184 — — — — 1,184 
Industrial 45 — — — — 45 
Other324 — — — — 324 
Total natural gas distribution revenues4,039 — — — — 4,039 
Wholesale electric revenues
PPA energy revenues1,107 234 87 20 790 — 
PPA capacity revenues624 156 51 45 376 — 
Non-PPA revenues250 65 35 407 409 — 
Total wholesale electric revenues1,981 455 173 472 1,575 — 
Other natural gas revenues
Gas marketing services528 — — — — 528 
Other
31 — — — — 31 
Total other natural gas revenues559 — — — — 559 
Other revenues1,355 213 578 39 55 — 
Total revenue from contracts with customers24,828 7,233 10,129 1,462 1,630 4,598 
Other revenue sources(*)
425 (183)(11)12 559 104 
Total operating revenues$25,253 $7,050 $10,118 $1,474 $2,189 $4,702 
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
2022
Operating revenues
Retail electric revenues
Residential$6,604 $2,638 $3,664 $302 $— $— 
Commercial5,369 1,685 3,385 299 — — 
Industrial3,764 1,507 1,921 336 — — 
Other102 14 79 9 — — 
Total retail electric revenues15,839 5,844 9,049 946 — — 
Natural gas distribution revenues
Residential2,843 — — — — 2,843 
Commercial763 — — — — 763 
Transportation1,186 — — — — 1,186 
Industrial84 — — — — 84 
Other342 — — — — 342 
Total natural gas distribution revenues5,218 — — — — 5,218 
Wholesale electric revenues
PPA energy revenues2,274 489 130 16 1,673 — 
PPA capacity revenues596 194 47 4 356 — 
Non-PPA revenues250 200 30 690 740 — 
Total wholesale electric revenues3,120 883 207 710 2,769 — 
Other natural gas revenues
Gas marketing services636 — — — — 636 
Other
51 — — — — 51 
Total other natural gas revenues687 — — — — 687 
Other revenues1,077 194 446 47 36 — 
Total revenue from contracts with customers25,941 6,921 9,702 1,703 2,805 5,905 
Other revenue sources(*)
3,338 896 1,882 (9)564 57 
Total operating revenues$29,279 $7,817 $11,584 $1,694 $3,369 $5,962 
(*)Other revenue sources relate to revenues from customers accounted for as derivatives and leases, alternative revenue programs at Southern Company Gas, and cost recovery mechanisms and revenues (including those related to fuel costs) that meet other scope exceptions for revenues from contracts with customers at the traditional electric operating companies.
Products and Services
Electric Utilities' Revenues
YearRetailWholesaleOtherTotal
(in millions)
2024$17,790 $2,431 $1,382 $21,603 
202316,343 2,467 1,188 19,998 
202218,197 3,641 1,035 22,873 
Southern Company Gas' Revenues
YearGas
Distribution
Operations		Gas
Marketing
Services		All OtherTotal
(in millions)
2024$3,899 $516 $41 $4,456 
20234,090 548 64 4,702 
20225,240 638 84 5,962 
Contract with customer, asset and liability
The following table reflects the closing balances of receivables, contract assets, and contract liabilities related to revenues from contracts with customers at December 31, 2024 and 2023:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Accounts Receivable
At December 31, 2024$3,048 $783 $1,244 $113 $106 $660 
At December 31, 20232,820 821 1,011 90 122 684 
Contract Assets
At December 31, 2024$323 $3 $184 $— $— $72 
At December 31, 2023271 2 121 — — 56 
Contract Liabilities
At December 31, 2024$140 $11 $34 $— $2 $3 
At December 31, 2023116 — 1 — 4 — 
Revenue, remaining performance obligation, expected timing of satisfaction Revenues from contracts with customers related to these performance obligations remaining at December 31, 2024 are expected to be recognized as follows:
20252026202720282029Thereafter
(in millions)
Southern Company$937 $427 $371 $343 $309 $2,636 
Alabama Power11 — — — — — 
Georgia Power69 30 15 16 2 27 
Mississippi Power(*)
63 66 69 73 — — 
Southern Power(*)
340 331 340 316 312 2,609 
Southern Company Gas2 — — — — — 
(*)Includes performance obligations related to affiliate PPAs with Georgia Power. See Note 1 under "Affiliate Transactions" for additional information.
v3.25.0.1
PROPERTY, PLANT, AND EQUIPMENT (Tables)
 12 Months Ended
Dec. 31, 2024
Property, Plant and Equipment [Abstract]  
Property, plant and equipment
The Registrants' property, plant, and equipment in service consisted of the following at December 31, 2024 and 2023:
At December 31, 2024:Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Electric utilities:
Generation$61,292 $16,801 $26,089 $2,946 $14,920 $— 
Transmission16,280 6,449 8,800 989 — — 
Distribution28,678 10,373 16,887 1,418 — — 
General/other6,547 2,878 3,260 344 41 — 
Electric utilities' plant in service112,797 36,501 55,036 5,697 14,961 — 
Southern Company Gas:
Natural gas transportation and distribution
18,896 — — — — 18,896 
Storage facilities1,748 — — — — 1,748 
Other1,694 — — — — 1,694 
Southern Company Gas plant in service22,338 — — — — 22,338 
Other plant in service2,008 — — — — — 
Total plant in service$137,143 $36,501 $55,036 $5,697 $14,961 $22,338 
At December 31, 2023:Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Electric utilities:
Generation$57,325 $16,584 $22,587 $2,909 $14,649 $— 
Transmission15,561 6,152 8,402 966 — — 
Distribution26,482 9,775 15,380 1,327 — — 
General/other6,305 2,918 3,001 321 41 — 
Electric utilities' plant in service105,673 35,429 49,370 5,523 14,690 — 
Southern Company Gas:
Natural gas transportation and distribution
17,798 — — — — 17,798 
Storage facilities1,565 — — — — 1,565 
Other1,477 — — — — 1,477 
Southern Company Gas plant in service20,840 — — — — 20,840 
Other plant in service1,915 — — — — — 
Total plant in service$128,428 $35,429 $49,370 $5,523 $14,690 $20,840 
The primary assets in Southern Power's property, plant, and equipment are generating facilities, which generally have estimated useful lives as follows:
Southern Power Generating FacilityUseful life
Natural gas
Up to 50 years
Solar
Up to 35 years
Wind
Up to 35 years
Deferred cloud implementation costs At December 31, 2024 and 2023, deferred cloud implementation costs, net of amortization, which are generally included in other deferred charges and assets on the Registrants' balance sheets, were as follows:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Deferred cloud implementation costs, net:
At December 31, 2024
$321 $92 $111 $13 $12 $35 
At December 31, 2023
325 85 99 13 15 43 
Amortization of deferred cloud implementation costs recognized in 2024, 2023, and 2022 was immaterial for Mississippi Power, Southern Power, and Southern Company Gas and was as follows for the other Registrants:
Southern Company
Alabama Power
Georgia Power
(in millions)
2024$56 $17 $22 
202346 11 19 
202229 8 12 
Composite straight-line rates Costs for these services from SCS in 2024, 2023, and 2022 were as follows:
Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern Company Gas
(in millions)
2024$813 $1,197 $130 $93 $290 
2023611 857 113 86 261 
2022549 762 115 86 262 
Mississippi Power's and Southern Power's power purchases from affiliates through the Southern Company power pool are included in purchased power on their respective statements of income and were as follows:
Mississippi
Power		Southern
Power
(in millions)
2024$8 $17 
20234 13 
20224 29 
Transportation costs under these agreements in 2024, 2023, and 2022 were as follows:
Alabama
Power		Georgia
Power		Southern
Power		Southern Company Gas
(in millions)
2024$13 $103 $35 $28 
202312 101 34 28 
202218 99 37 27 
The approximate rates for 2024, 2023, and 2022 were as follows:
202420232022
Alabama Power4.2 %4.1 %2.7 %
Georgia Power3.4 %3.8 %3.3 %
Mississippi Power3.3 %3.4 %3.4 %
Southern Company Gas2.9 %2.7 %2.7 %
Ownership and investment in jointly-owned facilities
At December 31, 2024, the Registrants' percentage ownership and investment (exclusive of nuclear fuel) in jointly-owned facilities in commercial operation were as follows:
Facility (Type)Percent
Ownership		Plant in ServiceAccumulated
Depreciation		CWIP
(in millions)
Alabama Power
Plant Greene County (natural gas) Units 1 and 2
60.0 %
(a)
$192 $140 $1 
Plant Miller (coal) Units 1 and 291.8 
(b)
2,180 829 7 
Georgia Power
Plant Hatch (nuclear) Units 1 and 2
50.1 %
(c)
$1,464 $604 $66 
Plant Vogtle (nuclear) Units 1 and 245.7 
(c)
3,621 2,342 162 
Plant Vogtle (nuclear) Units 3 and 4
45.7 
(c)
7,953 119 45 
Plant Scherer (coal) Units 1 and 28.4 
(c)
289 140 4 
Plant Scherer (coal) Unit 375.0 
(c)
1,316 720 22 
Rocky Mountain (pumped storage)25.4 
(d)
182 160 6 
Mississippi Power
Plant Greene County (natural gas) Units 1 and 2
40.0 %
(a)
$125 $88 $2 
Plant Daniel (coal) Units 1 and 250.0 
(e)
791 286 3 
Southern Company Gas
Dalton Pipeline (natural gas pipeline)50.0 %
(f)
$271 $32 $1 
(a)Jointly owned by Alabama Power and Mississippi Power and operated and maintained by Alabama Power.
(b)Jointly owned with PowerSouth and operated and maintained by Alabama Power.
(c)Georgia Power owns undivided interests in Plants Hatch, Vogtle, and Scherer in varying amounts jointly with one or more of the following entities: OPC, MEAG Power, Dalton, FP&L, and Jacksonville Electric Authority. Georgia Power has been contracted to operate and maintain the plants as agent for the co-owners and is jointly and severally liable for third-party claims related to these plants.
(d)Jointly owned with OPC, which is the operator of the plant.
(e)Jointly owned with FP&L. In accordance with the operating agreement, Mississippi Power acts as FP&L's agent with respect to the operation and maintenance of these units. See Note 2 under "Mississippi Power – Plant Daniel" for information on Mississippi Power's agreement with FP&L to acquire FP&L's 50% ownership interest in Plant Daniel Units 1 and 2.
(f)Jointly owned with The Williams Companies, Inc., the Dalton Pipeline is a 115-mile natural gas pipeline that serves as an extension of the Transcontinental Gas Pipe Line Company, LLC pipeline system into northwest Georgia. Southern Company Gas leases its 50% undivided ownership for approximately $26 million annually through 2042. The lessee is responsible for maintaining the pipeline during the lease term and for providing service to transportation customers under its FERC-regulated tariff.
v3.25.0.1
ASSET RETIREMENT OBLIGATIONS (Tables)
 12 Months Ended
Dec. 31, 2024
Asset Retirement Obligation Disclosure [Abstract]  
Details of AROs included in the balance sheets
Details of the AROs included in the balance sheets are as follows:
Southern CompanyAlabama PowerGeorgia PowerMississippi Power
Southern Power(*)
(in millions)
Balance at December 31, 2022$10,840 $4,287 $6,034 $179 $144 
Liabilities incurred90 — 90 — — 
Liabilities settled(617)(270)(304)(18)— 
Accretion expense
403 156 230 5 6 
Cash flow revisions(399)(15)(385)2 — 
Balance at December 31, 2023$10,317 $4,158 $5,665 $168 $150 
Liabilities incurred130 8 120 — 2 
Liabilities settled(566)(254)(270)(17)— 
Accretion expense
400 153 232 5 7 
Cash flow revisions(347)(7)(332)(8)— 
Balance at December 31, 2024$9,934 $4,058 $5,415 $148 $159 
(*)Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets.
Investment securities in the Funds
Investment securities in the Funds at December 31, 2024 and 2023 were as follows:
Southern CompanyAlabama
Power		Georgia
Power
(in millions)
At December 31, 2024:
Equity securities$1,413 $848 $565 
Debt securities976 335 641 
Other securities232 202 30 
Total investment securities in the Funds$2,621 $1,385 $1,236 
At December 31, 2023:
Equity securities$1,288 $796 $492 
Debt securities895 277 618 
Other securities239 186 53 
Total investment securities in the Funds
$2,422 $1,259 $1,163 
Fair value increases (decreases) of the Funds
The fair value increases (decreases) of the Funds, including unrealized gains (losses) and reinvested interest and dividends and excluding the Funds' expenses, for 2024, 2023, and 2022 are shown in the table below.
Southern CompanyAlabama
Power		Georgia
Power
(in millions)
Fair value increases (decreases)
2024$229 $143 $86 
2023281 157 124 
2022(360)(171)(189)
Unrealized gains (losses)
At December 31, 2024$113 $64 $49 
At December 31, 2023241 119 122 
At December 31, 2022(391)(204)(187)
At December 31, 2024, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows:
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical Assets Significant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2024:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Southern Company
Assets:
Energy-related derivatives(a)
$12 $77 $— $— $89 
Investments in trusts:(b)
Domestic equity849 250 — — 1,099 
Foreign equity148 175 — — 323 
U.S. Treasury and government agency securities— 371 — — 371 
Municipal bonds— 47 — — 47 
Pooled funds – fixed income— 7 — — 7 
Corporate bonds— 452 — — 452 
Mortgage and asset backed securities— 106 — — 106 
Private equity— — — 181 181 
Cash and cash equivalents1 — — — 1 
Other39 3 — 9 51 
Investments, available for sale:
U.S. Treasury and government agency securities2 7 — — 9 
Corporate bonds1 2 — — 3 
Mortgage and asset backed securities
— 10 — — 10 
Cash equivalents and restricted cash
533 19 — — 552 
Other investments9 31 8 — 48 
Total$1,594 $1,557 $8 $190 $3,349 
Liabilities:
Energy-related derivatives(a)
$5 $124 $— $— $129 
Interest rate derivatives— 269 — — 269 
Foreign currency derivatives— 218 — — 218 
Contingent consideration3 — 16 — 19 
Other— 13 11 — 24 
Total$8 $624 $27 $— $659 
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical Assets Significant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2024:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Alabama Power
Assets:
Energy-related derivatives
$— $26 $— $— $26 
Nuclear decommissioning trusts:(b)
Domestic equity459 241 — — 700 
Foreign equity148 — — — 148 
U.S. Treasury and government agency securities— 16 — — 16 
Municipal bonds— 1 — — 1 
Corporate bonds— 287 — — 287 
Mortgage and asset backed securities— 31 — — 31 
Private equity — — — 181 181 
Other11 1 — 9 21 
Cash equivalents and restricted cash
334 19 — — 353 
Other investments— 31 — — 31 
Total$952 $653 $— $190 $1,795 
Liabilities:
Energy-related derivatives$— $42 $— $— $42 
Georgia Power
Assets:
Energy-related derivatives$— $19 $— $— $19 
Nuclear decommissioning trusts:(b)
Domestic equity390 1 — — 391 
Foreign equity— 174 — — 174 
U.S. Treasury and government agency securities— 355 — — 355 
Municipal bonds— 46 — — 46 
Corporate bonds— 165 — — 165 
Mortgage and asset backed securities— 75 — — 75 
Other28 2 — — 30 
Cash equivalents35 — — — 35 
Total$453 $837 $— $— $1,290 
Liabilities:
Energy-related derivatives$— $42 $— $— $42 
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical Assets Significant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2024:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Mississippi Power
Assets:
Energy-related derivatives$— $19 $— $— $19 
Liabilities:
Energy-related derivatives$— $34 $— $— $34 
Southern Power
Assets:
Energy-related derivatives$— $4 $— $— $4 
Cash equivalents51 — — — 51 
Total$51 $4 $— $— $55 
Liabilities:
Foreign currency derivatives$— $51 $— $— $51 
Contingent consideration3 — 16 — 19 
Other— 13 11 — 24 
Total$3 $64 $27 $— $94 
Southern Company Gas
Assets:
Energy-related derivatives(a)
$12 $9 $— $— $21 
Non-qualified deferred compensation trusts:
Domestic equity— 8 — — 8 
Foreign equity— 1 — — 1 
Pooled funds - fixed income— 7 — — 7 
Cash and cash equivalents1 — — — 1 
Investments, available for sale:
U.S. Treasury and government agency securities2 7 — — 9 
Corporate bonds1 2 — — 3 
Mortgage and asset backed securities
— 10 — — 10 
Cash equivalents22 — — — 22 
Total$38 $44 $— $— $82 
Liabilities:
Energy-related derivatives(a)
$5 $6 $— $— $11 
Interest rate derivatives— 84 — — 84 
Total$5 $90 $— $— $95 
(a)Excludes cash collateral of $17 million.
(b)Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information.
At December 31, 2023, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows:
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2023:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Southern Company
Assets:
Energy-related derivatives(a)
$6 $49 $— $— $55 
Investments in trusts:(b)
Domestic equity764 216 — — 980 
Foreign equity145 171 — — 316 
U.S. Treasury and government agency securities— 369 — — 369 
Municipal bonds— 48 — — 48 
Pooled funds – fixed income— 6 — — 6 
Corporate bonds— 389 — — 389 
Mortgage and asset backed securities— 89 — — 89 
Private equity— — — 169 169 
Cash and cash equivalents3 — — — 3 
Other58 3 — 9 70 
Cash equivalents and restricted cash
253 15 — — 268 
Other investments9 27 8 — 44 
Total$1,238 $1,382 $8 $178 $2,806 
Liabilities:
Energy-related derivatives(a)
$46 $312 $— $— $358 
Interest rate derivatives— 264 — — 264 
Foreign currency derivatives— 122 — — 122 
Contingent consideration3 — 16 — 19 
Other— 13 — — 13 
Total$49 $711 $16 $— $776 
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2023:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Alabama Power
Assets:
Energy-related derivatives
$— $15 $— $— $15 
Nuclear decommissioning trusts:(b)
Domestic equity443 208 — — 651 
Foreign equity145 — — — 145 
U.S. Treasury and government agency securities— 20 — — 20 
Municipal bonds— 1 — — 1 
Corporate bonds— 231 — — 231 
Mortgage and asset backed securities— 25 — — 25 
Private equity — — — 169 169 
Other8 — — 9 17 
Cash equivalents and restricted cash
119 15 — — 134 
Other investments— 27 — — 27 
Total$715 $542 $— $178 $1,435 
Liabilities:
Energy-related derivatives$— $110 $— $— $110 
Georgia Power
Assets:
Energy-related derivatives$— $13 $— $— $13 
Nuclear decommissioning trusts:(b)
Domestic equity321 1 — — 322 
Foreign equity— 170 — — 170 
U.S. Treasury and government agency securities— 349 — — 349 
Municipal bonds— 47 — — 47 
Corporate bonds— 158 — — 158 
Mortgage and asset backed securities— 64 — — 64 
Other50 3 — — 53 
Total$371 $805 $— $— $1,176 
Liabilities:
Energy-related derivatives$— $124 $— $— $124 
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2023:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Mississippi Power
Assets:
Energy-related derivatives$— $15 $— $— $15 
Cash equivalents17 — — — 17 
Total$17 $15 $— $— $32 
Liabilities:
Energy-related derivatives$— $61 $— $— $61 
Southern Power
Assets:
Energy-related derivatives$— $3 $— $— $3 
Liabilities:
Energy-related derivatives$— $5 $— $— $5 
Foreign currency derivatives— 22 — — 22 
Contingent consideration3 — 16 — 19 
Other— 13 — — 13 
Total$3 $40 $16 $— $59 
Southern Company Gas
Assets:
Energy-related derivatives(a)
$6 $3 $— $— $9 
Non-qualified deferred compensation trusts:
Domestic equity— 7 — — 7 
Foreign equity— 1 — — 1 
Pooled funds - fixed income— 6 — — 6 
Cash and cash equivalents
3 — — — 3 
Total$9 $17 $— $— $26 
Liabilities:
Energy-related derivatives(a)
$46 $12 $— $— $58 
Interest rate derivatives— 79 — — 79 
Total$46 $91 $— $— $137 
(a)Excludes cash collateral of $62 million.
(b)Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information
Accumulated provisions for the external decommissioning trust funds
At December 31, 2024 and 2023, the accumulated provisions for the external decommissioning trust funds were as follows:
20242023
(in millions)
Alabama Power
Plant Farley$1,385 $1,259 
Georgia Power
Plant Hatch$735 $705 
Plant Vogtle Units 1 and 2460 434 
Plant Vogtle Units 3 and 441 24 
Total$1,236 $1,163 
Estimated costs of decommissioning The estimated costs of decommissioning at December 31, 2024 based on the most current studies were as follows:
Alabama Power
Georgia Power
Plant
Farley
Plant
 Hatch(*)
Plant Vogtle
 Units 1 and 2(*)
Plant Vogtle
 Unit 3 and 4(*)
Most current study year
2023202420242024
Decommissioning periods:
Beginning year2037203420472062
Completion year2087208820922074
(in millions)
Site study costs:
Radiated structures$1,402 $795 $674 $599 
Spent fuel management513 306 255 88 
Non-radiated structures133 77 107 89 
Total site study costs$2,048 $1,178 $1,036 $776 
(*)Based on Georgia Power's ownership interests.
v3.25.0.1
CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS (Tables)
 12 Months Ended
Dec. 31, 2024
Equity Method Investments and Joint Ventures [Abstract]  
Equity method investments
The carrying amounts of Southern Company Gas' equity method investments at December 31, 2024 and 2023 were as follows:
Investment BalanceDecember 31, 2024
December 31, 2023
(in millions)
SNG$1,245 $1,202 
Other
34 33 
Total$1,279 $1,235 
v3.25.0.1
FINANCING (Tables)
 12 Months Ended
Dec. 31, 2024
Debt Disclosure [Abstract]  
Summary of long-term debt
Details of long-term debt at December 31, 2024 and 2023 are provided in the following table:
At December 31, 2024
Balance Outstanding at
December 31,
MaturityWeighted Average
Interest Rate		20242023
(in millions)
Southern Company
Senior notes(a)
2025-20744.33%$44,862 $40,235 
Junior subordinated notes2027-20814.32%7,389 8,333 
FFB loans(b)
2025-20442.88%4,703 4,788 
Revenue bonds(c)
2025-20633.15%3,379 3,400 
First mortgage bonds(d)
2025-20643.79%2,775 2,500 
Medium-term notes2026-20277.03%84 84 
Other long-term debt2025-20454.96%209 234 
Finance lease obligations(e)
287 298 
Unamortized fair value adjustment275 302 
Unamortized debt premium (discount), net(58)(198)
Unamortized debt issuance expenses(419)(290)
Total long-term debt63,486 59,686 
Less: Amount due within one year4,718 2,476 
Total long-term debt excluding amount due within one year$58,768 $57,210 
Alabama Power
Senior notes2025-20733.94%$9,875 $9,875 
Revenue bonds(c)
2025-20633.11%1,300 1,321 
Other long-term debt2026-20306.11%61 75 
Finance lease obligations(e)
4 5 
Unamortized debt premium (discount), net(19)(20)
Unamortized debt issuance expenses(67)(73)
Total long-term debt11,154 11,183 
Less: Amount due within one year655 223 
Total long-term debt excluding amount due within one year$10,499 $10,960 
Georgia Power
Senior notes2025-20744.49%$11,292 $9,575 
Junior subordinated notes20775.00%270 270 
FFB loans(b)
2025-20442.88%4,703 4,788 
Revenue bonds(c)
2025-20623.18%1,968 1,968 
Finance lease obligations(e)
261 240 
Unamortized debt premium (discount), net(21)(19)
Unamortized debt issuance expenses(123)(122)
Total long-term debt18,350 16,700 
Less: Amount due within one year966 502 
Total long-term debt excluding amount due within one year$17,384 $16,198 
At December 31, 2024
Balance Outstanding at
December 31,
MaturityWeighted Average
Interest Rate		20242023
(in millions)
Mississippi Power
Senior notes2026-20544.33%$1,575 $1,525 
Revenue bonds(c)
2025-20523.16%111 111 
Finance lease obligations(e)
14 16 
Unamortized debt premium (discount), net2 1 
Unamortized debt issuance expenses(9)(9)
Total long-term debt1,693 1,644 
Less: Amount due within one year12 201 
Total long-term debt excluding amount due within one year$1,681 $1,443 
Southern Power
Senior notes(a)
2025-20464.05%$2,695 $2,728 
Unamortized debt premium (discount), net(4)(4)
Unamortized debt issuance expenses(11)(13)
Total long-term debt2,680 2,711 
Less: Amount due within one year500 — 
Total long-term debt excluding amount due within one year$2,180 $2,711 
Southern Company Gas
Senior notes2025-20514.41%$5,375 $4,930 
First mortgage bonds(d)
2025-20643.79%2,775 2,500 
Medium-term notes2026-20277.03%84 84 
Other long-term debt2025-20453.81%68 59 
Unamortized fair value adjustment275 302 
Unamortized debt premium (discount), net(9)(8)
Unamortized debt issuance expenses(37)(34)
Total long-term debt8,531 7,833 
Less: Amount due within one year302 — 
Total long-term debt excluding amount due within one year$8,229 $7,833 
(a)Includes a fair value gain (loss) of $(45) million and $(12) million at December 31, 2024 and 2023, respectively, related to Southern Power's foreign currency hedge on its euro-denominated senior notes.
(b)Secured by a first priority lien on (i) Georgia Power's undivided ownership interest in Plant Vogtle Units 3 and 4 (primarily the units, the related real property, and any nuclear fuel loaded in the reactor core) and (ii) Georgia Power's rights and obligations under the principal contracts relating to Plant Vogtle Units 3 and 4. See "DOE Loan Guarantee Borrowings" herein for additional information.
(c)Revenue bond obligations represent loans to the traditional electric operating companies from public authorities of funds derived from sales by such authorities of revenue bonds issued to finance pollution control and solid waste disposal and wastewater facilities. In some cases, the revenue bond obligations represent obligations under installment sales agreements with respect to facilities constructed with the proceeds of revenue bonds issued by public authorities. The traditional electric operating companies are required to make payments sufficient for the authorities to meet principal and interest requirements of such bonds. Proceeds from certain issuances are restricted until qualifying expenditures are incurred.
(d)Secured by substantially all of Nicor Gas' properties.
(e)Secured by the underlying lease ROU asset. See Note 9 for additional information.
Schedule of maturities of long-term debt for the next five years
Maturities of long-term debt for the next five years are as follows:
Southern Company(a)
Alabama Power(b)
Georgia
Power(c)
Mississippi Power
Southern Power(d)
Southern Company
Gas
(in millions)
2025$4,727 $658 $967 $12 $500 $300 
20263,792 47 451 66 964 530 
20274,075 551 1,015 10 — 154 
20282,827 107 868 357 — 150 
20291,990 — 861 1 — 150 
(a)See notes (b), (c), and (d) below.
(b)Alabama Power's 2025 maturities include $200 million aggregate principal amount of Series 2023A Floating Rate Senior Notes due May 15, 2073 that are repayable at the option of the holders at certain dates that began in 2024. As a result, the senior notes are classified as securities due within one year on the balance sheets of Southern Company and Alabama Power at December 31, 2024.
(c)Amounts include principal amortization related to the FFB borrowings; however, the final maturity date is February 20, 2044. See "DOE Loan Guarantee Borrowings" herein for additional information. Georgia Power's 2025 maturities include approximately $117 million aggregate principal amount of Series 2024C Floating Rate Senior Notes due November 15, 2074 that are repayable at the option of the holders at certain dates beginning in 2025. As a result, the senior notes are classified as securities due within one year on the balance sheets of Southern Company and Georgia Power at December 31, 2024.
(d)Southern Power's 2026 maturities include $564 million of euro-denominated debt at the U.S. dollar-denominated hedge settlement amount.
Summary of committed credit arrangements
At December 31, 2024, committed credit arrangements with banks were as follows:
Expires
Company2025202620272029TotalUnused
Expires within
One Year
(in millions)
Southern Company parent(a)
$150 $— $— $1,850 $2,000 $1,998 $150 
Alabama Power(b)
— 665 — 700 1,365 1,364 — 
Georgia Power300 — — 1,750 2,050 2,026 300 
Mississippi Power— — 275 — 275 275 — 
Southern Power(a)(c)
— — — 600 600 600 — 
Southern Company Gas(d)
100 — — 1,500 1,600 1,598 100 
SEGCO30 — — — 30 30 30 
Southern Company$580 $665 $275 $6,400 $7,920 $7,891 $580 
(a)Arrangement expiring in 2029 represents a $2.45 billion combined arrangement for Southern Company and Southern Power allowing for flexible sublimits.
(b)Includes $15 million expiring in 2026 at Alabama Property Company, a wholly-owned subsidiary of Alabama Power, of which $14 million was unused at December 31, 2024. Alabama Power is not party to this arrangement.
(c)Does not include Southern Power Company's $75 million and $100 million continuing letter of credit facilities for standby letters of credit, expiring in 2027 and 2026, respectively, of which $16 million and $11 million, respectively, was unused at December 31, 2024. Southern Power's subsidiaries are not parties to its bank credit arrangements or letter of credit facilities.
(d)Southern Company Gas, as the parent entity, guarantees the obligations of Southern Company Gas Capital, which is the borrower of $800 million of the credit arrangement expiring in 2029. Southern Company Gas' committed credit arrangement expiring in 2029 also includes $700 million for which Nicor Gas is the borrower and which is restricted for working capital needs of Nicor Gas. Pursuant to the multi-year credit arrangement expiring in 2029, the allocations between Southern Company Gas Capital and Nicor Gas may be adjusted. Nicor Gas is also the borrower under a $100 million credit arrangement expiring in 2025. See "Structural Considerations" herein for additional information.
Details of short-term borrowings Details of short-term borrowings for the applicable Registrants were as follows:
Notes Payable at December 31, 2024
Notes Payable at December 31, 2023
Amount
Outstanding		Weighted Average
Interest Rate		Amount
Outstanding		Weighted Average
Interest Rate
(in millions)(in millions)
Southern Company
Commercial paper$1,138 4.7 %$1,794 5.6 %
Short-term bank debt200 5.3 520 6.4 
Total$1,338 4.8 %$2,314 5.7 %
Alabama Power
Commercial paper
$— — %$40 5.5 %
Georgia Power
Commercial paper$— — %$809 5.6 %
Short-term bank debt200 5.3 520 6.4 
Total$200 5.3 %$1,329 5.9 %
Mississippi Power
Commercial paper$14 4.6 %$— — %
Southern Power
Commercial paper$— — %$138 5.5 %
Southern Company Gas
Commercial paper:
Southern Company Gas Capital$283 4.7 %$23 5.5 %
Nicor Gas172 4.6 392 5.5 
Total$455 4.7 %$415 5.5 %
Shares used to compute diluted EPS Shares used to compute diluted EPS were as follows:
 Average Common Stock Shares
 202420232022
 (in millions)
As reported shares1,096 1,092 1,075 
Effect of stock-based compensation6 6 6 
Diluted shares1,102 1,098 1,081 
Schedule of preferred stock
Preferred Stock Redeemed During 2022Par Value/Stated Capital Per ShareSharesRedemption
Price Per Share
4.92% Preferred Stock
$10080,000 $103.23
4.72% Preferred Stock
$10050,000 $102.18
4.64% Preferred Stock
$10060,000 $103.14
4.60% Preferred Stock
$100100,000 $104.20
4.52% Preferred Stock
$10050,000 $102.93
4.20% Preferred Stock
$100135,115 $105.00
5.00% Class A Preferred Stock
$2510,000,000 
$25.00
v3.25.0.1
LEASES (Tables)
 12 Months Ended
Dec. 31, 2024
Leases [Abstract]  
Major categories of lease obligations The major categories of lease obligations are as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
At December 31, 2024
Electric generating units(*)
$672 $56 $1,509 $— $— $— 
Real estate/land834 3 45 2 540 20 
Communication towers118 2 4 — — 21 
Railcars64 31 29 4 — — 
Other52 2 2 16 — — 
Total$1,740 $94 $1,589 $22 $540 $41 
At December 31, 2023
Electric generating units(*)
$670 $58 $1,028 $— $— $— 
Real estate/land871 4 54 2 546 28 
Communication towers123 1 4 — — 23 
Railcars64 32 27 5 — — 
Other60 3 2 18 — — 
Total$1,788 $98 $1,115 $25 $546 $51 
(*)Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information.
Balance sheet amounts recorded for operating and financing leases
Balance sheet amounts recorded for operating and finance leases are as follows:
Southern CompanyAlabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
At December 31, 2024
Operating Leases
Operating lease ROU assets, net$1,386 $84 $1,331 $8 $484 $38 
Operating lease obligations - current$200 $14 $169 $4 $29 $11 
Operating lease obligations - non-current1,253 76 1,159 4 511 30 
Total operating lease obligations(*)
$1,453 $90 $1,328 $8 $540 $41 
Finance Leases
Finance lease ROU assets, net$254 $4 $227 $14 $— $— 
Finance lease obligations - current$9 $1 $20 $1 $— $— 
Finance lease obligations - non-current278 3 241 13 — — 
Total finance lease obligations $287 $4 $261 $14 $— $— 
At December 31, 2023
Operating Leases
Operating lease ROU assets, net$1,432 $87 $884 $9 $488 $47 
Operating lease obligations - current$183 $12 $135 $3 $29 $11 
Operating lease obligations - non-current1,307 81 740 6 517 40 
Total operating lease obligations(*)
$1,490 $93 $875 $9 $546 $51 
Finance Leases
Finance lease ROU assets, net$272 $5 $203 $15 $— $— 
Finance lease obligations - current$11 $2 $18 $1 $— $— 
Finance lease obligations - non-current287 3 222 15 — — 
Total finance lease obligations$298 $5 $240 $16 $— $— 
(*)Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $567 million, $55 million, and $1.3 billion, respectively, at December 31, 2024 and $566 million, $58 million, and $813 million, respectively, at December 31, 2023.
Lease costs and other information
Lease costs for 2024, 2023, and 2022, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Lease cost
Operating lease cost(*)
$248 $19 $190 $4 $27 $12 
Finance lease cost:
Amortization of ROU assets20 2 23 1 — — 
Interest on lease obligations15 — 15 1 — — 
Total finance lease cost35 2 38 2 — — 
Short-term lease costs 37 15 15 — — — 
Variable lease cost48 (1)77 — 4 — 
Total lease cost $368 $35 $320 $6 $31 $12 
2023
Lease cost
Operating lease cost(*)
$252 $16 $192 $5 $34 $12 
Finance lease cost:
Amortization of ROU assets24 2 19 1 — — 
Interest on lease obligations14 — 17 — — — 
Total finance lease cost38 2 36 1 — — 
Short-term lease costs40 16 16 — — — 
Variable lease cost47 — 74 — 4 — 
Total lease cost$377 $34 $318 $6 $38 $12 
2022
Lease cost
Operating lease cost(*)
$297 $59 $198 $5 $32 $15 
Finance lease cost:
Amortization of ROU assets23 1 15 1 — — 
Interest on lease obligations13 — 17 1 — — 
Total finance lease cost36 1 32 2 — — 
Short-term lease costs64 44 13 — — — 
Variable lease cost125 13 105 — 5 — 
Sublease income(1)— — — — — 
Total lease cost$521 $117 $348 $7 $37 $15 
(*)Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $108 million, $5 million, and $168 million, respectively, in 2024, $112 million, $4 million, and $174 million, respectively, in 2023, and $162 million, $48 million, and $180 million, respectively, in 2022.
Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$243 $19 $186 $4 $33 $12 
Operating cash flows from finance leases15 — 21 — — — 
Financing cash flows from finance leases11 2 23 1 — — 
ROU assets obtained under operating leases146 11 609 — 10 1 
Reassessment of ROU assets under operating leases(7)— — — (7)— 
ROU assets obtained under finance leases1 — 44 — — — 
2023
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$253 $17 $199 $5 $33 $12 
Operating cash flows from finance leases15 — 22 — — — 
Financing cash flows from finance leases18 2 16 1 — — 
ROU assets obtained under operating leases100 30 26 1 7 7 
ROU assets obtained under finance leases3 3 18 — — — 
2022
Other information
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases$303 $58 $206 $5 $30 $14 
Operating cash flows from finance leases11 — 20 1 — — 
Financing cash flows from finance leases16 1 10 1 — — 
ROU assets obtained under operating leases56 10 17 9 — 3 
Reassessment of ROU assets under operating leases16 — — — 16 — 
ROU assets obtained under finance leases118 2 116 — — — 
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
At December 31, 2024
Weighted-average remaining lease term in years:
Operating leases16.410.27.94.332.36.8
Finance leases16.02.710.110.9N/AN/A
Weighted-average discount rate:
Operating leases 4.73 %5.04 %4.73 %3.83 %4.88 %3.84 %
Finance leases4.86 %4.05 %5.8 %2.74 %N/AN/A
At December 31, 2023
Weighted-average remaining lease term in years:
Operating leases17.211.17.54.633.17.0
Finance leases16.74.310.611.9N/AN/A
Weighted-average discount rate:
Operating leases4.68 %5.02 %4.58 %3.67 %4.89 %3.80 %
Finance leases4.85 %3.93 %5.95 %2.74 %N/AN/A
Maturities of operating lease liabilities
Maturities of lease liabilities are as follows:
At December 31, 2024
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
Maturity Analysis
Operating leases:
2025$239 $18 $228 $4 $31 $12 
2026212 15 224 3 29 9 
2027190 12 223 1 29 4 
2028170 9 217 — 29 3 
2029138 7 196 — 30 4 
Thereafter1,255 56 511 1 978 15 
Total2,204 117 1,599 9 1,126 47 
Less: Present value discount 751 27 271 1 586 6 
Operating lease obligations $1,453 $90 $1,328 $8 $540 $41 
Finance leases:
2025$28 $2 $39 $2 $— $— 
202627 1 41 2 — — 
202726 1 41 1 — — 
202825 — 42 1 — — 
202925 — 42 1 — — 
Thereafter290 — 139 9 — — 
Total421 4 344 16 — — 
Less: Present value discount134 — 83 2 — — 
Finance lease obligations$287 $4 $261 $14 $— $— 
Maturities of finance lease liabilities
Maturities of lease liabilities are as follows:
At December 31, 2024
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
Maturity Analysis
Operating leases:
2025$239 $18 $228 $4 $31 $12 
2026212 15 224 3 29 9 
2027190 12 223 1 29 4 
2028170 9 217 — 29 3 
2029138 7 196 — 30 4 
Thereafter1,255 56 511 1 978 15 
Total2,204 117 1,599 9 1,126 47 
Less: Present value discount 751 27 271 1 586 6 
Operating lease obligations $1,453 $90 $1,328 $8 $540 $41 
Finance leases:
2025$28 $2 $39 $2 $— $— 
202627 1 41 2 — — 
202726 1 41 1 — — 
202825 — 42 1 — — 
202925 — 42 1 — — 
Thereafter290 — 139 9 — — 
Total421 4 344 16 — — 
Less: Present value discount134 — 83 2 — — 
Finance lease obligations$287 $4 $261 $14 $— $— 
Lease income, operating leases
Lease income for 2024, 2023, and 2022, is as follows:
Southern
Company		Alabama PowerGeorgia PowerMississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Lease income - interest income on sales-type leases$24 $— $— $15 $9 $— 
Lease income - operating leases136 9 28 3 88 36 
Variable lease income417 1 — — 450 — 
Total lease income$577 $10 $28 $18 $547 $36 
2023
Lease income - interest income on sales-type leases$24 $— $— $14 $10 $— 
Lease income - operating leases164 35 29 2 85 37 
Variable lease income406 1 — — 437 — 
Total lease income$594 $36 $29 $16 $532 $37 
2022
Lease income - interest income on sales-type leases$25 $— $— $15 $10 $— 
Lease income - operating leases208 77 32 2 85 36 
Variable lease income417 1 — — 448 — 
Total lease income$650 $78 $32 $17 $543 $36 
Lease income, sales-type leases and Power Purchase Agreements
Lease income for 2024, 2023, and 2022, is as follows:
Southern
Company		Alabama PowerGeorgia PowerMississippi
Power		Southern PowerSouthern Company Gas
 (in millions)
2024
Lease income - interest income on sales-type leases$24 $— $— $15 $9 $— 
Lease income - operating leases136 9 28 3 88 36 
Variable lease income417 1 — — 450 — 
Total lease income$577 $10 $28 $18 $547 $36 
2023
Lease income - interest income on sales-type leases$24 $— $— $14 $10 $— 
Lease income - operating leases164 35 29 2 85 37 
Variable lease income406 1 — — 437 — 
Total lease income$594 $36 $29 $16 $532 $37 
2022
Lease income - interest income on sales-type leases$25 $— $— $15 $10 $— 
Lease income - operating leases208 77 32 2 85 36 
Variable lease income417 1 — — 448 — 
Total lease income$650 $78 $32 $17 $543 $36 
Undiscounted cash flows to be received under tolling arrangements accounted for as sales-type leases
The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows:
At December 31, 2024
Southern CompanyMississippi PowerSouthern
Power
 (in millions)
2025$52 $24 $15 
202638 23 15 
202737 22 15 
202836 21 15 
202935 20 15 
Thereafter302 132 170 
Total undiscounted cash flows$500 $242 $245 
Net investment in sales-type lease(*)
297 139 158 
Difference between undiscounted cash flows and discounted cash flows$203 $103 $87 
(*)For Mississippi Power, included in other current assets ($10 million and $10 million at December 31, 2024 and 2023, respectively) and other property and investments ($129 million and $138 million at December 31, 2024 and 2023, respectively) on the balance sheets. For Southern Power, included in other current assets ($15 million and $15 million at December 31, 2024 and 2023, respectively) and net investment in sales-type leases ($143 million and $148 million at December 31, 2024 and 2023, respectively) on the balance sheets.
Undiscounted cash flows to be received under PPAs accounted for as operating leases
The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows:
At December 31, 2024
Southern
Company		Alabama
Power		Southern
Power		Southern Company Gas
 (in millions)
2025$117 $6 $142 $35 
2026111 5 148 29 
2027109 4 150 28 
2028109 4 161 28 
2029112 3 164 28 
Thereafter621 31 506 326 
Total$1,179 $53 $1,271 $474 
v3.25.0.1
INCOME TAXES (Tables)
 12 Months Ended
Dec. 31, 2024
Income Tax Disclosure [Abstract]  
Details of income tax provisions
Details of income tax provisions are as follows:
2024
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern Power Southern Company Gas
(in millions)
Federal —
Current$221 $357 $200 $32 $(112)$84 
Deferred387 (111)211 2 106 86 
Total federal
608 246 411 34 (6)170 
State —
Current152 103 52 (1)6 42 
Deferred209 11 140 14 (13)46 
Total state
361 114 192 13 (7)88 
Total$969 $360 $603 $47 $(13)$258 
2023
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Federal —
Current$54 $242 $205 $49 $(320)$62 
Deferred299 (257)195 (26)334 68 
Total federal
353 (15)400 23 14 130 
State —
Current41 82 37 1 (1)24 
Deferred102 14 11 12 (1)57 
Total state
143 96 48 13 (2)81 
Total$496 $81 $448 $36 $12 $211 
2022
Southern CompanyAlabama PowerGeorgia
Power		Mississippi
Power		Southern PowerSouthern Company Gas
(in millions)
Federal —
Current$10 $54 $38 $42 $(43)$122 
Deferred455 259 152 (16)56 (3)
Total federal
465 313 190 26 13 119 
State —
Current27 14 (21)— 2 42 
Deferred303 96 201 11 5 19 
Total state
330 110 180 11 7 61 
Total$795 $423 $370 $37 $20 $180 
Summary of amortization of tax credits ITCs amortized in 2024, 2023, and 2022 were immaterial for the traditional electric operating companies and Southern Company Gas and were as follows for Southern Company and Southern Power:
Southern CompanySouthern Power
(in millions)
2024$109 $58 
202384 58 
202283 58 
Schedule of effective income tax reconciliation
A reconciliation of the federal statutory income tax rate to the effective income tax (benefit) rate is as follows:
2024
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
Federal statutory rate21.0 %21.0 %21.0 %21.0 %21.0 %21.0 %
State income tax, net of federal deduction3.6 5.0 1.7 4.4 (2.3)7.0 
Changes in valuation allowance, net of federal benefit
1.9 — 3.1 — — — 
Employee stock plans' dividend deduction(0.4)— — — — — 
Non-deductible book depreciation0.6 0.6 0.7 0.3 — — 
Flowback of excess deferred income taxes(3.9)(5.3)(2.2)(6.5)— (2.2)
AFUDC-Equity(0.8)(0.7)(1.0)— — — 
Federal PTCs(2.8)(0.1)(3.7)— (17.2)— 
ITC amortization(1.2)(0.1)(0.2)— (26.4)— 
Noncontrolling interests0.6 — — — 17.1 — 
Other(0.1)— (0.2)— 0.2 — 
Effective income tax (benefit) rate18.5 %20.4 %19.2 %19.2 %(7.6)%25.8 %
2023
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
Federal statutory rate21.0 %21.0 %21.0 %21.0 %21.0 %21.0 %
State income tax, net of federal deduction2.9 5.2 2.1 4.9 (0.7)7.8 
Changes in valuation allowance, net of federal benefit
(0.3)— (0.6)— — — 
Employee stock plans' dividend deduction(0.5)— — — — — 
Non-deductible book depreciation0.7 0.7 0.8 0.4 — — 
Flowback of excess deferred income taxes(9.2)(19.8)(2.6)(10.2)— (2.6)
AFUDC-Equity(1.1)(1.2)(1.2)— — — 
Federal PTCs(1.2)— (1.4)— (7.4)— 
ITC amortization(1.3)(0.1)(0.1)— (19.0)— 
Noncontrolling interests0.6 — — — 11.1 — 
Other(0.2)(0.2)(0.3)0.1 0.1 (0.6)
Effective income tax rate11.4 %5.6 %17.7 %16.2 %5.1 %25.6 %
2022
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
Federal statutory rate21.0 %21.0 %21.0 %21.0 %21.0 %21.0 %
State income tax, net of federal deduction7.8 4.8 3.3 4.4 1.9 6.4 
Changes in valuation allowance, net of federal benefit
(1.6)— 3.2 — — — 
Employee stock plans' dividend deduction(0.5)— — — — — 
Non-deductible book depreciation0.6 0.5 0.6 0.3 — — 
Flowback of excess deferred income taxes(6.6)(1.9)(9.6)(7.8)— (2.5)
AFUDC-Equity(1.1)(0.8)(1.5)— — — 
Federal PTCs— — — — (6.6)— 
ITC amortization(1.3)(0.1)(0.1)— (17.2)(0.1)
Noncontrolling interests0.5 — — — 8.4 — 
Other— 0.3 — 0.3 (0.1)(0.9)
Effective income tax rate18.8 %23.8 %16.9 %18.2 %7.4 %23.9 %
Tax effects between the carrying amounts of assets and liabilities
The tax effects of temporary differences between the carrying amounts of assets and liabilities in the financial statements of the Registrants and their respective tax bases, which give rise to deferred tax assets and liabilities, are as follows:
December 31, 2024
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Deferred tax liabilities —
Accelerated depreciation$9,828 $2,583 $3,810 $344 $1,309 $1,575 
Property basis differences3,025 1,497 918 192 — 412 
Employee benefit obligations1,067 362 470 54 13 60 
AROs727 458 221 — — — 
Under recovered fuel and natural gas costs 318 13 305 — — — 
Regulatory assets –
AROs1,886 658 1,193 35 — — 
Employee benefit obligations746 191 237 35 — 35 
Remaining book value of retired assets360 168 187 5 — — 
Storm damage reserves
216 — 216 — — — 
Premium on reacquired debt57 8 48 1 — — 
Other678 171 187 61 1 201 
Total deferred income tax liabilities18,908 6,109 7,792 727 1,323 2,283 
Deferred tax assets —
AROs2,613 1,116 1,414 35 — — 
CAMT carryforwards
40 — 18 — — 104 
ITC and PTC carryforwards1,380 48 719 — 384 — 
Employee benefit obligations897 196 279 49 16 87 
Estimated loss on plants under construction773 — 773 — — — 
Estimated loss on regulatory disallowance20 — — — — 20 
Other state deferred tax attributes366 — 26 224 49 16 
Federal effect of net state deferred tax liabilities402 197 100 — 23 107 
Other property basis differences176 — 75 — 85 — 
State effect of federal deferred taxes126 126 — — — — 
Other partnership basis differences60 — — — 60 — 
Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)18 18 — — — — 
Long-term debt fair value adjustment73 — — — — 73 
Other comprehensive losses48 3 — — 1 — 
Other601 227 160 50 20 86 
Total deferred income tax assets7,593 1,931 3,564 358 638 493 
Valuation allowance(333)— (157)(41)(27)(6)
Net deferred income tax assets7,260 1,931 3,407 317 611 487 
Net deferred income taxes (assets)/liabilities$11,648 $4,178 $4,385 $410 $712 $1,796 
Recognized in the balance sheets:
Accumulated deferred income taxes – assets$(82)$— $— $(82)$— $— 
Accumulated deferred income taxes – liabilities$11,730 $4,178 $4,385 $492 $712 $1,796 
December 31, 2023
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Deferred tax liabilities —
Accelerated depreciation$9,683 $2,566 $3,628 $339 $1,346 $1,576 
Property basis differences2,647 1,444 812 188 — 189 
Employee benefit obligations979 321 446 49 12 74 
AROs833 476 314 — — — 
Under recovered fuel and natural gas costs601 80 508 13 — — 
Regulatory assets –
AROs1,902 667 1,196 39 — — 
Employee benefit obligations797 213 260 37 — 11 
Remaining book value of retired assets369 143 221 5 — — 
Premium on reacquired debt63 9 53 1 — — 
Other700 182 223 43 2 191 
Total deferred income tax liabilities18,574 6,101 7,661 714 1,360 2,041 
Deferred tax assets —
AROs2,735 1,143 1,510 39 — — 
ITC and PTC carryforwards1,387 12 691 — 481 — 
Employee benefit obligations985 224 316 52 10 89 
Estimated loss on plants under construction857 — 857 — — — 
Estimated loss on regulatory disallowance
26 — — — — 26 
Other state deferred tax attributes363 — 13 231 49 8 
Federal effect of net state deferred tax liabilities418 215 92 — 27 101 
Other property basis differences197 — 83 — 97 — 
State effect of federal deferred taxes115 115 — — — — 
Other partnership basis differences85 — — — 85 — 
Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)34 30 — 3 — — 
Long-term debt fair value adjustment79 — — — — 79 
Other comprehensive losses67 4 4 — 6 — 
Other538 188 152 57 18 74 
Total deferred income tax assets7,886 1,931 3,718 382 773 377 
Valuation allowance(206)— (75)(41)(27)(7)
Net deferred income tax assets7,680 1,931 3,643 341 746 370 
Net deferred income taxes (assets)/liabilities$10,894 $4,170 $4,018 $373 $614 $1,671 
Recognized in the balance sheets:
Accumulated deferred income taxes – assets$(96)$— $— $(96)$— $— 
Accumulated deferred income taxes – liabilities$10,990 $4,170 $4,018 $469 $614 $1,671 
Summary of tax credit carryforwards
Federal ITC/PTC carryforwards at December 31, 2024 were as follows:
Southern CompanyAlabama
Power		Georgia
Power		Southern
Power
(in millions)
Federal ITC/PTC carryforwards$765 $48 $147 $384 
Tax year in which federal ITC/PTC carryforwards begin expiring2031203220312035
Year by which federal ITC/PTC carryforwards are expected to be utilized2028202820282028
Summary of operating loss carryforward
At December 31, 2024, the net state income tax benefit of state and local NOL carryforwards and associated valuation allowances for Southern Company's subsidiaries were as follows:
Company/JurisdictionApproximate Net State Income Tax Benefit of NOL CarryforwardsTax Year NOL
Begins Expiring
Net State Valuation Allowance for NOL Carryforwards
(in millions)(in millions)
Mississippi Power
Mississippi $178 2032$(32)
Southern Power
Oklahoma$26 2035$(11)
Florida10 2034(10)
Other states2 
2034
— 
Southern Power Total$38 $(21)
Other(*)
New York$11 2036$(11)
New York City14 2036(14)
Other states24 
2025
(4)
Southern Company Total$265 $(82)
(*)Represents other non-registrant Southern Company subsidiaries. Alabama Power, Georgia Power, and Southern Company Gas did not have material state or local NOL carryforwards at December 31, 2024.
Schedule of unrecognized tax benefits
Changes in unrecognized tax benefits for the periods presented were as follows:
Southern
Company
Georgia
Power
Southern
Company Gas
(in millions)
Unrecognized tax benefits at December 31, 2021$47 $— $— 
Tax positions changes —
Increase from prior periods33 — 32 
Unrecognized tax benefits at December 31, 202280 — 32 
Tax positions changes —
Increase from prior periods88 86 2 
Statute of limitations expiration(52)(9)— 
Unrecognized tax benefits at December 31, 2023
116 77 34 
Tax positions changes —
Increase from prior periods10 — 10 
Decrease from prior periods
(44)(43)— 
Unrecognized tax benefits at December 31, 2024
$82 $34 $44 
v3.25.0.1
RETIREMENT BENEFITS (Tables)
 12 Months Ended
Dec. 31, 2024
Retirement Benefits [Abstract]  
Summary of actuarial assumptions
The weighted average rates assumed in the actuarial calculations used to determine both the net periodic costs for the pension and other postretirement benefit plans for the following year and the benefit obligations as of the measurement date are presented below.
2024
Assumptions used to determine net
periodic costs:		Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
Pension plans
Discount rate – benefit obligations5.07 %5.08 %5.06 %5.06 %5.14 %5.05 %
Discount rate – interest costs4.94 4.94 4.94 4.93 5.01 4.93 
Discount rate – service costs5.19 5.20 5.21 5.19 5.20 5.13 
Expected long-term return on plan assets8.30 8.30 8.30 8.30 8.30 8.30 
Annual salary increase4.60 4.60 4.60 4.60 4.60 4.60 
Other postretirement benefit plans
Discount rate – benefit obligations4.99 %5.01 %4.98 %4.98 %5.06 %4.98 %
Discount rate – interest costs4.90 4.90 4.89 4.90 4.94 4.89 
Discount rate – service costs5.16 5.17 5.16 5.16 5.14 5.16 
Expected long-term return on plan assets7.67 7.97 7.59 7.43 — 6.36 
Annual salary increase4.60 4.60 4.60 4.60 4.60 4.60 
2023
Assumptions used to determine net
periodic costs:		Southern CompanyAlabama
Power		Georgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
Pension plans
Discount rate – benefit obligations5.25 %5.26 %5.25 %5.25 %5.31 %5.24 %
Discount rate – interest costs5.13 5.14 5.12 5.12 5.19 5.12 
Discount rate – service costs5.36 5.38 5.38 5.37 5.37 5.31 
Expected long-term return on plan assets8.40 8.40 8.40 8.40 8.40 8.40 
Annual salary increase4.80 4.80 4.80 4.80 4.80 4.80 
Other postretirement benefit plans
Discount rate – benefit obligations5.18 %5.20 %5.17 %5.17 %5.24 %5.16 %
Discount rate – interest costs5.08 5.09 5.07 5.08 5.12 5.07 
Discount rate – service costs5.34 5.35 5.34 5.33 5.33 5.33 
Expected long-term return on plan assets7.67 7.95 7.49 7.43 — 6.59 
Annual salary increase4.80 4.80 4.80 4.80 4.80 4.80 
2022
Assumptions used to determine net periodic costs:Southern CompanyAlabama
Power		Georgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
Pension plans
Discount rate – benefit obligations3.09 %3.12 %3.07 %3.07 %3.21 %3.04 %
Discount rate – interest costs2.55 2.58 2.51 2.54 2.79 2.53 
Discount rate – service costs3.34 3.36 3.37 3.35 3.36 3.21 
Expected long-term return on plan assets8.25 8.25 8.25 8.25 8.25 8.25 
Annual salary increase4.80 4.80 4.80 4.80 4.80 4.80 
Other postretirement benefit plans
Discount rate – benefit obligations2.90 %2.95 %2.87 %2.88 %3.07 %2.82 %
Discount rate – interest costs2.32 2.38 2.30 2.27 2.55 2.17 
Discount rate – service costs3.26 3.30 3.27 3.26 3.25 3.22 
Expected long-term return on plan assets7.21 7.54 6.88 7.22 — 6.08 
Annual salary increase4.80 4.80 4.80 4.80 4.80 4.80 
2024
Assumptions used to determine benefit obligations:Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
Pension plans
Discount rate5.76 %5.78 %5.75 %5.76 %5.84 %5.73 %
Annual salary increase4.60 4.60 4.60 4.60 4.60 4.60 
Other postretirement benefit plans
Discount rate5.64 %5.67 %5.61 %5.63 %5.73 %5.62 %
Annual salary increase4.60 4.60 4.60 4.60 4.60 4.60 
2023
Assumptions used to determine benefit obligations:Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
Pension plans
Discount rate5.07 %5.08 %5.06 %5.06 %5.14 %5.05 %
Annual salary increase4.60 4.60 4.60 4.60 4.60 4.60 
Other postretirement benefit plans
Discount rate4.99 %5.01 %4.98 %4.98 %5.06 %4.98 %
Annual salary increase4.60 4.60 4.60 4.60 4.60 4.60 
Schedule of health care cost trend rates The weighted average medical care cost trend rates used in measuring the APBO for the Registrants at December 31, 2024 were as follows:
Initial Cost Trend RateUltimate Cost Trend RateYear That Ultimate Rate is Reached
Pre-658.00 %4.50 %2033
Post-65 medical5.50 4.50 2033
Post-65 prescription11.00 4.50 2033
Schedule of accumulated and projected benefit obligations
The total accumulated benefit obligation for the pension plans at December 31, 2024 and 2023 was as follows:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
December 31, 2024$11,437 $2,617 $3,438 $519 $140 $779 
December 31, 202311,991 2,746 3,674 546 145 808 
The projected benefit obligations for the qualified and non-qualified pension plans at December 31, 2024 are shown in the following table. All pension plan assets are related to the qualified pension plan.
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Projected benefit obligations:
Qualified pension plan$11,886 $2,794 $3,622 $540 $146 $788 
Non-qualified pension plan678 114 111 27 21 54 
Amounts recognized in balance sheets
Amounts recognized in the balance sheets at December 31, 2024 and 2023 related to the Registrants' pension plans consist of the following:
Southern
Company		Alabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
December 31, 2024:
Prepaid pension costs(a)
$2,674 $746 $897 $124 $41 $191 
Other regulatory assets, deferred(b)
2,708 741 973 144 — 126 
Other current liabilities(68)(13)(13)(2)(2)(4)
Employee benefit obligations(c)
(611)(102)(98)(25)(18)(51)
Other regulatory liabilities, deferred(50)— — — — — 
AOCI52 — — — 11 (54)
December 31, 2023:
Prepaid pension costs(a)
$2,079 $585 $706 $99 $31 $158 
Other regulatory assets, deferred(b)
2,960 821 1,051 152 — 143 
Other current liabilities(64)(11)(13)(2)(2)(3)
Employee benefit obligations(c)
(649)(106)(131)(27)(21)(58)
Other regulatory liabilities, deferred(47)— — — — — 
AOCI79 — — — 20 (45)
(a)Included in prepaid pension and other postretirement benefit costs on Alabama Power's balance sheet and other deferred charges and assets on Southern Power's consolidated balance sheet.
(b)Amounts for Southern Company exclude regulatory assets of $155 million and $173 million at December 31, 2024 and 2023, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company.
(c)Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets.
Presented below are the amounts included in regulatory assets at December 31, 2024 and 2023 related to the portion of the defined benefit pension plan attributable to Southern Company, the traditional electric operating companies, and Southern Company Gas that had not yet been recognized in net periodic pension cost.
Southern
Company		Alabama PowerGeorgia
Power		Mississippi PowerSouthern Company Gas
(in millions)
Balance at December 31, 2024
Regulatory assets:
Prior service cost$8 $3 $5 $1 $(4)
Net loss2,650 738 968 143 91 
Regulatory amortization— — — — 39 
Total regulatory assets(*)
$2,658 $741 $973 $144 $126 
Balance at December 31, 2023
Regulatory assets:
Prior service cost$9 $4 $6 $1 $(7)
Net loss2,904 817 1,045 151 100 
Regulatory amortization— — — — 50 
Total regulatory assets(*)
$2,913 $821 $1,051 $152 $143 
(*)Amounts for Southern Company exclude regulatory assets of $155 million and $173 million at December 31, 2024 and 2023, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company.
Amounts recognized in the balance sheets at December 31, 2024 and 2023 related to the Registrants' other postretirement benefit plans consist of the following:
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern
Power		Southern Company Gas
(in millions)
December 31, 2024:
Prepaid other postretirement benefit costs(a)
$— $95 $— $— $— $— 
Other regulatory assets, deferred(b)
24 — 3 — — — 
Other current liabilities(6)— — — (1)— 
Employee benefit obligations(c)
(212)— (68)(31)(8)(15)
Other regulatory liabilities, deferred(213)(45)(67)(9)— (84)
AOCI(14)— — — — (15)
December 31, 2023:
Prepaid other postretirement benefit costs(a)
$— $74 $— $— $— $— 
Other regulatory assets, deferred(b)
23 — 11 — — — 
Other current liabilities(6)— — — (1)— 
Employee benefit obligations(c)
(285)— (79)(32)(8)(44)
Other regulatory liabilities, deferred(231)(48)(85)(10)— (68)
AOCI(9)— — — 1 (10)
(a)Included in prepaid pension and other postretirement benefit costs on Alabama Power's balance sheet.
(b)Amounts for Southern Company exclude regulatory assets of $16 million and $24 million at December 31, 2024 and 2023, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company.
(c)Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets.
Presented below are the amounts included in net regulatory assets (liabilities) at December 31, 2024 and 2023 related to the other postretirement benefit plans of Southern Company, the traditional electric operating companies, and Southern Company Gas that had not yet been recognized in net periodic other postretirement benefit cost.
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern Company Gas
(in millions)
Balance at December 31, 2024:
Regulatory assets (liabilities):
Prior service cost$11 $3 $4 $1 $— 
Net gain(200)(48)(68)(10)(71)
Regulatory amortization— — — — (13)
Total regulatory assets (liabilities)(*)
$(189)$(45)$(64)$(9)$(84)
Balance at December 31, 2023:
Regulatory assets (liabilities):
Prior service cost$13 $4 $5 $1 $— 
Net gain(216)(52)(79)(11)(64)
Regulatory amortization— — — — (4)
Total regulatory assets (liabilities)(*)
$(203)$(48)$(74)$(10)$(68)
(*)Amounts for Southern Company exclude regulatory assets of $16 million and $24 million at December 31, 2024 and 2023, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company.
Changes in projected benefit obligations and fair value of plan assets
Changes in the projected benefit obligations and the fair value of plan assets during the plan years ended December 31, 2024 and 2023 were as follows:
2024
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Change in benefit obligation
Benefit obligation at beginning of year$13,252 $3,076 $4,009 $599 $177 $882 
Service cost292 68 70 12 7 28 
Interest cost635 148 191 29 9 42 
Benefits paid(728)(162)(239)(33)(6)(46)
Actuarial gain(887)(222)(298)(40)(20)(64)
Balance at end of year12,564 2,908 3,733 567 167 842 
Change in plan assets
Fair value of plan assets at beginning of year14,618 3,544 4,571 669 185 980 
Actual return on plan assets604 148 152 23 7 39 
Employer contributions65 9 35 5 2 5 
Benefits paid(728)(162)(239)(33)(6)(46)
Fair value of plan assets at end of year14,559 3,539 4,519 664 188 978 
Accrued asset$1,995 $631 $786 $97 $21 $136 
2023
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Change in benefit obligation
Benefit obligation at beginning of year$12,602 $2,906 $3,851 $569 $163 $868 
Service cost275 64 68 11 6 24 
Interest cost626 145 191 28 8 42 
Benefits paid(744)(155)(224)(32)(6)(104)
Actuarial loss493 116 123 23 6 52 
Balance at end of year13,252 3,076 4,009 599 177 882 
Change in plan assets
Fair value of plan assets at beginning of year14,218 3,427 4,456 649 178 1,002 
Actual return on plan assets1,092 260 331 50 12 79 
Employer contributions52 11 9 2 2 3 
Benefits paid(744)(154)(225)(32)(7)(104)
Fair value of plan assets at end of year14,618 3,544 4,571 669 185 980 
Accrued asset$1,366 $468 $562 $70 $8 $98 
Components of net periodic benefit cost
Components of net periodic pension cost for the Registrants were as follows:
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
2024
Service cost$292 $68 $70 $12 $7 $28 
Interest cost635 148 191 29 9 42 
Expected return on plan assets(1,263)(307)(393)(58)(17)(85)
Recognized net loss(*)
55 16 19 3 — — 
Net amortization(*)
— 1 1 — — 15 
Prior service cost(*)
— — — — — (3)
Net periodic pension income$(281)$(74)$(112)$(14)$(1)$(3)
2023
Service cost$275 $64 $68 $11 $6 $24 
Interest cost626 145 191 28 8 42 
Expected return on plan assets(1,229)(297)(385)(56)(15)(85)
Recognized net (gain) loss(*)
32 9 13 2 — (5)
Net amortization(*)
— 1 1 — — 15 
Prior service cost(*)
— — — — — (3)
Net periodic pension income$(296)$(78)$(112)$(15)$(1)$(12)
2022
Service cost$412 $99 $103 $17 $9 $34 
Interest cost408 96 123 18 6 28 
Expected return on plan assets(1,265)(306)(399)(57)(15)(91)
Recognized net loss(*)
240 62 75 11 2 8 
Net amortization(*)
— 1 1 — — 15 
Prior service cost(*)
— — — — — (3)
Net periodic pension cost (income)$(205)$(48)$(97)$(11)$2 $(9)
(*)For Southern Company, excludes amounts related to net periodic pension cost of $20 million, $17 million, and $21 million for the years ended December 31, 2024, 2023, and 2022, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company.
Components of the other postretirement benefit plans' net periodic cost for the Registrants were as follows:
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
2024
Service cost$15 $4 $4 $1 $— $1 
Interest cost65 16 23 3 — 8 
Expected return on plan assets(89)(35)(32)(3)1 (13)
Net amortization(*)
(13)(3)(4)— — 6 
Net periodic other postretirement benefit cost (income)$(22)$(18)$(9)$1 $1 $2 
2023
Service cost$15 $4 $4 $1 $— $1 
Interest cost70 17 25 3 — 9 
Expected return on plan assets(83)(33)(29)(3)1 (10)
Net amortization(*)
(11)(3)(3)— — 6 
Net periodic other postretirement benefit cost (income)$(9)$(15)$(3)$1 $1 $6 
2022
Service cost$23 $6 $6 $1 $— $1 
Interest cost42 10 15 2 — 5 
Expected return on plan assets(80)(32)(28)(2)1 (9)
Net amortization(*)
(1)— 2 — — 6 
Net periodic other postretirement benefit cost (income)$(16)$(16)$(5)$1 $1 $3 
(*)For Southern Company, excludes amounts related to net periodic other postretirement benefit cost of $8 million for all years presented associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company.
Estimated pension benefit payments At December 31, 2024, estimated benefit payments were as follows:
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Benefit Payments:
2025$773 $170 $245 $34 $7 $58 
2026801 177 250 36 8 60 
2027823 183 254 37 8 62 
2028842 187 258 38 7 64 
2029862 192 262 38 8 66 
2030 to 20344,529 1,013 1,333 204 51 346 
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Benefit payments:
2025$112 $24 $40 $5 $1 $16 
2026112 25 40 5 1 16 
2027113 26 41 5 1 15 
2028114 26 41 5 1 15 
2029114 27 42 5 1 14 
2030 to 2034558 133 205 22 1 61 
Components of OCI related to defined benefit pension plan
The components of OCI related to the portion of the defined benefit pension plan attributable to Southern Company, Southern Power, and Southern Company Gas for the years ended December 31, 2024 and 2023 are presented in the following table:
Southern CompanySouthern
Power		Southern Company
Gas
(in millions)
AOCI:
Balance at December 31, 2022$24 $11 $(75)
Net loss62 9 29 
Reclassification adjustments:
Amortization of prior service costs1 — 1 
Amortization of net loss(8)— — 
Total reclassification adjustments(7)— 1 
Total change55 9 30 
Balance at December 31, 2023$79 $20 $(45)
Net gain(29)(9)(11)
Reclassification adjustments:
Amortization of prior service costs1 — 2 
Amortization of net gain1 — — 
Total reclassification adjustments2 — 2 
Total change(27)(9)(9)
Balance at December 31, 2024$52 $11 $(54)
The components of OCI related to the other postretirement benefit plans for the plan years ended December 31, 2024 and 2023 are presented in the following table:
Southern CompanySouthern
Power		Southern Company Gas
(in millions)
AOCI:
Balance at December 31, 2022$(4)$— $(2)
Net (gain) loss(12)1 — 
Reclassification adjustments:
Amortization of net gain (loss)7 — (8)
Total change(5)1 (8)
Balance at December 31, 2023$(9)$1 $(10)
Net gain(8)(1)(5)
Reclassification adjustments:
Amortization of net gain (loss)3 — — 
Total change(5)(1)(5)
Balance at December 31, 2024$(14)$— $(15)
Changes in the APBO and the fair value of plan assets
Changes in the APBO and the fair value of the Registrants' plan assets during the plan years ended December 31, 2024 and 2023 were as follows:
2024
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Change in benefit obligation
Benefit obligation at beginning of year$1,386 $329 $489 $57 $9 $172 
Service cost15 4 4 1 — 1 
Interest cost65 16 23 3 — 8 
Benefits paid(105)(25)(37)(4)(1)(12)
Actuarial (gain) loss(2)2 9 (2)1 (13)
Balance at end of year1,359 326 488 55 9 156 
Change in plan assets
Fair value of plan assets at beginning of year1,095 403 410 25 — 128 
Actual return on plan assets96 37 34 — — 18 
Employer contributions55 6 13 3 1 7 
Benefits paid(105)(25)(37)(4)(1)(12)
Fair value of plan assets at end of year1,141 421 420 24 — 141 
Accrued asset (liability)$(218)$95 $(68)$(31)$(9)$(15)
2023
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern PowerSouthern Company Gas
(in millions)
Change in benefit obligation
Benefit obligation at beginning of year$1,441 $344 $514 $59 $9 $179 
Service cost15 4 4 1 — 1 
Interest cost70 17 25 3 — 9 
Benefits paid(107)(24)(36)(4)(1)(18)
Actuarial (gain) loss(33)(12)(18)(2)1 1 
Balance at end of year1,386 329 489 57 9 172 
Change in plan assets
Fair value of plan assets at beginning of year998 372 368 24 — 113 
Actual return on plan assets131 52 51 2 — 19 
Employer contributions73 3 27 3 1 14 
Benefits paid(107)(24)(36)(4)(1)(18)
Fair value of plan assets at end of year1,095 403 410 25 — 128 
Accrued asset (liability)$(291)$74 $(79)$(32)$(9)$(44)
Changes in balances of regulatory assets and regulatory liabilities related to defined benefit pension plans
The changes in the balance of regulatory assets related to the portion of the defined benefit pension plan attributable to Southern Company, the traditional electric operating companies, and Southern Company Gas for the years ended December 31, 2024 and 2023 are presented in the following table:
Southern
Company		Alabama PowerGeorgia
Power		Mississippi PowerSouthern Company Gas
(in millions)
Regulatory assets (liabilities):(*)
Balance at December 31, 2022$2,371 $679 $887 $123 $111 
Net loss576 153 178 31 34 
Reclassification adjustments:
Amortization of prior service costs(1)(1)(1)— 2 
Amortization of net loss(33)(10)(13)(2)— 
Amortization of regulatory assets(*)
— — — — (4)
Total reclassification adjustments(34)(11)(14)(2)(2)
Total change542 142 164 29 32 
Balance at December 31, 2023$2,913 $821 $1,051 $152 $143 
Net gain(199)(63)(58)(5)(7)
Reclassification adjustments:
Amortization of prior service costs(1)(1)(1)— 2 
Amortization of net loss(55)(16)(19)(3)(1)
Amortization of regulatory assets(*)
— — — — (11)
Total reclassification adjustments(56)(17)(20)(3)(10)
Total change(255)(80)(78)(8)(17)
Balance at December 31, 2024$2,658 $741 $973 $144 $126 
(*)Amounts for Southern Company exclude regulatory assets of $155 million and $173 million at December 31, 2024 and 2023, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company.
The changes in the balance of net regulatory assets (liabilities) related to the other postretirement benefit plans for the plan years ended December 31, 2024 and 2023 are presented in the following table:
Southern CompanyAlabama PowerGeorgia
Power		Mississippi PowerSouthern Company Gas
(in millions)
Net regulatory assets (liabilities):(*)
Balance at December 31, 2022$(136)$(21)$(39)$(9)$(58)
Net gain(77)(30)(38)(1)— 
Reclassification adjustments:
Amortization of prior service costs(1)— (1)— — 
Amortization of net gain6 3 4 — — 
Amortization of regulatory assets(*)
— — — — (10)
Total reclassification adjustments5 3 3 — (10)
Total change(72)(27)(35)(1)(10)
Balance at December 31, 2023$(208)$(48)$(74)$(10)$(68)
Net (gain) loss8 1 6 1 (12)
Reclassification adjustments:
Amortization of prior service costs(2)(1)(1)— — 
Amortization of net gain13 3 5 — 5 
Amortization of regulatory assets(*)
— — — — (9)
Total reclassification adjustments11 2 4 — (4)
Total change19 3 10 1 (16)
Balance at December 31, 2024$(189)$(45)$(64)$(9)$(84)
(*)Amounts for Southern Company exclude regulatory assets of $16 million and $24 million at December 31, 2024 and 2023, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company.
Amounts included in AOCI related to defined benefit pension plans
Presented below are the amounts included in AOCI at December 31, 2024 and 2023 related to the portion of the defined benefit pension plan attributable to Southern Company, Southern Power, and Southern Company Gas that had not yet been recognized in net periodic pension cost.
Southern
Company		Southern
Power		Southern Company
Gas
(in millions)
Balance at December 31, 2024
AOCI:
Prior service cost$(1)$— $(1)
Net (gain) loss53 11 (53)
Total AOCI$52 $11 $(54)
Balance at December 31, 2023
AOCI:
Prior service cost$(1)$— $(2)
Net (gain) loss80 20 (43)
Total AOCI$79 $20 $(45)
Presented below are the amounts included in AOCI at December 31, 2024 and 2023 related to the other postretirement benefit plans of Southern Company, Southern Power, and Southern Company Gas that had not yet been recognized in net periodic other postretirement benefit cost.
Southern
Company		Southern
Power		Southern Company
Gas
(in millions)
Balance at December 31, 2024
AOCI:
Net (gain) loss$(14)$— $(15)
Balance at December 31, 2023
AOCI:
Prior service cost$1 $— $— 
Net (gain) loss(10)1 (10)
Total AOCI$(9)$1 $(10)
Summary of investment strategies and benefit plan asset fair values
A description of the major asset classes that the pension and other postretirement benefit plans are comprised of, along with the valuation methods used for fair value measurement, is provided below:
DescriptionValuation Methodology
Domestic equity: A mix of large and small capitalization stocks with generally an equal distribution of value and growth attributes, managed both actively and through passive index approaches.

International equity: A mix of large and small capitalization growth and value stocks with developed and emerging markets exposure, managed both actively and through fundamental indexing approaches.
Domestic and international equities such as common stocks, American depositary receipts, and real estate investment trusts that trade on public exchanges are classified as Level 1 investments and are valued at the closing price in the active market. Equity funds with unpublished prices that are comprised of publicly traded securities (such as commingled/pooled funds) are also valued at the closing price in the active market but are classified as Level 2.
Fixed income: A mix of domestic and international bonds.
Investments in fixed income securities, including fixed income pooled funds, are generally classified as Level 2 investments and are valued based on prices reported in the market place. Additionally, the value of fixed income securities takes into consideration certain items such as broker quotes, spreads, yield curves, interest rates, and discount rates that apply to the term of a specific instrument.
Trust-owned life insurance (TOLI): Investments of taxable trusts aimed at minimizing the impact of taxes on the portfolio.
Investments in TOLI policies are classified as Level 2 investments and are valued based on the underlying investments held in the policy's separate accounts. The underlying assets are equity and fixed income pooled funds that are comprised of Level 1 and Level 2 securities.
Real estate: Investments in equity or debt of real properties and in publicly traded real estate securities.

Special situations: Investments in opportunistic strategies with the objective of diversifying and enhancing returns and exploiting short-term inefficiencies, as well as investments in promising new strategies of a longer-term nature.

Private equity: Investments in private or public securities typically through privately-negotiated and/or structured transactions, including leveraged buyouts, venture capital, and distressed debt.

Private credit: Investments focused on debt instruments, of which returns are driven by income rather than capital appreciation.

Infrastructure: Investments in real assets, typically with long-term, predictable, and stable cash flows and a meaningful income component.
Investments in real estate, special situations, private equity, private credit, and infrastructure are typically invested in private partnerships and/or other pooled vehicles (Investment Funds) which are generally classified as Net Asset Value as a Practical Expedient, since the Investment Funds and underlying assets are not publicly traded and/or often have liquidity restrictions. The managers of the Investment Funds value the assets using various inputs and techniques depending on the nature of the underlying investments. Techniques may include purchase multiples for comparable transactions, comparable public company trading multiples, discounted cash flow analysis, prevailing market capitalization rates, recent sales of comparable investments, and independent third-party appraisals. The total market value of each of the Investment Funds is determined by aggregating the value of the underlying assets less liabilities.
Fair values of plan assets
The fair values, and actual allocations relative to the target allocations, of the Southern Company system's pension plans at December 31, 2024 and 2023 are presented below.
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)Total
(in millions)
Southern Company
Assets:
Equity:41 %41 %
Domestic equity$2,095 $835 $— $2,930 
International equity1,959 1,032 — 2,991 
Fixed income:30 31 
U.S. Treasury, government, and agency bonds— 1,780 — 1,780 
Mortgage- and asset-backed securities— 48 — 48 
Corporate bonds— 1,715 — 1,715 
Pooled funds— 792 — 792 
Cash equivalents and other255 — — 255 
Real estate investments361 — 1,563 1,924 12 13 
Special situations— — 237 237 3 2 
Private equity— — 1,797 1,797 9 12 
Private credit
— — 152 152 3 1 
Infrastructure
— — — — 2 — 
Total$4,670 $6,202 $3,749 $14,621 100 %100 %
Liabilities:
Derivatives$— $(33)$— $(33)
Total$4,670 $6,169 $3,749 $14,588 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)Total
(in millions)
Alabama Power
Assets:
Equity:41 %41 %
Domestic equity$509 $203 $— $712 
International equity476 251 — 727 
Fixed income:30 31 
U.S. Treasury, government, and agency bonds— 433 — 433 
Mortgage- and asset-backed securities— 12 — 12 
Corporate bonds— 417 — 417 
Pooled funds— 193 — 193 
Cash equivalents and other62 — — 62 
Real estate investments88 — 380 468 12 13 
Special situations— — 57 57 3 2 
Private equity— — 437 437 9 12 
Private credit
— — 37 37 3 1 
Infrastructure
— — — — 2 — 
Total$1,135 $1,509 $911 $3,555 100 %100 %
Liabilities:
Derivatives$— $(8)$— $(8)
Total$1,135 $1,501 $911 $3,547 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)Total
(in millions)
Georgia Power
Assets:
Equity:41 %41 %
Domestic equity$652 $259 $— $911 
International equity608 320 — 928 
Fixed income:30 31 
U.S. Treasury, government, and agency bonds— 552 — 552 
Mortgage- and asset-backed securities— 15 — 15 
Corporate bonds— 532 — 532 
Pooled funds— 246 — 246 
Cash equivalents and other79 — — 79 
Real estate investments112 — 485 597 12 13 
Special situations— — 73 73 3 2 
Private equity— — 558 558 9 12 
Private credit
— — 47 47 3 1 
Infrastructure
— — — — 2 — 
Total$1,451 $1,924 $1,163 $4,538 100 %100 %
Liabilities:
Derivatives$— $(10)$— $(10)
Total$1,451 $1,914 $1,163 $4,528 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)Total
(in millions)
Mississippi Power
Assets:
Equity:41 %41 %
Domestic equity$97 $38 $— $135 
International equity89 47 — 136 
Fixed income:30 31 
U.S. Treasury, government, and agency bonds— 81 — 81 
Mortgage- and asset-backed securities— 2 — 2 
Corporate bonds— 78 — 78 
Pooled funds— 36 — 36 
Cash equivalents and other12 — — 12 
Real estate investments16 — 71 87 12 13 
Special situations— — 11 11 3 2 
Private equity— — 82 82 9 12 
Private credit
— — 7 7 3 1 
Infrastructure
— — — — 2 — 
Total$214 $282 $171 $667 100 %100 %
Liabilities:
Derivatives$— $(2)$— $(2)
Total$214 $280 $171 $665 100 %100 %
Southern Power
Assets:
Equity:41 %41 %
Domestic equity$27 $11 $— $38 
International equity25 13 — 38 
Fixed income:30 31 
U.S. Treasury, government, and agency bonds— 23 — 23 
Mortgage- and asset-backed securities— 1 — 1 
Corporate bonds— 22 — 22 
Pooled funds— 10 — 10 
Cash equivalents and other3 — — 3 
Real estate investments5 — 20 25 12 13 
Special situations— — 3 3 3 2 
Private equity— — 23 23 9 12 
Private credit
— — 2 2 3 1 
Infrastructure
— — — — 2 — 
Total$60 $80 $48 $188 100%100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)Total
(in millions)
Southern Company Gas
Assets:
Equity:41 %41 %
Domestic equity$142 $56 $— $198 
International equity132 69 — 201 
Fixed income:30 31 
U.S. Treasury, government, and agency bonds— 120 — 120 
Mortgage- and asset-backed securities— 3 — 3 
Corporate bonds— 115 — 115 
Pooled funds— 53 — 53 
Cash equivalents and other17 — — 17 
Real estate investments24 — 105 129 12 13 
Special situations— — 16 16 3 2 
Private equity— — 121 121 9 12 
Private credit
— — 10 10 3 1 
Infrastructure
— — — — 2 — 
Total$315 $416 $252 $983 100 %100 %
Liabilities:
Derivatives$— $(2)$— $(2)
Total$315 $414 $252 $981 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2023:(Level 1)(Level 2)(NAV)Total
(in millions)
Southern Company
Assets:
Equity:41 %40 %
Domestic equity$1,959 $771 $— $2,730 
International equity1,947 1,052 — 2,999 
Fixed income:30 32 
U.S. Treasury, government, and agency bonds— 1,973 — 1,973 
Mortgage- and asset-backed securities— 44 — 44 
Corporate bonds— 1,724 — 1,724 
Pooled funds— 777 — 777 
Cash equivalents and other371 58 — 429 
Real estate investments369 — 1,684 2,053 12 14 
Special situations— — 245 245 3 2 
Private equity— — 1,761 1,761 9 12 
Private Credit— — 25 25 3 — 
Infrastructure— — — — 2 — 
Total$4,646 $6,399 $3,715 $14,760 100 %100 %
Alabama Power
Assets:
Equity:41 %40 %
Domestic equity$476 $187 $— $663 
International equity472 255 — 727 
Fixed income:30 32 
U.S. Treasury, government, and agency bonds— 479 — 479 
Mortgage- and asset-backed securities— 11 — 11 
Corporate bonds— 418 — 418 
Pooled funds— 188 — 188 
Cash equivalents and other90 14 — 104 
Real estate investments89 — 408 497 12 14 
Special situations— — 59 59 3 2 
Private equity— — 427 427 9 12 
Private credit
— — 6 6 3 — 
Infrastructure
— — — — 2 — 
Total$1,127 $1,552 $900 $3,579 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2023:(Level 1)(Level 2)(NAV)Total
(in millions)
Georgia Power
Assets:
Equity:41 %40 %
Domestic equity$611 $241 $— $852 
International equity609 329 — 938 
Fixed income:30 32 
U.S. Treasury, government, and agency bonds— 617 — 617 
Mortgage- and asset-backed securities— 14 — 14 
Corporate bonds— 539 — 539 
Pooled funds— 243 — 243 
Cash equivalents and other116 18 — 134 
Real estate investments115 — 527 642 12 14 
Special situations— — 77 77 3 2 
Private equity— — 551 551 9 12 
Private credit
— — 8 8 3 — 
Infrastructure
— — — — 2 — 
Total$1,451 $2,001 $1,163 $4,615 100 %100 %
Mississippi Power
Assets:
Equity:41 %40 %
Domestic equity$89 $35 $— $124 
International equity89 48 — 137 
Fixed income:30 32 
U.S. Treasury, government, and agency bonds— 90 — 90 
Mortgage- and asset-backed securities— 2 — 2 
Corporate bonds— 79 — 79 
Pooled funds— 36 — 36 
Cash equivalents and other17 3 — 20 
Real estate investments17 — 77 94 12 14 
Special situations— — 11 11 3 2 
Private equity— — 81 81 9 12 
Private credit
— — 1 1 3 — 
Infrastructure
— — — — 2 — 
Total$212 $293 $170 $675 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2023:(Level 1)(Level 2)(NAV)Total
(in millions)
Southern Power
Assets:
Equity:41 %40 %
Domestic equity$24 $10 $— $34 
International equity25 13 — 38 
Fixed income:30 32 
U.S. Treasury, government, and agency bonds— 25 — 25 
Mortgage - and asset backed securities
— 1 — 1 
Corporate bonds— 22 — 22 
Pooled funds— 10 — 10 
Cash equivalents and other5 1 — 6 
Real estate investments5 — 21 26 12 14 
Special situations— — 3 3 3 2 
Private equity— — 22 22 9 12 
Private credit
— — — — 3 — 
Infrastructure
— — — — 2 — 
Total$59 $82 $46 $187 100 %100 %
Southern Company Gas
Assets:
Equity:41 %40 %
Domestic equity$130 $52 $— $182 
International equity130 71 — 201 
Fixed income:30 32 
U.S. Treasury, government, and agency bonds— 132 — 132 
Mortgage- and asset-backed securities— 3 — 3 
Corporate bonds— 116 — 116 
Pooled funds— 52 — 52 
Cash equivalents and other25 4 — 29 
Real estate investments25 — 113 138 12 14 
Special situations— — 16 16 3 2 
Private equity— — 118 118 9 12 
Private credit
— — 2 2 3 — 
Infrastructure
— — — — 2 — 
Total$310 $430 $249 $989 100 %100 %
The fair values, and actual allocations relative to the target allocations, of the applicable Registrants' other postretirement benefit plan assets at December 31, 2024 and 2023 are presented below.
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTotalTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)
(in millions)
Southern Company
Assets:
Equity:61 %62 %
Domestic equity$94 $98 $— $192 
International equity54 83 — 137 
Fixed income:29 28 
U.S. Treasury, government, and agency bonds— 54 — 54 
Mortgage- and asset-backed securities— 1 — 1 
Corporate bonds— 48 — 48 
Pooled funds— 99 — 99 
Cash equivalents and other16 — — 16 
Trust-owned life insurance— 478 — 478 
Real estate investments11 — 43 54 4 5 
Special situations— — 6 6 1 1 
Private equity— — 50 50 3 4 
Private credit
— — 4 4 1 — 
Infrastructure
— — — — 1 — 
Total$175 $861 $103 $1,139 100 %100 %
Liabilities:
Derivatives$— $(1)$— $(1)
Total$175 $860 $103 $1,138 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTotalTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)
(in millions)
Alabama Power
Assets:
Equity:68 %68 %
Domestic equity$17 $7 $— $24 
International equity16 9 — 25 
Fixed income:23 24 
U.S. Treasury, government, and agency bonds— 14 — 14 
Corporate bonds— 14 — 14 
Pooled funds— 11 — 11 
Cash equivalents and other2 — — 2 
Trust-owned life insurance— 294 — 294 
Real estate investments3 — 13 16 3 4 
Special situations— — 2 2 1 1 
Private equity— — 15 15 3 3 
Private credit
— — 1 1 1 — 
Infrastructure
— — — — 1 — 
Total$38 $349 $31 $418 100 %100 %
Georgia Power
Assets:
Equity:59 %59 %
Domestic equity$52 $7 $— $59 
International equity16 41 — 57 
Fixed income:35 33 
U.S. Treasury, government, and agency bonds— 14 — 14 
Corporate bonds— 14 — 14 
Pooled funds— 48 — 48 
Cash equivalents and other10 — — 10 
Trust-owned life insurance— 184 — 184 
Real estate investments4 — 13 17 3 4 
Special situations— — 2 2 1 1 
Private equity— — 15 15 2 3 
Total$82 $308 $30 $420 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTotalTarget AllocationActual Allocation
At December 31, 2024:(Level 1)(Level 2)(NAV)
(in millions)
Mississippi Power
Assets:
Equity:34 %32 %
Domestic equity$3 $1 $— $4 
International equity3 1 — 4 
Fixed income:43 44 
U.S. Treasury, government, and agency bonds— 7 — 7 
Corporate bonds— 2 — 2 
Pooled funds— 1 — 1 
Cash equivalents and other1 — — 1 
Real estate investments— — 2 2 10 11 
Special situations— — — — 2 2 
Private equity— — 2 2 7 10 
Private credit
— — — — 3 1 
Infrastructure
— — — — 1 — 
Total$7 $12 $4 $23 100 %100 %
Southern Company Gas
Assets:
Equity:72 %73 %
Domestic equity$1 $76 $— $77 
International equity1 23 — 24 
Fixed income:26 25 
U.S. Treasury, government, and agency bonds— 1 — 1 
Corporate bonds— 1 — 1 
Pooled funds— 32 — 32 
Cash equivalents and other1 — — 1 
Real estate investments— — 1 1 1 1 
Private equity— — 1 1 1 1 
Total$3 $133 $2 $138 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2023:(Level 1)(Level 2)(NAV)Total
(in millions)
Southern Company
Assets:
Equity:60 %61 %
Domestic equity$85 $87 $— $172 
International equity53 82 — 135 
Fixed income:30 28 
U.S. Treasury, government, and agency bonds— 57 — 57 
Mortgage- and asset-backed securities— 2 — 2 
Corporate bonds— 47 — 47 
Pooled funds— 92 — 92 
Cash equivalents and other21 2 — 23 
Trust-owned life insurance— 456 — 456 
Real estate investments11 — 46 57 4 6 
Special situations— — 6 6 1 1 
Private equity— — 48 48 3 4 
Private credit
— — 1 1 1 — 
Infrastructure
— — — — 1 — 
Total$170 $825 $101 $1,096 100 %100 %
Alabama Power
Assets:
Equity:67 %66 %
Domestic equity$16 $6 $— $22 
International equity16 9 — 25 
Fixed income:23 23 
U.S. Treasury, government, and agency bonds— 16 — 16 
Corporate bonds— 14 — 14 
Pooled funds— 8 — 8 
Cash equivalents and other3 — — 3 
Trust-owned life insurance— 280 — 280 
Real estate investments3 — 14 17 4 6 
Special situations— — 2 2 1 1 
Private equity— — 15 15 3 4 
Private credit
— — — — 1 — 
Infrastructure
— — — — 1 — 
Total$38 $333 $31 $402 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2023:(Level 1)(Level 2)(NAV)Total
(in millions)
Georgia Power
Assets:
Equity:58 %57 %
Domestic equity$47 $6 $— $53 
International equity16 40 — 56 
Fixed income:35 35 
U.S. Treasury, government, and agency bonds— 16 — 16 
Corporate bonds— 14 — 14 
Pooled funds— 47 — 47 
Cash equivalents and other13 — — 13 
Trust-owned life insurance— 176 — 176 
Real estate investments4 — 14 18 3 4 
Special situations— — 2 2 1 1 
Private equity— — 14 14 2 3 
Private credit
— — — — 1 — 
Total$80 $299 $30 $409 100 %100 %
Mississippi Power
Assets:
Equity:34 %33 %
Domestic equity$3 $1 $— $4 
International equity3 1 — 4 
Fixed income:43 44 
U.S. Treasury, government, and agency bonds— 7 — 7 
Corporate bonds— 2 — 2 
Pooled funds— 1 — 1 
Cash equivalents and other1 — — 1 
Real estate investments1 — 2 3 10 11 
Special situations— — — — 2 2 
Private equity— — 2 2 7 10 
Private credit
— — — — 3 — 
Infrastructure
— — — — 1 — 
Total$8 $12 $4 $24 100 %100 %
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant
Other
Observable
Inputs		Net Asset Value as a Practical ExpedientTarget AllocationActual Allocation
At December 31, 2023:(Level 1)(Level 2)(NAV)Total
(in millions)
Southern Company Gas
Assets:
Equity:72 %72 %
Domestic equity$2 $67 $— $69 
International equity2 22 — 24 
Fixed income:26 26 
U.S. Treasury, government, and agency bonds— 1 — 1 
Corporate bonds— 1 — 1 
Pooled funds— 29 — 29 
Cash equivalents and other1 — — 1 
Real estate investments— — 1 1 1 1 
Private equity— — 1 1 1 1 
Total$5 $120 $2 $127 100 %100 %
Total matching contributions Total matching contributions made to the plans for 2024, 2023, and 2022 were as follows:
Southern CompanyAlabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern Company Gas
(in millions)
2024$137 $29 $31 $5 $3 $20 
2023131 28 31 5 3 18 
2022124 26 29 5 3 17 
v3.25.0.1
STOCK COMPENSATION (Tables)
 12 Months Ended
Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]  
Schedule of employees participating in stock-based compensation programs
At December 31, 2024, the number of current and former employees participating in stock-based compensation programs for the Registrants was as follows:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
Number of employees1,154 158 161 36 36 183 
Assumptions used in the pricing model and the weighted average grant-date fair value of performance share award units granted The following table shows the assumptions used in the pricing model and the weighted average grant-date fair value of TSR awards granted:
Year Ended December 31202420232022
Expected volatility19.1%30.0%29.6%
Interest rate4.0%3.8%1.7%
Weighted average grant-date fair value$80.99$76.83$79.69
Schedule of compensation costs and related tax benefits
Southern Company's total PSU compensation cost and the related tax benefit recognized in income for the years ended December 31, 2024, 2023, and 2022 were as follows:
202420232022
(in millions)
Compensation cost recognized in income$102 $107 $101 
Tax benefit of compensation cost recognized in income27 28 26 
Southern Company's total RSU compensation cost and the related tax benefit recognized in income for the years ended December 31, 2024, 2023, and 2022 were as follows:
202420232022
(in millions)
Compensation cost recognized in income$30 $30 $26 
Tax benefit of compensation cost recognized in income8 8 7 
Southern Company's total intrinsic value of options exercised and the related tax benefit for the years ended December 31, 2024, 2023, and 2022 were as follows:
202420232022
(in millions)
Intrinsic value of options exercised$10 $18 $49 
Tax benefit of options exercised2 4 12 
v3.25.0.1
FAIR VALUE MEASUREMENTS (Tables)
 12 Months Ended
Dec. 31, 2024
Fair Value Disclosures [Abstract]  
Assets and liabilities measured at fair value on a recurring basis
The fair value increases (decreases) of the Funds, including unrealized gains (losses) and reinvested interest and dividends and excluding the Funds' expenses, for 2024, 2023, and 2022 are shown in the table below.
Southern CompanyAlabama
Power		Georgia
Power
(in millions)
Fair value increases (decreases)
2024$229 $143 $86 
2023281 157 124 
2022(360)(171)(189)
Unrealized gains (losses)
At December 31, 2024$113 $64 $49 
At December 31, 2023241 119 122 
At December 31, 2022(391)(204)(187)
At December 31, 2024, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows:
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical Assets Significant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2024:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Southern Company
Assets:
Energy-related derivatives(a)
$12 $77 $— $— $89 
Investments in trusts:(b)
Domestic equity849 250 — — 1,099 
Foreign equity148 175 — — 323 
U.S. Treasury and government agency securities— 371 — — 371 
Municipal bonds— 47 — — 47 
Pooled funds – fixed income— 7 — — 7 
Corporate bonds— 452 — — 452 
Mortgage and asset backed securities— 106 — — 106 
Private equity— — — 181 181 
Cash and cash equivalents1 — — — 1 
Other39 3 — 9 51 
Investments, available for sale:
U.S. Treasury and government agency securities2 7 — — 9 
Corporate bonds1 2 — — 3 
Mortgage and asset backed securities
— 10 — — 10 
Cash equivalents and restricted cash
533 19 — — 552 
Other investments9 31 8 — 48 
Total$1,594 $1,557 $8 $190 $3,349 
Liabilities:
Energy-related derivatives(a)
$5 $124 $— $— $129 
Interest rate derivatives— 269 — — 269 
Foreign currency derivatives— 218 — — 218 
Contingent consideration3 — 16 — 19 
Other— 13 11 — 24 
Total$8 $624 $27 $— $659 
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical Assets Significant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2024:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Alabama Power
Assets:
Energy-related derivatives
$— $26 $— $— $26 
Nuclear decommissioning trusts:(b)
Domestic equity459 241 — — 700 
Foreign equity148 — — — 148 
U.S. Treasury and government agency securities— 16 — — 16 
Municipal bonds— 1 — — 1 
Corporate bonds— 287 — — 287 
Mortgage and asset backed securities— 31 — — 31 
Private equity — — — 181 181 
Other11 1 — 9 21 
Cash equivalents and restricted cash
334 19 — — 353 
Other investments— 31 — — 31 
Total$952 $653 $— $190 $1,795 
Liabilities:
Energy-related derivatives$— $42 $— $— $42 
Georgia Power
Assets:
Energy-related derivatives$— $19 $— $— $19 
Nuclear decommissioning trusts:(b)
Domestic equity390 1 — — 391 
Foreign equity— 174 — — 174 
U.S. Treasury and government agency securities— 355 — — 355 
Municipal bonds— 46 — — 46 
Corporate bonds— 165 — — 165 
Mortgage and asset backed securities— 75 — — 75 
Other28 2 — — 30 
Cash equivalents35 — — — 35 
Total$453 $837 $— $— $1,290 
Liabilities:
Energy-related derivatives$— $42 $— $— $42 
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical Assets Significant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2024:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Mississippi Power
Assets:
Energy-related derivatives$— $19 $— $— $19 
Liabilities:
Energy-related derivatives$— $34 $— $— $34 
Southern Power
Assets:
Energy-related derivatives$— $4 $— $— $4 
Cash equivalents51 — — — 51 
Total$51 $4 $— $— $55 
Liabilities:
Foreign currency derivatives$— $51 $— $— $51 
Contingent consideration3 — 16 — 19 
Other— 13 11 — 24 
Total$3 $64 $27 $— $94 
Southern Company Gas
Assets:
Energy-related derivatives(a)
$12 $9 $— $— $21 
Non-qualified deferred compensation trusts:
Domestic equity— 8 — — 8 
Foreign equity— 1 — — 1 
Pooled funds - fixed income— 7 — — 7 
Cash and cash equivalents1 — — — 1 
Investments, available for sale:
U.S. Treasury and government agency securities2 7 — — 9 
Corporate bonds1 2 — — 3 
Mortgage and asset backed securities
— 10 — — 10 
Cash equivalents22 — — — 22 
Total$38 $44 $— $— $82 
Liabilities:
Energy-related derivatives(a)
$5 $6 $— $— $11 
Interest rate derivatives— 84 — — 84 
Total$5 $90 $— $— $95 
(a)Excludes cash collateral of $17 million.
(b)Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information.
At December 31, 2023, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows:
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2023:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Southern Company
Assets:
Energy-related derivatives(a)
$6 $49 $— $— $55 
Investments in trusts:(b)
Domestic equity764 216 — — 980 
Foreign equity145 171 — — 316 
U.S. Treasury and government agency securities— 369 — — 369 
Municipal bonds— 48 — — 48 
Pooled funds – fixed income— 6 — — 6 
Corporate bonds— 389 — — 389 
Mortgage and asset backed securities— 89 — — 89 
Private equity— — — 169 169 
Cash and cash equivalents3 — — — 3 
Other58 3 — 9 70 
Cash equivalents and restricted cash
253 15 — — 268 
Other investments9 27 8 — 44 
Total$1,238 $1,382 $8 $178 $2,806 
Liabilities:
Energy-related derivatives(a)
$46 $312 $— $— $358 
Interest rate derivatives— 264 — — 264 
Foreign currency derivatives— 122 — — 122 
Contingent consideration3 — 16 — 19 
Other— 13 — — 13 
Total$49 $711 $16 $— $776 
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2023:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Alabama Power
Assets:
Energy-related derivatives
$— $15 $— $— $15 
Nuclear decommissioning trusts:(b)
Domestic equity443 208 — — 651 
Foreign equity145 — — — 145 
U.S. Treasury and government agency securities— 20 — — 20 
Municipal bonds— 1 — — 1 
Corporate bonds— 231 — — 231 
Mortgage and asset backed securities— 25 — — 25 
Private equity — — — 169 169 
Other8 — — 9 17 
Cash equivalents and restricted cash
119 15 — — 134 
Other investments— 27 — — 27 
Total$715 $542 $— $178 $1,435 
Liabilities:
Energy-related derivatives$— $110 $— $— $110 
Georgia Power
Assets:
Energy-related derivatives$— $13 $— $— $13 
Nuclear decommissioning trusts:(b)
Domestic equity321 1 — — 322 
Foreign equity— 170 — — 170 
U.S. Treasury and government agency securities— 349 — — 349 
Municipal bonds— 47 — — 47 
Corporate bonds— 158 — — 158 
Mortgage and asset backed securities— 64 — — 64 
Other50 3 — — 53 
Total$371 $805 $— $— $1,176 
Liabilities:
Energy-related derivatives$— $124 $— $— $124 
Fair Value Measurements Using
Quoted Prices in Active Markets for Identical AssetsSignificant Other Observable InputsSignificant Unobservable InputsNet Asset Value as a Practical Expedient
At December 31, 2023:(Level 1)(Level 2)(Level 3)(NAV)Total
(in millions)
Mississippi Power
Assets:
Energy-related derivatives$— $15 $— $— $15 
Cash equivalents17 — — — 17 
Total$17 $15 $— $— $32 
Liabilities:
Energy-related derivatives$— $61 $— $— $61 
Southern Power
Assets:
Energy-related derivatives$— $3 $— $— $3 
Liabilities:
Energy-related derivatives$— $5 $— $— $5 
Foreign currency derivatives— 22 — — 22 
Contingent consideration3 — 16 — 19 
Other— 13 — — 13 
Total$3 $40 $16 $— $59 
Southern Company Gas
Assets:
Energy-related derivatives(a)
$6 $3 $— $— $9 
Non-qualified deferred compensation trusts:
Domestic equity— 7 — — 7 
Foreign equity— 1 — — 1 
Pooled funds - fixed income— 6 — — 6 
Cash and cash equivalents
3 — — — 3 
Total$9 $17 $— $— $26 
Liabilities:
Energy-related derivatives(a)
$46 $12 $— $— $58 
Interest rate derivatives— 79 — — 79 
Total$46 $91 $— $— $137 
(a)Excludes cash collateral of $62 million.
(b)Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information
Financial instruments not having carrying amount equal to fair value
At December 31, 2024 and 2023, other financial instruments for which the carrying amount did not equal fair value were as follows:
Southern
  Company(*)
Alabama PowerGeorgia PowerMississippi PowerSouthern Power
Southern Company
 Gas(*)
(in billions)
At December 31, 2024:
Long-term debt, including securities due within one year:
Carrying amount$63.2 $11.2 $18.1 $1.7 $2.7 $8.5 
Fair value57.7 9.8 16.2 1.5 2.6 7.4 
At December 31, 2023:
Long-term debt, including securities due within one year:
Carrying amount$59.4 $11.2 $16.5 $1.6 $2.7 $7.8 
Fair value55.0 10.1 15.1 1.4 2.6 6.8 
(*)The carrying amount of Southern Company Gas' long-term debt includes fair value adjustments from the effective date of the 2016 merger with Southern Company. Southern Company Gas amortizes the fair value adjustments over the remaining lives of the respective bonds, the latest being through 2043.
v3.25.0.1
DERIVATIVES (Tables)
 12 Months Ended
Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Schedule of energy-related derivatives
At December 31, 2024, the net volume of energy-related derivative contracts for natural gas positions, together with the longest hedge date over which the respective entity is hedging its exposure to the variability in future cash flows for forecasted transactions and the longest non-hedge date for derivatives not designated as hedges, were as follows:
Net
Purchased
mmBtu		Longest
Hedge
Date		Longest
Non-Hedge
Date
(in millions)
Southern Company(*)
43120302028
Alabama Power1232027—
Georgia Power1162027—
Mississippi Power1032028—
Southern Power620302025
Southern Company Gas(*)
8320272028
(*)Southern Company Gas' derivative instruments include both long and short natural gas positions. A long position is a contract to purchase natural gas and a short position is a contract to sell natural gas. Southern Company Gas' volume represents the net of long natural gas positions of 90 million mmBtu and short natural gas positions of 7 million mmBtu at December 31, 2024, which is also included in Southern Company's total volume.
Notional amount of interest rate derivatives
At December 31, 2024, the following interest rate derivatives were outstanding:
Notional
Amount		Weighted Average Interest Rate PaidInterest
Rate
Received		Hedge
Maturity
Date		Fair Value
Gain (Loss) December 31, 2024
(in millions)(in millions)
Fair Value Hedges of Existing Debt
Southern Company parent$400 
1-month SOFR + 0.80%
1.75%March 2028$(42)
Southern Company parent1,000 
1-month SOFR + 2.48%
3.70%April 2030(143)
Southern Company Gas500 
1-month SOFR + 0.49%
1.75%January 2031(84)
Southern Company$1,900 $(269)
Schedule of foreign exchange contracts
At December 31, 2024, the following foreign currency derivatives were outstanding:
Pay NotionalPay RateReceive NotionalReceive RateHedge
Maturity Date		Fair Value
Gain (Loss) December 31, 2024
(in millions)(in millions) (in millions)
Cash Flow Hedges of Existing Debt
Southern Power$564 3.78%€500 1.85%June 2026$(51)
Fair Value Hedges of Existing Debt
Southern Company parent1,476 3.39%1,250 1.88%September 2027(167)
Southern Company$2,040 €1,750 $(218)
Fair value of energy-related derivatives and interest rate derivatives
The fair value of energy-related derivatives, interest rate derivatives, and foreign currency derivatives was reflected as either assets or liabilities in the balance sheets (included in "Other" or shown separately as "Risk Management Activities") as follows:
20242023
Derivative Category and Balance Sheet LocationAssetsLiabilitiesAssetsLiabilities
(in millions)
Southern Company
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$33 $82 $12 $198 
Non-current
42 40 31 117 
Total derivatives designated as hedging instruments for regulatory purposes75 122 43 315 
Derivatives designated as hedging instruments in cash flow and fair value hedges
Energy-related derivatives:
Current
4 3 — 29 
Non-current
4 — 3 4 
Interest rate derivatives:
Current
— 61 — 74 
Non-current
— 208 — 190 
Foreign currency derivatives:
Current
— 36 — 34 
Non-current
— 182 — 88 
Total derivatives designated as hedging instruments in cash flow and fair value hedges8 490 3 419 
Energy-related derivatives not designated as hedging instruments
Current
5 3 8 8 
Non-current
1 — 1 2 
Total derivatives not designated as hedging instruments6 3 9 10 
Gross amounts recognized 89 615 55 744 
Gross amounts offset(a)
(44)(61)(23)(85)
Net amounts recognized in the Balance Sheets(b)
$45 $554 $32 $659 
Alabama Power
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$11 $30 $6 $69 
Non-current
15 12 9 41 
Total derivatives designated as hedging instruments for regulatory purposes26 42 15 110 
Gross amounts offset(19)(19)(10)(10)
Net amounts recognized in the Balance Sheets$7 $23 $5 $100 
20242023
Derivative Category and Balance Sheet LocationAssetsLiabilitiesAssetsLiabilities
(in millions)
Georgia Power
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$6 $32 $2 $82 
Non-current
13 9 10 42 
Total derivatives designated as hedging instruments for regulatory purposes19 41 12 124 
Energy-related derivatives not designated as hedging instruments
Current
— 1 — — 
Non-current
— — 1 — 
Total derivatives not designated as hedging instruments— 1 1 — 
Gross amounts recognized19 42 13 124 
Gross amounts offset(15)(15)(11)(11)
Net amounts recognized in the Balance Sheets$4 $27 $2 $113 
Mississippi Power
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$5 $15 $3 $27 
Non-current
14 19 12 34 
Total derivatives designated as hedging instruments for regulatory purposes19 34 15 61 
Gross amounts offset(17)(17)(14)(14)
Net amounts recognized in the Balance Sheets$2 $17 $1 $47 
Southern Power
Derivatives designated as hedging instruments in cash flow hedges
Energy-related derivatives:
Current
$1 $— $— $5 
Non-current
3 — 3 — 
Foreign currency derivatives:
Current
— 11 — 11 
Non-current
— 40 — 11 
Total derivatives designated as hedging instruments in cash flow hedges
4 51 3 27 
Net amounts recognized in the Balance Sheets$4 $51 $3 $27 
20242023
Derivative Category and Balance Sheet LocationAssetsLiabilitiesAssetsLiabilities
(in millions)
Southern Company Gas
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$11 $5 $1 $20 
Derivatives designated as hedging instruments in cash flow and fair value hedges
Energy-related derivatives:
Current
3 3 — 24 
Non-current
1 — — 4 
Interest rate derivatives:
Current
— 17 — 20 
Non-current
— 67 — 59 
Total derivatives designated as hedging instruments in cash flow and fair value hedges4 87 — 107 
Energy-related derivatives not designated as hedging instruments
Current
5 2 7 8 
Non-current
1 — 1 2 
Total derivatives not designated as hedging instruments6 2 8 10 
Gross amounts recognized21 94 9 137 
Gross amounts offset(a)
7 (10)12 (50)
Net amounts recognized in the Balance Sheets(b)
$28 $84 $21 $87 
(a)Gross amounts offset includes cash collateral held on deposit in broker margin accounts of $17 million and $62 million at December 31, 2024 and 2023, respectively.
(b)Net amounts of derivative instruments outstanding exclude immaterial premium and intrinsic value associated with weather derivatives for all periods presented.
Pre-tax effects on the balance sheets
At December 31, 2024 and 2023, the pre-tax effects of unrealized derivative gains (losses) arising from energy-related derivative instruments designated as regulatory hedging instruments and deferred were as follows:
Regulatory Hedge Unrealized Gain (Loss) Recognized in the Balance Sheets
Derivative Category and Balance Sheet
Location		Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern Company Gas
 (in millions)
At December 31, 2024:
Energy-related derivatives:
Other regulatory assets, current$(61)$(23)$(26)$(11)$(1)
Other regulatory assets, deferred(5)— — (5)— 
Other regulatory liabilities, current8 4 — — 4 
Other regulatory liabilities, deferred8 3 4 1 — 
Total energy-related derivative gains (losses)$(50)$(16)$(22)$(15)$3 
At December 31, 2023:
Energy-related derivatives:
Other regulatory assets, current$(180)$(67)$(80)$(25)$(8)
Other regulatory assets, deferred(87)(32)(33)(22)— 
Other regulatory liabilities, current9 4 — 1 4 
Other regulatory liabilities, deferred1 — 1 — — 
Total energy-related derivative gains (losses)$(257)$(95)$(112)$(46)$(4)
Pre-tax effects of hedging on AOCI
For the years ended December 31, 2024, 2023, and 2022, the pre-tax effects of cash flow and fair value hedge accounting on AOCI for the applicable Registrants were as follows:
Gain (Loss) From Derivatives Recognized in OCI202420232022
(in millions)
Southern Company
Cash flow hedges:
Energy-related derivatives$(7)$(81)$3 
Interest rate derivatives23 (12)46 
Foreign currency derivatives(40)14 (105)
Fair value hedges(*):
Foreign currency derivatives16 21 (24)
Total$(8)$(58)$(80)
Georgia Power
Cash flow hedges:
Interest rate derivatives$24 $(2)$31 
Mississippi Power
Cash flow hedges:
Interest rate derivatives$7 $— $— 
Southern Power
Cash flow hedges:
Energy-related derivatives$(1)$(18)$(15)
Foreign currency derivatives(40)14 (105)
Total$(41)$(4)$(120)
Southern Company Gas
Cash flow hedges:
Energy-related derivatives$(6)$(63)$18 
Interest rate derivatives(5)— — 
Total$(11)$(63)$18 
(*)Represents amounts excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI.
Pre-tax effect of interest rate and energy related derivatives
The pre-tax effects of cash flow and fair value hedge accounting on income for the years ended December 31, 2024, 2023, and 2022 were as follows:
Gain (Loss)
Statements of Income Location
Derivative Category
202420232022
(in millions)
Southern Company
Cost of natural gas
Energy-related cash flow hedges
$(40)$(44)$37 
Other operations and maintenance
Energy-related cash flow hedges
(2)(2)— 
Depreciation and amortization
Energy-related cash flow hedges
(6)(23)(5)
Interest expense, net of amounts capitalized
Interest rate cash flow hedges
(16)(35)(25)
Foreign currency cash flow hedges
(12)(11)(19)
Interest rate fair value hedges
(4)37 (291)
Other income (expense), net
Foreign currency cash flow hedges
(33)19 (83)
Foreign currency fair value hedges
2 69 (106)
Amount excluded from effectiveness testing recognized in earnings
(16)(21)24 
Southern Power
Depreciation and amortization
Energy-related cash flow hedges
$(6)$(23)$(5)
Interest expense, net of amounts capitalized
Foreign currency cash flow hedges
(12)(11)(19)
Other income (expense), net
Foreign currency cash flow hedges
(33)19 (83)
Southern Company Gas
Cost of natural gas
Energy-related cash flow hedges
$(40)$(44)$37 
Other operations and maintenance
Energy-related cash flow hedges
(2)(2)— 
Interest expense, net of amounts capitalized
Interest rate cash flow hedges
(1)(19)(4)
Interest rate fair value hedges
(5)6 (86)
Schedule of fair value hedging instruments, statements of financial performance and financial position, location
At December 31, 2024 and 2023, the following amounts were recorded on the balance sheets related to cumulative basis adjustments for fair value hedges:
Carrying Amount of
the Hedged Item		Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item
Balance Sheet Location of Hedged ItemsAt December 31, 2024At December 31, 2023At December 31, 2024At December 31, 2023
(in millions)(in millions)
Southern Company
Long-term debt$(2,936)$(3,024)$242 $235 
Southern Company Gas
Long-term debt$(422)$(427)$75 $70 
Pre-tax effect of interest rate and energy related derivatives
The pre-tax effects of energy-related derivatives not designated as hedging instruments on the statements of income of Southern Company and Southern Company Gas for the years ended December 31, 2024, 2023, and 2022 were as follows:
Gain (Loss)
Derivatives in Non-Designated Hedging RelationshipsStatements of Income Location202420232022
(in millions)
Energy-related derivatives
Natural gas revenues(*)
$— $— $(11)
Cost of natural gas94 59 (65)
Total derivatives in non-designated hedging relationships$94 $59 $(76)
(*)Excludes the impact of weather derivatives recorded in natural gas revenues of $12 million, $15 million, and $(7) million for 2024, 2023 and 2022, respectively, as they are accounted for based on intrinsic value rather than fair value.
v3.25.0.1
ACQUISITIONS AND DISPOSITIONS (Tables)
 12 Months Ended
Dec. 31, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]  
Schedule of construction projects
Project
Facility		Resource
Approximate Nameplate Capacity (MW)
Location
Actual/Projected COD
PPA Contract Period
Projects Under Construction at December 31, 2024
Millers Branch
Phase I
Solar
200
Haskell County, TX
Fourth quarter 2025
20 years
Phase II
Solar
180Haskell County, TX
Second quarter 2026
15 years
Phase III
Solar
132Haskell County, TX
Fourth quarter 2026
15 years
Projects Completed During 2024
South Cheyenne
Solar
150
Laramie County, WY
April 2024
20 years
Projects Completed During 2022
Garland Solar Storage(a)
Battery energy storage88Kern County, CA
September 2021 through February 2022(b)
20 years
Tranquillity Solar Storage(a)
Battery energy storage72Fresno County, CA
November 2021 through
March 2022(c)
20 years
(a)Southern Power consolidates each project's operating results in its financial statements and the tax equity partner and two other partners each own a noncontrolling interest. See Note 9 under "Lessor" for additional information.
(b)The facility has a total capacity of 88 MWs, of which 73 MWs were placed in service in 2021 and 15 MWs were placed in service in 2022.
(c)The facility has a total capacity of 72 MWs, of which 32 MWs were placed in service in 2021 and 40 MWs were placed in service in 2022.
v3.25.0.1
SEGMENT AND RELATED INFORMATION (Tables)
 12 Months Ended
Dec. 31, 2024
Segment Reporting [Abstract]  
Financial data for business segments
Financial data for business segments and products and services for the years ended December 31, 2024, 2023, and 2022 was as follows:
Electric Utilities
Traditional
Electric
Operating
Companies		Southern
Power		EliminationsTotalSouthern Company Gas
Total Reportable Segments
All
Other		EliminationsConsolidated
(in millions)
2024
Operating revenues$19,977 $2,014 $(388)$21,603 $4,456 $26,059 $843 $(178)$26,724 
Other segment items(a)(b)(c)(d)
10,057 1,060 (388)10,729 2,613 13,342 802 (149)13,995 
Depreciation and amortization(e)
3,512 522 — 4,034 650 4,684 71 — 4,755 
Earnings from equity method investments8 — — 8 146 154 (17)2 139 
Interest expense1,255 117 — 1,372 341 1,713 1,030 — 2,743 
Income taxes (benefit)1,016 (13)— 1,003 258 1,261 (292)— 969 
Segment net income (loss)(b)(c)(d)(e)(f)
$4,145 $328 $— $4,473 $740 $5,213 $(785)$(27)$4,401 
Goodwill$— $2 $— $2 $5,015 $5,017 $144 $— $5,161 
Total assets105,577 12,653 (1,025)117,205 26,177 143,382 2,371 (573)145,180 
2023
Operating revenues$18,358 $2,189 $(549)$19,998 $4,702 $24,700 $718 $(165)$25,253 
Other segment items(a)(c)(g)(h)
9,643 1,187 (549)10,281 3,124 13,405 699 (150)13,954 
Depreciation and amortization3,361 504 — 3,865 582 4,447 78 — 4,525 
Earnings from equity method investments(1)— — (1)140 139 5 — 144 
Interest expense1,145 129 — 1,274 310 1,584 879 (17)2,446 
Income taxes (benefit)571 12 — 583 211 794 (298)— 496 
Segment net income (loss)(c)(f)(g)(h)
$3,637 $357 $— $3,994 $615 $4,609 $(635)$2 $3,976 
Goodwill$— $2 $— $2 $5,015 $5,017 $144 $— $5,161 
Total assets100,429 12,761 (545)112,645 25,083 137,728 2,446 (843)139,331 
2022
Operating revenues$20,408 $3,369 $(904)$22,873 $5,962 $28,835 $593 $(149)$29,279 
Other segment items(a)(c)(i)(j)
12,820 2,341 (904)14,257 4,536 18,793 771 (138)19,426 
Depreciation and amortization2,513 516 — 3,029 559 3,588 75 — 3,663 
Earnings from equity method investments— — — — 148 148 3 — 151 
Interest expense929 138 — 1,067 263 1,330 694 (2)2,022 
Income taxes (benefit)828 20 — 848 180 1,028 (233)— 795 
Segment net income (loss)(c)(f)(i)(j)
$3,318 $354 $— $3,672 $572 $4,244 $(711)$(9)$3,524 
Goodwill$— $2 $— $2 $5,015 $5,017 $144 $— $5,161 
Total assets95,861 13,081 (659)108,283 24,621 132,904 2,665 (678)134,891 
(a)Primarily consists of fuel, purchased power, cost of natural gas, cost of other sales, other operations and maintenance, taxes other than income taxes, charges (credits) to income for estimated probable losses, losses (gains) on asset dispositions, impairment charges, AFUDC equity, non-service cost-related retirement benefits income, and net income (loss) attributable to noncontrolling interests.
(b)For the traditional electric operating companies, includes a pre-tax impairment loss at Alabama Power of $36 million ($27 million after tax) related to Alabama Power discontinuing the development of a multi-use commercial facility. See Note 1 under "Impairment of Long-Lived Assets" for additional information.
(c)For the traditional electric operating companies, includes pre-tax charges (credits) to income at Georgia Power for the estimated probable loss associated with the construction and completion of Plant Vogtle Units 3 and 4 of $(21) million ($(16) million after tax) in 2024, $(68) million ($(50) million after tax) in 2023, and $183 million ($137 million after tax) in 2022. See Note 2 under "Georgia Power – Nuclear Construction" for additional information.
(d)For the traditional electric operating companies, includes a pre-tax gain at Georgia power of approximately $114 million ($84 million after tax) related to the sale of transmission line assets under the integrated transmission system agreement. See Note 2 under "Georgia Power – Transmission Asset Sales" for additional information.
(e)For Southern Power, includes pre-tax accelerated depreciation of $9 million ($7 million after tax) related to the commitment to repower 200 MWs of the Kay Wind facility. See Note 15 under "Southern Power – Development Projects" for additional information.
(f)Attributable to Southern Company.
(g)For Southern Power, includes an $18 million pre-tax loss recovery ($9 million after tax and partnership allocations) related to an arbitration award and a $16 million pre-tax gain ($12 million after tax) on the sale of spare parts. See Note 3 under "General Litigation Matters – Southern Power" for additional information.
(h)For Southern Company Gas, includes pre-tax charges totaling approximately $96 million ($72 million after tax) associated with the disallowance of certain capital investments at Nicor Gas. See Note 2 under "Southern Company Gas" for additional information.
(i)For Southern Company Gas, includes pre-tax impairment charges totaling approximately $131 million ($99 million after tax) related to the sale of natural gas storage facilities. See Note 15 under "Southern Company Gas" for additional information.
(j)For the "All Other" column, includes a $119 million goodwill impairment loss (pre-tax and after tax) at PowerSecure. See Note 1 under "Goodwill and Other Intangible Assets" for additional information.
Financial data for Alabama Power's and Georgia Power's significant segment expenses and other segment information for the years ended December 31, 2024, 2023, and 2022 was as follows:
202420232022
(in millions)
Alabama Power
Operating revenues$7,554 $7,050 $7,817 
Utility operations and maintenance
Rate RSE expenses1,480 1,421 1,645 
Rate CNP Compliance expenses279 254 237 
Total utility operations and maintenance1,759 1,675 1,882 
Other segment items(a)(b)
2,125 2,098 2,915 
Depreciation and amortization1,459 1,401 875 
Interest expense448 425 382 
Income taxes360 81 423 
Segment net income(b)
$1,403 $1,370 $1,340 
Capital expenditures$2,114 $2,159 $2,206 
Georgia Power
Operating revenues$11,331 $10,118 $11,584 
Utility operations and maintenance2,210 1,901 2,237 
Other segment items(a)(c)(d)
3,476 3,382 5,249 
Depreciation and amortization1,774 1,681 1,430 
Interest expense725 626 485 
Income taxes603 448 370 
Segment net income(c)(d)
$2,543 $2,080 $1,813 
Capital expenditures$5,355 $5,394 $4,219 
(a)Primarily consists of fuel, purchased power, expenses from unregulated products and services, losses (gains) on asset dispositions, impairment charges, amortization of cloud software, taxes other than income taxes, charges (credits) to income for estimated probable losses, AFUDC equity, and non-service cost-related retirement benefits income. Also includes earnings from equity method investments, which were immaterial for all periods presented.
(b)For 2024, includes a pre-tax impairment loss of $36 million ($27 million after tax) related to Alabama Power discontinuing the development of a multi-use commercial facility. See Note 1 under "Impairment of Long-Lived Assets" for additional information.
(c)Includes pre-tax charges (credits) to income for the estimated probable loss associated with the construction and completion of Plant Vogtle Units 3 and 4 of $(21) million ($(16) million after tax) in 2024, $(68) million ($(50) million after tax) in 2023, and $183 million ($137 million after tax) in 2022. See Note 2 under "Georgia Power – Nuclear Construction" for additional information.
(d)For 2024, includes a pre-tax gain of approximately $114 million ($84 million after tax) related to the sale of transmission line assets under the integrated transmission system agreement. See Note 2 under "Georgia Power – Transmission Asset Sales" for additional information.
Financial data for business segments for the years ended December 31, 2024, 2023, and 2022 was as follows:
Gas Distribution OperationsGas Pipeline InvestmentsGas Marketing Services
Total Reportable Segments
All OtherEliminationsConsolidated
(in millions)
2024
Operating revenues$3,899 $32 $516 $4,447 $23 $(14)$4,456 
Other segment items(a)
2,236 6 356 2,598 29 (14)2,613 
Depreciation and amortization630 5 14 649 1 — 650 
Earnings from equity method investments— 146 — 146 — — 146 
Interest expense311 35 3 349 (8)— 341 
Income taxes172 31 41 244 14 — 258 
Segment net income (loss)
$550 $101 $102 $753 $(13)$— $740 
Total assets$24,067 $1,573 $1,696 $27,336 $10,047 $(11,206)$26,177 
2023
Operating revenues$4,105 $32 $548 $4,685 $36 $(19)$4,702 
Other segment items(a)(b)
2,702 5 402 3,109 34 (19)3,124 
Depreciation and amortization561 5 15 581 1 — 582 
Earnings from equity method investments— 140 — 140 — — 140 
Interest expense275 32 3 310 — — 310 
Income taxes126 32 37 195 16 — 211 
Segment net income (loss)(b)
$441 $98 $91 $630 $(15)$— $615 
Total assets$22,906 $1,534 $1,615 $26,055 $9,675 $(10,647)$25,083 
2022
Operating revenues$5,267 $32 $638 $5,937 $55 $(30)$5,962 
Other segment items(a)(c)
3,907 6 488 4,401 165 (30)4,536 
Depreciation and amortization516 5 16 537 22 — 559 
Earnings from equity method investments— 148 — 148 — — 148 
Interest expense229 27 3 259 4 — 263 
Income taxes (benefit)145 35 37 217 (37)— 180 
Segment net income (loss)(c)
$470 $107 $94 $671 $(99)$— $572 
Total assets$22,040 $1,577 $1,616 $25,233 $8,943 $(9,555)$24,621 
(a)Primarily consists of cost of natural gas, other operations and maintenance, taxes other than income taxes, impairment charges, estimated loss on regulatory disallowance, AFUDC equity, and non-service cost-related retirement benefits income.
(b)For gas distribution operations, includes pre-tax charges totaling approximately $96 million ($72 million after tax) associated with the disallowance of certain capital investments at Nicor Gas. See Note 2 under "Southern Company Gas" for additional information.
(c)For the "All Other" column, includes pre-tax impairment charges totaling approximately $131 million ($99 million after tax) related to the sale of natural gas storage facilities. See Note 15 under "Southern Company Gas" for additional information.
Disaggregation of revenue
The following table disaggregates revenue from contracts with customers for the periods presented:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
2024
Operating revenues
Retail electric revenues
Residential$8,276 $3,133 $4,835 $308 $— $— 
Commercial6,585 2,042 4,219 324 — — 
Industrial3,892 1,742 1,808 342 — — 
Other124 13 102 9 — — 
Total retail electric revenues18,877 6,930 10,964 983 — — 
Natural gas distribution revenues
Residential1,753 — — — — 1,753 
Commercial417 — — — — 417 
Transportation1,295 — — — — 1,295 
Industrial 34 — — — — 34 
Other316 — — — — 316 
Total natural gas distribution revenues3,815 — — — — 3,815 
Wholesale electric revenues
PPA energy revenues1,059 206 94 4 778 — 
PPA capacity revenues641 108 136 63 400 — 
Non-PPA revenues226 139 5 375 230 — 
Total wholesale electric revenues1,926 453 235 442 1,408 — 
Other natural gas revenues
Gas marketing services507 — — — — 507 
Other
18 — — — — 18 
Total other natural gas revenues
525 — — — — 525 
Other revenues1,621 240 721 52 37 — 
Total revenue from contracts with customers26,764 7,623 11,920 1,477 1,445 4,340 
Other revenue sources(*)
(40)(69)(589)(14)569 116 
Total operating revenues$26,724 $7,554 $11,331 $1,463 $2,014 $4,456 
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
2023
Operating revenues
Retail electric revenues
Residential$7,309 $2,904 $4,105 $300 $— $— 
Commercial5,860 1,928 3,624 308 — — 
Industrial3,613 1,721 1,558 334 — — 
Other112 12 91 9 — — 
Total retail electric revenues16,894 6,565 9,378 951 — — 
Natural gas distribution revenues
Residential1,981 — — — — 1,981 
Commercial505 — — — — 505 
Transportation1,184 — — — — 1,184 
Industrial 45 — — — — 45 
Other324 — — — — 324 
Total natural gas distribution revenues4,039 — — — — 4,039 
Wholesale electric revenues
PPA energy revenues1,107 234 87 20 790 — 
PPA capacity revenues624 156 51 45 376 — 
Non-PPA revenues250 65 35 407 409 — 
Total wholesale electric revenues1,981 455 173 472 1,575 — 
Other natural gas revenues
Gas marketing services528 — — — — 528 
Other
31 — — — — 31 
Total other natural gas revenues559 — — — — 559 
Other revenues1,355 213 578 39 55 — 
Total revenue from contracts with customers24,828 7,233 10,129 1,462 1,630 4,598 
Other revenue sources(*)
425 (183)(11)12 559 104 
Total operating revenues$25,253 $7,050 $10,118 $1,474 $2,189 $4,702 
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern PowerSouthern Company Gas
(in millions)
2022
Operating revenues
Retail electric revenues
Residential$6,604 $2,638 $3,664 $302 $— $— 
Commercial5,369 1,685 3,385 299 — — 
Industrial3,764 1,507 1,921 336 — — 
Other102 14 79 9 — — 
Total retail electric revenues15,839 5,844 9,049 946 — — 
Natural gas distribution revenues
Residential2,843 — — — — 2,843 
Commercial763 — — — — 763 
Transportation1,186 — — — — 1,186 
Industrial84 — — — — 84 
Other342 — — — — 342 
Total natural gas distribution revenues5,218 — — — — 5,218 
Wholesale electric revenues
PPA energy revenues2,274 489 130 16 1,673 — 
PPA capacity revenues596 194 47 4 356 — 
Non-PPA revenues250 200 30 690 740 — 
Total wholesale electric revenues3,120 883 207 710 2,769 — 
Other natural gas revenues
Gas marketing services636 — — — — 636 
Other
51 — — — — 51 
Total other natural gas revenues687 — — — — 687 
Other revenues1,077 194 446 47 36 — 
Total revenue from contracts with customers25,941 6,921 9,702 1,703 2,805 5,905 
Other revenue sources(*)
3,338 896 1,882 (9)564 57 
Total operating revenues$29,279 $7,817 $11,584 $1,694 $3,369 $5,962 
(*)Other revenue sources relate to revenues from customers accounted for as derivatives and leases, alternative revenue programs at Southern Company Gas, and cost recovery mechanisms and revenues (including those related to fuel costs) that meet other scope exceptions for revenues from contracts with customers at the traditional electric operating companies.
Products and Services
Electric Utilities' Revenues
YearRetailWholesaleOtherTotal
(in millions)
2024$17,790 $2,431 $1,382 $21,603 
202316,343 2,467 1,188 19,998 
202218,197 3,641 1,035 22,873 
Southern Company Gas' Revenues
YearGas
Distribution
Operations		Gas
Marketing
Services		All OtherTotal
(in millions)
2024$3,899 $516 $41 $4,456 
20234,090 548 64 4,702 
20225,240 638 84 5,962 
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - General (Narrative) (Details)
Dec. 31, 2024
company
state
New Accounting Pronouncements or Change in Accounting Principle [Line Items]  
Number of traditional electric operating companies | company 3
Traditional Electric Operating Companies  
New Accounting Pronouncements or Change in Accounting Principle [Line Items]  
Number of states in which entity provides utilities | state 3
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Costs for Affiliate Transactions (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Alabama Power | Southern Company Services, Inc.      
Related Party Transaction [Line Items]      
Costs for services $ 813 $ 611 $ 549
Alabama Power | Southern Natural Gas Company, LLC      
Related Party Transaction [Line Items]      
Costs for services 13 12 18
Georgia Power | Southern Company Services, Inc.      
Related Party Transaction [Line Items]      
Costs for services 1,197 857 762
Georgia Power | Southern Natural Gas Company, LLC      
Related Party Transaction [Line Items]      
Costs for services 103 101 99
Mississippi Power | Southern Company Services, Inc.      
Related Party Transaction [Line Items]      
Costs for services 130 113 115
Mississippi Power | Alabama Power | Power Pool      
Related Party Transaction [Line Items]      
Costs for services 8 4 4
Southern Power | Southern Company Services, Inc.      
Related Party Transaction [Line Items]      
Costs for services 93 86 86
Southern Power | Alabama Power | Power Pool      
Related Party Transaction [Line Items]      
Costs for services 17 13 29
Southern Power | Southern Natural Gas Company, LLC      
Related Party Transaction [Line Items]      
Costs for services 35 34 37
Southern Company Gas | Southern Company Services, Inc.      
Related Party Transaction [Line Items]      
Costs for services 290 261 262
Southern Company Gas | Southern Natural Gas Company, LLC      
Related Party Transaction [Line Items]      
Costs for services $ 28 $ 28 $ 27
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Affiliate Transactions (Narrative) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Southern Nuclear Operating Company, Inc. | Alabama Power      
Related Party Transaction [Line Items]      
Costs for services $ 260 $ 251 $ 267
Southern Nuclear Operating Company, Inc. | Georgia Power      
Related Party Transaction [Line Items]      
Costs for services 835 899 895
Southern Power | Georgia Power      
Related Party Transaction [Line Items]      
Costs for services 203 143 151
PowerSecure | Southern Company Gas | US General Services Administration      
Related Party Transaction [Line Items]      
Costs for services 13 29 10
Contract amount     74
Southern Company Services, Inc. | Alabama Power      
Related Party Transaction [Line Items]      
Costs for services 813 611 549
Southern Company Services, Inc. | Georgia Power      
Related Party Transaction [Line Items]      
Costs for services 1,197 857 762
Southern Company Services, Inc. | Southern Power      
Related Party Transaction [Line Items]      
Costs for services 93 86 86
Southern Company Services, Inc. | Southern Company Gas      
Related Party Transaction [Line Items]      
Costs for services 290 261 262
Southern Company Services, Inc. | Mississippi Power      
Related Party Transaction [Line Items]      
Costs for services 130 113 115
Non-Fuel Expense | Mississippi Power | Alabama Power      
Related Party Transaction [Line Items]      
Costs for services 7 5 6
Purchased Power from Affiliates | Southern Power      
Related Party Transaction [Line Items]      
Costs for services 149 145 154
Operating Lease PPA | Southern Power      
Related Party Transaction [Line Items]      
Costs for services 121 116 116
Operating Lease PPA | Mississippi Power      
Related Party Transaction [Line Items]      
Costs for services 60    
Electric Transmission | Southern Company Services, Inc. | Southern Power      
Related Party Transaction [Line Items]      
Costs for services $ 25 $ 33 $ 39
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenues (Narrative) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Disaggregation of Revenue [Line Items]      
Total operating revenues $ 26,724 $ 25,253 $ 29,279
Southern Company Gas      
Disaggregation of Revenue [Line Items]      
Period for collection of revenue prior to billings 24 months    
Total operating revenues $ 4,456 4,702 5,962
Southern Company Gas | Alternative revenue programs      
Disaggregation of Revenue [Line Items]      
Total operating revenues $ 43 $ 20 $ (5)
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration of Revenue (Narrative) (Details)
 12 Months Ended
Dec. 31, 2024
Mississippi Power | Wholesale Customers | Long-Term Contract | Customer Concentration Risk  
Concentration Risk [Line Items]  
Concentration risk (as percent) 13.90%
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Income and Other Taxes (Narrative) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Southern Power      
Tax Credit Carryforward [Line Items]      
Percentage reduction in tax basis of assets 50.00%    
Southern Company Gas      
Tax Credit Carryforward [Line Items]      
Excise taxes collected $ 115 $ 133 $ 162
Included In Operating Expenses | Southern Company Gas      
Tax Credit Carryforward [Line Items]      
Excise taxes collected $ 112 $ 129 $ 158
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Total AFUDC and Interest Capitalized (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Capitalized Contract Cost [Line Items]      
Total AFUDC and interest capitalized $ 339 $ 400 $ 327
Alabama Power      
Capitalized Contract Cost [Line Items]      
Total AFUDC and interest capitalized 76 109 90
Georgia Power      
Capitalized Contract Cost [Line Items]      
Total AFUDC and interest capitalized 209 251 213
Southern Power      
Capitalized Contract Cost [Line Items]      
Total AFUDC and interest capitalized 7 3 0
Southern Company Gas      
Capitalized Contract Cost [Line Items]      
Total AFUDC and interest capitalized $ 47 $ 37 $ 24
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Average AFUDC Composite Rates (Details)
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Alabama Power      
Capitalized Contract Cost [Line Items]      
Composite rate 8.10% 8.10% 7.90%
Georgia Power      
Capitalized Contract Cost [Line Items]      
Composite rate 7.70% 7.60% 7.30%
Mississippi Power      
Capitalized Contract Cost [Line Items]      
Composite rate 0.00% 0.00% 5.30%
Atlanta Gas Light      
Capitalized Contract Cost [Line Items]      
Composite rate 7.70% 7.40% 7.60%
Chattanooga Gas      
Capitalized Contract Cost [Line Items]      
Composite rate 7.10% 7.10% 7.10%
Nicor Gas      
Capitalized Contract Cost [Line Items]      
Composite rate 5.60% 4.60% 2.00%
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Impairment and Goodwill and Other Intangible Assets and Liabilities (Narrative) (Details) - USD ($)
$ in Millions
 3 Months Ended
Sep. 30, 2024
Dec. 31, 2022
Goodwill [Line Items]    
Goodwill impairment   $ 119
Alabama Power    
Goodwill [Line Items]    
Impairment charges $ 36  
Impairment charges, after tax $ 27  
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Goodwill Balances (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Goodwill [Line Items]      
Goodwill $ 5,161 $ 5,161 $ 5,161
Southern Company Gas      
Goodwill [Line Items]      
Goodwill 5,015 5,015  
Gas distribution operations | Southern Company Gas      
Goodwill [Line Items]      
Goodwill 4,034 4,034  
Gas marketing services | Southern Company Gas      
Goodwill [Line Items]      
Goodwill $ 981 $ 981  
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Other Intangible Assets (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]    
Gross Carrying Amount $ 669 $ 669
Accumulated Amortization (412) (376)
Other Intangible Assets, Net 257 293
Intangible assets, gross 744 744
Intangible assets, net 332 368
FCC licenses    
Finite-Lived Intangible Assets [Line Items]    
Gross Carrying Amount 75 75
Accumulated Amortization 0 0
Other Intangible Assets, Net 75 75
Customer relationships    
Finite-Lived Intangible Assets [Line Items]    
Gross Carrying Amount 212 212
Accumulated Amortization (182) (172)
Other Intangible Assets, Net 30 40
Trade names    
Finite-Lived Intangible Assets [Line Items]    
Gross Carrying Amount 64 64
Accumulated Amortization (59) (53)
Other Intangible Assets, Net 5 11
PPA fair value adjustments    
Finite-Lived Intangible Assets [Line Items]    
Gross Carrying Amount 390 390
Accumulated Amortization (168) (148)
Other Intangible Assets, Net 222 242
Other    
Finite-Lived Intangible Assets [Line Items]    
Gross Carrying Amount 3 3
Accumulated Amortization (3) (3)
Other Intangible Assets, Net 0 0
Southern Power    
Finite-Lived Intangible Assets [Line Items]    
Accumulated Amortization (168) (148)
Southern Power | PPA fair value adjustments    
Finite-Lived Intangible Assets [Line Items]    
Gross Carrying Amount 390 390
Accumulated Amortization (168) (148)
Other Intangible Assets, Net 222 242
Southern Company Gas    
Finite-Lived Intangible Assets [Line Items]    
Gross Carrying Amount 182 182
Accumulated Amortization (173) (166)
Other Intangible Assets, Net 9 16
Intangible assets, net 9 16
Southern Company Gas | Customer relationships    
Finite-Lived Intangible Assets [Line Items]    
Gross Carrying Amount   156
Accumulated Amortization (150) (145)
Other Intangible Assets, Net 6 11
Southern Company Gas | Trade names    
Finite-Lived Intangible Assets [Line Items]    
Gross Carrying Amount   26
Accumulated Amortization (23) (21)
Other Intangible Assets, Net $ 3 $ 5
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Amortization of Other Intangible Assets (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]      
Amortization associated with other intangible assets $ 35 $ 38 $ 39
Estimated future amortization      
2025 32    
2026 27    
2027 23    
2028 23    
2029 23    
Southern Power      
Finite-Lived Intangible Assets [Line Items]      
Amortization associated with other intangible assets 20 20 20
Estimated future amortization      
2025 20    
2026 20    
2027 20    
2028 20    
2029 19    
Southern Company Gas      
Estimated future amortization      
2025 6    
2026 3    
2027 0    
2028 0    
2029 0    
Southern Company Gas | Gas marketing services      
Finite-Lived Intangible Assets [Line Items]      
Amortization associated with other intangible assets 7 $ 10 $ 11
Operating Revenues      
Finite-Lived Intangible Assets [Line Items]      
Amortization associated with other intangible assets $ 20    
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Transmission Receivables/Prepayments (Narrative) (Details)
 12 Months Ended
Dec. 31, 2024
Southern Power  
Disaggregation of Revenue [Line Items]  
Period of reimbursement for transmission costs 5 years
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Restricted Cash and Cash Equivalents Items [Line Items]        
Cash and cash equivalents $ 1,070 $ 748    
Restricted cash:        
Total cash, cash equivalents, and restricted cash 1,101 921 $ 2,037 $ 1,829
Other current assets        
Restricted cash:        
Restricted cash 31 141    
Other deferred charges and assets        
Restricted cash:        
Restricted cash   31    
Alabama Power        
Restricted Cash and Cash Equivalents Items [Line Items]        
Cash and cash equivalents 585 324    
Restricted cash:        
Total cash, cash equivalents, and restricted cash 585 409 687 1,060
Alabama Power | Other current assets        
Restricted cash:        
Restricted cash 0 85    
Alabama Power | Other deferred charges and assets        
Restricted cash:        
Restricted cash   0    
Georgia Power        
Restricted Cash and Cash Equivalents Items [Line Items]        
Cash and cash equivalents 97 9    
Restricted cash:        
Total cash, cash equivalents, and restricted cash 118 75 480 33
Georgia Power | Other current assets        
Restricted cash:        
Restricted cash 21 37    
Georgia Power | Other deferred charges and assets        
Restricted cash:        
Restricted cash   29    
Southern Power        
Restricted Cash and Cash Equivalents Items [Line Items]        
Cash and cash equivalents 159 124    
Restricted cash:        
Total cash, cash equivalents, and restricted cash 168 144 133 135
Southern Power | Other current assets        
Restricted cash:        
Restricted cash 9 17    
Southern Power | Other deferred charges and assets        
Restricted cash:        
Restricted cash   3    
Southern Power | Proceeds From Issuance Of Solid Waste Disposal Facility Revenue Bonds        
Restricted cash:        
Restricted cash 9 17    
Southern Power | Estimated Construction Completion Costs | Deuel Harvest        
Restricted cash:        
Restricted cash   3    
Southern Company Gas        
Restricted Cash and Cash Equivalents Items [Line Items]        
Cash and cash equivalents 43 33    
Restricted cash:        
Total cash, cash equivalents, and restricted cash 44 35 $ 83 $ 48
Southern Company Gas | Other current assets        
Restricted cash:        
Restricted cash $ 1 2    
Southern Company Gas | Other deferred charges and assets        
Restricted cash:        
Restricted cash   $ 0    
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Storm Damage and Reliability Reserves (Details) - USD ($)
$ in Millions
 1 Months Ended 12 Months Ended 24 Months Ended
Jan. 01, 2023
Sep. 30, 2024
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2022
Apr. 11, 2024
Apr. 30, 2023
Mar. 31, 2023
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Balance at December 31, 2023 $ 216.0   $ 66.0 $ 216.0          
Balance at December 31, 2024       66.0 $ 216.0 $ 216.0      
Balance at December 31, 2024     (705.0)            
Reliability reserve, amount deferred     84.0 63.0 191.0 191.0      
Major storms                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Storm damage reserves         239.0        
Accrual                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Accrual     79.0 61.0          
Weather-related damages                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Weather-related damages     (850.0) (211.0)          
Alabama Power                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Balance at December 31, 2023 97.0   76.0 97.0          
Balance at December 31, 2024     70.0 76.0 97.0 97.0      
Reliability reserve, amount deferred     63.0 52.0 166.0 166.0      
Alabama Power | Major storms                  
Liability for Catastrophe Claims [Line Items]                  
Additional accruals authorized by state PSCs     21.0            
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Storm damage reserves         19.0        
Alabama Power | Accrual                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Accrual     34.0 18.0          
Alabama Power | Weather-related damages                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Weather-related damages     (40.0) (39.0)          
Charges against storm damage reserves     24.0            
Georgia Power                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Balance at December 31, 2023 83.0     83.0          
Balance at December 31, 2024         83.0 83.0      
Balance at December 31, 2024     (827.0) (54.0)          
Storm damage reserves 31.0         213.0      
Georgia Power | Major storms                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Weather-related damages   $ (870.0)              
Balance at December 31, 2024     750.0            
Storm damage reserves         213.0        
Georgia Power | Accrual                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Accrual     31.0 31.0          
Georgia Power | Weather-related damages                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Weather-related damages     (804.0) (168.0)          
Charges against storm damage reserves     82.0            
Mississippi Power                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Balance at December 31, 2023 $ 36.0   44.0 36.0          
Balance at December 31, 2024     52.0 44.0 36.0 36.0      
Reliability reserve, amount deferred     21.0 11.0 25.0 $ 25.0 $ 12.6 $ 11.7 $ 8.3
Mississippi Power | Major storms                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Storm damage reserves     12.6 11.7 $ 6.9        
Mississippi Power | Accrual                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Accrual     14.0 12.0          
Mississippi Power | Weather-related damages                  
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]                  
Weather-related damages     (6.0) $ (4.0)          
Charges against storm damage reserves     $ 0.0            
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Natural Gas for Sale (Narrative) (Details) - Nicor Gas
$ in Millions
Dec. 31, 2024
USD ($)
Inventory [Line Items]  
LIFO inventory balance $ 188
Estimated replacement cost of inventory $ 326
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Provision for Uncollectible Accounts (Narrative) (Details)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Accounting Policies [Abstract]      
Uncollectible accounts, average percent of revenues (less than) 1.00% 1.00% 1.00%
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration of Credit Risk (Narrative) (Details) - Atlanta Gas Light
Dec. 31, 2024
customer
Concentration Risk [Line Items]  
Number of customers in Georgia 14
Percent of highest month's estimated bill 200.00%
v3.25.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of AOCI (Loss) Balances, Net of Tax Effects (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance $ 35,225 $ 34,532 $ 32,276
Total other comprehensive income 99 (10) 71
Ending balance 36,674 35,225 34,532
Other 19 (5) (6)
Qualifying Hedges      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (121) (149) (162)
Total other comprehensive income 75 28 13
Ending balance (46) (121) (149)
Pension and Other Postretirement Benefit Plans      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (56) (18) (76)
Total other comprehensive income 24 (38) 58
Ending balance (32) (56) (18)
Accumulated Other Comprehensive Income (Loss)(*)      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (177) (167) (237)
Total other comprehensive income 99 (10) 71
Ending balance (78) (177) (167)
Other 0   (1)
Southern Power      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance 6,698 6,916 6,598
Total other comprehensive income 15 1 10
Ending balance 6,682 6,698 6,916
Other   (1) (1)
Southern Power | Qualifying Hedges      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (1) (9) 1
Total other comprehensive income 8 8 (10)
Ending balance 7 (1) (9)
Southern Power | Pension and Other Postretirement Benefit Plans      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (16) (9) (29)
Total other comprehensive income 7 (7) 20
Ending balance (9) (16) (9)
Southern Power | Accumulated Other Comprehensive Income (Loss)(*)      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (17) (18) (27)
Total other comprehensive income 15 1 10
Ending balance (2) (17) (18)
Other     (1)
Southern Company Gas      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Total other comprehensive income 32 (15) 7
Other (1)    
Southern Company Gas | Qualifying Hedges      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (24) (25) (14)
Total other comprehensive income 21 1 (11)
Ending balance (3) (24) (25)
Southern Company Gas | Pension and Other Postretirement Benefit Plans      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance 40 56 38
Total other comprehensive income 11 (16) 18
Ending balance 51 40 56
Southern Company Gas | Accumulated Other Comprehensive Income (Loss)(*)      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance 16 31 24
Total other comprehensive income 32 (15) 7
Ending balance $ 48 $ 16 $ 31
v3.25.0.1
REGULATORY MATTERS - Schedule of Regulatory Assets and Liabilities (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Jan. 01, 2023
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 7,041 $ 6,523    
Regulatory asset amortization period 4 years      
Regulatory asset   66 $ 216  
Regulatory liabilities $ 705      
Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 2,356 2,720    
Regulatory asset 70 76 97  
Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 6,139 5,090    
Regulatory asset     83  
Costs recovered annually 5 5 12  
Regulatory liabilities $ 827 54    
Georgia Power | Plant Vogtle Units 3 and 4        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 10 years      
Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 59 90    
Regulatory asset 52 44 $ 36  
Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ (2,252) (2,225)    
Fuel Hedging (Realized And Unrealized) losses | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory liability amortization period 3 years 6 months      
Fuel Hedging (Realized And Unrealized) losses | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory liability amortization period 3 years      
Fuel Hedging (Realized And Unrealized) losses | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory liability amortization period 4 years      
Deferred Income Tax Credits        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ (4,536) (4,686)    
Deferred Income Tax Credits | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (1,398) (1,506)    
Deferred Income Tax Credits | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (2,149) (2,161)    
Deferred Income Tax Credits | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (219) (241)    
Deferred Income Tax Credits | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (755) (759)    
Other Cost of Removal Obligations        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (1,176) (287)    
Other Cost of Removal Obligations | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 24 (3)    
Other Cost of Removal Obligations | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 816 (46)    
Other Cost of Removal Obligations | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (170) 0    
Other Cost of Removal Obligations | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (1,846) (238)    
Over Recovered Regulatory Clause Revenues        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (285) (1,312)    
Over Recovered Regulatory Clause Revenues | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (29) 28    
Over Recovered Regulatory Clause Revenues | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (52) 617    
Over Recovered Regulatory Clause Revenues | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 (186)    
Over Recovered Regulatory Clause Revenues | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ (204) (1,771)    
Regulatory liability amortization period 5 years      
Reliability reserves        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ (188) (179)    
Reliability reserves | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (131) (143)    
Reliability reserves | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Reliability reserves | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (57) (36)    
Reliability reserves | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Storm/Property Damage Reserves        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (122) (120)    
Storm/Property Damage Reserves | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (70) (76)    
Storm/Property Damage Reserves | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Storm/Property Damage Reserves | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (52) (44)    
Storm/Property Damage Reserves | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Nuclear Fuel Disposal Cost Recovery        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (100)      
Nuclear Fuel Disposal Cost Recovery | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (100)      
Nuclear Fuel Disposal Cost Recovery | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0      
Nuclear Fuel Disposal Cost Recovery | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0      
Nuclear Fuel Disposal Cost Recovery | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0      
Other Regulatory Liabilities        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets (180) (333)    
Other Regulatory Liabilities | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ (28) (94)    
Regulatory liability amortization period 1 year      
Other Regulatory Liabilities | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ (14) (23)    
Regulatory liability amortization period 3 years      
Other Regulatory Liabilities | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ (6) (2)    
Regulatory liability amortization period 1 year      
Other Regulatory Liabilities | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ (31) (101)    
Regulatory liability amortization period 20 years      
Deferred Income Tax Charges | Georgia Power | Plant Vogtle Units 3 and 4        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory liabilities $ 102      
Deferred Income Tax Charges | Southern Company Gas | Plant Vogtle Units 3 and 4        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory liabilities 24      
AROs        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 5,810 5,733    
AROs | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 1,906 1,936    
AROs | Alabama Power | Maximum        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 64 years      
AROs | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 3,658 3,505    
AROs | Georgia Power | Maximum        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 54 years      
AROs | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 248 247    
AROs | Mississippi Power | Maximum        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 67 years      
AROs | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 0 0    
AROs | Southern Company Gas | Maximum        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 85 years      
Retiree Benefit Plans        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 2,605 3,011    
Retiree Benefit Plans | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 680 815    
Retiree Benefit Plans | Alabama Power | Maximum        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 14 years      
Retiree Benefit Plans | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 892 976    
Retiree Benefit Plans | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 134 140    
Retiree Benefit Plans | Mississippi Power | Maximum        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 14 years      
Retiree Benefit Plans | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 44 146    
Remaining Net Book Value of Retired Assets        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 1,198 1,357    
Remaining Net Book Value of Retired Assets | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 454 499    
Remaining Net Book Value of Retired Assets | Alabama Power | Plant Gorgas Units 8, 9, And 10        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 419      
Remaining Net Book Value of Retired Assets | Alabama Power | Plant Barry Unit 4        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 35      
Regulatory asset amortization period 10 years      
Remaining Net Book Value of Retired Assets | Alabama Power | Maximum | Plant Gorgas Units 8, 9, And 10        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 13 years      
Remaining Net Book Value of Retired Assets | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 729 841    
Remaining Net Book Value of Retired Assets | Georgia Power | Plant Wansley Units 1 and 2        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 418      
Remaining Net Book Value of Retired Assets | Georgia Power | Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 302      
Remaining Net Book Value of Retired Assets | Georgia Power | Maximum | Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 11 years      
Remaining Net Book Value of Retired Assets | Georgia Power | Minimum | Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 1 year      
Remaining Net Book Value of Retired Assets | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 15 17    
Remaining Net Book Value of Retired Assets | Mississippi Power | Plant Watson and Plant Greene County | Retail electric revenues        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 10 years      
Remaining Net Book Value of Retired Assets | Mississippi Power | Plant Watson and Plant Greene County | Wholesale electric revenues        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 10 years      
Remaining Net Book Value of Retired Assets | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 0 0    
Deferred Income Tax Charges        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 927 897    
Deferred Income Tax Charges | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 264 262    
Deferred Income Tax Charges | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 634 605    
Deferred Income Tax Charges | Georgia Power | Plant Vogtle Units 3 and 4        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 29      
Regulatory asset amortization period 10 years      
Regulatory asset $ 135      
Deferred Income Tax Charges | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 27 28    
Deferred Income Tax Charges | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Under Recovered Regulatory Clause Revenues        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 167 413    
Under Recovered Regulatory Clause Revenues | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 119 381    
Under Recovered Regulatory Clause Revenues | Alabama Power | Maximum        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 6 years      
Under Recovered Regulatory Clause Revenues | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 0 0    
Regulatory asset amortization period 2 years      
Under Recovered Regulatory Clause Revenues | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 17 12    
Under Recovered Regulatory Clause Revenues | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 31 20    
Fuel Hedging (Realized And Unrealized) losses        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 69 270    
Fuel Hedging (Realized And Unrealized) losses | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 23 100    
Regulatory asset amortization period       5 years
Fuel Hedging (Realized And Unrealized) losses | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 29 121    
Fuel Hedging (Realized And Unrealized) losses | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 17 49    
Fuel Hedging (Realized And Unrealized) losses | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Regulatory asset amortization period       2 years
Deferred Depreciation        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 535 270    
Deferred Depreciation | Plant Scherer Units 1 through 3        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 139      
Regulatory asset amortization period 6 years      
Deferred Depreciation | Plant Bowen Units 1 and 2        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 80      
Deferred Depreciation | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 286 143    
Deferred Depreciation | Alabama Power | Plant Barry Unit 5        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 114      
Deferred Depreciation | Alabama Power | Plant Barry        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 48      
Deferred Depreciation | Alabama Power | Plant Gaston Unit 5        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 124      
Deferred Depreciation | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 249 127    
Deferred Depreciation | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Deferred Depreciation | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Environmental Remediation        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 249 255    
Environmental Remediation | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Environmental Remediation | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 16 20    
Environmental Remediation | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Environmental Remediation | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 233 235    
Loss on Reacquired Debt        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 219 238    
Loss on Reacquired Debt | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 32 35    
Loss on Reacquired Debt | Alabama Power | Maximum        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 23 years      
Loss on Reacquired Debt | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 183 197    
Loss on Reacquired Debt | Georgia Power | Maximum        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 28 years      
Loss on Reacquired Debt | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 4 5    
Loss on Reacquired Debt | Mississippi Power | Maximum        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 17 years      
Loss on Reacquired Debt | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 0 1    
Loss on Reacquired Debt | Southern Company Gas | Maximum        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 3 years      
Vacation Pay        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 224 217    
Regulatory asset amortization period 1 year      
Vacation Pay | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 85 83    
Vacation Pay | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 112 107    
Vacation Pay | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 12 11    
Vacation Pay | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 15 16    
Software and Cloud Computing Costs        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 200 150    
Regulatory asset amortization period 5 years      
Software and Cloud Computing Costs | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 76 59    
Regulatory asset amortization period 10 years      
Software and Cloud Computing Costs | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 116 84    
Software and Cloud Computing Costs | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 4 2    
Software and Cloud Computing Costs | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 4 5    
Regulatory asset amortization period 10 years      
Regulatory Clauses        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 162 140    
Regulatory Clauses | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 82 112    
Regulatory Clauses | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Regulatory Clauses | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Regulatory Clauses | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 80 28    
Storm Damage        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 859 92    
Storm Damage | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Storm Damage | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 827 54    
Storm Damage | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 32 38    
Storm Damage | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Nuclear Outage        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 92 83    
Nuclear Outage | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 39 50    
Nuclear Outage | Alabama Power | Plant Farley        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 18 months      
Nuclear Outage | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 53 33    
Nuclear Outage | Georgia Power | Maximum | Plant Hatch (nuclear) Units 1 and 2        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 24 months      
Nuclear Outage | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 0 0    
Nuclear Outage | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Long Term Debt Fair Value Adjustment        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 52 60    
Long Term Debt Fair Value Adjustment | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Long Term Debt Fair Value Adjustment | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Long Term Debt Fair Value Adjustment | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Long Term Debt Fair Value Adjustment | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 52 60    
Long Term Debt Fair Value Adjustment | Southern Company Gas | Maximum        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 14 years      
Qualifying Repairs Of Natural Gas Distribution Systems        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 53 40    
Qualifying Repairs Of Natural Gas Distribution Systems | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Qualifying Repairs Of Natural Gas Distribution Systems | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Qualifying Repairs Of Natural Gas Distribution Systems | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Qualifying Repairs Of Natural Gas Distribution Systems | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 53 40    
Qualifying Repairs Of Natural Gas Distribution Systems | Atlanta Gas Light        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 20 years      
Plant Daniel Units 3 and 4        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 23 25    
Plant Daniel Units 3 and 4 | Retail electric revenues        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 16      
Plant Daniel Units 3 and 4 | Wholesale electric revenues        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 8      
Plant Daniel Units 3 and 4 | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Plant Daniel Units 3 and 4 | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Plant Daniel Units 3 and 4 | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 23 25    
Plant Daniel Units 3 and 4 | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 0 0    
Other Regulatory Assets        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets 184 189    
Other Regulatory Assets | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 42 39    
Regulatory asset amortization period 19 years      
Other Regulatory Assets | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 40 33    
Regulatory asset amortization period 10 years      
Other Regulatory Assets | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 30 25    
Regulatory asset amortization period 10 years      
Other Regulatory Assets | Southern Company Gas        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 72 $ 93    
Regulatory asset amortization period 15 years      
CCR AROs | Alabama Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 38 years      
CCR AROs | Georgia Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Regulatory asset amortization period 3 years     4 years
Regulatory Clauses, Amortized Through PEP | Mississippi Power        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Net regulatory assets $ 17      
v3.25.0.1
REGULATORY MATTERS - APC Certificate of Convenience and Necessity and RGC (Details) - Alabama Power
$ in Millions
Oct. 24, 2024
USD ($)
MW
Jun. 30, 2023
MW
Jun. 14, 2023
MW
Jun. 13, 2023
MW
Apr. 04, 2023
MW
Schedule of Regulatory Assets and Liabilities [Line Items]          
Renewable generation certificate, authorized generating capacity (in MWs)   500      
Additional renewable capacity (in MWs)     2,400    
Size of allowable projects (in MWs)     200 80  
Approval limit (in MWs)     400 160  
Renewable generation certificate, generating capacity (in MWs)         498
Tenaska Alabama Partners, L.P.          
Schedule of Regulatory Assets and Liabilities [Line Items]          
Consideration transferred | $ $ 622        
Approximate nameplate capacity (in MWs) 855        
v3.25.0.1
REGULATORY MATTERS - APC Rate RSE (Details) - Alabama Power - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Nov. 27, 2024
Oct. 03, 2023
Public Utilities, General Disclosures [Line Items]            
Rate adjustment period   2 years        
Maximum percentage of rate RSE   4.00%        
Maximum annual percentage of ratio rate   5.00%        
Adjusting point of weighted cost of equity   5.98%        
Percent of basis points   0.07%        
Authorized ROE   53.90% 52.30%      
Customer refundable fees, refund payments, tranche one, percentage   25.00%        
Customer refundable fees, refund payments, tranche two, percentage   40.00%        
Customer refundable fees, refund payments, tranche two, percentage   75.00%        
Customer refundable fees, refund payments, tranche one, review year with rate RSE upward adjustment, percentage   50.00%        
Rate RSE refund liability   $ 12 $ 15 $ 62    
Rate RSE increase         4.87%  
Rate RSE increase amount         $ 325  
Customer refund     304      
Deferred income taxes   $ 67 $ 81     $ 24
Minimum            
Public Utilities, General Disclosures [Line Items]            
Public utilities, actual weighted common equity return, threshold, percentage   6.15%        
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche one   6.15% 6.15% 6.15%    
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche two   6.65%        
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche three   7.15%        
Public utilities, actual weighted common equity return, threshold, review year with rate RSE upward adjustment, percentage   6.15%        
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, review year with rate RSE upward adjustment, percentage, tranche one   6.15%        
Maximum            
Public Utilities, General Disclosures [Line Items]            
Public utilities, actual weighted common equity return, threshold, percentage   7.65%        
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche one   6.65%        
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche two   7.15%        
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche three   7.65%        
Customer refundable fees, refund payments, percentage   7.65%        
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, review year with rate RSE upward adjustment, percentage, tranche one   6.90%        
Customer refundable fees, refund payments, review year with rate RSE upward adjustment, percentage   6.90%        
Scenario, Forecast            
Public Utilities, General Disclosures [Line Items]            
Authorized ROE 55.00%          
Deferred income taxes $ 14          
v3.25.0.1
REGULATORY MATTERS - APC Rate CNP New Plant (Details) - Alabama Power
$ in Millions
 1 Months Ended 12 Months Ended
Jun. 30, 2023
USD ($)
Dec. 31, 2020
MW
Dec. 01, 2023
USD ($)
Oct. 03, 2022
USD ($)
Public Utilities, General Disclosures [Line Items]        
Increase to annual revenue requirement     $ 91 $ 34
Increase to annual revenue requirement, percentage     1.40% 0.60%
Requested rate increase (decrease), amount $ 78      
Requested rate increase (decrease), percentage 1.10%      
Plant Barry Unit 8        
Public Utilities, General Disclosures [Line Items]        
Approximate Nameplate Capacity (MW) | MW   720    
v3.25.0.1
REGULATORY MATTERS - APC Rate CNP (Details) - Alabama Power - USD ($)
$ in Millions
 1 Months Ended 12 Months Ended
Dec. 31, 2022
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Schedule of Regulatory Assets and Liabilities [Line Items]        
Under recovered certified power purchase agreements   $ 84 $ 103  
Retail revenue requirement for environmental compliance   50 $ 23 $ 255
Retail revenue requirement for environmental compliance, as a percentage     (0.30%) 3.70%
Over (under) recovered environmental clause   (35) $ (33)  
Public utilities, approved rate increase (decrease), amount $ 318      
Approved rate increase, percent 4.60%      
Other regulatory assets, current        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Under recovered certified power purchase agreements   17 18  
Over (under) recovered environmental clause     (8)  
Other regulatory assets, deferred        
Schedule of Regulatory Assets and Liabilities [Line Items]        
Under recovered certified power purchase agreements   $ 67 85  
Over (under) recovered environmental clause     $ (25)  
v3.25.0.1
REGULATORY MATTERS - APC Rate ECR (Details) - Alabama Power
$ in Millions
 1 Months Ended 12 Months Ended
May 08, 2024
USD ($)
$ / KWH_Kilowatt_hour
Jan. 31, 2026
$ / KWH_Kilowatt_hour
Jan. 31, 2025
USD ($)
$ / KWH_Kilowatt_hour
Dec. 31, 2023
USD ($)
$ / KWH_Kilowatt_hour
Dec. 31, 2022
USD ($)
$ / KWH_Kilowatt_hour
Nov. 30, 2022
$ / KWH_Kilowatt_hour
Aug. 31, 2022
USD ($)
$ / KWH_Kilowatt_hour
Jul. 31, 2022
$ / KWH_Kilowatt_hour
Dec. 31, 2024
USD ($)
$ / KWH_Kilowatt_hour
Schedule of Regulatory Assets and Liabilities [Line Items]                  
Current billing rates under rate ECR (usd per KWH) | $ / KWH_Kilowatt_hour 0.03015     0.03270 3.510 2.557 2.557 1.960 0.05910
Current billing rates under rate ECR, amount $ 135     $ 126 $ 500   $ 310    
Over (under) recovered fuel cost       $ (246)         $ (29)
Scenario, Forecast                  
Schedule of Regulatory Assets and Liabilities [Line Items]                  
Current billing rates under rate ECR (usd per KWH) | $ / KWH_Kilowatt_hour   0.05910 0.02600            
Current billing rates under rate ECR, amount     $ 218            
v3.25.0.1
REGULATORY MATTERS - APC Accounting Orders and Plant Greene County (Details)
$ in Millions
Dec. 31, 2024
USD ($)
MW
Dec. 31, 2023
USD ($)
Dec. 31, 2021
MW
Dec. 31, 2020
MW
Public Utilities, General Disclosures [Line Items]        
Other deferred charges and assets | $ $ 19,599 $ 19,069    
Alabama Power        
Public Utilities, General Disclosures [Line Items]        
Other deferred charges and assets | $ $ 5,175 5,090    
Percent ownership 14.00%      
Alabama Power | Plant Greene County Units 1 and 2        
Public Utilities, General Disclosures [Line Items]        
Percent ownership 60.00%      
Required fossil-stream generation retirements (in MWs) | MW 300      
Mississippi Power        
Public Utilities, General Disclosures [Line Items]        
Other deferred charges and assets | $ $ 841 $ 887    
Required fossil-stream generation retirements (in MWs) | MW       950
Mississippi Power | Plant Greene County Units 1 and 2        
Public Utilities, General Disclosures [Line Items]        
Percent ownership 40.00%      
Required fossil-stream generation retirements (in MWs) | MW     206  
v3.25.0.1
REGULATORY MATTERS - APC Rate NDR and Reliability Reserve Accounting Order (Details) - USD ($)
 3 Months Ended 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Jul. 12, 2022
Public Utilities, General Disclosures [Line Items]            
Reclassified amount $ (97,017,000,000) $ (90,703,000,000) $ (97,017,000,000) $ (90,703,000,000)    
Other regulatory assets 804,000,000 1,120,000,000 804,000,000 1,120,000,000    
Reliability reserve, amount deferred 84,000,000 63,000,000 84,000,000 63,000,000 $ 191,000,000  
Revision of Prior Period, Reclassification, Adjustment            
Public Utilities, General Disclosures [Line Items]            
Reclassified amount         600,000,000  
Other utility plant, net         600,000,000  
Alabama Power            
Public Utilities, General Disclosures [Line Items]            
Minimum natural disaster reserve balance, triggering establishment charge 50,000,000   50,000,000      
Natural disaster reserve authorized limit 75,000,000   75,000,000   35,000,000  
Maximum rate NDR charge per month, monthly residential customer account 2.50   2.50     $ 5.00
Maximum rate NDR charge per month, monthly nonresidential customer account 5.00   5.00     $ 10.00
Annual recovery amount     12,000,000 12,000,000 14,000,000  
NDR, expected recovery amount     12,000,000      
Regulatory asset, amortization period 70,000,000 76,000,000 70,000,000 76,000,000    
Reclassified amount (24,760,000,000) (24,298,000,000) (24,760,000,000) (24,298,000,000)    
Other regulatory assets 332,000,000 385,000,000 332,000,000 385,000,000    
Reliability reserve, amount deferred 63,000,000 52,000,000 $ 63,000,000 $ 52,000,000 $ 166,000,000  
Alabama Power | Reliability reserves            
Public Utilities, General Disclosures [Line Items]            
Accrual $ 12,000,000 $ 23,000,000        
Alabama Power | Maximum            
Public Utilities, General Disclosures [Line Items]            
Maximum period for recovery deferred stock related operations and maintenance costs and any future reserve deficits     48 months      
Alabama Power | Minimum            
Public Utilities, General Disclosures [Line Items]            
Maximum period for recovery deferred stock related operations and maintenance costs and any future reserve deficits     24 months      
v3.25.0.1
REGULATORY MATTERS - GPC Tariffs (Details) - Georgia Power
$ in Millions
Dec. 31, 2024
USD ($)
Public Utilities, General Disclosures [Line Items]  
Requested rate increase (decrease), amount, due in next fiscal year $ 216
Requested rate increase (decrease), amount, due in 2024 191
Requested rate increase (decrease), amount, due in 2025 306
Traditional Base  
Public Utilities, General Disclosures [Line Items]  
Requested rate increase (decrease), amount, due in next fiscal year 194
Requested rate increase (decrease), amount, due in 2024 275
Requested rate increase (decrease), amount, due in 2025 194
ECCR  
Public Utilities, General Disclosures [Line Items]  
Requested rate increase (decrease), amount, due in next fiscal year (21)
Requested rate increase (decrease), amount, due in 2024 (99)
Requested rate increase (decrease), amount, due in 2025 126
DSM  
Public Utilities, General Disclosures [Line Items]  
Requested rate increase (decrease), amount, due in next fiscal year 37
Requested rate increase (decrease), amount, due in 2024 10
Requested rate increase (decrease), amount, due in 2025 (22)
MFF  
Public Utilities, General Disclosures [Line Items]  
Requested rate increase (decrease), amount, due in next fiscal year 6
Requested rate increase (decrease), amount, due in 2024 5
Requested rate increase (decrease), amount, due in 2025 9
Traditional Base, Georgia State  
Public Utilities, General Disclosures [Line Items]  
Requested rate increase (decrease), amount, due in next fiscal year $ 122
v3.25.0.1
REGULATORY MATTERS - GPC Rate Plans and Integrated Resource Plan (Details)
$ in Millions
 1 Months Ended 3 Months Ended 12 Months Ended 56 Months Ended 60 Months Ended
Dec. 31, 2024
USD ($)
agreement
Dec. 03, 2024
MW
Jun. 27, 2024
agreement
Jan. 12, 2024
MW
Oct. 27, 2023
MW
Jan. 31, 2025
MW
Jun. 30, 2023
USD ($)
May 31, 2023
USD ($)
Sep. 30, 2024
facility
MW
Jun. 30, 2024
USD ($)
Dec. 31, 2028
MW
Dec. 31, 2025
USD ($)
MW
Dec. 31, 2024
USD ($)
MW
Dec. 31, 2023
USD ($)
turbine
MW
Dec. 31, 2022
USD ($)
agreement
MW
Dec. 31, 2019
Dec. 31, 2028
MW
Dec. 31, 2028
MW
Mar. 31, 2023
USD ($)
Public Utilities, General Disclosures [Line Items]                                      
Regulatory asset amortization period 4 years                       4 years            
Georgia Power                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested number of power purchase agreements to be certified | agreement                             6        
Requested additional generating capacity (in MW)                 265       1,567   8,500        
Requested number of affiliate power purchase agreements to be certified | agreement 2   5                                
Requested rate increase (decrease), amount | $               $ 1,100             $ 14,000        
Requested recovery of construction costs | $                   $ 10     $ 760            
Public Utilities, Number Of Battery Energy Storage Facilities | facility                 4                    
Total certified amount | $ $ 2,800                       $ 2,800            
Georgia Power | SEGCO                                      
Public Utilities, General Disclosures [Line Items]                                      
Ownership percentage, equity method investment 50.00%                       50.00%            
Georgia Power | Plant Scherer (coal) Unit 3                                      
Public Utilities, General Disclosures [Line Items]                                      
Percent Ownership 75.00%                       75.00%            
Georgia Power | Plant Scherer (coal) Units 1 and 2                                      
Public Utilities, General Disclosures [Line Items]                                      
Percent Ownership 8.40%                       8.40%            
Georgia Power | Plant Hatch Units 1 And 2                                      
Public Utilities, General Disclosures [Line Items]                                      
Percent Ownership 50.10%                       50.10%            
Georgia Power | Plant Vogtle (nuclear) Units 1 and 2                                      
Public Utilities, General Disclosures [Line Items]                                      
Percent Ownership 45.70%                       45.70%            
Georgia Power | ECCR                                      
Public Utilities, General Disclosures [Line Items]                                      
Regulatory asset amortization period 4 years                       4 years            
Approved rate decrease | $                         $ 60 $ 20          
Compliance costs expected to be incurred | $                         $ 265 $ 300          
Georgia Power | 2022 Alternate Rate Plan                                      
Public Utilities, General Disclosures [Line Items]                                      
Retail rate of return on common equity 10.50%                       10.50%            
Equity rate of return on common equity 56.00%                       56.00%            
Portion of actual earnings above approved ROE band refunded to customers                         40.00%            
Portion of actual earnings above approved ROE band applied to reduce regulatory assets                         40.00%            
Portion of actual earnings above approved ROE band retained by subsidiary company                         20.00%            
Georgia Power | 2019 Alternate Rate Plan                                      
Public Utilities, General Disclosures [Line Items]                                      
Retail rate of return on common equity                               10.50%      
Portion of actual earnings above approved ROE band refunded to customers                               40.00%      
Portion of actual earnings above approved ROE band applied to reduce regulatory assets                               40.00%      
Portion of actual earnings above approved ROE band retained by subsidiary company                               20.00%      
Customer refund liability in absence of base rate case | $                                     $ 117
Georgia Power | Scenario, Forecast                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)                     228 380         230 750  
Georgia Power | Scenario, Forecast | ECCR                                      
Public Utilities, General Disclosures [Line Items]                                      
Approved rate increase | $                       $ 123              
Compliance costs expected to be incurred | $                       $ 330              
Georgia Power | Subsequent Event                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)           1,100                          
Georgia Power | Subsequent Event | SEGCO                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)           500                          
Georgia Power | Subsequent Event | Plant Scherer (coal) Unit 3                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)           614                          
Georgia Power | Subsequent Event | Plant Scherer Unit 3                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)           187                          
Georgia Power | Subsequent Event | Plant Bowen Units 1 Through 4                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)           3,160                          
Georgia Power | Subsequent Event | Plant Scherer (coal) Units 1 and 2                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)           137                          
Georgia Power | Subsequent Event | Plant McIntosh Units 10 And 11                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)           1,319                          
Addition to nameplate capacity           194                          
Georgia Power | Subsequent Event | Plant McIntosh Units 1 Through 8                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)           640                          
Addition to nameplate capacity           74                          
Georgia Power | Subsequent Event | Plant Hatch Units 1 And 2                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)           900                          
Georgia Power | Subsequent Event | Plant Vogtle (nuclear) Units 1 and 2                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)           1,060                          
Addition to nameplate capacity           112                          
Georgia Power | Subsequent Event | Plant Goat Rock Units 3 Through 6                                      
Public Utilities, General Disclosures [Line Items]                                      
Addition to nameplate capacity           16                          
Georgia Power | Plant Yates                                      
Public Utilities, General Disclosures [Line Items]                                      
Number of turbines | turbine                           3          
Approved additional generating capacity (in MW)       442                              
Georgia Power | Plant Bowen Units 1 and 2                                      
Public Utilities, General Disclosures [Line Items]                                      
Approved additional generating capacity (in MW)                           1,400          
Georgia Power | Customer Refunds | 2019 Alternate Rate Plan                                      
Public Utilities, General Disclosures [Line Items]                                      
Portion of actual earnings above approved ROE band refunded to customers, value | $                                     $ 117
Alabama Power                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested rate increase (decrease), amount | $             $ 78                        
Percent Ownership 14.00%                       14.00%            
Alabama Power | SEGCO                                      
Public Utilities, General Disclosures [Line Items]                                      
Ownership percentage, equity method investment 50.00%                       50.00%            
Alabama Power | Subsequent Event | SEGCO                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)           500                          
Maximum | Georgia Power                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)   500     500       500                    
Maximum | Georgia Power | 2022 Alternate Rate Plan                                      
Public Utilities, General Disclosures [Line Items]                                      
Retail rate of return on common equity 11.90%                       11.90%            
Maximum | Georgia Power | 2019 Alternate Rate Plan                                      
Public Utilities, General Disclosures [Line Items]                                      
Retail rate of return on common equity                             12.00% 12.00%      
Maximum | Georgia Power | Subsequent Event                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)           4,000                          
Maximum | Georgia Power | Plant Yates                                      
Public Utilities, General Disclosures [Line Items]                                      
Requested additional generating capacity (in MW)                           1,400          
Minimum | Georgia Power | 2022 Alternate Rate Plan                                      
Public Utilities, General Disclosures [Line Items]                                      
Retail rate of return on common equity 9.50%                       9.50%            
Minimum | Georgia Power | 2019 Alternate Rate Plan                                      
Public Utilities, General Disclosures [Line Items]                                      
Retail rate of return on common equity                               9.50%      
v3.25.0.1
REGULATORY MATTERS - GPC Transmission Asset Sales, Fuel Cost, and Storm Damage Recovery (Details) - USD ($)
$ in Millions
 1 Months Ended 3 Months Ended 12 Months Ended 24 Months Ended
Apr. 24, 2024
Jan. 01, 2023
Sep. 30, 2024
May 31, 2023
Jun. 30, 2024
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2022
Mar. 07, 2024
Public Utilities, General Disclosures [Line Items]                    
To be recovered amount       $ 2,200            
Regulatory liabilities           $ 705        
Regulatory asset             $ 66 $ 216 $ 216  
Public utilities, property, plant and equipment, net           104,689 99,844      
Deferred amount to be billed in 2025           476 533      
Other operations and maintenance           6,539 6,093 6,824    
Major storms                    
Public Utilities, General Disclosures [Line Items]                    
Storm damage reserves               239    
Georgia Power                    
Public Utilities, General Disclosures [Line Items]                    
Requested rate increase (decrease), amount       $ 1,100       14,000    
Requested rate increase (decrease), percentage       54.00%            
Recovery period       3 years            
Over (under) recovered fuel balance           $ (1,200) (1,900)      
Required period for options and hedges           36 months        
Storm damage reserves   $ 31             213  
Regulatory liabilities           $ 827 54      
Regulatory asset               83 $ 83  
Public utilities, property, plant and equipment, net           44,038 40,995      
Deferred amount to be billed in 2025           262 305      
Other operations and maintenance           2,372 2,083 2,349    
Georgia Power | Major storms                    
Public Utilities, General Disclosures [Line Items]                    
Storm damage reserves               $ 213    
Weather related damages     $ 870              
Regulatory asset           750        
Public utilities, property, plant and equipment, net           90        
Deferred amount to be billed in 2025           30        
Georgia Power | Under Recovered Fuel Clause Revenues                    
Public Utilities, General Disclosures [Line Items]                    
Over (under) recovered fuel balance           (713) (694)      
Georgia Power | Deferred Under Recovered Fuel Clause Revenues                    
Public Utilities, General Disclosures [Line Items]                    
Over (under) recovered fuel balance           (453) (1,200)      
Georgia Power | Other regulatory assets, current                    
Public Utilities, General Disclosures [Line Items]                    
Regulatory liabilities           31 31      
Georgia Power | Other Regulatory Assets                    
Public Utilities, General Disclosures [Line Items]                    
Regulatory liabilities           $ 795 $ 23      
Georgia Power | Maximum                    
Public Utilities, General Disclosures [Line Items]                    
Approved rate increase, percent       40.00%            
Public utilities, approved rate increase (decrease), amount       $ 200            
Southern Company And Georgia Power | Disposal Group, Held-for-sale, Not Discontinued Operations                    
Public Utilities, General Disclosures [Line Items]                    
Net book value                   $ 236
Purchase price $ 351                  
Gain on sale         $ 114          
Gain on sale, after tax         $ 84          
v3.25.0.1
REGULATORY MATTERS - GPC Nuclear Construction and Cost and Schedule (Details)
$ in Millions
 3 Months Ended 12 Months Ended 192 Months Ended
Jun. 30, 2024
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Dec. 31, 2012
utility
MW
Dec. 31, 2024
USD ($)
Public Utilities, General Disclosures [Line Items]            
Pre-tax credit to income   $ 21 $ 68 $ (183)    
Georgia Power            
Public Utilities, General Disclosures [Line Items]            
Number of construction units approved | utility         2  
Electric generating capacity (in MWs) | MW         1,100  
Pre-tax credit to income $ 21 $ 21 68 $ (183)    
After tax credit to income $ 16          
Plant Vogtle Units 3 and 4 | Georgia Power            
Public Utilities, General Disclosures [Line Items]            
Percent ownership   45.70%       45.70%
Total project capital cost forecast   $ 10,732       $ 10,732
Net investment   (10,663)       (10,663)
Remaining estimate to complete   69       69
Estimated cost to complete, costs not shared with other owners   1,200       1,200
Total AFUDC and interest capitalized, accrual amount   440 $ 14     440
Estimated construction financing costs   3,530       3,530
Proceeds from recovery of financing costs           3,080
Plant Vogtle Units 3 and 4 | Georgia Power | Twenty Fifth Vogtle Construction Monitoring Report            
Public Utilities, General Disclosures [Line Items]            
Maximum guarantee   1,700       $ 1,700
Customer refund   $ 188        
v3.25.0.1
REGULATORY MATTERS - GPC Joint Owner Contracts (Details) - USD ($)
$ in Millions
 1 Months Ended 3 Months Ended 12 Months Ended
Oct. 31, 2023
Jun. 30, 2024
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2022
Public Utilities, General Disclosures [Line Items]          
Agreement with third party, amount of costs over projected forecast to be paid by company         20.00%
Georgia Power          
Public Utilities, General Disclosures [Line Items]          
Pre-tax charge to income   $ 7.6   $ 567.0  
After tax charge to income   $ 5.7   $ 424.0  
Plant Vogtle Units 3 and 4 | Georgia Power          
Public Utilities, General Disclosures [Line Items]          
Remaining share of construction costs, agreement to pay, percentage 66.00%        
Pre-tax charge to income     $ 228.0    
After tax charge to income     $ 170.0    
Plant Vogtle Units 3 and 4 | Georgia Power | MEAG Power          
Public Utilities, General Disclosures [Line Items]          
Agreement with third party, expected cost         $ 91.0
Plant Vogtle Units 3 and 4 | Georgia Power | Oglethorpe Power Corporation          
Public Utilities, General Disclosures [Line Items]          
Agreement with third party, expected cost $ 99.0        
Plant Vogtle Units 3 and 4 | Georgia Power | Dalton Utilities          
Public Utilities, General Disclosures [Line Items]          
Agreement with third party, expected cost $ 5.3        
v3.25.0.1
REGULATORY MATTERS - GPC Regulatory Matters (Details) - USD ($)
$ in Millions
 1 Months Ended 3 Months Ended 12 Months Ended 192 Months Ended
May 01, 2024
Aug. 01, 2023
Apr. 30, 2024
May 31, 2023
Dec. 31, 2022
Jun. 30, 2024
Dec. 31, 2023
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2009
Dec. 31, 2024
Public Utilities, General Disclosures [Line Items]                          
Net regulatory assets             $ 6,523.0 $ 7,041.0 $ 6,523.0       $ 7,041.0
Regulatory asset amortization period               4 years         4 years
Deferred Income Tax Charges                          
Public Utilities, General Disclosures [Line Items]                          
Net regulatory assets             897.0 $ 927.0 897.0       $ 927.0
Georgia Power                          
Public Utilities, General Disclosures [Line Items]                          
Requested recovery of construction costs           $ 10.0   760.0          
Requested rate increase (decrease), amount       $ 1,100.0           $ 14,000.0      
Net regulatory assets             5,090.0 6,139.0 5,090.0       6,139.0
Pre-tax charge to income           7.6     567.0        
After tax charge to income           5.7     424.0        
Requested rate increase (decrease), percentage       54.00%                  
Georgia Power | Deferred Income Tax Charges                          
Public Utilities, General Disclosures [Line Items]                          
Net regulatory assets             605.0 $ 634.0 605.0       634.0
Plant Vogtle Units 3 and 4 | Georgia Power                          
Public Utilities, General Disclosures [Line Items]                          
Estimated in-service capital cost                       $ 4,418.0  
Proceeds from recovery of financing costs                         $ 3,080.0
Requested recovery of construction costs                       7,562.0  
Increase (decrease) in tariff         $ 36.0                
Public utilities, approved rate increase (decrease), amount                     $ 2,100.0 5,462.0  
Requested rate increase (decrease), amount                       730.0  
Regulatory asset amortization period               10 years         10 years
Requested recovery of rate base items                       1,020.0  
Approved recovery of retail base rate                     362.0    
Requested recovery of remaining retail rate base items                       $ 647.0  
Return on equity reduction, negative impact on earnings     $ 10.0     $ 80.0     $ 310.0 $ 300.0      
Pre-tax charge to income             228.0            
After tax charge to income             $ 170.0            
Authorized ROE           0.00%              
Requested rate increase (decrease), percentage 5.00%                        
Plant Vogtle Units 3 and 4 | Georgia Power | Deferred Income Tax Charge, Debt Component                          
Public Utilities, General Disclosures [Line Items]                          
Net regulatory assets               $ 23.0         $ 23.0
Plant Vogtle Units 3 and 4 | Georgia Power | Deferred Income Tax Charges                          
Public Utilities, General Disclosures [Line Items]                          
Net regulatory assets               $ 29.0         $ 29.0
Regulatory asset amortization period               10 years         10 years
Plant Vogtle Units 3 and 4 | Georgia Power | Deferred Income Tax Charge, Equity Component                          
Public Utilities, General Disclosures [Line Items]                          
Net regulatory assets               $ 39.0         $ 39.0
Plant Vogtle Units 3 and 4 | Georgia Power                          
Public Utilities, General Disclosures [Line Items]                          
Public utilities, approved rate increase (decrease), amount                     2,100.0    
Requested rate increase (decrease), amount                     $ 3,600.0    
Requested rate increase, annual amount   $ 318.0                      
v3.25.0.1
REGULATORY MATTERS - MPC Performance Evaluation Plan (Details) - Mississippi Power
$ in Millions
 1 Months Ended 12 Months Ended
Jul. 31, 2024
USD ($)
Jun. 30, 2023
USD ($)
Jun. 30, 2022
USD ($)
Dec. 31, 2024
scale
filing
Dec. 31, 2021
USD ($)
Public Utilities, General Disclosures [Line Items]          
Scale of performance evaluation | scale       10  
Performance evaluation plan, number of filings per calendar year | filing       2  
Public utilities, approved rate increase (decrease), amount | $ $ (5) $ (7) $ 18   $ 9
Approved rate decrease, percent     (1.90%)    
Weighted Average | Measurement Input, Average Customer Price          
Public Utilities, General Disclosures [Line Items]          
Performance evaluation plan, measurement input       0.40  
Weighted Average | Measurement Input, Service Reliability          
Public Utilities, General Disclosures [Line Items]          
Performance evaluation plan, measurement input       0.40  
Weighted Average | Measurement Input, Customer Satisfaction          
Public Utilities, General Disclosures [Line Items]          
Performance evaluation plan, measurement input       0.20  
v3.25.0.1
REGULATORY MATTERS - MPC Integrated Resource Plan (Details)
$ in Millions
 1 Months Ended
Jan. 09, 2025
MW
Apr. 26, 2024
Oct. 31, 2023
MW
Dec. 31, 2024
USD ($)
Nov. 08, 2024
USD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2021
MW
Dec. 31, 2020
MW
Public Utilities, General Disclosures [Line Items]                
Net regulatory assets | $       $ 7,041   $ 6,523    
Mississippi Power                
Public Utilities, General Disclosures [Line Items]                
Required fossil-stream generation retirements (in MWs)               950
Approved additional generating capacity (in MW)     750          
Review period   120 days            
Net regulatory assets | $       $ 59   $ 90    
Mississippi Power | Subsequent Event                
Public Utilities, General Disclosures [Line Items]                
Approved additional generating capacity (in MW) 600              
Mississippi Power | Plant Watson Unit 4                
Public Utilities, General Disclosures [Line Items]                
Required fossil-stream generation retirements (in MWs)             268  
Mississippi Power | Plant Greene County Units 1 and 2                
Public Utilities, General Disclosures [Line Items]                
Required fossil-stream generation retirements (in MWs)             206  
Percent ownership       40.00%        
Mississippi Power | Plant Greene County Units 1 and 2 | Alabama Power                
Public Utilities, General Disclosures [Line Items]                
Percent ownership             40.00%  
Mississippi Power | Plant Daniel                
Public Utilities, General Disclosures [Line Items]                
Required fossil-stream generation retirements (in MWs)             502  
Percent ownership   50.00%         50.00%  
Net regulatory assets | $       $ 478        
Mississippi Power | Plant Daniel | Minimum                
Public Utilities, General Disclosures [Line Items]                
Acquisition payment receivable | $         $ 35      
Mississippi Power | Plant Daniel | Maximum                
Public Utilities, General Disclosures [Line Items]                
Acquisition payment receivable | $         $ 38      
v3.25.0.1
REGULATORY MATTERS - MPC Environmental Compliance Overview Plan (Details) - Mississippi Power - USD ($)
$ in Millions
 1 Months Ended 12 Months Ended
Feb. 14, 2025
Feb. 13, 2025
Oct. 25, 2024
Jul. 31, 2024
May 31, 2024
Jun. 30, 2023
Apr. 30, 2023
Jun. 30, 2022
Apr. 30, 2022
Dec. 31, 2021
Public Utilities, General Disclosures [Line Items]                    
Public utilities, approved rate increase (decrease), amount       $ (5)   $ (7)   $ 18   $ 9
Requested rate increase (decrease), amount     $ 11              
Subsequent Event                    
Public Utilities, General Disclosures [Line Items]                    
Requested rate increase (decrease), amount   $ 8                
Environmental Compliance Overview Plan                    
Public Utilities, General Disclosures [Line Items]                    
Public utilities, approved rate increase (decrease), amount         $ 9   $ 3   $ 1  
Environmental Compliance Overview Plan | Subsequent Event                    
Public Utilities, General Disclosures [Line Items]                    
Requested rate increase (decrease), amount $ 6                  
v3.25.0.1
REGULATORY MATTERS - MPC Fuel Cost Recovery and Ad Valorem Tax Adjustment (Details) - Mississippi Power - USD ($)
$ in Millions
 1 Months Ended 12 Months Ended
Feb. 06, 2024
Jul. 31, 2024
Jun. 30, 2023
Jul. 31, 2022
Jun. 30, 2022
Feb. 28, 2022
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2021
Oct. 31, 2024
Oct. 31, 2023
Public Utilities, General Disclosures [Line Items]                        
Public utilities, approved rate increase (decrease), amount   $ (5) $ (7)   $ 18         $ 9    
Ad Valorem Tax Adjustment                        
Public Utilities, General Disclosures [Line Items]                        
Public utilities, approved rate increase (decrease), amount       $ 5                
Retail electric revenues                        
Public Utilities, General Disclosures [Line Items]                        
Public utilities, approved rate increase (decrease), amount $ 18         $ 43            
Over (under) recovered fuel cost               $ (32) $ (50)   $ (25) $ (61)
Retail ECM                        
Public Utilities, General Disclosures [Line Items]                        
Over (under) recovered fuel cost               32 27      
MRA Revenue                        
Public Utilities, General Disclosures [Line Items]                        
Public utilities, approved rate increase (decrease), amount               4 22      
Over (under) recovered fuel cost               $ 19 $ (5)      
MRA Revenue | Scenario, Forecast                        
Public Utilities, General Disclosures [Line Items]                        
Public utilities, approved rate increase (decrease), amount             $ (19)          
v3.25.0.1
REGULATORY MATTERS - MPC System Restoration Rider and Reliability Reserve Accounting Order (Details) - USD ($)
$ in Thousands
 1 Months Ended 12 Months Ended
Jul. 31, 2024
Jun. 30, 2023
Jun. 30, 2022
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Apr. 11, 2024
Apr. 30, 2023
Mar. 31, 2023
Public Utilities, General Disclosures [Line Items]                    
Reliability reserve, amount deferred       $ 84,000 $ 63,000 $ 191,000        
Net regulatory assets       7,041,000 6,523,000          
Reliability reserves                    
Public Utilities, General Disclosures [Line Items]                    
Net regulatory assets       (188,000) (179,000)          
Major storms                    
Public Utilities, General Disclosures [Line Items]                    
Storm damage reserves accrual           239,000        
Mississippi Power                    
Public Utilities, General Disclosures [Line Items]                    
Threshold above which actual damages are charged to the reserve (individually exceed)       50            
Public utilities, approved rate increase (decrease), amount $ (5,000) $ (7,000) $ 18,000       $ 9,000      
Reliability reserve, amount deferred       21,000 11,000 25,000   $ 12,600 $ 11,700 $ 8,300
Net regulatory assets       59,000 90,000          
Mississippi Power | Reliability reserves                    
Public Utilities, General Disclosures [Line Items]                    
Net regulatory assets       (57,000) (36,000)          
Mississippi Power | Retail electric revenues                    
Public Utilities, General Disclosures [Line Items]                    
Property damage reserve       52,000 45,000          
Mississippi Power | Major storms                    
Public Utilities, General Disclosures [Line Items]                    
Storm damage reserves accrual       $ 12,600 $ 11,700 $ 6,900        
v3.25.0.1
REGULATORY MATTERS - MPC Municipal and Rural Associations Tariff (Details) - Mississippi Power
$ in Millions
 1 Months Ended
Dec. 23, 2024
USD ($)
Oct. 25, 2024
USD ($)
May 28, 2024
USD ($)
Jul. 31, 2023
USD ($)
Jul. 31, 2022
USD ($)
Dec. 31, 2024
MW
Aug. 31, 2022
Public Utilities, General Disclosures [Line Items]              
Requested rate increase (decrease), amount   $ 11          
Municipal and Rural Associations Tariff              
Public Utilities, General Disclosures [Line Items]              
Counterparty's option to decrease services, percentage 2.50%            
Requested rate increase (decrease), amount $ 1   $ 8 $ 16 $ 23    
Refund to customers $ 4     $ 6      
Cooperative Energy              
Public Utilities, General Disclosures [Line Items]              
Counterparty's option to decrease services, percentage             2.50%
Power being supplied to counterparty | MW           385  
Counterparty's electricity requirement at MRA delivery points           100.00%  
v3.25.0.1
REGULATORY MATTERS - GAS Schedule of Utility Regulation and Rate Design (Details)
 1 Months Ended 12 Months Ended
Nov. 30, 2023
Aug. 31, 2023
Dec. 31, 2024
Nicor Gas      
Public Utilities, General Disclosures [Line Items]      
Authorized ROE 9.51%   9.51%
Atlanta Gas Light      
Public Utilities, General Disclosures [Line Items]      
Authorized ROE     10.25%
Virginia Natural Gas      
Public Utilities, General Disclosures [Line Items]      
Authorized ROE   9.70% 9.70%
Chattanooga Gas      
Public Utilities, General Disclosures [Line Items]      
Authorized ROE     9.80%
v3.25.0.1
REGULATORY MATTERS - GAS Infrastructure Replacement Programs and Capital Projects and Natural Gas Recovery (Details)
$ in Millions
 1 Months Ended 3 Months Ended 12 Months Ended
Dec. 24, 2024
USD ($)
Jul. 02, 2024
USD ($)
Jun. 07, 2024
USD ($)
Nov. 30, 2023
USD ($)
Dec. 31, 2023
USD ($)
Jun. 30, 2023
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
mi
Dec. 31, 2019
USD ($)
Dec. 31, 2014
Public Utilities, General Disclosures [Line Items]                        
Revenues             $ (26,724.0) $ (25,253.0) $ (29,279.0)      
Total operating expenses             19,656.0 19,427.0 23,909.0      
Southern Company Gas                        
Public Utilities, General Disclosures [Line Items]                        
Capital expenditures             186.0          
Pretax charge to income             0.0 96.0 0.0      
Revenues             (4,456.0) (4,702.0) (5,962.0)      
Total operating expenses             3,329.0 3,763.0 5,148.0      
Southern Company Gas | Natural Gas Cost Under Recovery                        
Public Utilities, General Disclosures [Line Items]                        
Over (under) recovered fuel cost         $ 214.0   (193.0) 214.0        
Southern Company Gas | SAVE                        
Public Utilities, General Disclosures [Line Items]                        
Program duration period     5 years                  
Capital expenditures             75.0          
Infrastructure replacement program, approved investment variance amount     $ 5.0                  
Nicor Gas                        
Public Utilities, General Disclosures [Line Items]                        
Infrastructure disallowed         69.0              
Pretax charge to income         58.0 $ 38.0 (96.0)          
After tax charge to income         $ 44.0 28.0 (72.0)          
Nicor Gas | Other Transmission and Distribution Capital Investments                        
Public Utilities, General Disclosures [Line Items]                        
Infrastructure disallowed       $ 95.9                
Nicor Gas | Investing In Illinois Qualifying Infrastructure Plant                        
Public Utilities, General Disclosures [Line Items]                        
Infrastructure disallowed $ 14.0     126.8     $ 63.0       $ 32.0  
Capital expenditures                     $ 415.0  
Revenues           8.0            
Total operating expenses           $ 30.0            
Nicor Gas | QIP Rider                        
Public Utilities, General Disclosures [Line Items]                        
Infrastructure disallowed       $ 31.0                
Nicor Gas | Maximum                        
Public Utilities, General Disclosures [Line Items]                        
Infrastructure investment, annual customer rate increase                       4.00%
Infrastructure investment, annual customer rate increase in any given year                       5.50%
Virginia Natural Gas | SAVE                        
Public Utilities, General Disclosures [Line Items]                        
Program duration period             6 years          
Infrastructure replacement program, approved investment variance amount             $ 5.0          
Atlanta Gas Light                        
Public Utilities, General Disclosures [Line Items]                        
Gain contingency, unrecorded amount             22.0          
Annual proceeds from strategic economic development projects             15.0          
Approved annual recovery of capital investment   $ 600.0             286.0      
Chattanooga Gas                        
Public Utilities, General Disclosures [Line Items]                        
Program duration period                   7 years    
Pipeline replacement program, length of distribution main | mi                   73    
Total project capital cost forecast                   $ 118.0    
Operating Segments                        
Public Utilities, General Disclosures [Line Items]                        
Revenues             (26,059.0) (24,700.0) (28,835.0)      
Operating Segments | Southern Company Gas                        
Public Utilities, General Disclosures [Line Items]                        
Revenues             (4,447.0) (4,685.0) (5,937.0)      
Operating Segments | Gas distribution operations | Southern Company Gas                        
Public Utilities, General Disclosures [Line Items]                        
Gross property additions             1,700.0          
Revenues             $ (3,899.0) $ (4,105.0) $ (5,267.0)      
v3.25.0.1
REGULATORY MATTERS - GAS Schedule of Infrastructure Replacement Programs and Capital Projects (Details) - Southern Company Gas
$ in Millions
 12 Months Ended
Dec. 31, 2024
USD ($)
mi
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Public Utilities, General Disclosures [Line Items]      
Capital Expenditures in 2024 $ 186    
Capital Expenditures Since Project Inception $ 868    
Pipe Installed Since Project Inception (in miles) | mi 651    
Scope of Program (in miles) | mi 1,011    
SAVE      
Public Utilities, General Disclosures [Line Items]      
Capital Expenditures in 2024 $ 75    
Capital Expenditures Since Project Inception $ 561    
Pipe Installed Since Project Inception (in miles) | mi 598    
Scope of Program (in miles) | mi 938    
Program Duration 18 years    
System Reinforcement Rider      
Public Utilities, General Disclosures [Line Items]      
Capital Expenditures in 2024 $ 99 $ 104 $ 76
Capital Expenditures Since Project Inception $ 279    
Pipe Installed Since Project Inception (in miles) | mi 29    
Program Duration 6 years    
Pipeline Replacement Program      
Public Utilities, General Disclosures [Line Items]      
Capital Expenditures in 2024 $ 12    
Capital Expenditures Since Project Inception $ 28    
Pipe Installed Since Project Inception (in miles) | mi 24    
Scope of Program (in miles) | mi 73    
Program Duration 7 years    
v3.25.0.1
REGULATORY MATTERS - GAS Rate Proceedings and Deferral of Incremental COVID-19 Costs (Details) - USD ($)
$ in Millions
 1 Months Ended 3 Months Ended 12 Months Ended
Jan. 01, 2027
Jan. 01, 2026
Jan. 03, 2025
Jan. 01, 2025
Dec. 24, 2024
Aug. 01, 2024
Jul. 02, 2024
Jun. 07, 2024
Jan. 01, 2024
Jan. 01, 2023
Nov. 30, 2023
Aug. 31, 2023
Nov. 30, 2021
Apr. 30, 2021
Dec. 31, 2023
Jun. 30, 2023
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2019
Public Utilities, General Disclosures [Line Items]                                        
Net regulatory assets                             $ 6,523.0   $ 7,041.0 $ 6,523.0    
Nicor Gas                                        
Public Utilities, General Disclosures [Line Items]                                        
Public utilities, approved rate increase (decrease), amount                     $ 223.0                  
Authorized ROE                     9.51%           9.51%      
Public utilities, approved equity capital structure, percentage                     50.00%                  
Infrastructure disallowed                             69.0          
Pretax charge to income                             58.0 $ 38.0 $ (96.0)      
After tax charge to income                             44.0 $ 28.0 (72.0)      
Nicor Gas | Subsequent Event                                        
Public Utilities, General Disclosures [Line Items]                                        
Authorized ROE     10.35%                                  
Public utilities, approved equity capital structure, percentage     54.60%                                  
Requested rate increase (decrease), amount     $ 309.0                                  
Nicor Gas | Investing In Illinois Qualifying Infrastructure Plant                                        
Public Utilities, General Disclosures [Line Items]                                        
Infrastructure disallowed         $ 14.0           $ 126.8           63.0     $ 32.0
Nicor Gas | QIP Rider                                        
Public Utilities, General Disclosures [Line Items]                                        
Infrastructure disallowed                     31.0                  
Nicor Gas | Other Transmission and Distribution Capital Investments                                        
Public Utilities, General Disclosures [Line Items]                                        
Infrastructure disallowed                     $ 95.9                  
Atlanta Gas Light                                        
Public Utilities, General Disclosures [Line Items]                                        
Public utilities, approved rate increase (decrease), amount                                 $ (9.0) (7.0) $ (5.0)  
Authorized ROE                                 10.25%      
Public utilities, maximum base rate percentage                                 5.00%      
Integrated capacity delivery plan, capital budgets and related operations and maintenance spending, term                           10 years            
Approved rate decrease, percent                         10.00%              
Integrated capacity delivery plan, capital forecast plan, years one through three                         $ 1,700.0              
Approved annual recovery of capital investment             $ 600.0                       286.0  
Atlanta Gas Light | Minimum                                        
Public Utilities, General Disclosures [Line Items]                                        
Authorized ROE                                 10.05%      
Integrated capacity delivery plan, capital forecast plan, years one through ten                           $ 500.0            
Atlanta Gas Light | Maximum                                        
Public Utilities, General Disclosures [Line Items]                                        
Authorized ROE                                 10.45%      
Integrated capacity delivery plan, capital forecast plan, years one through ten                           $ 600.0            
Southern Company Gas                                        
Public Utilities, General Disclosures [Line Items]                                        
Pretax charge to income                                 $ 0.0 96.0 $ 0.0  
Requested rate increase (decrease), amount                 $ 53.0 $ 53.0                    
Net regulatory assets                             $ (2,225.0)   $ (2,252.0) $ (2,225.0)    
Southern Company Gas | Scenario, Forecast                                        
Public Utilities, General Disclosures [Line Items]                                        
Requested rate increase (decrease), amount $ 74.0 $ 73.0   $ 72.0                                
Southern Company Gas | SAVE                                        
Public Utilities, General Disclosures [Line Items]                                        
Approved infrastructure replacement program, approved investment amount, current fiscal year               $ 355.0                        
Infrastructure replacement program, approved investment variance amount               $ 5.0                        
Program duration period               5 years                        
Southern Company Gas | SAVE | 2029                                        
Public Utilities, General Disclosures [Line Items]                                        
Approved infrastructure replacement program, approved investment amount, current fiscal year               $ 70.0                        
Southern Company Gas | SAVE | 2027                                        
Public Utilities, General Disclosures [Line Items]                                        
Approved infrastructure replacement program, approved investment amount, current fiscal year               70.0                        
Southern Company Gas | SAVE | 2025                                        
Public Utilities, General Disclosures [Line Items]                                        
Approved infrastructure replacement program, approved investment amount, current fiscal year               70.0                        
Southern Company Gas | SAVE | 2028                                        
Public Utilities, General Disclosures [Line Items]                                        
Approved infrastructure replacement program, approved investment amount, current fiscal year               70.0                        
Southern Company Gas | SAVE | 2026                                        
Public Utilities, General Disclosures [Line Items]                                        
Approved infrastructure replacement program, approved investment amount, current fiscal year               $ 70.0                        
Virginia Natural Gas                                        
Public Utilities, General Disclosures [Line Items]                                        
Public utilities, approved rate increase (decrease), amount                       $ 48.0                
Authorized ROE                       9.70%         9.70%      
Public utilities, approved equity capital structure, percentage                       49.06%                
Requested rate increase (decrease), amount                   $ 69.0                    
Virginia Natural Gas | Virginia Commission                                        
Public Utilities, General Disclosures [Line Items]                                        
Authorized ROE           10.45%                            
Public utilities, approved equity capital structure, percentage           54.92%                            
Requested rate increase (decrease), amount           $ 63.0                            
Virginia Natural Gas | SAVE                                        
Public Utilities, General Disclosures [Line Items]                                        
Approved infrastructure replacement program, approved investment amount, current fiscal year                                 $ 365.0      
Infrastructure replacement program, approved investment variance amount                                 $ 5.0      
Program duration period                                 6 years      
Virginia Natural Gas | SAVE | Virginia Commission                                        
Public Utilities, General Disclosures [Line Items]                                        
Requested rate increase (decrease), amount           $ 17.0                            
Virginia Natural Gas | SAVE | Year 2023                                        
Public Utilities, General Disclosures [Line Items]                                        
Approved infrastructure replacement program, approved investment amount, current fiscal year                                 $ 70.0      
Virginia Natural Gas | SAVE | Year 2022                                        
Public Utilities, General Disclosures [Line Items]                                        
Approved infrastructure replacement program, approved investment amount, current fiscal year                                 70.0      
Virginia Natural Gas | SAVE | Year 2024                                        
Public Utilities, General Disclosures [Line Items]                                        
Approved infrastructure replacement program, approved investment amount, current fiscal year                                 $ 70.0      
v3.25.0.1
REGULATORY MATTERS - GAS Schedule of Unrecognized Ratemaking Amounts (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Schedule of Regulatory Assets and Liabilities [Line Items]      
Regulatory asset   $ 66 $ 216
Regulatory Asset Off Balance Sheet | Atlanta Gas Light      
Schedule of Regulatory Assets and Liabilities [Line Items]      
Regulatory asset $ 11 23  
Regulatory Asset Off Balance Sheet | Virginia Natural Gas      
Schedule of Regulatory Assets and Liabilities [Line Items]      
Regulatory asset 10 10  
Regulatory Asset Off Balance Sheet | Chattanooga Gas      
Schedule of Regulatory Assets and Liabilities [Line Items]      
Regulatory asset 7 7  
Regulatory Asset Off Balance Sheet | Nicor Gas      
Schedule of Regulatory Assets and Liabilities [Line Items]      
Regulatory asset 0 3  
Regulatory Asset Off Balance Sheet | Southern Company Gas      
Schedule of Regulatory Assets and Liabilities [Line Items]      
Regulatory asset $ 28 $ 43  
v3.25.0.1
REGULATORY MATTERS - GAS Capital Projects Schedule of QIP (Details) - Nicor Gas - USD ($)
$ in Millions
 1 Months Ended 3 Months Ended 12 Months Ended
Dec. 24, 2024
Nov. 30, 2023
Dec. 31, 2023
Dec. 31, 2024
Dec. 31, 2019
Commitments [Line Items]          
Disallowed     $ 69.0    
Investing In Illinois Qualifying Infrastructure Plant          
Commitments [Line Items]          
Capital Investments       $ 3,228.0  
Disallowed $ 14.0 $ 126.8   63.0 $ 32.0
Investing In Illinois Qualifying Infrastructure Plant | Complete          
Commitments [Line Items]          
Capital Investments       1,246.0  
Disallowed       0.0  
Investing In Illinois Qualifying Infrastructure Plant | Complete, Appealed          
Commitments [Line Items]          
Capital Investments       415.0  
Disallowed       32.0  
Investing In Illinois Qualifying Infrastructure Plant | Filed March 2021          
Commitments [Line Items]          
Capital Investments       402.0  
Investing In Illinois Qualifying Infrastructure Plant | Filed March 2022          
Commitments [Line Items]          
Capital Investments       392.0  
Investing In Illinois Qualifying Infrastructure Plant | Filed March 2023          
Commitments [Line Items]          
Capital Investments       408.0  
Disallowed       6.0  
Investing In Illinois Qualifying Infrastructure Plant | Filed March 2024          
Commitments [Line Items]          
Capital Investments       365.0  
Disallowed       $ 25.0  
v3.25.0.1
CONTINGENCIES, COMMITMENTS, AND GUARANTEES - SO Litigation (Details) - Kemper County energy facility assets, net - Mississippi Power - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2016
Dec. 31, 2010
Loss Contingencies [Line Items]      
Government grants expected   $ 137 $ 270
Government grants received $ 387    
v3.25.0.1
CONTINGENCIES, COMMITMENTS, AND GUARANTEES - GPC Litigation (Details) - claim
 1 Months Ended
Jan. 31, 2023
Feb. 28, 2022
Oct. 31, 2021
Class Action Lawsuit | Pending Litigation | Georgia Power      
Loss Contingencies [Line Items]      
Number of additional complaints filed 8 8 8
v3.25.0.1
CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Environmental Remediation (Details) - USD ($)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Georgia Power      
Environmental Exit Cost [Line Items]      
Costs recovered annually $ 5,000,000 $ 5,000,000 $ 12,000,000
Environmental remediation liability, current 13,000,000 14,000,000  
Accrued environmental remediation 0 0  
Under recovered environmental remediation costs, other regulatory assets, current 5,000,000 5,000,000  
Under recovered environmental remediation costs, other regulatory assets, deferred 11,000,000 15,000,000  
Southern Company Gas      
Environmental Exit Cost [Line Items]      
Environmental remediation liability, current 24,000,000 30,000,000  
Accrued environmental remediation 198,000,000 192,000,000  
Under recovered environmental remediation costs, other regulatory assets, current 32,000,000 40,000,000  
Under recovered environmental remediation costs, other regulatory assets, deferred 201,000,000 195,000,000  
Alabama Power      
Environmental Exit Cost [Line Items]      
Environmental remediation liability, current 0 0  
Southern Company      
Environmental Exit Cost [Line Items]      
Environmental remediation liability, current 37,000,000 44,000,000  
Accrued environmental remediation 198,000,000 192,000,000  
Under recovered environmental remediation costs, other regulatory assets, current 37,000,000 45,000,000  
Under recovered environmental remediation costs, other regulatory assets, deferred $ 212,000,000 $ 210,000,000  
Environmental Loss Contingency, Current, Statement of Financial Position [Extensible Enumeration] Other Liabilities, Current Other Liabilities, Current  
v3.25.0.1
CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Nuclear Fuel Disposal Costs and Nuclear Insurance (Details)
$ in Millions
 12 Months Ended 108 Months Ended
Dec. 31, 2024
USD ($)
plant
Dec. 31, 2019
USD ($)
Jointly Owned Utility Plant Interests [Line Items]    
Maximum fund for public liability claims arising from a single nuclear incident under price - anderson amendments act $ 16,300  
Maximum insurance coverage provided by American Nuclear Insurers to each nuclear plant 500  
Maximum amount that a company could be assessed per incident for each licensed reactor 166  
Maximum aggregate amount that a reactor can assess in a calendar period for each incident $ 25  
Block period considered for inflation adjustment against maximum assessment per reactor 5 years  
Maximum deductible waiting period 182 days  
Maximum coverage per occurrence per unit limit to obtain replacement power $ 490  
Aggregate payment for claims resulting from terrorist acts in one year period $ 3,200  
Alabama Power and Georgia Power    
Jointly Owned Utility Plant Interests [Line Items]    
Number of nuclear fuel plants | plant 3  
Maximum property damage insurance provided to nuclear generating facilities $ 1,500  
Maximum additional coverage provided for losses under excess insurance 1,250  
Maximum additional coverage provided for losses under excess insurance, non-nuclear losses $ 750  
Elected deductible waiting period 84 days  
Alabama Power    
Jointly Owned Utility Plant Interests [Line Items]    
Maximum assessment, excluding any applicable state premium taxes $ 332  
Maximum aggregate amount to be paid in one year 49  
Current maximum annual assessments under NEIL policies 60  
Alabama Power | Positive Outcome of Litigation    
Jointly Owned Utility Plant Interests [Line Items]    
Outstanding claims   $ 100
Georgia Power    
Jointly Owned Utility Plant Interests [Line Items]    
Maximum assessment, excluding any applicable state premium taxes 473  
Maximum aggregate amount to be paid in one year 71  
Current maximum annual assessments under NEIL policies $ 80  
Georgia Power | Court Of Federal Claims    
Jointly Owned Utility Plant Interests [Line Items]    
Litigation settlement   $ 121
v3.25.0.1
CONTINGENCIES, COMMITMENTS, AND GUARANTEES - MPC and Traditional Electric Operating Companies Other Matters (Details) - USD ($)
$ in Millions
 12 Months Ended 60 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2025
Loss Contingencies [Line Items]        
Period costs $ 130 $ 90    
Mississippi Power        
Loss Contingencies [Line Items]        
Period costs 0 0    
Alabama Power        
Loss Contingencies [Line Items]        
Period costs 8 0    
Kemper County energy facility assets, net | Mississippi Power        
Loss Contingencies [Line Items]        
Pre-tax charge to income 12 17 $ 15  
After tax charge to income $ 9 $ 12 $ 12  
Scenario, Forecast | Kemper County energy facility assets, net | Mississippi Power | Maximum        
Loss Contingencies [Line Items]        
Period costs       $ 15
v3.25.0.1
CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Commitments (Details) - Georgia Power - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Plant Vogtle (nuclear) Units 1 and 2      
Recorded Unconditional Purchase Obligation [Line Items]      
Capacity payments $ 4 $ 3 $ 4
Total 35    
Recorded unconditional purchase obligation, year one 3    
Recorded unconditional purchase obligation, year four 2    
Recorded unconditional purchase obligation, year three 2    
Recorded unconditional purchase obligation, year two 2    
Recorded unconditional purchase obligation, after year five $ 24    
MEAG Power      
Recorded Unconditional Purchase Obligation [Line Items]      
Percent Ownership 5.00%    
v3.25.0.1
CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Guarantees (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Recorded Unconditional Purchase Obligation [Line Items]    
Notes payable $ 1,338 $ 2,314
Alabama Power    
Recorded Unconditional Purchase Obligation [Line Items]    
Jointly owned affiliate equity 56  
Jointly owned affiliate long term debt 80  
Notes payable 0 $ 40
SEGCO | Alabama Power    
Recorded Unconditional Purchase Obligation [Line Items]    
Guarantee of unsecured senior notes 100  
Notes payable $ 0  
v3.25.0.1
REVENUE FROM CONTRACTS WITH CUSTOMERS - Disaggregate Revenue Sources (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers $ 26,764 $ 24,828 $ 25,941
Total operating revenues 26,724 25,253 29,279
Retail electric revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 18,877 16,894 15,839
Residential      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 8,276 7,309 6,604
Commercial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 6,585 5,860 5,369
Industrial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 3,892 3,613 3,764
Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 124 112 102
Natural gas distribution revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 3,815 4,039 5,218
Residential      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 1,753 1,981 2,843
Commercial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 417 505 763
Transportation      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 1,295 1,184 1,186
Industrial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 34 45 84
Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 316 324 342
Wholesale electric revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 1,926 1,981 3,120
PPA energy revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 1,059 1,107 2,274
PPA capacity revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 641 624 596
Non-PPA revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 226 250 250
Other natural gas revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 525 559 687
Gas marketing services      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 507 528 636
Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 18 31 51
Other revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 1,621 1,355 1,077
Other revenue sources      
Disaggregation of Revenue [Line Items]      
Other (40) 425 3,338
Alabama Power      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 7,623 7,233 6,921
Total operating revenues 7,554 7,050 7,817
Alabama Power | Retail electric revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 6,930 6,565 5,844
Alabama Power | Residential      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 3,133 2,904 2,638
Alabama Power | Commercial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 2,042 1,928 1,685
Alabama Power | Industrial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 1,742 1,721 1,507
Alabama Power | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 13 12 14
Alabama Power | Natural gas distribution revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Alabama Power | Residential      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Alabama Power | Commercial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Alabama Power | Transportation      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Alabama Power | Industrial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Alabama Power | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Alabama Power | Wholesale electric revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 453 455 883
Alabama Power | PPA energy revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 206 234 489
Alabama Power | PPA capacity revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 108 156 194
Alabama Power | Non-PPA revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 139 65 200
Alabama Power | Other natural gas revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Alabama Power | Gas marketing services      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Alabama Power | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Alabama Power | Other revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 240 213 194
Alabama Power | Other revenue sources      
Disaggregation of Revenue [Line Items]      
Other (69) (183) 896
Georgia Power      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 11,920 10,129 9,702
Total operating revenues 11,331 10,118 11,584
Georgia Power | Retail electric revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 10,964 9,378 9,049
Georgia Power | Residential      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 4,835 4,105 3,664
Georgia Power | Commercial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 4,219 3,624 3,385
Georgia Power | Industrial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 1,808 1,558 1,921
Georgia Power | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 102 91 79
Georgia Power | Natural gas distribution revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Georgia Power | Residential      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Georgia Power | Commercial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Georgia Power | Transportation      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Georgia Power | Industrial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Georgia Power | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Georgia Power | Wholesale electric revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 235 173 207
Georgia Power | PPA energy revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 94 87 130
Georgia Power | PPA capacity revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 136 51 47
Georgia Power | Non-PPA revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 5 35 30
Georgia Power | Other natural gas revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Georgia Power | Gas marketing services      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Georgia Power | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Georgia Power | Other revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 721 578 446
Georgia Power | Other revenue sources      
Disaggregation of Revenue [Line Items]      
Other (589) (11) 1,882
Mississippi Power      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 1,477 1,462 1,703
Total operating revenues 1,463 1,474 1,694
Mississippi Power | Retail electric revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 983 951 946
Mississippi Power | Residential      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 308 300 302
Mississippi Power | Commercial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 324 308 299
Mississippi Power | Industrial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 342 334 336
Mississippi Power | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 9 9 9
Mississippi Power | Natural gas distribution revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Mississippi Power | Residential      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Mississippi Power | Commercial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Mississippi Power | Transportation      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Mississippi Power | Industrial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Mississippi Power | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Mississippi Power | Wholesale electric revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 442 472 710
Mississippi Power | PPA energy revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 4 20 16
Mississippi Power | PPA capacity revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 63 45 4
Mississippi Power | Non-PPA revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 375 407 690
Mississippi Power | Other natural gas revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Mississippi Power | Gas marketing services      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Mississippi Power | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Mississippi Power | Other revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 52 39 47
Mississippi Power | Other revenue sources      
Disaggregation of Revenue [Line Items]      
Other (14) 12 (9)
Southern Power      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 1,445 1,630 2,805
Total operating revenues 2,014 2,189 3,369
Southern Power | Retail electric revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Residential      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Commercial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Industrial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Natural gas distribution revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Residential      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Commercial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Transportation      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Industrial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Wholesale electric revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 1,408 1,575 2,769
Southern Power | PPA energy revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 778 790 1,673
Southern Power | PPA capacity revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 400 376 356
Southern Power | Non-PPA revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 230 409 740
Southern Power | Other natural gas revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Gas marketing services      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Power | Other revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 37 55 36
Southern Power | Other revenue sources      
Disaggregation of Revenue [Line Items]      
Other 569 559 564
Southern Company Gas      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 4,340 4,598 5,905
Total operating revenues 4,456 4,702 5,962
Southern Company Gas | Retail electric revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Company Gas | Residential      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Company Gas | Commercial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Company Gas | Industrial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Company Gas | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Company Gas | Natural gas distribution revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 3,815 4,039 5,218
Southern Company Gas | Residential      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 1,753 1,981 2,843
Southern Company Gas | Commercial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 417 505 763
Southern Company Gas | Transportation      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 1,295 1,184 1,186
Southern Company Gas | Industrial      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 34 45 84
Southern Company Gas | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 316 324 342
Southern Company Gas | Wholesale electric revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Company Gas | PPA energy revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Company Gas | PPA capacity revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Company Gas | Non-PPA revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Company Gas | Other natural gas revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 525 559 687
Southern Company Gas | Gas marketing services      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 507 528 636
Southern Company Gas | Other      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 18 31 51
Southern Company Gas | Other revenues      
Disaggregation of Revenue [Line Items]      
Revenue from contracts with customers 0 0 0
Southern Company Gas | Other revenue sources      
Disaggregation of Revenue [Line Items]      
Other $ 116 $ 104 $ 57
v3.25.0.1
REVENUE FROM CONTRACTS WITH CUSTOMERS - Contract Balances (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Disaggregation of Revenue [Line Items]    
Accounts Receivable $ 3,048 $ 2,820
Contract Assets 323 271
Contract Liabilities 140 116
Contract with customer, liability, revenue recognized 98 36
Unregulated Distributed Generation    
Disaggregation of Revenue [Line Items]    
Contract Assets 67 91
Contract Liabilities 95 115
Alabama Power    
Disaggregation of Revenue [Line Items]    
Accounts Receivable 783 821
Contract Assets 3 2
Contract Liabilities 11 0
Georgia Power    
Disaggregation of Revenue [Line Items]    
Accounts Receivable 1,244 1,011
Contract Assets 184 121
Contract Liabilities 34 1
Mississippi Power    
Disaggregation of Revenue [Line Items]    
Accounts Receivable 113 90
Contract Assets 0 0
Contract Liabilities 0 0
Southern Power    
Disaggregation of Revenue [Line Items]    
Accounts Receivable 106 122
Contract Assets 0 0
Contract Liabilities 2 4
Southern Company Gas    
Disaggregation of Revenue [Line Items]    
Accounts Receivable 660 684
Contract Assets 72 56
Contract Liabilities 3 $ 0
Southern Company Gas | Energy Efficiency Enhancement And Upgrade    
Disaggregation of Revenue [Line Items]    
Contract Liabilities $ 68  
v3.25.0.1
REVENUE FROM CONTRACTS WITH CUSTOMERS - Performance Obligations (Details)
$ in Millions
Dec. 31, 2024
USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 937
Expected timing of satisfaction 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 427
Expected timing of satisfaction 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 371
Expected timing of satisfaction 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 343
Expected timing of satisfaction 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 309
Expected timing of satisfaction 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 2,636
Expected timing of satisfaction
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 11
Expected timing of satisfaction 1 year
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
Expected timing of satisfaction 1 year
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
Expected timing of satisfaction 1 year
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
Expected timing of satisfaction 1 year
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
Expected timing of satisfaction 1 year
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
Expected timing of satisfaction
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 69
Expected timing of satisfaction 1 year
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 30
Expected timing of satisfaction 1 year
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 15
Expected timing of satisfaction 1 year
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 16
Expected timing of satisfaction 1 year
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 2
Expected timing of satisfaction 1 year
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 27
Expected timing of satisfaction
Mississippi Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 63
Expected timing of satisfaction 1 year
Mississippi Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 66
Expected timing of satisfaction 1 year
Mississippi Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 69
Expected timing of satisfaction 1 year
Mississippi Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 73
Expected timing of satisfaction 1 year
Mississippi Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
Expected timing of satisfaction 1 year
Mississippi Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
Expected timing of satisfaction
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 340
Expected timing of satisfaction 1 year
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 331
Expected timing of satisfaction 1 year
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 340
Expected timing of satisfaction 1 year
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 316
Expected timing of satisfaction 1 year
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 312
Expected timing of satisfaction 1 year
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 2,609
Expected timing of satisfaction
Southern Company Gas | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 2
Expected timing of satisfaction 1 year
Southern Company Gas | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
Expected timing of satisfaction 1 year
Southern Company Gas | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
Expected timing of satisfaction 1 year
Southern Company Gas | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
Expected timing of satisfaction 1 year
Southern Company Gas | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
Expected timing of satisfaction 1 year
Southern Company Gas | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
Expected timing of satisfaction
v3.25.0.1
PROPERTY, PLANT, AND EQUIPMENT - Property, Plant and Equipment (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Electric utilities:    
Generation $ 61,292 $ 57,325
Transmission 16,280 15,561
Distribution 28,678 26,482
General/other 6,547 6,305
Electric utilities' plant in service 112,797 105,673
Southern Company Gas:    
Natural gas transportation and distribution 18,896 17,798
Storage facilities 1,748 1,565
Other 1,694 1,477
Southern Company Gas plant in service 22,338 20,840
Other plant in service 2,008 1,915
Total plant in service 137,143 128,428
Alabama Power    
Electric utilities:    
Generation 16,801 16,584
Transmission 6,449 6,152
Distribution 10,373 9,775
General/other 2,878 2,918
Electric utilities' plant in service 36,501 35,429
Southern Company Gas:    
Natural gas transportation and distribution 0 0
Storage facilities 0 0
Other 0 0
Southern Company Gas plant in service 0 0
Other plant in service 0 0
Total plant in service 36,501 35,429
Georgia Power    
Electric utilities:    
Generation 26,089 22,587
Transmission 8,800 8,402
Distribution 16,887 15,380
General/other 3,260 3,001
Electric utilities' plant in service 55,036 49,370
Southern Company Gas:    
Natural gas transportation and distribution 0 0
Storage facilities 0 0
Other 0 0
Southern Company Gas plant in service 0 0
Other plant in service 0 0
Total plant in service 55,036 49,370
Mississippi Power    
Electric utilities:    
Generation 2,946 2,909
Transmission 989 966
Distribution 1,418 1,327
General/other 344 321
Electric utilities' plant in service 5,697 5,523
Southern Company Gas:    
Natural gas transportation and distribution 0 0
Storage facilities 0 0
Other 0 0
Southern Company Gas plant in service 0 0
Other plant in service 0 0
Total plant in service 5,697 5,523
Southern Power    
Electric utilities:    
Generation 14,920 14,649
Transmission 0 0
Distribution 0 0
General/other 41 41
Electric utilities' plant in service 14,961 14,690
Southern Company Gas:    
Natural gas transportation and distribution 0 0
Storage facilities 0 0
Other 0 0
Southern Company Gas plant in service 0 0
Other plant in service 0 0
Total plant in service 14,961 14,690
Southern Company Gas    
Electric utilities:    
Generation 0 0
Transmission 0 0
Distribution 0 0
General/other 0 0
Electric utilities' plant in service 0 0
Southern Company Gas:    
Natural gas transportation and distribution 18,896 17,798
Storage facilities 1,748 1,565
Other 1,694 1,477
Southern Company Gas plant in service 22,338 20,840
Other plant in service 0 0
Total plant in service $ 22,338 $ 20,840
v3.25.0.1
PROPERTY, PLANT, AND EQUIPMENT - Additional Information (Narrative) (Details) - USD ($)
$ in Millions
 1 Months Ended 12 Months Ended
Feb. 13, 2025
Oct. 25, 2024
Jan. 01, 2024
Jan. 01, 2023
Jun. 30, 2023
May 31, 2023
Dec. 31, 2024
Dec. 31, 2022
Dec. 31, 2023
Property, Plant and Equipment [Line Items]                  
Regulatory asset amortization period             4 years    
Less: Accumulated depreciation             $ 40,126   $ 37,725
Utility plant in service                  
Property, Plant and Equipment [Line Items]                  
Less: Accumulated depreciation             38,900   36,600
Other plant in service                  
Property, Plant and Equipment [Line Items]                  
Less: Accumulated depreciation             $ 1,200   1,100
Maximum | Other plant in service                  
Property, Plant and Equipment [Line Items]                  
Depreciation period of original cost             40 years    
Alabama Power                  
Property, Plant and Equipment [Line Items]                  
Requested rate increase (decrease), amount         $ 78        
Less: Accumulated depreciation             $ 11,741   11,131
Georgia Power                  
Property, Plant and Equipment [Line Items]                  
Requested rate increase (decrease), amount           $ 1,100   $ 14,000  
Less: Accumulated depreciation             14,806   13,955
Southern Company Gas                  
Property, Plant and Equipment [Line Items]                  
Requested rate increase (decrease), amount     $ 53 $ 53          
Less: Accumulated depreciation             5,887   5,534
Southern Company Gas | Utility plant in service                  
Property, Plant and Equipment [Line Items]                  
Less: Accumulated depreciation             5,600   5,300
Southern Company Gas | Other plant in service                  
Property, Plant and Equipment [Line Items]                  
Less: Accumulated depreciation             $ 252   210
Southern Company Gas | Maximum | Transportation equipment                  
Property, Plant and Equipment [Line Items]                  
Depreciation period of original cost             10 years    
Southern Company Gas | Maximum | Storage facilities                  
Property, Plant and Equipment [Line Items]                  
Depreciation period of original cost             40 years    
Southern Company Gas | Maximum | Other assets                  
Property, Plant and Equipment [Line Items]                  
Depreciation period of original cost             78 years    
Southern Company Gas | Minimum | Transportation equipment                  
Property, Plant and Equipment [Line Items]                  
Depreciation period of original cost             5 years    
Southern Company Gas | Minimum | Storage facilities                  
Property, Plant and Equipment [Line Items]                  
Depreciation period of original cost             5 years    
Mississippi Power                  
Property, Plant and Equipment [Line Items]                  
Requested rate increase (decrease), amount   $ 11              
Less: Accumulated depreciation             $ 1,833   $ 1,792
Mississippi Power | Subsequent Event                  
Property, Plant and Equipment [Line Items]                  
Requested rate increase (decrease), amount $ 8                
Mississippi Power | Chevron Products Company [Member]                  
Property, Plant and Equipment [Line Items]                  
Net book value of co-generation assets             $ 139    
Plant Farley | Alabama Power | Nuclear Outage                  
Property, Plant and Equipment [Line Items]                  
Regulatory asset amortization period             18 months    
Plant Hatch Units 1 and 2 | Georgia Power | Nuclear Outage | Maximum                  
Property, Plant and Equipment [Line Items]                  
Regulatory asset amortization period             24 months    
Plant Vogtle Nuclear Units One , Two, and Three | Georgia Power | Nuclear Outage                  
Property, Plant and Equipment [Line Items]                  
Regulatory asset amortization period             18 months    
v3.25.0.1
PROPERTY, PLANT, AND EQUIPMENT - Deferred Cloud Implementation Costs (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Property, Plant and Equipment [Line Items]      
Total deferred charges and other assets $ 19,599 $ 19,069  
Deferred Cloud Implementation Costs      
Property, Plant and Equipment [Line Items]      
Total deferred charges and other assets 321 325  
Amortization 56 46 $ 29
Alabama Power      
Property, Plant and Equipment [Line Items]      
Total deferred charges and other assets 5,175 5,090  
Alabama Power | Deferred Cloud Implementation Costs      
Property, Plant and Equipment [Line Items]      
Total deferred charges and other assets 92 85  
Amortization 17 11 8
Georgia Power      
Property, Plant and Equipment [Line Items]      
Total deferred charges and other assets 11,142 10,200  
Georgia Power | Deferred Cloud Implementation Costs      
Property, Plant and Equipment [Line Items]      
Total deferred charges and other assets 111 99  
Amortization 22 19 12
Mississippi Power      
Property, Plant and Equipment [Line Items]      
Total deferred charges and other assets 841 887  
Mississippi Power | Deferred Cloud Implementation Costs      
Property, Plant and Equipment [Line Items]      
Total deferred charges and other assets 13 13  
Amortization 0 0 0
Southern Power      
Property, Plant and Equipment [Line Items]      
Total deferred charges and other assets 950 998  
Southern Power | Deferred Cloud Implementation Costs      
Property, Plant and Equipment [Line Items]      
Total deferred charges and other assets 12 15  
Amortization 0 0 $ 0
Southern Company Gas      
Property, Plant and Equipment [Line Items]      
Total deferred charges and other assets 902 890  
Southern Company Gas | Deferred Cloud Implementation Costs      
Property, Plant and Equipment [Line Items]      
Total deferred charges and other assets $ 35 $ 43  
v3.25.0.1
PROPERTY, PLANT, AND EQUIPMENT - Composite Straight-Line Rates (Details) - Utility plant in service
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Alabama Power      
Property, Plant and Equipment [Line Items]      
Composite rate 4.20% 4.10% 2.70%
Georgia Power      
Property, Plant and Equipment [Line Items]      
Composite rate 3.40% 3.80% 3.30%
Mississippi Power      
Property, Plant and Equipment [Line Items]      
Composite rate 3.30% 3.40% 3.40%
Southern Company Gas      
Property, Plant and Equipment [Line Items]      
Composite rate 2.90% 2.70% 2.70%
v3.25.0.1
PROPERTY, PLANT, AND EQUIPMENT - Southern Power Useful Lives (Details) - Southern Power - Maximum
Dec. 31, 2024
Natural Gas Generating Facility  
Property, Plant and Equipment [Line Items]  
Useful life 50 years
Solar Generating Facility  
Property, Plant and Equipment [Line Items]  
Useful life 35 years
Wind Generating Facility  
Property, Plant and Equipment [Line Items]  
Useful life 35 years
v3.25.0.1
PROPERTY, PLANT, AND EQUIPMENT - Ownership and Investment in Jointly-Owned Facilities (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2024
USD ($)
mi
Alabama Power  
Other Ownership Interests [Line Items]  
Percent Ownership 14.00%
Alabama Power | Plant Greene County (natural gas) Units 1 and 2  
Other Ownership Interests [Line Items]  
Percent Ownership 60.00%
Plant in Service $ 192
Accumulated Depreciation 140
CWIP $ 1
Alabama Power | Plant Miller (coal) Units 1 and 2  
Other Ownership Interests [Line Items]  
Percent Ownership 91.80%
Plant in Service $ 2,180
Accumulated Depreciation 829
CWIP 7
Georgia Power | Plant Hatch (nuclear) Units 1 and 2  
Other Ownership Interests [Line Items]  
Plant in Service 1,464
Accumulated Depreciation 604
CWIP $ 66
Georgia Power | Plant Vogtle (nuclear) Units 1 and 2  
Other Ownership Interests [Line Items]  
Percent Ownership 45.70%
Plant in Service $ 3,621
Accumulated Depreciation 2,342
CWIP $ 162
Georgia Power | Plant Vogtle (nuclear) Units 3 and 4  
Other Ownership Interests [Line Items]  
Percent Ownership 45.70%
Plant in Service $ 7,953
Accumulated Depreciation 119
CWIP $ 45
Georgia Power | Plant Scherer (coal) Units 1 and 2  
Other Ownership Interests [Line Items]  
Percent Ownership 8.40%
Plant in Service $ 289
Accumulated Depreciation 140
CWIP $ 4
Georgia Power | Plant Scherer (coal) Unit 3  
Other Ownership Interests [Line Items]  
Percent Ownership 75.00%
Plant in Service $ 1,316
Accumulated Depreciation 720
CWIP $ 22
Georgia Power | Rocky Mountain (pumped storage)  
Other Ownership Interests [Line Items]  
Percent Ownership 25.40%
Plant in Service $ 182
Accumulated Depreciation 160
CWIP $ 6
Mississippi Power | Plant Greene County (natural gas) Units 1 and 2  
Other Ownership Interests [Line Items]  
Percent Ownership 40.00%
Plant in Service $ 125
Accumulated Depreciation 88
CWIP $ 2
Mississippi Power | Plant Daniel (coal) Units 1 and 2  
Other Ownership Interests [Line Items]  
Percent Ownership 50.00%
Plant in Service $ 791
Accumulated Depreciation 286
CWIP $ 3
Southern Company Gas | Dalton Pipeline (natural gas pipeline)  
Other Ownership Interests [Line Items]  
Percent Ownership 50.00%
Plant in Service $ 271
Accumulated Depreciation 32
CWIP $ 1
Pipeline infrastructure (miles) | mi 115
Agreement to lease undivided ownership (percent) 50.00%
Future minimum payments receivable $ 26
v3.25.0.1
ASSET RETIREMENT OBLIGATIONS - Details of AROs Included in the Balance Sheets (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Balance at beginning of year $ 10,317 $ 10,840
Liabilities incurred 130 90
Liabilities settled (566) (617)
Accretion expense 400 403
Cash flow revisions (347) (399)
Balance at end of year 9,934 10,317
Alabama Power    
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Balance at beginning of year 4,158 4,287
Liabilities incurred 8 0
Liabilities settled (254) (270)
Accretion expense 153 156
Cash flow revisions (7) (15)
Balance at end of year 4,058 4,158
Georgia Power    
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Balance at beginning of year 5,665 6,034
Liabilities incurred 120 90
Liabilities settled (270) (304)
Accretion expense 232 230
Cash flow revisions (332) (385)
Balance at end of year 5,415 5,665
Mississippi Power    
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Balance at beginning of year 168 179
Liabilities incurred 0 0
Liabilities settled (17) (18)
Accretion expense 5 5
Cash flow revisions (8) 2
Balance at end of year 148 168
Southern Power    
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Balance at beginning of year 150 144
Liabilities incurred 2 0
Liabilities settled 0 0
Accretion expense 7 6
Cash flow revisions 0 0
Balance at end of year $ 159 $ 150
v3.25.0.1
ASSET RETIREMENT OBLIGATIONS - Narrative (Details) - USD ($)
 1 Months Ended 12 Months Ended
May 01, 2024
Aug. 01, 2023
Nov. 30, 2024
Sep. 30, 2024
Nov. 30, 2023
Sep. 30, 2023
Jun. 30, 2023
Dec. 31, 2024
Dec. 31, 2022
Dec. 31, 2019
Feb. 14, 2024
Dec. 31, 2023
Mar. 06, 2023
Jointly Owned Utility Plant Interests [Line Items]                          
Asset retirement obligations               $ 9,934,000,000 $ 10,840,000,000     $ 10,317,000,000  
Plant Vogtle Units 3 and 4                          
Jointly Owned Utility Plant Interests [Line Items]                          
Asset retirement obligations                         $ 90,000,000
Plant Vogtle Unit 4                          
Jointly Owned Utility Plant Interests [Line Items]                          
Asset retirement obligations                     $ 118,000,000    
Alabama Power                          
Jointly Owned Utility Plant Interests [Line Items]                          
Decrease to ARO             $ 15,000,000            
Asset retirement obligations               4,058,000,000 4,287,000,000     4,158,000,000  
Alabama Power | Internal reserves                          
Jointly Owned Utility Plant Interests [Line Items]                          
Accumulated provisions for decommissioning               $ 12,000,000       13,000,000  
Alabama Power | Plant Farley                          
Jointly Owned Utility Plant Interests [Line Items]                          
Estimated inflation rate               4.50%          
Estimated trust earnings rate               7.00%          
Alabama Power | Plant Farley                          
Jointly Owned Utility Plant Interests [Line Items]                          
Site-specific estimate of decommissioning costs, period of updates made               5 years          
Georgia Power                          
Jointly Owned Utility Plant Interests [Line Items]                          
Decrease to ARO     $ 60,000,000 $ 389,000,000 $ 210,000,000 $ 175,000,000              
Asset retirement obligations               $ 5,415,000,000 6,034,000,000     5,665,000,000  
Georgia Power | Plant Hatch                          
Jointly Owned Utility Plant Interests [Line Items]                          
Estimated inflation rate               2.50%          
Estimated trust earnings rate               4.50%          
Georgia Power | Plant Vogtle Units 3 and 4                          
Jointly Owned Utility Plant Interests [Line Items]                          
Estimated inflation rate               2.30%          
Estimated trust earnings rate               4.30%          
Georgia Power | Plant Hatch and Plant Vogtle Units 1 And 2                          
Jointly Owned Utility Plant Interests [Line Items]                          
Annual decommissioning cost for ratemaking                 0 $ 4,000,000      
Georgia Power | Plant Vogtle Units 3 and 4                          
Jointly Owned Utility Plant Interests [Line Items]                          
Annual decommissioning cost for ratemaking   $ 8,000,000                      
Georgia Power | Plant Vogtle Unit 4                          
Jointly Owned Utility Plant Interests [Line Items]                          
Annual decommissioning cost for ratemaking $ 8,000,000                        
Mississippi Power                          
Jointly Owned Utility Plant Interests [Line Items]                          
Asset retirement obligations               $ 148,000,000 $ 179,000,000     $ 168,000,000  
v3.25.0.1
ASSET RETIREMENT OBLIGATIONS - Investment Securities in the Funds (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Marketable Securities [Line Items]    
Total investment securities in the Funds $ 2,621 $ 2,422
Equity securities    
Marketable Securities [Line Items]    
Total investment securities in the Funds 1,413 1,288
Debt securities    
Marketable Securities [Line Items]    
Total investment securities in the Funds 976 895
Other securities    
Marketable Securities [Line Items]    
Total investment securities in the Funds 232 239
Alabama Power    
Marketable Securities [Line Items]    
Total investment securities in the Funds 1,385 1,259
Alabama Power | Equity securities    
Marketable Securities [Line Items]    
Total investment securities in the Funds 848 796
Alabama Power | Debt securities    
Marketable Securities [Line Items]    
Total investment securities in the Funds 335 277
Alabama Power | Other securities    
Marketable Securities [Line Items]    
Total investment securities in the Funds 202 186
Georgia Power    
Marketable Securities [Line Items]    
Total investment securities in the Funds 1,236 1,163
Georgia Power | Equity securities    
Marketable Securities [Line Items]    
Total investment securities in the Funds 565 492
Georgia Power | Debt securities    
Marketable Securities [Line Items]    
Total investment securities in the Funds 641 618
Georgia Power | Other securities    
Marketable Securities [Line Items]    
Total investment securities in the Funds $ 30 $ 53
v3.25.0.1
ASSET RETIREMENT OBLIGATIONS - Fair Value Increases (Decreases) of the Funds (Details) - Securities held in the Funds - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Fair value increases (decreases)      
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]      
Fair value increases (decreases) of the Funds $ 229 $ 281 $ (360)
Unrealized gains (losses)      
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]      
Fair value increases (decreases) of the Funds 113 241 (391)
Alabama Power | Fair value increases (decreases)      
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]      
Fair value increases (decreases) of the Funds 143 157 (171)
Alabama Power | Unrealized gains (losses)      
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]      
Fair value increases (decreases) of the Funds 64 119 (204)
Georgia Power | Fair value increases (decreases)      
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]      
Fair value increases (decreases) of the Funds 86 124 (189)
Georgia Power | Unrealized gains (losses)      
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]      
Fair value increases (decreases) of the Funds $ 49 $ 122 $ (187)
v3.25.0.1
ASSET RETIREMENT OBLIGATIONS - Accumulated Provisions for the External Decommissioning Trust Funds (Details) - External decommissioning trust funds - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Georgia Power    
Public Utilities, General Disclosures [Line Items]    
Accumulated provisions for decommissioning $ 1,236 $ 1,163
Plant Farley | Alabama Power    
Public Utilities, General Disclosures [Line Items]    
Accumulated provisions for decommissioning 1,385 1,259
Plant Hatch | Georgia Power    
Public Utilities, General Disclosures [Line Items]    
Accumulated provisions for decommissioning 735 705
Plant Vogtle Units 1 and 2 | Georgia Power    
Public Utilities, General Disclosures [Line Items]    
Accumulated provisions for decommissioning 460 434
Plant Vogtle Units 3 and 4 | Georgia Power    
Public Utilities, General Disclosures [Line Items]    
Accumulated provisions for decommissioning $ 41 $ 24
v3.25.0.1
ASSET RETIREMENT OBLIGATIONS - Estimated Costs of Decommissioning (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2024
USD ($)
Alabama Power | Plant Farley  
Public Utilities, General Disclosures [Line Items]  
Decommissioning periods: Beginning year 2037
Decommissioning periods: Completion year 2087
Site study costs $ 2,048
Alabama Power | Radiated structures | Plant Farley  
Public Utilities, General Disclosures [Line Items]  
Site study costs 1,402
Alabama Power | Spent fuel management | Plant Farley  
Public Utilities, General Disclosures [Line Items]  
Site study costs 513
Alabama Power | Non-radiated structures | Plant Farley  
Public Utilities, General Disclosures [Line Items]  
Site study costs $ 133
Georgia Power | Plant Hatch  
Public Utilities, General Disclosures [Line Items]  
Decommissioning periods: Beginning year 2034
Decommissioning periods: Completion year 2088
Site study costs $ 1,178
Georgia Power | Plant Vogtle Units 1 and 2  
Public Utilities, General Disclosures [Line Items]  
Decommissioning periods: Beginning year 2047
Decommissioning periods: Completion year 2092
Site study costs $ 1,036
Georgia Power | Plant Vogtle Units 3 and 4  
Public Utilities, General Disclosures [Line Items]  
Decommissioning periods: Beginning year 2062
Decommissioning periods: Completion year 2074
Site study costs $ 776
Georgia Power | Radiated structures | Plant Hatch  
Public Utilities, General Disclosures [Line Items]  
Site study costs 795
Georgia Power | Radiated structures | Plant Vogtle Units 1 and 2  
Public Utilities, General Disclosures [Line Items]  
Site study costs 674
Georgia Power | Radiated structures | Plant Vogtle Units 3 and 4  
Public Utilities, General Disclosures [Line Items]  
Site study costs 599
Georgia Power | Spent fuel management | Plant Hatch  
Public Utilities, General Disclosures [Line Items]  
Site study costs 306
Georgia Power | Spent fuel management | Plant Vogtle Units 1 and 2  
Public Utilities, General Disclosures [Line Items]  
Site study costs 255
Georgia Power | Spent fuel management | Plant Vogtle Units 3 and 4  
Public Utilities, General Disclosures [Line Items]  
Site study costs 88
Georgia Power | Non-radiated structures | Plant Hatch  
Public Utilities, General Disclosures [Line Items]  
Site study costs 77
Georgia Power | Non-radiated structures | Plant Vogtle Units 1 and 2  
Public Utilities, General Disclosures [Line Items]  
Site study costs 107
Georgia Power | Non-radiated structures | Plant Vogtle Units 3 and 4  
Public Utilities, General Disclosures [Line Items]  
Site study costs $ 89
v3.25.0.1
CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - Southern Company (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]    
Equity investments in unconsolidated subsidiaries $ 1,416 $ 1,368
Southern Holdings Company    
Schedule of Equity Method Investments [Line Items]    
Equity investments in unconsolidated subsidiaries $ 128 $ 126
v3.25.0.1
CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - SEGCO Equity Method Investments Narrative (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2024
USD ($)
MW
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Alabama Power      
Jointly Owned Utility Plant Interests [Line Items]      
Percent ownership 14.00%    
Alabama Power | SEGCO      
Jointly Owned Utility Plant Interests [Line Items]      
Ownership percentage, equity method investment 50.00%    
Alabama Power | SEGCO      
Jointly Owned Utility Plant Interests [Line Items]      
Total megawatt capacity (in MWs) | MW 1,020    
Share of purchased power $ 115 $ 112 $ 124
Dividends paid by equity method investment $ 20 25 14
Georgia Power | SEGCO      
Jointly Owned Utility Plant Interests [Line Items]      
Ownership percentage, equity method investment 50.00%    
Georgia Power | SEGCO      
Jointly Owned Utility Plant Interests [Line Items]      
Share of purchased power $ 118 $ 115 $ 127
SEGCO | Alabama Power      
Jointly Owned Utility Plant Interests [Line Items]      
Percent ownership 86.00%    
v3.25.0.1
CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - Narrative (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2024
USD ($)
investor
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Redeemable Noncontrolling Interest [Line Items]      
Total assets $ 145,180 $ 139,331 $ 134,891
Liabilities 108,506 104,106  
Equity investments in unconsolidated subsidiaries 1,416 1,368  
Earnings from equity method investments 139 144 151
Southern Power      
Redeemable Noncontrolling Interest [Line Items]      
Total assets 12,653 12,761  
Liabilities 5,971 6,063  
Proceeds from sale of equity method investments $ 50 38  
Southern Power | SP Solar Holdings I, LP      
Redeemable Noncontrolling Interest [Line Items]      
Sale of equity interest in limited partnership 33.00%    
Southern Company Gas      
Redeemable Noncontrolling Interest [Line Items]      
Total assets $ 26,177 25,083 24,621
Liabilities 15,181 14,280  
Equity investments in unconsolidated subsidiaries 1,279 1,235  
Earnings from equity method investments 146 140 148
Southern Company Gas | SNG      
Redeemable Noncontrolling Interest [Line Items]      
Equity investments in unconsolidated subsidiaries 1,245 1,202  
Earnings from equity method investments $ 146 139 $ 146
Wholly Owned Subsidiary Of Southern Power | Southern Power | SP Solar Holdings I, LP      
Redeemable Noncontrolling Interest [Line Items]      
Ownership interest 66.00%    
Wholly Owned Subsidiary Of Southern Power | Southern Power | SP Wind      
Redeemable Noncontrolling Interest [Line Items]      
Ownership interest 100.00%    
SP Solar Holdings I, LP | Southern Power      
Redeemable Noncontrolling Interest [Line Items]      
Distribution made to limited partner, cash distributions paid, percentage 67.00%    
SP Solar Holdings I, LP | Global Atlantic      
Redeemable Noncontrolling Interest [Line Items]      
Distribution made to limited partner, cash distributions paid, percentage 33.00%    
SP Wind | Southern Power      
Redeemable Noncontrolling Interest [Line Items]      
Distribution made to limited partner, cash distributions paid, percentage 60.00%    
Number of financial investors | investor 3    
SP Wind | Financial Investors      
Redeemable Noncontrolling Interest [Line Items]      
Distribution made to limited partner, cash distributions paid, percentage 40.00%    
General Partner | Wholly Owned Subsidiary Of Southern Power | Southern Power | SP Solar Holdings I, LP      
Redeemable Noncontrolling Interest [Line Items]      
Ownership interest 1.00%    
Variable Interest Entity, Primary Beneficiary | SP Solar Holdings I, LP | Southern Power      
Redeemable Noncontrolling Interest [Line Items]      
Total assets $ 5,400 5,600  
Liabilities 372 399  
Noncontrolling interests related to other partners' interest 1,000    
Variable Interest Entity, Primary Beneficiary | SP Wind | Southern Power      
Redeemable Noncontrolling Interest [Line Items]      
Total assets 2,000 2,100  
Liabilities 177 187  
Noncontrolling interests related to other partners' interest 35 38  
Variable Interest Entity, Primary Beneficiary | Other Variable Interest Entities | Southern Power      
Redeemable Noncontrolling Interest [Line Items]      
Total assets 1,600 1,700  
Liabilities 224 230  
Noncontrolling interests related to other partners' interest $ 691 $ 761  
v3.25.0.1
CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - Balance Sheet Information (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]    
Equity investments in unconsolidated subsidiaries $ 1,416 $ 1,368
Southern Company Gas    
Schedule of Equity Method Investments [Line Items]    
Equity investments in unconsolidated subsidiaries 1,279 1,235
SNG | Southern Company Gas    
Schedule of Equity Method Investments [Line Items]    
Equity investments in unconsolidated subsidiaries 1,245 1,202
Other | Southern Company Gas    
Schedule of Equity Method Investments [Line Items]    
Equity investments in unconsolidated subsidiaries $ 34 $ 33
v3.25.0.1
FINANCING - Long-Term Debt (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Debt Instrument [Line Items]    
Finance lease obligations $ 287 $ 298
Unamortized fair value adjustment 275 302
Unamortized debt premium (discount), net (58) (198)
Unamortized debt issuance expense (419) (290)
Total long-term debt 63,486 59,686
Less: Amount due within one year 4,718 2,476
Long-Term Debt $ 58,768 57,210
Senior notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.33%  
Long-term debt, gross $ 44,862 40,235
Junior subordinated notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.32%  
Long-term debt, gross $ 7,389 8,333
FFB loans    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 2.88%  
Long-term debt, gross $ 4,703 4,788
Pollution control revenue bonds    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.15%  
Long-term debt, gross $ 3,379 3,400
First mortgage bonds    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.79%  
Long-term debt, gross $ 2,775 2,500
Medium-term notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 7.03%  
Long-term debt, gross $ 84 84
Other long-term debt    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.96%  
Long-term debt, gross $ 209 234
Alabama Power    
Debt Instrument [Line Items]    
Finance lease obligations 4 5
Unamortized debt premium (discount), net (19) (20)
Unamortized debt issuance expense (67) (73)
Total long-term debt 11,154 11,183
Less: Amount due within one year 655 223
Long-Term Debt $ 10,499 10,960
Alabama Power | Senior notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.94%  
Long-term debt, gross $ 9,875 9,875
Alabama Power | Pollution control revenue bonds    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.11%  
Long-term debt, gross $ 1,300 1,321
Alabama Power | Other long-term debt    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 6.11%  
Long-term debt, gross $ 61 75
Georgia Power    
Debt Instrument [Line Items]    
Finance lease obligations 261 240
Unamortized debt premium (discount), net (21) (19)
Unamortized debt issuance expense (123) (122)
Total long-term debt 18,350 16,700
Less: Amount due within one year 966 502
Long-Term Debt $ 17,384 16,198
Georgia Power | Senior notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.49%  
Long-term debt, gross $ 11,292 9,575
Georgia Power | Junior subordinated notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 5.00%  
Long-term debt, gross $ 270 270
Georgia Power | FFB loans    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 2.88%  
Long-term debt, gross $ 4,703 4,788
Georgia Power | Pollution control revenue bonds    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.18%  
Long-term debt, gross $ 1,968 1,968
Mississippi Power    
Debt Instrument [Line Items]    
Finance lease obligations 14 16
Unamortized debt premium (discount), net 2 1
Unamortized debt issuance expense (9) (9)
Total long-term debt 1,693 1,644
Less: Amount due within one year 12 201
Long-Term Debt $ 1,681 1,443
Mississippi Power | Senior notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.33%  
Long-term debt, gross $ 1,575 1,525
Mississippi Power | Pollution control revenue bonds    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.16%  
Long-term debt, gross $ 111 111
Southern Power    
Debt Instrument [Line Items]    
Finance lease obligations 0 0
Unamortized debt premium (discount), net (4) (4)
Unamortized debt issuance expense (11) (13)
Total long-term debt 2,680 2,711
Less: Amount due within one year 500 0
Long-Term Debt 2,180 2,711
Fair value gain (loss) $ (45) (12)
Southern Power | Senior notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.05%  
Long-term debt, gross $ 2,695 2,728
Southern Company Gas    
Debt Instrument [Line Items]    
Finance lease obligations 0 0
Unamortized fair value adjustment 275 302
Unamortized debt premium (discount), net (9) (8)
Unamortized debt issuance expense (37) (34)
Total long-term debt 8,531 7,833
Less: Amount due within one year 302 0
Long-Term Debt $ 8,229 7,833
Southern Company Gas | Senior notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.41%  
Long-term debt, gross $ 5,375 4,930
Southern Company Gas | First mortgage bonds    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.79%  
Long-term debt, gross $ 2,775 2,500
Southern Company Gas | Medium-term notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 7.03%  
Long-term debt, gross $ 84 84
Southern Company Gas | Other long-term debt    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.81%  
Long-term debt, gross $ 68 $ 59
v3.25.0.1
FINANCING - Maturities of Long-Term Debt (Details)
$ in Millions
Dec. 31, 2024
USD ($)
Debt Instrument [Line Items]  
2025 $ 4,727
2026 3,792
2027 4,075
2028 2,827
2029 1,990
Alabama Power  
Debt Instrument [Line Items]  
2025 658
2026 47
2027 551
2028 107
2029 0
Alabama Power | Series 2023A Convertible Senior Notes Due 2025  
Debt Instrument [Line Items]  
2025 200
Georgia Power  
Debt Instrument [Line Items]  
2025 967
2026 451
2027 1,015
2028 868
2029 861
Georgia Power | Series 2023C Convertible Senior Notes Due 2074  
Debt Instrument [Line Items]  
2025 117
Mississippi Power  
Debt Instrument [Line Items]  
2025 12
2026 66
2027 10
2028 357
2029 1
Southern Power  
Debt Instrument [Line Items]  
2025 500
2026 964
2027 0
2028 0
2029 0
Southern Power | Euro-denominated Debt  
Debt Instrument [Line Items]  
2026 564
Southern Company Gas  
Debt Instrument [Line Items]  
2025 300
2026 530
2027 154
2028 150
2029 $ 150
v3.25.0.1
FINANCING - DOE Loan Guarantee Borrowings (Details) - USD ($)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2019
Dec. 31, 2021
Debt Instrument [Line Items]          
Remaining borrowing capacity $ 7,891,000,000        
Line of credit facility, maximum borrowing capacity 7,920,000,000        
Georgia Power          
Debt Instrument [Line Items]          
Remaining borrowing capacity 2,026,000,000        
Principal amortization payments 86,000,000 $ 86,000,000 $ 88,000,000    
Line of credit facility, maximum borrowing capacity $ 2,050,000,000        
Basis spread on variable rate 0.375%        
Amortization period 5 years        
FFB Credit Facility | Georgia Power          
Debt Instrument [Line Items]          
Eligible project costs to be reimbursed       $ 5,130,000,000  
Remaining borrowing capacity         $ 0
Principal amortization payments $ 86,000,000        
Line of credit facility, maximum borrowing capacity $ 4,700,000,000 $ 4,800,000,000      
v3.25.0.1
FINANCING - Equity Units (Details) - USD ($)
$ / shares in Units, $ in Millions
 1 Months Ended 2 Months Ended 12 Months Ended
Aug. 01, 2022
Dec. 31, 2024
Aug. 31, 2022
Feb. 19, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
May 31, 2022
Debt Instrument [Line Items]                
Common stock issued to settle purchase contracts (in shares)   436,614            
Proceeds from issuance of common stock         $ 143.0 $ 36.0 $ 1,808.0  
Stock forward price (in dollars per share)         $ 83.3293      
Private Placement                
Debt Instrument [Line Items]                
Common stock issued to settle purchase contracts (in shares)   143,920            
Subsequent Event                
Debt Instrument [Line Items]                
Common stock issued to settle purchase contracts (in shares)       292,694        
Series 2019A Remarketable Junior Subordinated Notes | Junior subordinated notes                
Debt Instrument [Line Items]                
Remarketed principal amount               $ 862.5
Quarterly interest rate               4.475%
Series 2019B Remarketable Junior Subordinated Notes | Junior subordinated notes                
Debt Instrument [Line Items]                
Remarketed principal amount               $ 862.5
Quarterly interest rate               5.113%
2019 Series A Equity Units | Junior subordinated notes                
Debt Instrument [Line Items]                
Common stock issued to settle purchase contracts (in shares)     25,200,000          
Proceeds from issuance of common stock $ 1,725.0              
v3.25.0.1
FINANCING - Convertible Senior Notes (Details)
$ / shares in Units, $ in Millions
 1 Months Ended 2 Months Ended 12 Months Ended
Dec. 31, 2024
$ / shares
shares
Nov. 30, 2024
$ / shares
shares
May 31, 2024
USD ($)
shares
Feb. 19, 2025
shares
Dec. 31, 2024
d
$ / shares
Mar. 31, 2023
USD ($)
Feb. 28, 2023
USD ($)
Debt Instrument [Line Items]              
Common stock issued to settle purchase contracts (in shares) | shares 436,614            
Stock forward price (in dollars per share) | $ / shares         $ 83.3293    
Subsequent Event              
Debt Instrument [Line Items]              
Common stock issued to settle purchase contracts (in shares) | shares       292,694      
At-The-Market              
Debt Instrument [Line Items]              
Common stock issued to settle purchase contracts (in shares) | shares     50,000,000        
At-The-Market, Forward Price 1              
Debt Instrument [Line Items]              
Common stock issued to settle purchase contracts (in shares) | shares   1,000,000          
Stock forward price (in dollars per share) | $ / shares   $ 86.5645          
At-The-Market, Forward Price 2              
Debt Instrument [Line Items]              
Common stock issued to settle purchase contracts (in shares) | shares   1,000,000          
Stock forward price (in dollars per share) | $ / shares   $ 87.9658          
Private Placement              
Debt Instrument [Line Items]              
Common stock issued to settle purchase contracts (in shares) | shares 143,920            
Series 2024A Convertible Senior Notes | Convertible Debt              
Debt Instrument [Line Items]              
Debt instrument, face amount | $     $ 1,500        
Quarterly interest rate     4.50%        
Conversion price (in dollars per share) | $ / shares $ 92.45       $ 92.45    
Redemption price (percentage)         100.00%    
Series 2024A Convertible Senior Notes | Convertible Debt | Debt Conversion Terms One              
Debt Instrument [Line Items]              
Trading days of debt instrument         20    
Consecutive trading days         30    
Percentage of stock price trigger         130.00%    
Series 2024A Convertible Senior Notes | Convertible Debt | Debt Conversion Terms Two              
Debt Instrument [Line Items]              
Trading days of debt instrument         5    
Percentage of stock price trigger         98.00%    
Series 2023A Convertible Senior Notes Due 2025 | Convertible Debt              
Debt Instrument [Line Items]              
Debt instrument, face amount | $           $ 225 $ 1,500
Quarterly interest rate             3.875%
Conversion price (in dollars per share) | $ / shares $ 84.16       $ 84.16    
Redemption price (percentage)         100.00%    
Series 2023A Convertible Senior Notes Due 2025 | Convertible Debt | Debt Conversion Terms One              
Debt Instrument [Line Items]              
Trading days of debt instrument         20    
Consecutive trading days         30    
Percentage of stock price trigger         130.00%    
Series 2023A Convertible Senior Notes Due 2025 | Convertible Debt | Debt Conversion Terms Two              
Debt Instrument [Line Items]              
Trading days of debt instrument         5    
Consecutive trading days         10    
Percentage of stock price trigger         98.00%    
v3.25.0.1
FINANCING - Bank Credit Arrangements (Details)
$ in Millions
Dec. 31, 2024
USD ($)
Line of Credit Facility [Line Items]  
2025 $ 580
2026 665
2027 275
2029 6,400
Total 7,920
Unused 7,891
Expires within One Year 580
Southern Company  
Line of Credit Facility [Line Items]  
2025 150
2026 0
2027 0
2029 1,850
Total 2,000
Unused 1,998
Expires within One Year 150
Alabama Power  
Line of Credit Facility [Line Items]  
2025 0
2026 665
2027 0
2029 700
Total 1,365
Unused 1,364
Expires within One Year 0
Georgia Power  
Line of Credit Facility [Line Items]  
2025 300
2026 0
2027 0
2029 1,750
Total 2,050
Unused 2,026
Expires within One Year 300
Mississippi Power  
Line of Credit Facility [Line Items]  
2025 0
2026 0
2027 275
2029 0
Total 275
Unused 275
Expires within One Year 0
Southern Power  
Line of Credit Facility [Line Items]  
2025 0
2026 0
2027 0
2029 600
Total 600
Unused 600
Expires within One Year 0
Southern Power | Continuing Letter of Credit Facility A  
Line of Credit Facility [Line Items]  
2025 100
2026 75
Unused 16
Southern Power | Continuing Letter of Credit Facility B  
Line of Credit Facility [Line Items]  
Unused 11
Southern Company Gas  
Line of Credit Facility [Line Items]  
2025 100
2026 0
2027 0
2029 1,500
Total 1,600
Unused 1,598
Expires within One Year 100
Other Subsidiaries  
Line of Credit Facility [Line Items]  
2025 30
2026 0
2027 0
2029 0
Total 30
Unused 30
Expires within One Year 30
Southern Company and Southern Power  
Line of Credit Facility [Line Items]  
2029 2,450
Southern Company Gas Capital  
Line of Credit Facility [Line Items]  
Total 800
Nicor Gas  
Line of Credit Facility [Line Items]  
2025 100
Total 700
Alabama Property Company  
Line of Credit Facility [Line Items]  
2026 15
Unused $ 14
v3.25.0.1
FINANCING - Bank Credit Arrangements Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Line of Credit Facility [Line Items]    
Ratio of indebtedness to capitalization, debt covenant, required 70.00%  
Amount of variable rate pollution control revenue bonds outstanding requiring liquidity support $ 1,700  
Other Subsidiaries    
Line of Credit Facility [Line Items]    
Ratio of indebtedness to capitalization, debt covenant, required 65.00%  
Alabama Power    
Line of Credit Facility [Line Items]    
Amount of variable rate pollution control revenue bonds outstanding requiring liquidity support $ 796  
Remarketed pollution control bonds 207  
Georgia Power    
Line of Credit Facility [Line Items]    
Amount of variable rate pollution control revenue bonds outstanding requiring liquidity support 819  
Remarketed pollution control bonds 157  
Mississippi Power    
Line of Credit Facility [Line Items]    
Amount of variable rate pollution control revenue bonds outstanding requiring liquidity support 69  
Southern Power | Power Purchase Agreement    
Line of Credit Facility [Line Items]    
Debt instrument, collateral amount $ 106 $ 106
v3.25.0.1
FINANCING - Notes Payable (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Short-term Debt [Line Items]    
Amount Outstanding $ 1,338 $ 2,314
Weighted Average Interest Rate 4.80% 5.70%
Commercial paper    
Short-term Debt [Line Items]    
Amount Outstanding $ 1,138 $ 1,794
Weighted Average Interest Rate 4.70% 5.60%
Short-term bank debt    
Short-term Debt [Line Items]    
Amount Outstanding $ 200 $ 520
Weighted Average Interest Rate 5.30% 6.40%
Alabama Power    
Short-term Debt [Line Items]    
Amount Outstanding $ 0 $ 40
Alabama Power | Commercial paper    
Short-term Debt [Line Items]    
Amount Outstanding $ 0 $ 40
Weighted Average Interest Rate 0.00% 5.50%
Georgia Power    
Short-term Debt [Line Items]    
Amount Outstanding $ 200 $ 1,329
Weighted Average Interest Rate 5.30% 5.90%
Georgia Power | Commercial paper    
Short-term Debt [Line Items]    
Amount Outstanding $ 0 $ 809
Weighted Average Interest Rate 0.00% 5.60%
Georgia Power | Short-term bank debt    
Short-term Debt [Line Items]    
Amount Outstanding $ 200 $ 520
Weighted Average Interest Rate 5.30% 6.40%
Southern Power    
Short-term Debt [Line Items]    
Amount Outstanding $ 0 $ 138
Southern Power | Commercial paper    
Short-term Debt [Line Items]    
Amount Outstanding $ 0 $ 138
Weighted Average Interest Rate 0.00% 5.50%
Southern Company Gas    
Short-term Debt [Line Items]    
Amount Outstanding $ 455 $ 415
Southern Company Gas | Commercial paper    
Short-term Debt [Line Items]    
Amount Outstanding $ 455 $ 415
Weighted Average Interest Rate 4.70% 5.50%
Southern Company Gas Capital | Commercial paper    
Short-term Debt [Line Items]    
Amount Outstanding $ 283 $ 23
Weighted Average Interest Rate 4.70% 5.50%
Nicor Gas | Commercial paper    
Short-term Debt [Line Items]    
Amount Outstanding $ 172 $ 392
Weighted Average Interest Rate 4.60% 5.50%
Mississippi Power    
Short-term Debt [Line Items]    
Amount Outstanding $ 14 $ 0
Mississippi Power | Commercial paper    
Short-term Debt [Line Items]    
Amount Outstanding $ 14 $ 0
Weighted Average Interest Rate 4.60% 0.00%
v3.25.0.1
FINANCING - Outstanding Classes of Capital Stock Narrative (Details)
shares in Millions
 12 Months Ended
Dec. 31, 2024
shares
Debt Instrument [Line Items]  
Stock issued employee and director stock plans (in shares) 5.8
Number of shares reserved for issuance to stock-based compensation plan (in shares) 177.0
Southern Company Common Stock  
Debt Instrument [Line Items]  
Remaining shares available for awards (in shares) 25.0
v3.25.0.1
FINANCING - Diluted Earnings Per Share (Details) - shares
shares in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Debt Disclosure [Abstract]      
As reported shares (in shares) 1,096 1,092 1,075
Effect of stock-based compensation (in shares) 6 6 6
Diluted shares (in shares) 1,102 1,098 1,081
v3.25.0.1
FINANCING - Preferred Stock Redemption (Details) - Alabama Power
 12 Months Ended
Dec. 31, 2022
$ / shares
shares
4.92% Preferred Stock  
Debt Instrument, Redemption [Line Items]  
Dividend rate percentage 0.0492
Par Value/Stated Capital Per Share (in dollars per share) $ 100
Shares outstanding (in shares) | shares 80,000
Redemption Price Per Share (in dollars per share) $ 103.23
4.72% Preferred Stock  
Debt Instrument, Redemption [Line Items]  
Dividend rate percentage 0.0472
Par Value/Stated Capital Per Share (in dollars per share) $ 100
Shares outstanding (in shares) | shares 50,000
Redemption Price Per Share (in dollars per share) $ 102.18
4.64% Preferred Stock  
Debt Instrument, Redemption [Line Items]  
Dividend rate percentage 0.0464
Par Value/Stated Capital Per Share (in dollars per share) $ 100
Shares outstanding (in shares) | shares 60,000
Redemption Price Per Share (in dollars per share) $ 103.14
4.60% Preferred Stock  
Debt Instrument, Redemption [Line Items]  
Dividend rate percentage 0.0460
Par Value/Stated Capital Per Share (in dollars per share) $ 100
Shares outstanding (in shares) | shares 100,000
Redemption Price Per Share (in dollars per share) $ 104.20
4.52% Preferred Stock  
Debt Instrument, Redemption [Line Items]  
Dividend rate percentage 0.0452
Par Value/Stated Capital Per Share (in dollars per share) $ 100
Shares outstanding (in shares) | shares 50,000
Redemption Price Per Share (in dollars per share) $ 102.93
4.20% Preferred Stock  
Debt Instrument, Redemption [Line Items]  
Dividend rate percentage 0.0420
Par Value/Stated Capital Per Share (in dollars per share) $ 100
Shares outstanding (in shares) | shares 135,115
Redemption Price Per Share (in dollars per share) $ 105.00
5.00% Class A Preferred Stock  
Debt Instrument, Redemption [Line Items]  
Dividend rate percentage 0.0500
Par Value/Stated Capital Per Share (in dollars per share) $ 25
Shares outstanding (in shares) | shares 10,000,000
Redemption Price Per Share (in dollars per share) $ 25.00
v3.25.0.1
FINANCING - Dividend Restrictions and Structural Considerations Narrative (Details)
$ in Billions
 12 Months Ended
Dec. 31, 2024
USD ($)
Variable Interest Entity [Line Items]  
Undistributed retained earnings of subsidiaries $ 6.5
Southern Company Gas  
Variable Interest Entity [Line Items]  
Retained earnings, unappropriated $ 1.6
v3.25.0.1
LEASES - Major Categories of Lease Obligations (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Lessee, Lease, Description [Line Items]    
Lease obligations $ 1,740 $ 1,788
Alabama Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 94 98
Georgia Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 1,589 1,115
Mississippi Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 22 25
Southern Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 540 546
Southern Company Gas    
Lessee, Lease, Description [Line Items]    
Lease obligations 41 51
Electric generating units(*)    
Lessee, Lease, Description [Line Items]    
Lease obligations 672 670
Electric generating units(*) | Alabama Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 56 58
Electric generating units(*) | Georgia Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 1,509 1,028
Electric generating units(*) | Mississippi Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 0 0
Electric generating units(*) | Southern Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 0 0
Electric generating units(*) | Southern Company Gas    
Lessee, Lease, Description [Line Items]    
Lease obligations 0 0
Real estate/land    
Lessee, Lease, Description [Line Items]    
Lease obligations 834 871
Real estate/land | Alabama Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 3 4
Real estate/land | Georgia Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 45 54
Real estate/land | Mississippi Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 2 2
Real estate/land | Southern Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 540 546
Real estate/land | Southern Company Gas    
Lessee, Lease, Description [Line Items]    
Lease obligations 20 28
Communication towers    
Lessee, Lease, Description [Line Items]    
Lease obligations 118 123
Communication towers | Alabama Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 2 1
Communication towers | Georgia Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 4 4
Communication towers | Mississippi Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 0 0
Communication towers | Southern Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 0 0
Communication towers | Southern Company Gas    
Lessee, Lease, Description [Line Items]    
Lease obligations 21 23
Railcars    
Lessee, Lease, Description [Line Items]    
Lease obligations 64 64
Railcars | Alabama Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 31 32
Railcars | Georgia Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 29 27
Railcars | Mississippi Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 4 5
Railcars | Southern Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 0 0
Railcars | Southern Company Gas    
Lessee, Lease, Description [Line Items]    
Lease obligations 0 0
Other    
Lessee, Lease, Description [Line Items]    
Lease obligations 52 60
Other | Alabama Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 2 3
Other | Georgia Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 2 2
Other | Mississippi Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 16 18
Other | Southern Power    
Lessee, Lease, Description [Line Items]    
Lease obligations 0 0
Other | Southern Company Gas    
Lessee, Lease, Description [Line Items]    
Lease obligations $ 0 $ 0
v3.25.0.1
LEASES - Additional Information (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2024
USD ($)
agreement
Jun. 27, 2024
agreement
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Lessee, Lease, Description [Line Items]          
Operating lease obligations $ 1,453   $ 1,453 $ 1,490  
Maximum | Real estate          
Lessee, Lease, Description [Line Items]          
Remaining terms     20 years    
Maximum | Land          
Lessee, Lease, Description [Line Items]          
Lessee, lease term     44 years    
Maximum | Communication towers          
Lessee, Lease, Description [Line Items]          
Lessee, lease term     16 years    
Maximum | Fuel cells          
Lessee, Lease, Description [Line Items]          
Lessor, lease term, operating lease 9 years   9 years    
Alabama Power          
Lessee, Lease, Description [Line Items]          
Operating lease obligations $ 90   $ 90 93  
Alabama Power | Maximum | Electric generating units          
Lessee, Lease, Description [Line Items]          
Operating lease remaining lease term 15 years   15 years    
Alabama Power | Minimum | Electric generating units          
Lessee, Lease, Description [Line Items]          
Operating lease remaining lease term 3 years   3 years    
Georgia Power          
Lessee, Lease, Description [Line Items]          
Requested number of affiliate power purchase agreements to be certified | agreement 2 5      
Lease not yet commenced, term 10 years   10 years    
Lease not yet commenced amount $ 83   $ 83    
Operating lease obligations $ 1,328   1,328 875  
Variable lease, payment     45 42 $ 45
Georgia Power | Purchased power, affiliates          
Lessee, Lease, Description [Line Items]          
Variable lease, payment     $ 22 21 $ 21
Georgia Power | Maximum | Outdoor lighting          
Lessee, Lease, Description [Line Items]          
Lessor, lease term, operating lease 15 years   15 years    
Mississippi Power          
Lessee, Lease, Description [Line Items]          
Operating lease obligations $ 8   $ 8 9  
Mississippi Power | Maximum | Electric generating units          
Lessee, Lease, Description [Line Items]          
Lessor, sales-type lease, term of contract 14 years   14 years    
Southern Power          
Lessee, Lease, Description [Line Items]          
Operating lease obligations $ 540   $ 540 546  
Southern Power | Maximum | Electric generating units          
Lessee, Lease, Description [Line Items]          
Lessor, lease term, operating lease 22 years   22 years    
Lessor, sales-type lease, term of contract 17 years   17 years    
Southern Company Gas          
Lessee, Lease, Description [Line Items]          
Lease not yet commenced, term 11 years 6 months   11 years 6 months    
Lease not yet commenced amount $ 105   $ 105    
Operating lease obligations 41   $ 41 51  
Southern Company Gas | Maximum          
Lessee, Lease, Description [Line Items]          
Lessor, remaining term     18 years    
Affiliate | Georgia Power | Electric generating units          
Lessee, Lease, Description [Line Items]          
Operating lease obligations $ 893   $ 893 $ 416  
Traditional Electric Operating Companies | Maximum | Outdoor lighting          
Lessee, Lease, Description [Line Items]          
Lessor, lease term, operating lease 10 years   10 years    
v3.25.0.1
LEASES - Balance Sheet Amounts Recorded for Operating and Financing Leases (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Operating Leases    
Operating lease ROU assets, net $ 1,386 $ 1,432
Operating lease obligations - current 200 183
Operating lease obligations - non-current 1,253 1,307
Total operating lease obligations $ 1,453 $ 1,490
Finance Leases    
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Public Utilities, Other Depreciable Property, Plant And Equipment, Plant In Service Public Utilities, Other Depreciable Property, Plant And Equipment, Plant In Service
Finance lease ROU assets, net $ 254 $ 272
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Other Liabilities, Current Other Liabilities, Current
Finance lease obligations - current $ 9 $ 11
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Long-Term Debt Long-Term Debt
Finance lease obligations - non-current $ 278 $ 287
Total finance lease obligations 287 298
Assets Subject to Power Purchase Agreement    
Operating Leases    
Total operating lease obligations 567 566
Alabama Power    
Operating Leases    
Operating lease ROU assets, net $ 84 $ 87
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Other Liabilities, Current Other Liabilities, Current
Operating lease obligations - current $ 14 $ 12
Operating lease obligations - non-current 76 81
Total operating lease obligations $ 90 $ 93
Finance Leases    
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Public Utilities, Other Depreciable Property, Plant And Equipment, Plant In Service Public Utilities, Other Depreciable Property, Plant And Equipment, Plant In Service
Finance lease ROU assets, net $ 4 $ 5
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Other Liabilities, Current Other Liabilities, Current
Finance lease obligations - current $ 1 $ 2
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Long-Term Debt Long-Term Debt
Finance lease obligations - non-current $ 3 $ 3
Total finance lease obligations 4 5
Alabama Power | Assets Subject to Power Purchase Agreement    
Operating Leases    
Total operating lease obligations 55 58
Georgia Power    
Operating Leases    
Operating lease ROU assets, net 1,331 884
Operating lease obligations - current 169 135
Operating lease obligations - non-current 1,159 740
Total operating lease obligations $ 1,328 $ 875
Finance Leases    
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Public Utilities, Other Depreciable Property, Plant And Equipment, Plant In Service Public Utilities, Other Depreciable Property, Plant And Equipment, Plant In Service
Finance lease ROU assets, net $ 227 $ 203
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Other Liabilities, Current Other Liabilities, Current
Finance lease obligations - current $ 20 $ 18
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Long-Term Debt Long-Term Debt
Finance lease obligations - non-current $ 241 $ 222
Total finance lease obligations 261 240
Georgia Power | Assets Subject to Power Purchase Agreement    
Operating Leases    
Total operating lease obligations $ 1,300 $ 813
Mississippi Power    
Operating Leases    
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Other deferred charges and assets Other deferred charges and assets
Operating lease ROU assets, net $ 8 $ 9
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Other Liabilities, Current Other Liabilities, Current
Operating lease obligations - current $ 4 $ 3
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Other Liabilities, Noncurrent Other Liabilities, Noncurrent
Operating lease obligations - non-current $ 4 $ 6
Total operating lease obligations $ 8 $ 9
Finance Leases    
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Public Utilities, Other Depreciable Property, Plant And Equipment, Plant In Service Public Utilities, Other Depreciable Property, Plant And Equipment, Plant In Service
Finance lease ROU assets, net $ 14 $ 15
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Other Liabilities, Current Other Liabilities, Current
Finance lease obligations - current $ 1 $ 1
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Long-Term Debt Long-Term Debt
Finance lease obligations - non-current $ 13 $ 15
Total finance lease obligations 14 16
Southern Power    
Operating Leases    
Operating lease ROU assets, net $ 484 $ 488
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Other Liabilities, Current Other Liabilities, Current
Operating lease obligations - current $ 29 $ 29
Operating lease obligations - non-current 511 517
Total operating lease obligations 540 546
Finance Leases    
Finance lease ROU assets, net 0 0
Finance lease obligations - current 0 0
Finance lease obligations - non-current 0 0
Total finance lease obligations 0 0
Southern Company Gas    
Operating Leases    
Operating lease ROU assets, net $ 38 $ 47
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Other Liabilities, Current Other Liabilities, Current
Operating lease obligations - current $ 11 $ 11
Operating lease obligations - non-current 30 40
Total operating lease obligations 41 51
Finance Leases    
Finance lease ROU assets, net 0 0
Finance lease obligations - current 0 0
Finance lease obligations - non-current 0 0
Total finance lease obligations $ 0 $ 0
v3.25.0.1
LEASES - Lease Costs (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Lease cost      
Operating lease cost $ 248 $ 252 $ 297
Finance lease cost:      
Amortization of ROU assets 20 24 23
Interest on lease obligations 15 14 13
Total finance lease cost 35 38 36
Short-term lease costs 37 40 64
Variable lease cost 48 47 125
Sublease income     (1)
Total lease cost 368 377 521
Assets Subject to Power Purchase Agreement      
Lease cost      
Operating lease cost 108 112 162
Alabama Power      
Lease cost      
Operating lease cost 19 16 59
Finance lease cost:      
Amortization of ROU assets 2 2 1
Interest on lease obligations 0 0 0
Total finance lease cost 2 2 1
Short-term lease costs 15 16 44
Variable lease cost   0 13
Variable lease cost (1)    
Sublease income     0
Total lease cost 35 34 117
Alabama Power | Assets Subject to Power Purchase Agreement      
Lease cost      
Operating lease cost 5 4 48
Georgia Power      
Lease cost      
Operating lease cost 190 192 198
Finance lease cost:      
Amortization of ROU assets 23 19 15
Interest on lease obligations 15 17 17
Total finance lease cost 38 36 32
Short-term lease costs 15 16 13
Variable lease cost 77 74 105
Sublease income     0
Total lease cost 320 318 348
Georgia Power | Assets Subject to Power Purchase Agreement      
Lease cost      
Operating lease cost 168 174 180
Mississippi Power      
Lease cost      
Operating lease cost 4 5 5
Finance lease cost:      
Amortization of ROU assets 1 1 1
Interest on lease obligations 1 0 1
Total finance lease cost 2 1 2
Short-term lease costs 0 0 0
Variable lease cost 0 0 0
Sublease income     0
Total lease cost 6 6 7
Southern Power      
Lease cost      
Operating lease cost 27 34 32
Finance lease cost:      
Amortization of ROU assets 0 0 0
Interest on lease obligations 0 0 0
Total finance lease cost 0 0 0
Short-term lease costs 0 0 0
Variable lease cost 4 4 5
Sublease income     0
Total lease cost 31 38 37
Southern Company Gas      
Lease cost      
Operating lease cost 12 12 15
Finance lease cost:      
Amortization of ROU assets 0 0 0
Interest on lease obligations 0 0 0
Total finance lease cost 0 0 0
Short-term lease costs 0 0 0
Variable lease cost 0 0 0
Sublease income     0
Total lease cost $ 12 $ 12 $ 15
v3.25.0.1
LEASES - Other Information (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Cash paid for amounts included in the measurements of lease obligations:      
Operating cash flows from operating leases $ 243 $ 253 $ 303
Operating cash flows from finance leases 15 15 11
Financing cash flows from finance leases 11 18 16
ROU assets obtained under operating leases 146 100 56
Reassessment of ROU assets under operating leases (7)   16
ROU assets obtained under finance leases $ 1 $ 3 118
Weighted-average remaining lease term in years:      
Operating leases 16 years 4 months 24 days 17 years 2 months 12 days  
Finance leases 16 years 16 years 8 months 12 days  
Weighted-average discount rate:      
Operating leases 4.73% 4.68%  
Finance leases 4.86% 4.85%  
Alabama Power      
Cash paid for amounts included in the measurements of lease obligations:      
Operating cash flows from operating leases $ 19 $ 17 58
Operating cash flows from finance leases 0 0 0
Financing cash flows from finance leases 2 2 1
ROU assets obtained under operating leases 11 30 10
Reassessment of ROU assets under operating leases 0   0
ROU assets obtained under finance leases $ 0 $ 3 2
Weighted-average remaining lease term in years:      
Operating leases 10 years 2 months 12 days 11 years 1 month 6 days  
Finance leases 2 years 8 months 12 days 4 years 3 months 18 days  
Weighted-average discount rate:      
Operating leases 5.04% 5.02%  
Finance leases 4.05% 3.93%  
Georgia Power      
Cash paid for amounts included in the measurements of lease obligations:      
Operating cash flows from operating leases $ 186 $ 199 206
Operating cash flows from finance leases 21 22 20
Financing cash flows from finance leases 23 16 10
ROU assets obtained under operating leases 609 26 17
Reassessment of ROU assets under operating leases 0   0
ROU assets obtained under finance leases $ 44 $ 18 116
Weighted-average remaining lease term in years:      
Operating leases 7 years 10 months 24 days 7 years 6 months  
Finance leases 10 years 1 month 6 days 10 years 7 months 6 days  
Weighted-average discount rate:      
Operating leases 4.73% 4.58%  
Finance leases 5.80% 5.95%  
Mississippi Power      
Cash paid for amounts included in the measurements of lease obligations:      
Operating cash flows from operating leases $ 4 $ 5 5
Operating cash flows from finance leases 0 0 1
Financing cash flows from finance leases 1 1 1
ROU assets obtained under operating leases 0 1 9
Reassessment of ROU assets under operating leases 0   0
ROU assets obtained under finance leases $ 0 $ 0 0
Weighted-average remaining lease term in years:      
Operating leases 4 years 3 months 18 days 4 years 7 months 6 days  
Finance leases 10 years 10 months 24 days 11 years 10 months 24 days  
Weighted-average discount rate:      
Operating leases 3.83% 3.67%  
Finance leases 2.74% 2.74%  
Southern Power      
Cash paid for amounts included in the measurements of lease obligations:      
Operating cash flows from operating leases $ 33 $ 33 30
Operating cash flows from finance leases 0 0 0
Financing cash flows from finance leases 0 0 0
ROU assets obtained under operating leases 10 7 0
Reassessment of ROU assets under operating leases (7)   16
ROU assets obtained under finance leases $ 0 $ 0 0
Weighted-average remaining lease term in years:      
Operating leases 32 years 3 months 18 days 33 years 1 month 6 days  
Weighted-average discount rate:      
Operating leases 4.88% 4.89%  
Southern Company Gas      
Cash paid for amounts included in the measurements of lease obligations:      
Operating cash flows from operating leases $ 12 $ 12 14
Operating cash flows from finance leases 0 0 0
Financing cash flows from finance leases 0 0 0
ROU assets obtained under operating leases 1 7 3
Reassessment of ROU assets under operating leases 0   0
ROU assets obtained under finance leases $ 0 $ 0 $ 0
Weighted-average remaining lease term in years:      
Operating leases 6 years 9 months 18 days 7 years  
Weighted-average discount rate:      
Operating leases 3.84% 3.80%  
v3.25.0.1
LEASES - Maturities of Lease Liabilities (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Operating leases:    
2025 $ 239  
2026 212  
2027 190  
2028 170  
2029 138  
Thereafter 1,255  
Total 2,204  
Less: Present value discount 751  
Operating lease obligations 1,453 $ 1,490
Finance leases:    
2025 28  
2026 27  
2027 26  
2028 25  
2029 25  
Thereafter 290  
Total 421  
Less: Present value discount 134  
Finance lease obligations 287 298
Alabama Power    
Operating leases:    
2025 18  
2026 15  
2027 12  
2028 9  
2029 7  
Thereafter 56  
Total 117  
Less: Present value discount 27  
Operating lease obligations 90 93
Finance leases:    
2025 2  
2026 1  
2027 1  
2028 0  
2029 0  
Thereafter 0  
Total 4  
Less: Present value discount 0  
Finance lease obligations 4 5
Georgia Power    
Operating leases:    
2025 228  
2026 224  
2027 223  
2028 217  
2029 196  
Thereafter 511  
Total 1,599  
Less: Present value discount 271  
Operating lease obligations 1,328 875
Finance leases:    
2025 39  
2026 41  
2027 41  
2028 42  
2029 42  
Thereafter 139  
Total 344  
Less: Present value discount 83  
Finance lease obligations 261 240
Mississippi Power    
Operating leases:    
2025 4  
2026 3  
2027 1  
2028 0  
2029 0  
Thereafter 1  
Total 9  
Less: Present value discount 1  
Operating lease obligations 8 9
Finance leases:    
2025 2  
2026 2  
2027 1  
2028 1  
2029 1  
Thereafter 9  
Total 16  
Less: Present value discount 2  
Finance lease obligations 14 16
Southern Power    
Operating leases:    
2025 31  
2026 29  
2027 29  
2028 29  
2029 30  
Thereafter 978  
Total 1,126  
Less: Present value discount 586  
Operating lease obligations 540 546
Finance leases:    
2025 0  
2026 0  
2027 0  
2028 0  
2029 0  
Thereafter 0  
Total 0  
Less: Present value discount 0  
Finance lease obligations 0 0
Southern Company Gas    
Operating leases:    
2025 12  
2026 9  
2027 4  
2028 3  
2029 4  
Thereafter 15  
Total 47  
Less: Present value discount 6  
Operating lease obligations 41 51
Finance leases:    
2025 0  
2026 0  
2027 0  
2028 0  
2029 0  
Thereafter 0  
Total 0  
Less: Present value discount 0  
Finance lease obligations $ 0 $ 0
v3.25.0.1
LEASES - Lease Income (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Lessor, Lease, Description [Line Items]      
Lease income - interest income on sales-type leases $ 24 $ 24 $ 25
Lease income - operating leases 136 164 208
Variable lease income 417 406 417
Total lease income $ 577 $ 594 $ 650
Operating lease, income, comprehensive income, extensible list, not disclosed, flag Lease income - operating leases Lease income - operating leases Lease income - operating leases
Alabama Power      
Lessor, Lease, Description [Line Items]      
Lease income - interest income on sales-type leases $ 0 $ 0 $ 0
Lease income - operating leases 9 35 77
Variable lease income 1 1 1
Total lease income 10 36 78
Georgia Power      
Lessor, Lease, Description [Line Items]      
Lease income - interest income on sales-type leases 0 0 0
Lease income - operating leases 28 29 32
Variable lease income 0 0 0
Total lease income 28 29 32
Mississippi Power      
Lessor, Lease, Description [Line Items]      
Lease income - interest income on sales-type leases 15 14 15
Lease income - operating leases 3 2 2
Variable lease income 0 0 0
Total lease income 18 16 17
Southern Power      
Lessor, Lease, Description [Line Items]      
Lease income - interest income on sales-type leases 9 10 10
Lease income - operating leases 88 85 85
Variable lease income 450 437 448
Total lease income 547 532 543
Southern Company Gas      
Lessor, Lease, Description [Line Items]      
Lease income - interest income on sales-type leases 0 0 0
Lease income - operating leases 36 37 36
Variable lease income 0 0 0
Total lease income $ 36 $ 37 $ 36
v3.25.0.1
LEASES - Undiscounted Cash Flows to be Received Under Tolling Arrangements Accounted for as Sales-type Leases (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]    
2025 $ 52  
2026 38  
2027 37  
2028 36  
2029 35  
Thereafter 302  
Total undiscounted cash flows 500  
Lease receivable 297  
Difference between undiscounted cash flows and discounted cash flows 203  
Mississippi Power    
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]    
2025 24  
2026 23  
2027 22  
2028 21  
2029 20  
Thereafter 132  
Total undiscounted cash flows 242  
Lease receivable 139  
Difference between undiscounted cash flows and discounted cash flows 103  
Southern Power    
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]    
2025 15  
2026 15  
2027 15  
2028 15  
2029 15  
Thereafter 170  
Total undiscounted cash flows 245  
Lease receivable 158  
Difference between undiscounted cash flows and discounted cash flows 87  
Other Property and Investments | Mississippi Power    
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]    
Lease receivable 129 $ 138
Other current assets | Mississippi Power    
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]    
Lease receivable 10 10
Other current assets | Southern Power    
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]    
Lease receivable 15 15
Net investment in sales-type leases | Southern Power    
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]    
Lease receivable $ 143 $ 148
v3.25.0.1
LEASES - Undiscounted Cash Flows to be Received Under PPAs Accounted for as Operating Leases (Details)
$ in Millions
Dec. 31, 2024
USD ($)
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]  
2025 $ 117
2026 111
2027 109
2028 109
2029 112
Thereafter 621
Total 1,179
Alabama Power  
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]  
2025 6
2026 5
2027 4
2028 4
2029 3
Thereafter 31
Total 53
Southern Power  
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]  
2025 142
2026 148
2027 150
2028 161
2029 164
Thereafter 506
Total 1,271
Southern Company Gas  
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]  
2025 35
2026 29
2027 28
2028 28
2029 28
Thereafter 326
Total $ 474
v3.25.0.1
LEASES - Leveraged Leases (Narrative) (Details)
 12 Months Ended
Dec. 31, 2024
leveragedLease
Leases [Abstract]  
Number of leveraged leases 1
Remaining lease term 7 years
v3.25.0.1
INCOME TAXES - Current and Deferred Income Tax Provisions (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Federal —      
Current $ 221 $ 54 $ 10
Deferred 387 299 455
Total federal taxes 608 353 465
State —      
Current 152 41 27
Deferred 209 102 303
Total state taxes 361 143 330
Income taxes 969 496 795
Alabama Power      
Federal —      
Current 357 242 54
Deferred (111) (257) 259
Total federal taxes 246 (15) 313
State —      
Current 103 82 14
Deferred 11 14 96
Total state taxes 114 96 110
Income taxes 360 81 423
Georgia Power      
Federal —      
Current 200 205 38
Deferred 211 195 152
Total federal taxes 411 400 190
State —      
Current 52 37 (21)
Deferred 140 11 201
Total state taxes 192 48 180
Income taxes 603 448 370
Mississippi Power      
Federal —      
Current 32 49 42
Deferred 2 (26) (16)
Total federal taxes 34 23 26
State —      
Current (1) 1 0
Deferred 14 12 11
Total state taxes 13 13 11
Income taxes 47 36 37
Southern Power      
Federal —      
Current (112) (320) (43)
Deferred 106 334 56
Total federal taxes (6) 14 13
State —      
Current 6 (1) 2
Deferred (13) (1) 5
Total state taxes (7) (2) 7
Income taxes (13) 12 20
Southern Company Gas      
Federal —      
Current 84 62 122
Deferred 86 68 (3)
Total federal taxes 170 130 119
State —      
Current 42 24 42
Deferred 46 57 19
Total state taxes 88 81 61
Income taxes $ 258 $ 211 $ 180
v3.25.0.1
INCOME TAXES - Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Income Tax Disclosure [Line Items]      
Deferred income tax assets $ 7,593 $ 7,886  
State investment tax credit carryforward 515    
Operating loss carryforwards, valuation allowance 82    
Southern Power      
Income Tax Disclosure [Line Items]      
Deferred income tax assets $ 638 773  
Percentage reduction in tax basis of assets 50.00%    
Operating loss carryforwards, valuation allowance $ 21    
Proceeds From Tax Credit Transfer 24    
Southern Power | ITCs and other credits carryforward      
Income Tax Disclosure [Line Items]      
Reduction in income tax expense, investment tax credits 71 332 $ 49
Southern Power | Production Tax Credit Carryforward      
Income Tax Disclosure [Line Items]      
Effective income tax rate reconciliation, tax credit, production, amount 32 26 27
Georgia Power      
Income Tax Disclosure [Line Items]      
Deferred income tax assets 3,564 3,718  
State investment tax credit carryforward 472    
Georgia Power | Production Tax Credit Carryforward      
Income Tax Disclosure [Line Items]      
Payments for transferred tax credit 131 39  
Mississippi Power      
Income Tax Disclosure [Line Items]      
Deferred income tax assets 358 382  
Southern Company Gas      
Income Tax Disclosure [Line Items]      
Deferred income tax assets 493 377  
State and Local Jurisdiction      
Income Tax Disclosure [Line Items]      
Valuation allowance 161    
Change in valuation allowance 101    
State and Local Jurisdiction | Georgia Power      
Income Tax Disclosure [Line Items]      
Valuation allowance 124    
Change in valuation allowance 64    
Proceeds From Tax Credit Transfer 11    
State and Local Jurisdiction | Georgia Power | ITCs and other credits carryforward      
Income Tax Disclosure [Line Items]      
Reduction in income tax expense, investment tax credits 44 $ 49 53
Deferred Charges Related To Income Taxes, Current | Other Noncurrent Assets | Southern Power | Unrealized Tax Credits      
Income Tax Disclosure [Line Items]      
Deferred income tax assets 0   $ 17
Mississippi | Mississippi Power      
Income Tax Disclosure [Line Items]      
Operating loss carryforwards, valuation allowance 32    
Oklahoma | Southern Power      
Income Tax Disclosure [Line Items]      
Operating loss carryforwards, valuation allowance 11    
Florida | Southern Power      
Income Tax Disclosure [Line Items]      
Operating loss carryforwards, valuation allowance $ 10    
v3.25.0.1
INCOME TAXES - Amortization of Deferred Credits (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Income Tax Disclosure [Line Items]      
Amortization of investment tax credits $ 109 $ 84 $ 83
Southern Power      
Income Tax Disclosure [Line Items]      
Amortization of investment tax credits $ 58 $ 58 $ 58
v3.25.0.1
INCOME TAXES - Reconciliation of Federal Statutory Income Tax Rate (Details)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Reconciliation of federal statutory income tax rate to effective income tax rate      
Federal statutory rate 21.00% 21.00% 21.00%
State income tax, net of federal deduction 3.60% 2.90% 7.80%
Changes in valuation allowance, net of federal benefit 1.90% (0.30%) (1.60%)
Employee stock plans' dividend deduction (0.40%) (0.50%) (0.50%)
Non-deductible book depreciation 0.60% 0.70% 0.60%
Flowback of excess deferred income taxes (3.90%) (9.20%) (6.60%)
AFUDC-Equity (0.80%) (1.10%) (1.10%)
Federal PTCs (2.80%) (1.20%) 0.00%
ITC amortization (1.20%) (1.30%) (1.30%)
Noncontrolling interests 0.60% 0.60% 0.50%
Other (0.10%) (0.20%) 0.00%
Effective income tax (benefit) rate 18.50% 11.40% 18.80%
Alabama Power      
Reconciliation of federal statutory income tax rate to effective income tax rate      
Federal statutory rate 21.00% 21.00% 21.00%
State income tax, net of federal deduction 5.00% 5.20% 4.80%
Changes in valuation allowance, net of federal benefit 0.00% 0.00% 0.00%
Employee stock plans' dividend deduction 0.00% 0.00% 0.00%
Non-deductible book depreciation 0.60% 0.70% 0.50%
Flowback of excess deferred income taxes (5.30%) (19.80%) (1.90%)
AFUDC-Equity (0.70%) (1.20%) (0.80%)
Federal PTCs (0.10%) 0.00% 0.00%
ITC amortization (0.10%) (0.10%) (0.10%)
Noncontrolling interests 0.00% 0.00% 0.00%
Other 0.00% (0.20%) 0.30%
Effective income tax (benefit) rate 20.40% 5.60% 23.80%
Georgia Power      
Reconciliation of federal statutory income tax rate to effective income tax rate      
Federal statutory rate 21.00% 21.00% 21.00%
State income tax, net of federal deduction 1.70% 2.10% 3.30%
Changes in valuation allowance, net of federal benefit 3.10% (0.60%) 3.20%
Employee stock plans' dividend deduction 0.00% 0.00% 0.00%
Non-deductible book depreciation 0.70% 0.80% 0.60%
Flowback of excess deferred income taxes (2.20%) (2.60%) (9.60%)
AFUDC-Equity (1.00%) (1.20%) (1.50%)
Federal PTCs (3.70%) (1.40%) 0.00%
ITC amortization (0.20%) (0.10%) (0.10%)
Noncontrolling interests 0.00% 0.00% 0.00%
Other (0.20%) (0.30%) 0.00%
Effective income tax (benefit) rate 19.20% 17.70% 16.90%
Mississippi Power      
Reconciliation of federal statutory income tax rate to effective income tax rate      
Federal statutory rate 21.00% 21.00% 21.00%
State income tax, net of federal deduction 4.40% 4.90% 4.40%
Changes in valuation allowance, net of federal benefit 0.00% 0.00% 0.00%
Employee stock plans' dividend deduction 0.00% 0.00% 0.00%
Non-deductible book depreciation 0.30% 0.40% 0.30%
Flowback of excess deferred income taxes (6.50%) (10.20%) (7.80%)
AFUDC-Equity 0.00% 0.00% 0.00%
Federal PTCs 0.00% 0.00% 0.00%
ITC amortization 0.00% 0.00% 0.00%
Noncontrolling interests 0.00% 0.00% 0.00%
Other 0.00% 0.10% 0.30%
Effective income tax (benefit) rate 19.20% 16.20% 18.20%
Southern Power      
Reconciliation of federal statutory income tax rate to effective income tax rate      
Federal statutory rate 21.00% 21.00% 21.00%
State income tax, net of federal deduction (2.30%) (0.70%) 1.90%
Changes in valuation allowance, net of federal benefit 0.00% 0.00% 0.00%
Employee stock plans' dividend deduction 0.00% 0.00% 0.00%
Non-deductible book depreciation 0.00% 0.00% 0.00%
Flowback of excess deferred income taxes 0.00% 0.00% 0.00%
AFUDC-Equity 0.00% 0.00% 0.00%
Federal PTCs (17.20%) (7.40%) (6.60%)
ITC amortization (26.40%) (19.00%) (17.20%)
Noncontrolling interests 17.10% 11.10% 8.40%
Other 0.20% 0.10% (0.10%)
Effective income tax (benefit) rate (7.60%) 5.10% 7.40%
Southern Company Gas      
Reconciliation of federal statutory income tax rate to effective income tax rate      
Federal statutory rate 21.00% 21.00% 21.00%
State income tax, net of federal deduction 7.00% 7.80% 6.40%
Changes in valuation allowance, net of federal benefit 0.00% 0.00% 0.00%
Employee stock plans' dividend deduction 0.00% 0.00% 0.00%
Non-deductible book depreciation 0.00% 0.00% 0.00%
Flowback of excess deferred income taxes (2.20%) (2.60%) (2.50%)
AFUDC-Equity 0.00% 0.00% 0.00%
Federal PTCs 0.00% 0.00% 0.00%
ITC amortization 0.00% 0.00% (0.10%)
Noncontrolling interests 0.00% 0.00% 0.00%
Other 0.00% (0.60%) (0.90%)
Effective income tax (benefit) rate 25.80% 25.60% 23.90%
v3.25.0.1
INCOME TAXES - Deferred Tax Assets and Liabilities (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Deferred tax liabilities —    
Deferred income tax liabilities $ 18,908 $ 18,574
Deferred tax assets —    
Deferred income tax assets 7,593 7,886
Valuation allowance (333) (206)
Net deferred income tax assets 7,260 7,680
Net deferred income taxes liabilities 11,648 10,894
Accumulated deferred income taxes – assets (82) (96)
Accumulated deferred income taxes – liabilities 11,730 10,990
Accelerated depreciation    
Deferred tax liabilities —    
Deferred income tax liabilities 9,828 9,683
Property basis differences    
Deferred tax liabilities —    
Deferred income tax liabilities 3,025 2,647
Employee benefit obligations    
Deferred tax liabilities —    
Deferred income tax liabilities 1,067 979
Deferred tax assets —    
Deferred income tax assets 897 985
AROs    
Deferred tax liabilities —    
Deferred income tax liabilities 727 833
Under recovered fuel and natural gas costs    
Deferred tax liabilities —    
Deferred income tax liabilities 318 601
AROs    
Deferred tax liabilities —    
Deferred income tax liabilities 1,886 1,902
Employee benefit obligations    
Deferred tax liabilities —    
Deferred income tax liabilities 746 797
Remaining book value of retired assets    
Deferred tax liabilities —    
Deferred income tax liabilities 360 369
Storm damage reserves    
Deferred tax liabilities —    
Deferred income tax liabilities 216  
Premium on reacquired debt    
Deferred tax liabilities —    
Deferred income tax liabilities 57 63
Other    
Deferred tax liabilities —    
Deferred income tax liabilities 678 700
AROs    
Deferred tax assets —    
Deferred income tax assets 2,613 2,735
CAMT Carryforwards    
Deferred tax assets —    
Deferred income tax assets 40  
ITC and PTC carryforwards    
Deferred tax assets —    
Deferred income tax assets 1,380 1,387
Estimated loss on plants under construction    
Deferred tax assets —    
Deferred income tax assets 773 857
Estimated loss on regulatory disallowance    
Deferred tax assets —    
Deferred income tax assets 20 26
Other state deferred tax attributes    
Deferred tax assets —    
Deferred income tax assets 366 363
Federal effect of net state deferred tax assets/liabilities    
Deferred tax assets —    
Deferred income tax assets 402 418
Other property basis differences    
Deferred tax assets —    
Deferred income tax assets 176 197
State effect of federal deferred taxes    
Deferred tax assets —    
Deferred income tax assets 126 115
Other partnership basis differences    
Deferred tax assets —    
Deferred income tax assets 60 85
Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)    
Deferred tax assets —    
Deferred income tax assets 18 34
Long-term debt fair value adjustment    
Deferred tax assets —    
Deferred income tax assets 73 79
Other comprehensive losses    
Deferred tax assets —    
Deferred income tax assets 48 67
Other    
Deferred tax assets —    
Deferred income tax assets 601 538
Alabama Power    
Deferred tax liabilities —    
Deferred income tax liabilities 6,109 6,101
Deferred tax assets —    
Deferred income tax assets 1,931 1,931
Valuation allowance 0 0
Net deferred income tax assets 1,931 1,931
Net deferred income taxes liabilities 4,178 4,170
Accumulated deferred income taxes – assets 0 0
Accumulated deferred income taxes – liabilities 4,178 4,170
Alabama Power | Accelerated depreciation    
Deferred tax liabilities —    
Deferred income tax liabilities 2,583 2,566
Alabama Power | Property basis differences    
Deferred tax liabilities —    
Deferred income tax liabilities 1,497 1,444
Alabama Power | Employee benefit obligations    
Deferred tax liabilities —    
Deferred income tax liabilities 362 321
Deferred tax assets —    
Deferred income tax assets 196 224
Alabama Power | AROs    
Deferred tax liabilities —    
Deferred income tax liabilities 458 476
Alabama Power | Under recovered fuel and natural gas costs    
Deferred tax liabilities —    
Deferred income tax liabilities 13 80
Alabama Power | AROs    
Deferred tax liabilities —    
Deferred income tax liabilities 658 667
Alabama Power | Employee benefit obligations    
Deferred tax liabilities —    
Deferred income tax liabilities 191 213
Alabama Power | Remaining book value of retired assets    
Deferred tax liabilities —    
Deferred income tax liabilities 168 143
Alabama Power | Storm damage reserves    
Deferred tax liabilities —    
Deferred income tax liabilities 0  
Alabama Power | Premium on reacquired debt    
Deferred tax liabilities —    
Deferred income tax liabilities 8 9
Alabama Power | Other    
Deferred tax liabilities —    
Deferred income tax liabilities 171 182
Alabama Power | AROs    
Deferred tax assets —    
Deferred income tax assets 1,116 1,143
Alabama Power | CAMT Carryforwards    
Deferred tax assets —    
Deferred income tax assets 0  
Alabama Power | ITC and PTC carryforwards    
Deferred tax assets —    
Deferred income tax assets 48 12
Alabama Power | Estimated loss on plants under construction    
Deferred tax assets —    
Deferred income tax assets 0 0
Alabama Power | Estimated loss on regulatory disallowance    
Deferred tax assets —    
Deferred income tax assets 0 0
Alabama Power | Other state deferred tax attributes    
Deferred tax assets —    
Deferred income tax assets 0 0
Alabama Power | Federal effect of net state deferred tax assets/liabilities    
Deferred tax assets —    
Deferred income tax assets 197 215
Alabama Power | Other property basis differences    
Deferred tax assets —    
Deferred income tax assets 0 0
Alabama Power | State effect of federal deferred taxes    
Deferred tax assets —    
Deferred income tax assets 126 115
Alabama Power | Other partnership basis differences    
Deferred tax assets —    
Deferred income tax assets 0 0
Alabama Power | Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)    
Deferred tax assets —    
Deferred income tax assets 18 30
Alabama Power | Long-term debt fair value adjustment    
Deferred tax assets —    
Deferred income tax assets 0 0
Alabama Power | Other comprehensive losses    
Deferred tax assets —    
Deferred income tax assets 3 4
Alabama Power | Other    
Deferred tax assets —    
Deferred income tax assets 227 188
Georgia Power    
Deferred tax liabilities —    
Deferred income tax liabilities 7,792 7,661
Deferred tax assets —    
Deferred income tax assets 3,564 3,718
Valuation allowance (157) (75)
Net deferred income tax assets 3,407 3,643
Net deferred income taxes liabilities 4,385 4,018
Accumulated deferred income taxes – assets 0 0
Accumulated deferred income taxes – liabilities 4,385 4,018
Georgia Power | Accelerated depreciation    
Deferred tax liabilities —    
Deferred income tax liabilities 3,810 3,628
Georgia Power | Property basis differences    
Deferred tax liabilities —    
Deferred income tax liabilities 918 812
Georgia Power | Employee benefit obligations    
Deferred tax liabilities —    
Deferred income tax liabilities 470 446
Deferred tax assets —    
Deferred income tax assets 279 316
Georgia Power | AROs    
Deferred tax liabilities —    
Deferred income tax liabilities 221 314
Georgia Power | Under recovered fuel and natural gas costs    
Deferred tax liabilities —    
Deferred income tax liabilities 305 508
Georgia Power | AROs    
Deferred tax liabilities —    
Deferred income tax liabilities 1,193 1,196
Georgia Power | Employee benefit obligations    
Deferred tax liabilities —    
Deferred income tax liabilities 237 260
Georgia Power | Remaining book value of retired assets    
Deferred tax liabilities —    
Deferred income tax liabilities 187 221
Georgia Power | Storm damage reserves    
Deferred tax liabilities —    
Deferred income tax liabilities 216  
Georgia Power | Premium on reacquired debt    
Deferred tax liabilities —    
Deferred income tax liabilities 48 53
Georgia Power | Other    
Deferred tax liabilities —    
Deferred income tax liabilities 187 223
Georgia Power | AROs    
Deferred tax assets —    
Deferred income tax assets 1,414 1,510
Georgia Power | CAMT Carryforwards    
Deferred tax assets —    
Deferred income tax assets 18  
Georgia Power | ITC and PTC carryforwards    
Deferred tax assets —    
Deferred income tax assets 719 691
Georgia Power | Estimated loss on plants under construction    
Deferred tax assets —    
Deferred income tax assets 773 857
Georgia Power | Estimated loss on regulatory disallowance    
Deferred tax assets —    
Deferred income tax assets 0 0
Georgia Power | Other state deferred tax attributes    
Deferred tax assets —    
Deferred income tax assets 26 13
Georgia Power | Federal effect of net state deferred tax assets/liabilities    
Deferred tax assets —    
Deferred income tax assets 100 92
Georgia Power | Other property basis differences    
Deferred tax assets —    
Deferred income tax assets 75 83
Georgia Power | State effect of federal deferred taxes    
Deferred tax assets —    
Deferred income tax assets 0 0
Georgia Power | Other partnership basis differences    
Deferred tax assets —    
Deferred income tax assets 0 0
Georgia Power | Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)    
Deferred tax assets —    
Deferred income tax assets 0 0
Georgia Power | Long-term debt fair value adjustment    
Deferred tax assets —    
Deferred income tax assets 0 0
Georgia Power | Other comprehensive losses    
Deferred tax assets —    
Deferred income tax assets 0 4
Georgia Power | Other    
Deferred tax assets —    
Deferred income tax assets 160 152
Mississippi Power    
Deferred tax liabilities —    
Deferred income tax liabilities 727 714
Deferred tax assets —    
Deferred income tax assets 358 382
Valuation allowance (41) (41)
Net deferred income tax assets 317 341
Net deferred income taxes liabilities 410 373
Accumulated deferred income taxes – assets (82) (96)
Accumulated deferred income taxes – liabilities 492 469
Mississippi Power | Accelerated depreciation    
Deferred tax liabilities —    
Deferred income tax liabilities 344 339
Mississippi Power | Property basis differences    
Deferred tax liabilities —    
Deferred income tax liabilities 192 188
Mississippi Power | Employee benefit obligations    
Deferred tax liabilities —    
Deferred income tax liabilities 54 49
Deferred tax assets —    
Deferred income tax assets 49 52
Mississippi Power | AROs    
Deferred tax liabilities —    
Deferred income tax liabilities 0 0
Mississippi Power | Under recovered fuel and natural gas costs    
Deferred tax liabilities —    
Deferred income tax liabilities 0 13
Mississippi Power | AROs    
Deferred tax liabilities —    
Deferred income tax liabilities 35 39
Mississippi Power | Employee benefit obligations    
Deferred tax liabilities —    
Deferred income tax liabilities 35 37
Mississippi Power | Remaining book value of retired assets    
Deferred tax liabilities —    
Deferred income tax liabilities 5 5
Mississippi Power | Storm damage reserves    
Deferred tax liabilities —    
Deferred income tax liabilities 0  
Mississippi Power | Premium on reacquired debt    
Deferred tax liabilities —    
Deferred income tax liabilities 1 1
Mississippi Power | Other    
Deferred tax liabilities —    
Deferred income tax liabilities 61 43
Mississippi Power | AROs    
Deferred tax assets —    
Deferred income tax assets 35 39
Mississippi Power | CAMT Carryforwards    
Deferred tax assets —    
Deferred income tax assets 0  
Mississippi Power | ITC and PTC carryforwards    
Deferred tax assets —    
Deferred income tax assets 0 0
Mississippi Power | Estimated loss on plants under construction    
Deferred tax assets —    
Deferred income tax assets 0 0
Mississippi Power | Estimated loss on regulatory disallowance    
Deferred tax assets —    
Deferred income tax assets 0 0
Mississippi Power | Other state deferred tax attributes    
Deferred tax assets —    
Deferred income tax assets 224 231
Mississippi Power | Federal effect of net state deferred tax assets/liabilities    
Deferred tax assets —    
Deferred income tax assets 0 0
Mississippi Power | Other property basis differences    
Deferred tax assets —    
Deferred income tax assets 0 0
Mississippi Power | State effect of federal deferred taxes    
Deferred tax assets —    
Deferred income tax assets 0 0
Mississippi Power | Other partnership basis differences    
Deferred tax assets —    
Deferred income tax assets 0 0
Mississippi Power | Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)    
Deferred tax assets —    
Deferred income tax assets 0 3
Mississippi Power | Long-term debt fair value adjustment    
Deferred tax assets —    
Deferred income tax assets 0 0
Mississippi Power | Other comprehensive losses    
Deferred tax assets —    
Deferred income tax assets 0 0
Mississippi Power | Other    
Deferred tax assets —    
Deferred income tax assets 50 57
Southern Power    
Deferred tax liabilities —    
Deferred income tax liabilities 1,323 1,360
Deferred tax assets —    
Deferred income tax assets 638 773
Valuation allowance (27) (27)
Net deferred income tax assets 611 746
Net deferred income taxes liabilities 712 614
Accumulated deferred income taxes – assets 0 0
Accumulated deferred income taxes – liabilities 712 614
Southern Power | Accelerated depreciation    
Deferred tax liabilities —    
Deferred income tax liabilities 1,309 1,346
Southern Power | Property basis differences    
Deferred tax liabilities —    
Deferred income tax liabilities 0 0
Southern Power | Employee benefit obligations    
Deferred tax liabilities —    
Deferred income tax liabilities 13 12
Deferred tax assets —    
Deferred income tax assets 16 10
Southern Power | AROs    
Deferred tax liabilities —    
Deferred income tax liabilities 0 0
Southern Power | Under recovered fuel and natural gas costs    
Deferred tax liabilities —    
Deferred income tax liabilities 0 0
Southern Power | AROs    
Deferred tax liabilities —    
Deferred income tax liabilities 0 0
Southern Power | Employee benefit obligations    
Deferred tax liabilities —    
Deferred income tax liabilities 0 0
Southern Power | Remaining book value of retired assets    
Deferred tax liabilities —    
Deferred income tax liabilities 0 0
Southern Power | Storm damage reserves    
Deferred tax liabilities —    
Deferred income tax liabilities 0  
Southern Power | Premium on reacquired debt    
Deferred tax liabilities —    
Deferred income tax liabilities 0 0
Southern Power | Other    
Deferred tax liabilities —    
Deferred income tax liabilities 1 2
Southern Power | AROs    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Power | CAMT Carryforwards    
Deferred tax assets —    
Deferred income tax assets 0  
Southern Power | ITC and PTC carryforwards    
Deferred tax assets —    
Deferred income tax assets 384 481
Southern Power | Estimated loss on plants under construction    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Power | Estimated loss on regulatory disallowance    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Power | Other state deferred tax attributes    
Deferred tax assets —    
Deferred income tax assets 49 49
Southern Power | Federal effect of net state deferred tax assets/liabilities    
Deferred tax assets —    
Deferred income tax assets 23 27
Southern Power | Other property basis differences    
Deferred tax assets —    
Deferred income tax assets 85 97
Southern Power | State effect of federal deferred taxes    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Power | Other partnership basis differences    
Deferred tax assets —    
Deferred income tax assets 60 85
Southern Power | Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Power | Long-term debt fair value adjustment    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Power | Other comprehensive losses    
Deferred tax assets —    
Deferred income tax assets 1 6
Southern Power | Other    
Deferred tax assets —    
Deferred income tax assets 20 18
Southern Company Gas    
Deferred tax liabilities —    
Deferred income tax liabilities 2,283 2,041
Deferred tax assets —    
Deferred income tax assets 493 377
Valuation allowance (6) (7)
Net deferred income tax assets 487 370
Net deferred income taxes liabilities 1,796 1,671
Accumulated deferred income taxes – assets 0 0
Accumulated deferred income taxes – liabilities 1,796 1,671
Southern Company Gas | Accelerated depreciation    
Deferred tax liabilities —    
Deferred income tax liabilities 1,575 1,576
Southern Company Gas | Property basis differences    
Deferred tax liabilities —    
Deferred income tax liabilities 412 189
Southern Company Gas | Employee benefit obligations    
Deferred tax liabilities —    
Deferred income tax liabilities 60 74
Deferred tax assets —    
Deferred income tax assets 87 89
Southern Company Gas | AROs    
Deferred tax liabilities —    
Deferred income tax liabilities 0 0
Southern Company Gas | Under recovered fuel and natural gas costs    
Deferred tax liabilities —    
Deferred income tax liabilities 0 0
Southern Company Gas | AROs    
Deferred tax liabilities —    
Deferred income tax liabilities 0 0
Southern Company Gas | Employee benefit obligations    
Deferred tax liabilities —    
Deferred income tax liabilities 35 11
Southern Company Gas | Remaining book value of retired assets    
Deferred tax liabilities —    
Deferred income tax liabilities 0 0
Southern Company Gas | Storm damage reserves    
Deferred tax liabilities —    
Deferred income tax liabilities 0  
Southern Company Gas | Premium on reacquired debt    
Deferred tax liabilities —    
Deferred income tax liabilities 0 0
Southern Company Gas | Other    
Deferred tax liabilities —    
Deferred income tax liabilities 201 191
Southern Company Gas | AROs    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Company Gas | CAMT Carryforwards    
Deferred tax assets —    
Deferred income tax assets 104  
Southern Company Gas | ITC and PTC carryforwards    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Company Gas | Estimated loss on plants under construction    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Company Gas | Estimated loss on regulatory disallowance    
Deferred tax assets —    
Deferred income tax assets 20 26
Southern Company Gas | Other state deferred tax attributes    
Deferred tax assets —    
Deferred income tax assets 16 8
Southern Company Gas | Federal effect of net state deferred tax assets/liabilities    
Deferred tax assets —    
Deferred income tax assets 107 101
Southern Company Gas | Other property basis differences    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Company Gas | State effect of federal deferred taxes    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Company Gas | Other partnership basis differences    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Company Gas | Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Company Gas | Long-term debt fair value adjustment    
Deferred tax assets —    
Deferred income tax assets 73 79
Southern Company Gas | Other comprehensive losses    
Deferred tax assets —    
Deferred income tax assets 0 0
Southern Company Gas | Other    
Deferred tax assets —    
Deferred income tax assets $ 86 $ 74
v3.25.0.1
INCOME TAXES - Federal ITC/PTC Carryforwards (Details)
$ in Millions
Dec. 31, 2024
USD ($)
ITC and PTC carryforwards  
Operating Loss Carryforwards [Line Items]  
Federal ITC/PTC carryforwards $ 765
ITC and PTC carryforwards | Alabama Power  
Operating Loss Carryforwards [Line Items]  
Federal ITC/PTC carryforwards 48
ITC and PTC carryforwards | Georgia Power  
Operating Loss Carryforwards [Line Items]  
Federal ITC/PTC carryforwards 147
ITC and PTC carryforwards | Southern Power  
Operating Loss Carryforwards [Line Items]  
Federal ITC/PTC carryforwards 384
Corporate Alternative Minimum Tax Credit Carryforward  
Operating Loss Carryforwards [Line Items]  
Federal ITC/PTC carryforwards $ 40
v3.25.0.1
INCOME TAXES - NOL Carryforwards (Details)
$ in Millions
Dec. 31, 2024
USD ($)
Operating Loss Carryforwards [Line Items]  
Approximate Net State Income Tax Benefit of NOL Carryforwards $ 265
Operating loss carryforwards, valuation allowance (82)
Mississippi Power | Mississippi  
Operating Loss Carryforwards [Line Items]  
Approximate Net State Income Tax Benefit of NOL Carryforwards 178
Operating loss carryforwards, valuation allowance (32)
Southern Power  
Operating Loss Carryforwards [Line Items]  
Approximate Net State Income Tax Benefit of NOL Carryforwards 38
Operating loss carryforwards, valuation allowance (21)
Southern Power | Oklahoma  
Operating Loss Carryforwards [Line Items]  
Approximate Net State Income Tax Benefit of NOL Carryforwards 26
Operating loss carryforwards, valuation allowance (11)
Southern Power | Florida  
Operating Loss Carryforwards [Line Items]  
Approximate Net State Income Tax Benefit of NOL Carryforwards 10
Operating loss carryforwards, valuation allowance (10)
Southern Power | Other states  
Operating Loss Carryforwards [Line Items]  
Approximate Net State Income Tax Benefit of NOL Carryforwards 2
Operating loss carryforwards, valuation allowance 0
Other Subsidiaries | Other states  
Operating Loss Carryforwards [Line Items]  
Approximate Net State Income Tax Benefit of NOL Carryforwards 24
Operating loss carryforwards, valuation allowance (4)
Other Subsidiaries | New York  
Operating Loss Carryforwards [Line Items]  
Approximate Net State Income Tax Benefit of NOL Carryforwards 11
Operating loss carryforwards, valuation allowance (11)
Other Subsidiaries | New York City  
Operating Loss Carryforwards [Line Items]  
Approximate Net State Income Tax Benefit of NOL Carryforwards 14
Operating loss carryforwards, valuation allowance $ (14)
v3.25.0.1
INCOME TAXES - Changes in Unrecognized Tax Benefits (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Changes in unrecognized tax benefits [Roll Forward]      
Beginning balance $ 116 $ 80 $ 47
Increase from prior periods 10 88 33
Decrease from prior periods (44)    
Ending balance 82 116 80
Estimated loss on plants under construction      
Changes in unrecognized tax benefits [Roll Forward]      
Statute of limitations expiration   (52)  
Georgia Power      
Changes in unrecognized tax benefits [Roll Forward]      
Beginning balance 77 0 0
Increase from prior periods 0 86 0
Decrease from prior periods (43)    
Ending balance 34 77 0
Georgia Power | Estimated loss on plants under construction      
Changes in unrecognized tax benefits [Roll Forward]      
Statute of limitations expiration   (9)  
Southern Company Gas      
Changes in unrecognized tax benefits [Roll Forward]      
Beginning balance 34 32 0
Increase from prior periods 10 2 32
Decrease from prior periods 0    
Ending balance $ 44 34 $ 32
Southern Company Gas | Estimated loss on plants under construction      
Changes in unrecognized tax benefits [Roll Forward]      
Statute of limitations expiration   $ 0  
v3.25.0.1
RETIREMENT BENEFITS - Narrative (Details) - USD ($)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]    
Plan asset amortization period 5 years  
Pension plans    
Defined Benefit Plan Disclosure [Line Items]    
Employer contributions $ 65,000,000 $ 52,000,000
Expected future employer contributions, next fiscal year 0  
Actuarial losses $ (887,000,000) $ 493,000,000
Change in discount rate 0.69% 0.18%
Pension plans | Qualified pension plan    
Defined Benefit Plan Disclosure [Line Items]    
Employer contributions $ 0  
Other postretirement benefit plans    
Defined Benefit Plan Disclosure [Line Items]    
Employer contributions 55,000,000 $ 73,000,000
Expected future employer contributions, next fiscal year 0  
Actuarial losses $ (2,000,000) $ (33,000,000)
v3.25.0.1
RETIREMENT BENEFITS - Actuarial Assumptions (Details)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.07% 5.25% 3.09%
Expected long-term return on plan assets 8.30% 8.40% 8.25%
Annual salary increase, net periodic costs 4.60% 4.80% 4.80%
Pension plans | Discount rate – interest costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 4.94% 5.13% 2.55%
Pension plans | Discount rate – service costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 5.19% 5.36% 3.34%
Pension plans | Employee benefit obligations      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.76% 5.07%  
Annual salary increase, benefit obligations 4.60% 4.60%  
Other postretirement benefit plans      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 4.99% 5.18% 2.90%
Expected long-term return on plan assets 7.67% 7.67% 7.21%
Annual salary increase, net periodic costs 4.60% 4.80% 4.80%
Other postretirement benefit plans | Discount rate – interest costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 4.90% 5.08% 2.32%
Other postretirement benefit plans | Discount rate – service costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 5.16% 5.34% 3.26%
Other postretirement benefit plans | Employee benefit obligations      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.64% 4.99%  
Annual salary increase, benefit obligations 4.60% 4.60%  
Alabama Power | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.08% 5.26% 3.12%
Expected long-term return on plan assets 8.30% 8.40% 8.25%
Annual salary increase, net periodic costs 4.60% 4.80% 4.80%
Alabama Power | Pension plans | Discount rate – interest costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 4.94% 5.14% 2.58%
Alabama Power | Pension plans | Discount rate – service costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 5.20% 5.38% 3.36%
Alabama Power | Pension plans | Employee benefit obligations      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.78% 5.08%  
Annual salary increase, benefit obligations 4.60% 4.60%  
Alabama Power | Other postretirement benefit plans      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.01% 5.20% 2.95%
Expected long-term return on plan assets 7.97% 7.95% 7.54%
Annual salary increase, net periodic costs 4.60% 4.80% 4.80%
Alabama Power | Other postretirement benefit plans | Discount rate – interest costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 4.90% 5.09% 2.38%
Alabama Power | Other postretirement benefit plans | Discount rate – service costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 5.17% 5.35% 3.30%
Alabama Power | Other postretirement benefit plans | Employee benefit obligations      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.67% 5.01%  
Annual salary increase, benefit obligations 4.60% 4.60%  
Georgia Power | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.06% 5.25% 3.07%
Expected long-term return on plan assets 8.30% 8.40% 8.25%
Annual salary increase, net periodic costs 4.60% 4.80% 4.80%
Georgia Power | Pension plans | Discount rate – interest costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 4.94% 5.12% 2.51%
Georgia Power | Pension plans | Discount rate – service costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 5.21% 5.38% 3.37%
Georgia Power | Pension plans | Employee benefit obligations      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.75% 5.06%  
Annual salary increase, benefit obligations 4.60% 4.60%  
Georgia Power | Other postretirement benefit plans      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 4.98% 5.17% 2.87%
Expected long-term return on plan assets 7.59% 7.49% 6.88%
Annual salary increase, net periodic costs 4.60% 4.80% 4.80%
Georgia Power | Other postretirement benefit plans | Discount rate – interest costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 4.89% 5.07% 2.30%
Georgia Power | Other postretirement benefit plans | Discount rate – service costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 5.16% 5.34% 3.27%
Georgia Power | Other postretirement benefit plans | Employee benefit obligations      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.61% 4.98%  
Annual salary increase, benefit obligations 4.60% 4.60%  
Mississippi Power | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.06% 5.25% 3.07%
Expected long-term return on plan assets 8.30% 8.40% 8.25%
Annual salary increase, net periodic costs 4.60% 4.80% 4.80%
Mississippi Power | Pension plans | Discount rate – interest costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 4.93% 5.12% 2.54%
Mississippi Power | Pension plans | Discount rate – service costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 5.19% 5.37% 3.35%
Mississippi Power | Pension plans | Employee benefit obligations      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.76% 5.06%  
Annual salary increase, benefit obligations 4.60% 4.60%  
Mississippi Power | Other postretirement benefit plans      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 4.98% 5.17% 2.88%
Expected long-term return on plan assets 7.43% 7.43% 7.22%
Annual salary increase, net periodic costs 4.60% 4.80% 4.80%
Mississippi Power | Other postretirement benefit plans | Discount rate – interest costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 4.90% 5.08% 2.27%
Mississippi Power | Other postretirement benefit plans | Discount rate – service costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 5.16% 5.33% 3.26%
Mississippi Power | Other postretirement benefit plans | Employee benefit obligations      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.63% 4.98%  
Annual salary increase, benefit obligations 4.60% 4.60%  
Southern Power | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.14% 5.31% 3.21%
Expected long-term return on plan assets 8.30% 8.40% 8.25%
Annual salary increase, net periodic costs 4.60% 4.80% 4.80%
Southern Power | Pension plans | Discount rate – interest costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 5.01% 5.19% 2.79%
Southern Power | Pension plans | Discount rate – service costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 5.20% 5.37% 3.36%
Southern Power | Pension plans | Employee benefit obligations      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.84% 5.14%  
Annual salary increase, benefit obligations 4.60% 4.60%  
Southern Power | Other postretirement benefit plans      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.06% 5.24% 3.07%
Expected long-term return on plan assets 0.00% 0.00% 0.00%
Annual salary increase, net periodic costs 4.60% 4.80% 4.80%
Southern Power | Other postretirement benefit plans | Discount rate – interest costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 4.94% 5.12% 2.55%
Southern Power | Other postretirement benefit plans | Discount rate – service costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 5.14% 5.33% 3.25%
Southern Power | Other postretirement benefit plans | Employee benefit obligations      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.73% 5.06%  
Annual salary increase, benefit obligations 4.60% 4.60%  
Southern Company Gas | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.05% 5.24% 3.04%
Expected long-term return on plan assets 8.30% 8.40% 8.25%
Annual salary increase, net periodic costs 4.60% 4.80% 4.80%
Southern Company Gas | Pension plans | Discount rate – interest costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 4.93% 5.12% 2.53%
Southern Company Gas | Pension plans | Discount rate – service costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 5.13% 5.31% 3.21%
Southern Company Gas | Pension plans | Employee benefit obligations      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.73% 5.05%  
Annual salary increase, benefit obligations 4.60% 4.60%  
Southern Company Gas | Other postretirement benefit plans      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 4.98% 5.16% 2.82%
Expected long-term return on plan assets 6.36% 6.59% 6.08%
Annual salary increase, net periodic costs 4.60% 4.80% 4.80%
Southern Company Gas | Other postretirement benefit plans | Discount rate – interest costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 4.89% 5.07% 2.17%
Southern Company Gas | Other postretirement benefit plans | Discount rate – service costs      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate, net periodic benefit costs 5.16% 5.33% 3.22%
Southern Company Gas | Other postretirement benefit plans | Employee benefit obligations      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate – benefit obligations 5.62% 4.98%  
Annual salary increase, benefit obligations 4.60% 4.60%  
v3.25.0.1
RETIREMENT BENEFITS - Schedule of Health Care Cost Trend Rates (Details)
Dec. 31, 2024
Pre-65  
Defined Benefit Plan Disclosure [Line Items]  
Initial Cost Trend Rate 8.00%
Ultimate Cost Trend Rate 4.50%
Post-65 medical  
Defined Benefit Plan Disclosure [Line Items]  
Initial Cost Trend Rate 5.50%
Ultimate Cost Trend Rate 4.50%
Post-65 prescription  
Defined Benefit Plan Disclosure [Line Items]  
Initial Cost Trend Rate 11.00%
Ultimate Cost Trend Rate 4.50%
v3.25.0.1
RETIREMENT BENEFITS - Accumulated Benefit Obligation (Details) - Pension plans - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]    
Total accumulated benefit obligation for the pension plans $ 11,437 $ 11,991
Alabama Power    
Defined Benefit Plan Disclosure [Line Items]    
Total accumulated benefit obligation for the pension plans 2,617 2,746
Georgia Power    
Defined Benefit Plan Disclosure [Line Items]    
Total accumulated benefit obligation for the pension plans 3,438 3,674
Mississippi Power    
Defined Benefit Plan Disclosure [Line Items]    
Total accumulated benefit obligation for the pension plans 519 546
Southern Power    
Defined Benefit Plan Disclosure [Line Items]    
Total accumulated benefit obligation for the pension plans 140 145
Southern Company Gas    
Defined Benefit Plan Disclosure [Line Items]    
Total accumulated benefit obligation for the pension plans $ 779 $ 808
v3.25.0.1
RETIREMENT BENEFITS - Changes in Projected Benefit Obligations and Fair Value of Plan Assets (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Pension plans      
Change in benefit obligation      
Benefit obligation at beginning of year $ 13,252 $ 12,602  
Service cost 292 275 $ 412
Interest cost 635 626 408
Benefits paid (728) (744)  
Actuarial gain (887) 493  
Balance at end of year 12,564 13,252 12,602
Change in plan assets      
Fair value of plan assets at beginning of year 14,618 14,218  
Actual return on plan assets 604 1,092  
Employer contributions 65 52  
Benefits paid (728) (744)  
Fair value of plan assets at end of year 14,559 14,618 14,218
Accrued asset 1,995 1,366  
Other postretirement benefit plans      
Change in benefit obligation      
Benefit obligation at beginning of year 1,386 1,441  
Service cost 15 15 23
Interest cost 65 70 42
Benefits paid (105) (107)  
Actuarial gain (2) (33)  
Balance at end of year 1,359 1,386 1,441
Change in plan assets      
Fair value of plan assets at beginning of year 1,095 998  
Actual return on plan assets 96 131  
Employer contributions 55 73  
Benefits paid (105) (107)  
Fair value of plan assets at end of year 1,141 1,095 998
Accrued asset (218) (291)  
Alabama Power | Pension plans      
Change in benefit obligation      
Benefit obligation at beginning of year 3,076 2,906  
Service cost 68 64 99
Interest cost 148 145 96
Benefits paid (162) (155)  
Actuarial gain (222) 116  
Balance at end of year 2,908 3,076 2,906
Change in plan assets      
Fair value of plan assets at beginning of year 3,544 3,427  
Actual return on plan assets 148 260  
Employer contributions 9 11  
Benefits paid (162) (154)  
Fair value of plan assets at end of year 3,539 3,544 3,427
Accrued asset 631 468  
Alabama Power | Other postretirement benefit plans      
Change in benefit obligation      
Benefit obligation at beginning of year 329 344  
Service cost 4 4 6
Interest cost 16 17 10
Benefits paid (25) (24)  
Actuarial gain 2 (12)  
Balance at end of year 326 329 344
Change in plan assets      
Fair value of plan assets at beginning of year 403 372  
Actual return on plan assets 37 52  
Employer contributions 6 3  
Benefits paid (25) (24)  
Fair value of plan assets at end of year 421 403 372
Accrued asset 95 74  
Georgia Power | Pension plans      
Change in benefit obligation      
Benefit obligation at beginning of year 4,009 3,851  
Service cost 70 68 103
Interest cost 191 191 123
Benefits paid (239) (224)  
Actuarial gain (298) 123  
Balance at end of year 3,733 4,009 3,851
Change in plan assets      
Fair value of plan assets at beginning of year 4,571 4,456  
Actual return on plan assets 152 331  
Employer contributions 35 9  
Benefits paid (239) (225)  
Fair value of plan assets at end of year 4,519 4,571 4,456
Accrued asset 786 562  
Georgia Power | Other postretirement benefit plans      
Change in benefit obligation      
Benefit obligation at beginning of year 489 514  
Service cost 4 4 6
Interest cost 23 25 15
Benefits paid (37) (36)  
Actuarial gain 9 (18)  
Balance at end of year 488 489 514
Change in plan assets      
Fair value of plan assets at beginning of year 410 368  
Actual return on plan assets 34 51  
Employer contributions 13 27  
Benefits paid (37) (36)  
Fair value of plan assets at end of year 420 410 368
Accrued asset (68) (79)  
Mississippi Power | Pension plans      
Change in benefit obligation      
Benefit obligation at beginning of year 599 569  
Service cost 12 11 17
Interest cost 29 28 18
Benefits paid (33) (32)  
Actuarial gain (40) 23  
Balance at end of year 567 599 569
Change in plan assets      
Fair value of plan assets at beginning of year 669 649  
Actual return on plan assets 23 50  
Employer contributions 5 2  
Benefits paid (33) (32)  
Fair value of plan assets at end of year 664 669 649
Accrued asset 97 70  
Mississippi Power | Other postretirement benefit plans      
Change in benefit obligation      
Benefit obligation at beginning of year 57 59  
Service cost 1 1 1
Interest cost 3 3 2
Benefits paid (4) (4)  
Actuarial gain (2) (2)  
Balance at end of year 55 57 59
Change in plan assets      
Fair value of plan assets at beginning of year 25 24  
Actual return on plan assets 0 2  
Employer contributions 3 3  
Benefits paid (4) (4)  
Fair value of plan assets at end of year 24 25 24
Accrued asset (31) (32)  
Southern Power | Pension plans      
Change in benefit obligation      
Benefit obligation at beginning of year 177 163  
Service cost 7 6 9
Interest cost 9 8 6
Benefits paid (6) (6)  
Actuarial gain (20) 6  
Balance at end of year 167 177 163
Change in plan assets      
Fair value of plan assets at beginning of year 185 178  
Actual return on plan assets 7 12  
Employer contributions 2 2  
Benefits paid (6) (7)  
Fair value of plan assets at end of year 188 185 178
Accrued asset 21 8  
Southern Power | Other postretirement benefit plans      
Change in benefit obligation      
Benefit obligation at beginning of year 9 9  
Service cost 0 0 0
Interest cost 0 0 0
Benefits paid (1) (1)  
Actuarial gain 1 1  
Balance at end of year 9 9 9
Change in plan assets      
Fair value of plan assets at beginning of year 0 0  
Actual return on plan assets 0 0  
Employer contributions 1 1  
Benefits paid (1) (1)  
Fair value of plan assets at end of year 0 0 0
Accrued asset (9) (9)  
Southern Company Gas | Pension plans      
Change in benefit obligation      
Benefit obligation at beginning of year 882 868  
Service cost 28 24 34
Interest cost 42 42 28
Benefits paid (46) (104)  
Actuarial gain (64) 52  
Balance at end of year 842 882 868
Change in plan assets      
Fair value of plan assets at beginning of year 980 1,002  
Actual return on plan assets 39 79  
Employer contributions 5 3  
Benefits paid (46) (104)  
Fair value of plan assets at end of year 978 980 1,002
Accrued asset 136 98  
Southern Company Gas | Other postretirement benefit plans      
Change in benefit obligation      
Benefit obligation at beginning of year 172 179  
Service cost 1 1 1
Interest cost 8 9 5
Benefits paid (12) (18)  
Actuarial gain (13) 1  
Balance at end of year 156 172 179
Change in plan assets      
Fair value of plan assets at beginning of year 128 113  
Actual return on plan assets 18 19  
Employer contributions 7 14  
Benefits paid (12) (18)  
Fair value of plan assets at end of year 141 128 $ 113
Accrued asset $ (15) $ (44)  
v3.25.0.1
RETIREMENT BENEFITS - Projected Benefit Plan Obligations (Details) - Pension plans - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: $ 12,564 $ 13,252 $ 12,602
Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 2,908 3,076 2,906
Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 3,733 4,009 3,851
Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 567 599 569
SOUTHERN POWER CO      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 167 177 163
Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 842 $ 882 $ 868
Qualified pension plan      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 11,886    
Qualified pension plan | Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 2,794    
Qualified pension plan | Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 3,622    
Qualified pension plan | Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 540    
Qualified pension plan | SOUTHERN POWER CO      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 146    
Qualified pension plan | Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 788    
Non-qualified pension plan      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 678    
Non-qualified pension plan | Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 114    
Non-qualified pension plan | Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 111    
Non-qualified pension plan | Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 27    
Non-qualified pension plan | SOUTHERN POWER CO      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: 21    
Non-qualified pension plan | Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligations: $ 54    
v3.25.0.1
RETIREMENT BENEFITS - Amounts Recognized in Balance Sheets and Amounts in AOCI (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]      
Other regulatory assets, deferred $ 7,037 $ 6,264  
Other current liabilities (1,100) (1,029)  
Employee benefit obligations (1,011) (1,115)  
Other regulatory liabilities, deferred (692) (715)  
Regulatory asset   66 $ 216
Other deferred charges and assets 1,467 1,468  
Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Prepaid pension costs 2,674 2,079  
Other regulatory assets, deferred 2,708 2,960  
Other current liabilities (68) (64)  
Employee benefit obligations (611) (649)  
Other regulatory liabilities, deferred (50) (47)  
AOCI 52 79  
Other Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Other regulatory assets, deferred 24 23  
Other current liabilities (6) (6)  
Employee benefit obligations (212) (285)  
Other regulatory liabilities, deferred (213) (231)  
AOCI (14) (9)  
Prepaid pension and other postretirement benefit costs 0 0  
Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Other regulatory assets, deferred 1,815 1,858  
Other current liabilities (219) (191)  
Employee benefit obligations (148) (155)  
Other regulatory liabilities, deferred (271) (291)  
Regulatory asset 70 76 97
Prepaid pension and other postretirement benefit costs 841 659  
Other deferred charges and assets 391 414  
Alabama Power | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Prepaid pension costs 746 585  
Other regulatory assets, deferred 741 821  
Other current liabilities (13) (11)  
Employee benefit obligations (102) (106)  
Other regulatory liabilities, deferred 0 0  
AOCI 0 0  
Alabama Power | Other Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Other regulatory assets, deferred 0 0  
Other current liabilities 0 0  
Employee benefit obligations 0 0  
Other regulatory liabilities, deferred (45) (48)  
AOCI 0 0  
Prepaid pension and other postretirement benefit costs 95 74  
Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Other regulatory assets, deferred 3,814 2,890  
Other current liabilities (296) (365)  
Employee benefit obligations (205) (248)  
Regulatory asset     83
Other deferred charges and assets 615 508  
Georgia Power | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Prepaid pension costs 897 706  
Other regulatory assets, deferred 973 1,051  
Other current liabilities (13) (13)  
Employee benefit obligations (98) (131)  
Other regulatory liabilities, deferred 0 0  
AOCI 0 0  
Georgia Power | Other Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Other regulatory assets, deferred 3 11  
Other current liabilities 0 0  
Employee benefit obligations (68) (79)  
Other regulatory liabilities, deferred (67) (85)  
AOCI 0 0  
Prepaid pension and other postretirement benefit costs 0 0  
Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Other regulatory assets, deferred 259 285  
Other current liabilities (95) (90)  
Employee benefit obligations (65) (67)  
Other regulatory liabilities, deferred (121) (92)  
Regulatory asset 52 44 $ 36
Other deferred charges and assets 74 85  
Mississippi Power | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Prepaid pension costs 124 99  
Other regulatory assets, deferred 144 152  
Other current liabilities (2) (2)  
Employee benefit obligations (25) (27)  
Other regulatory liabilities, deferred 0 0  
AOCI 0 0  
Mississippi Power | Other Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Other regulatory assets, deferred 0 0  
Other current liabilities 0 0  
Employee benefit obligations (31) (32)  
Other regulatory liabilities, deferred (9) (10)  
AOCI 0 0  
Prepaid pension and other postretirement benefit costs 0 0  
Southern Power      
Defined Benefit Plan Disclosure [Line Items]      
Other current liabilities (96) (97)  
Other deferred charges and assets 232 262  
Southern Power | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Prepaid pension costs 41 31  
Other regulatory assets, deferred 0 0  
Other current liabilities (2) (2)  
Employee benefit obligations (18) (21)  
Other regulatory liabilities, deferred 0 0  
AOCI 11 20  
Southern Power | Other Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Other regulatory assets, deferred 0 0  
Other current liabilities (1) (1)  
Employee benefit obligations (8) (8)  
Other regulatory liabilities, deferred 0 0  
AOCI 0 1  
Prepaid pension and other postretirement benefit costs 0 0  
Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Other regulatory assets, deferred 481 504  
Other current liabilities (237) (232)  
Employee benefit obligations (78) (110)  
Other deferred charges and assets 192 181  
Southern Company Gas | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Prepaid pension costs 191 158  
Other regulatory assets, deferred 126 143  
Other current liabilities (4) (3)  
Employee benefit obligations (51) (58)  
Other regulatory liabilities, deferred 0 0  
AOCI (54) (45)  
Regulatory asset 155 173  
Southern Company Gas | Other Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Other regulatory assets, deferred 0 0  
Other current liabilities 0 0  
Employee benefit obligations (15) (44)  
Other regulatory liabilities, deferred (84) (68)  
AOCI (15) (10)  
Regulatory asset 16 24  
Prepaid pension and other postretirement benefit costs $ 0 $ 0  
v3.25.0.1
RETIREMENT BENEFITS - Regulatory Assets (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets $ 7,041 $ 6,523  
Regulatory asset   66 $ 216
Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 2,356 2,720  
Regulatory asset 70 76 97
Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 6,139 5,090  
Regulatory asset     83
Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 59 90  
Regulatory asset 52 44 $ 36
Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets (2,252) (2,225)  
Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 2,658 2,913  
Pension plans | Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 741 821  
Pension plans | Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 973 1,051  
Pension plans | Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 144 152  
Pension plans | Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 126 143  
Regulatory asset 155 173  
Other Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 189 203  
Other Postretirement Benefits Plan | Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 45 48  
Other Postretirement Benefits Plan | Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 64 74  
Other Postretirement Benefits Plan | Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 9 (10)  
Other Postretirement Benefits Plan | Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 84 68  
Regulatory asset 16 24  
Prior Service Cost | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 8 9  
Prior Service Cost | Pension plans | Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 3 4  
Prior Service Cost | Pension plans | Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 5 6  
Prior Service Cost | Pension plans | Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 1 1  
Prior Service Cost | Pension plans | Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets (4) (7)  
Prior Service Cost | Other Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 11 13  
Prior Service Cost | Other Postretirement Benefits Plan | Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 3 4  
Prior Service Cost | Other Postretirement Benefits Plan | Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 4 5  
Prior Service Cost | Other Postretirement Benefits Plan | Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 1 1  
Prior Service Cost | Other Postretirement Benefits Plan | Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 0 0  
Net Actuarial Gain (Loss) | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 2,650 2,904  
Net Actuarial Gain (Loss) | Pension plans | Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 738 817  
Net Actuarial Gain (Loss) | Pension plans | Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 968 1,045  
Net Actuarial Gain (Loss) | Pension plans | Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 143 151  
Net Actuarial Gain (Loss) | Pension plans | Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 91 100  
Net Actuarial Gain (Loss) | Other Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 200 216  
Net Actuarial Gain (Loss) | Other Postretirement Benefits Plan | Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 48 52  
Net Actuarial Gain (Loss) | Other Postretirement Benefits Plan | Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 68 79  
Net Actuarial Gain (Loss) | Other Postretirement Benefits Plan | Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 10 11  
Net Actuarial Gain (Loss) | Other Postretirement Benefits Plan | Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 71 64  
Regulatory Amortization | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 0 0  
Regulatory Amortization | Pension plans | Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 0 0  
Regulatory Amortization | Pension plans | Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 0 0  
Regulatory Amortization | Pension plans | Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 0 0  
Regulatory Amortization | Pension plans | Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 39 50  
Regulatory Amortization | Other Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 0 0  
Regulatory Amortization | Other Postretirement Benefits Plan | Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 0 0  
Regulatory Amortization | Other Postretirement Benefits Plan | Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 0 0  
Regulatory Amortization | Other Postretirement Benefits Plan | Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets 0 0  
Regulatory Amortization | Other Postretirement Benefits Plan | Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Net regulatory assets $ (13) $ (4)  
v3.25.0.1
RETIREMENT BENEFITS - Changes in Regulatory Assets (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance $ 6,523      
Total Stockholders' Equity (See accompanying statements) 36,674 $ 35,225 $ 34,532 $ 32,276
Total other comprehensive income (loss) 99 (10) 71  
Ending balance 7,041 6,523    
Regulatory asset   66 216  
Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Total Stockholders' Equity (See accompanying statements) (32) (56) (18) (76)
Total other comprehensive income (loss) 24 (38) 58  
Pension plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 2,913      
Ending balance 2,658 2,913    
Pension plans | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 2,913 2,371    
Total Stockholders' Equity (See accompanying statements) 52 79 24  
Reclassification adjustments 2 (7)    
Total other comprehensive income (loss) (27) 55    
Ending balance 2,658 2,913 2,371  
Pension plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (56) (34)    
Total other comprehensive income (loss) (255) 542    
Pension plans | Net loss        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (29) 62    
Reclassification adjustments 1 (8)    
Pension plans | Net loss | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (199) 576    
Reclassification adjustments (55) (33)    
Pension plans | Change in prior service costs        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 1 1    
Pension plans | Change in prior service costs | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (1) (1)    
Pension plans | Amortization of regulatory assets | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
Other Postretirement Benefits Plan        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 203      
Reclassification adjustments 3 7    
Ending balance 189 203    
Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance (208) (136)    
Total Stockholders' Equity (See accompanying statements) (14) (9) (4)  
Total other comprehensive income (loss) (5) (5)    
Ending balance (189) (208) (136)  
Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 11 5    
Total other comprehensive income (loss) 19 (72)    
Other Postretirement Benefits Plan | Net loss        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (8) (12)    
Other Postretirement Benefits Plan | Net loss | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (8) 77    
Reclassification adjustments 13 6    
Other Postretirement Benefits Plan | Change in prior service costs | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (2) (1)    
Other Postretirement Benefits Plan | Amortization of regulatory assets | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
Alabama Power        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 2,720      
Total other comprehensive income (loss) 2 2 4  
Ending balance 2,356 2,720    
Regulatory asset 70 76 97  
Alabama Power | Pension plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 821      
Ending balance 741 821    
Alabama Power | Pension plans | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 821 679    
Ending balance 741 821 679  
Alabama Power | Pension plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (17) (11)    
Total other comprehensive income (loss) (80) 142    
Alabama Power | Pension plans | Net loss | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (63) 153    
Reclassification adjustments (16) (10)    
Alabama Power | Pension plans | Change in prior service costs | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (1) (1)    
Alabama Power | Pension plans | Amortization of regulatory assets | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
Alabama Power | Other Postretirement Benefits Plan        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 48      
Ending balance 45 48    
Alabama Power | Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance (48) (21)    
Ending balance (45) (48) (21)  
Alabama Power | Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 2 3    
Total other comprehensive income (loss) 3 (27)    
Alabama Power | Other Postretirement Benefits Plan | Net loss | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (1) 30    
Reclassification adjustments 3 3    
Alabama Power | Other Postretirement Benefits Plan | Change in prior service costs | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (1) 0    
Alabama Power | Other Postretirement Benefits Plan | Amortization of regulatory assets | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
Georgia Power        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 5,090      
Total other comprehensive income (loss) 22 3 28  
Ending balance 6,139 5,090    
Regulatory asset     83  
Georgia Power | Pension plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 1,051      
Ending balance 973 1,051    
Georgia Power | Pension plans | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 1,051 887    
Ending balance 973 1,051 887  
Georgia Power | Pension plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (20) (14)    
Total other comprehensive income (loss) (78) 164    
Georgia Power | Pension plans | Net loss | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (58) 178    
Reclassification adjustments (19) (13)    
Georgia Power | Pension plans | Change in prior service costs | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (1) (1)    
Georgia Power | Pension plans | Amortization of regulatory assets | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
Georgia Power | Other Postretirement Benefits Plan        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 74      
Ending balance 64 74    
Georgia Power | Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance (74) (39)    
Ending balance (64) (74) (39)  
Georgia Power | Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 4 3    
Total other comprehensive income (loss) 10 (35)    
Georgia Power | Other Postretirement Benefits Plan | Net loss | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (6) 38    
Reclassification adjustments 5 4    
Georgia Power | Other Postretirement Benefits Plan | Change in prior service costs | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (1) (1)    
Georgia Power | Other Postretirement Benefits Plan | Amortization of regulatory assets | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
Mississippi Power        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 90      
Total other comprehensive income (loss) 5 0 0  
Ending balance 59 90    
Regulatory asset 52 44 36  
Mississippi Power | Pension plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 152      
Ending balance 144 152    
Mississippi Power | Pension plans | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 152 123    
Ending balance 144 152 123  
Mississippi Power | Pension plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (3) (2)    
Total other comprehensive income (loss) (8) 29    
Mississippi Power | Pension plans | Net loss | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (5) 31    
Reclassification adjustments (3) (2)    
Mississippi Power | Pension plans | Change in prior service costs | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
Mississippi Power | Pension plans | Amortization of regulatory assets | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
Mississippi Power | Other Postretirement Benefits Plan        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance (10)      
Ending balance 9 (10)    
Mississippi Power | Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance (10) (9)    
Ending balance (9) (10) (9)  
Mississippi Power | Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
Total other comprehensive income (loss) 1 (1)    
Mississippi Power | Other Postretirement Benefits Plan | Net loss | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (1) 1    
Reclassification adjustments 0 0    
Mississippi Power | Other Postretirement Benefits Plan | Change in prior service costs | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
Mississippi Power | Other Postretirement Benefits Plan | Amortization of regulatory assets | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
Southern Company Gas        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance (2,225)      
Total other comprehensive income (loss) 32 (15) 7  
Ending balance (2,252) (2,225)    
Southern Company Gas | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Total Stockholders' Equity (See accompanying statements) 51 40 56 38
Total other comprehensive income (loss) 11 (16) 18  
Southern Company Gas | Pension plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 143      
Ending balance 126 143    
Regulatory asset 155 173    
Southern Company Gas | Pension plans | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 143 111    
Total Stockholders' Equity (See accompanying statements) (54) (45) (75)  
Reclassification adjustments 2 1    
Total other comprehensive income (loss) (9) 30    
Ending balance 126 143 111  
Southern Company Gas | Pension plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (10) (2)    
Total other comprehensive income (loss) (17) 32    
Southern Company Gas | Pension plans | Net loss        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (11) 29    
Reclassification adjustments 0 0    
Southern Company Gas | Pension plans | Net loss | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (7) 34    
Reclassification adjustments (1) 0    
Southern Company Gas | Pension plans | Change in prior service costs        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 2 1    
Southern Company Gas | Pension plans | Change in prior service costs | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 2 2    
Southern Company Gas | Pension plans | Amortization of regulatory assets | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (11) (4)    
Southern Company Gas | Other Postretirement Benefits Plan        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 68      
Reclassification adjustments 0 (8)    
Ending balance 84 68    
Regulatory asset 16 24    
Southern Company Gas | Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance (68) (58)    
Total Stockholders' Equity (See accompanying statements) (15) (10) (2)  
Total other comprehensive income (loss) (5) (8)    
Ending balance (84) (68) (58)  
Southern Company Gas | Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (4) (10)    
Total other comprehensive income (loss) (16) (10)    
Southern Company Gas | Other Postretirement Benefits Plan | Net loss        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (5) 0    
Southern Company Gas | Other Postretirement Benefits Plan | Net loss | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) 12 0    
Reclassification adjustments 5 0    
Southern Company Gas | Other Postretirement Benefits Plan | Change in prior service costs | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
Southern Company Gas | Other Postretirement Benefits Plan | Amortization of regulatory assets | Regulatory Assets        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments (9) (10)    
SOUTHERN POWER CO        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Total Stockholders' Equity (See accompanying statements) 6,682 6,698 6,916 6,598
Total other comprehensive income (loss) 15 1 10  
SOUTHERN POWER CO | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Total Stockholders' Equity (See accompanying statements) (9) (16) (9) $ (29)
Total other comprehensive income (loss) 7 (7) 20  
SOUTHERN POWER CO | Pension plans | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Total Stockholders' Equity (See accompanying statements) 11 20 11  
Reclassification adjustments 0 0    
Total other comprehensive income (loss) (9) 9    
SOUTHERN POWER CO | Pension plans | Net loss        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) (9) 9    
Reclassification adjustments 0 0    
SOUTHERN POWER CO | Pension plans | Change in prior service costs        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
SOUTHERN POWER CO | Other Postretirement Benefits Plan        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Reclassification adjustments 0 0    
SOUTHERN POWER CO | Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Total Stockholders' Equity (See accompanying statements) 0 1 $ 0  
Total other comprehensive income (loss) (1) 1    
SOUTHERN POWER CO | Other Postretirement Benefits Plan | Net loss        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Net gain (loss) $ (1) $ 1    
v3.25.0.1
RETIREMENT BENEFITS - Components of Accumulated OCI (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning balance $ 35,225 $ 34,532 $ 32,276
Total other comprehensive income (loss) 99 (10) 71
Ending balance 36,674 35,225 34,532
Pension and Other Postretirement Benefit Plans      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning balance (56) (18) (76)
Total other comprehensive income (loss) 24 (38) 58
Ending balance (32) (56) (18)
Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Prior service cost (1) (1)  
Net loss 53 80  
AOCI 52 79  
Pension plans | Pension and Other Postretirement Benefit Plans      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning balance 79 24  
Reclassification adjustments 2 (7)  
Total other comprehensive income (loss) (27) 55  
Ending balance 52 79 24
Pension plans | Net loss      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Net loss (29) 62  
Reclassification adjustments 1 (8)  
Other Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Prior service cost   1  
Net loss (14) (10)  
AOCI (14) (9)  
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Reclassification adjustments 3 7  
Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning balance (9) (4)  
Total other comprehensive income (loss) (5) (5)  
Ending balance (14) (9) (4)
Other Postretirement Benefits Plan | Net loss      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Net loss (8) (12)  
Southern Power      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning balance 6,698 6,916 6,598
Total other comprehensive income (loss) 15 1 10
Ending balance 6,682 6,698 6,916
Southern Power | Pension and Other Postretirement Benefit Plans      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning balance (16) (9) (29)
Total other comprehensive income (loss) 7 (7) 20
Ending balance (9) (16) (9)
Southern Power | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Prior service cost 0 0  
Net loss 11 20  
AOCI 11 20  
Southern Power | Pension plans | Pension and Other Postretirement Benefit Plans      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning balance 20 11  
Reclassification adjustments 0 0  
Total other comprehensive income (loss) (9) 9  
Ending balance 11 20 11
Southern Power | Pension plans | Net loss      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Net loss (9) 9  
Reclassification adjustments 0 0  
Southern Power | Other Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Prior service cost   0  
Net loss 0 1  
AOCI 0 1  
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Reclassification adjustments 0 0  
Southern Power | Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning balance 1 0  
Total other comprehensive income (loss) (1) 1  
Ending balance 0 1 0
Southern Power | Other Postretirement Benefits Plan | Net loss      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Net loss (1) 1  
Southern Company Gas      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Total other comprehensive income (loss) 32 (15) 7
Southern Company Gas | Pension and Other Postretirement Benefit Plans      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning balance 40 56 38
Total other comprehensive income (loss) 11 (16) 18
Ending balance 51 40 56
Southern Company Gas | Pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Prior service cost (1) (2)  
Net loss (53) (43)  
AOCI (54) (45)  
Southern Company Gas | Pension plans | Pension and Other Postretirement Benefit Plans      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning balance (45) (75)  
Reclassification adjustments 2 1  
Total other comprehensive income (loss) (9) 30  
Ending balance (54) (45) (75)
Southern Company Gas | Pension plans | Net loss      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Net loss (11) 29  
Reclassification adjustments 0 0  
Southern Company Gas | Other Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Prior service cost   0  
Net loss (15) (10)  
AOCI (15) (10)  
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Reclassification adjustments 0 (8)  
Southern Company Gas | Other Postretirement Benefits Plan | Pension and Other Postretirement Benefit Plans      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning balance (10) (2)  
Total other comprehensive income (loss) (5) (8)  
Ending balance (15) (10) $ (2)
Southern Company Gas | Other Postretirement Benefits Plan | Net loss      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Net loss $ (5) $ 0  
v3.25.0.1
RETIREMENT BENEFITS - Components of Net Periodic Benefit Cost and Estimated Future Benefit Payments (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Pension plans      
Components of net periodic      
Service cost $ 292 $ 275 $ 412
Interest cost 635 626 408
Expected return on plan assets (1,263) (1,229) (1,265)
Recognized net loss(*) 55 32 240
Net amortization(*) 0 0 0
Prior service cost(*) 0 0 0
Total change (281) (296) (205)
Benefit payments:      
2025 773    
2026 801    
2027 823    
2028 842    
2029 862    
2030 to 2034 4,529    
Unamortized amounts 20 17 21
Other Postretirement Benefits Plan      
Components of net periodic      
Service cost 15 15 23
Interest cost 65 70 42
Expected return on plan assets (89) (83) (80)
Prior service cost(*) (13) (11) (1)
Total change (22) (9) (16)
Benefit payments:      
2025 112    
2026 112    
2027 113    
2028 114    
2029 114    
2030 to 2034 558    
Unamortized amounts 8    
Alabama Power | Pension plans      
Components of net periodic      
Service cost 68 64 99
Interest cost 148 145 96
Expected return on plan assets (307) (297) (306)
Recognized net loss(*) 16 9 62
Net amortization(*) 1 1 1
Prior service cost(*) 0 0 0
Total change (74) (78) (48)
Benefit payments:      
2025 170    
2026 177    
2027 183    
2028 187    
2029 192    
2030 to 2034 1,013    
Alabama Power | Other Postretirement Benefits Plan      
Components of net periodic      
Service cost 4 4 6
Interest cost 16 17 10
Expected return on plan assets (35) (33) (32)
Prior service cost(*) (3) (3) 0
Total change (18) (15) (16)
Benefit payments:      
2025 24    
2026 25    
2027 26    
2028 26    
2029 27    
2030 to 2034 133    
Georgia Power | Pension plans      
Components of net periodic      
Service cost 70 68 103
Interest cost 191 191 123
Expected return on plan assets (393) (385) (399)
Recognized net loss(*) 19 13 75
Net amortization(*) 1 1 1
Prior service cost(*) 0 0 0
Total change (112) (112) (97)
Benefit payments:      
2025 245    
2026 250    
2027 254    
2028 258    
2029 262    
2030 to 2034 1,333    
Georgia Power | Other Postretirement Benefits Plan      
Components of net periodic      
Service cost 4 4 6
Interest cost 23 25 15
Expected return on plan assets (32) (29) (28)
Prior service cost(*) (4) (3) 2
Total change (9) (3) (5)
Benefit payments:      
2025 40    
2026 40    
2027 41    
2028 41    
2029 42    
2030 to 2034 205    
Mississippi Power | Pension plans      
Components of net periodic      
Service cost 12 11 17
Interest cost 29 28 18
Expected return on plan assets (58) (56) (57)
Recognized net loss(*) 3 2 11
Net amortization(*) 0 0 0
Prior service cost(*) 0 0 0
Total change (14) (15) (11)
Benefit payments:      
2025 34    
2026 36    
2027 37    
2028 38    
2029 38    
2030 to 2034 204    
Mississippi Power | Other Postretirement Benefits Plan      
Components of net periodic      
Service cost 1 1 1
Interest cost 3 3 2
Expected return on plan assets (3) (3) (2)
Prior service cost(*) 0 0 0
Total change 1 1 1
Benefit payments:      
2025 5    
2026 5    
2027 5    
2028 5    
2029 5    
2030 to 2034 22    
Southern Power | Pension plans      
Components of net periodic      
Service cost 7 6 9
Interest cost 9 8 6
Expected return on plan assets (17) (15) (15)
Recognized net loss(*) 0 0 2
Net amortization(*) 0 0 0
Prior service cost(*) 0 0 0
Total change (1) (1) 2
Benefit payments:      
2025 7    
2026 8    
2027 8    
2028 7    
2029 8    
2030 to 2034 51    
Southern Power | Other Postretirement Benefits Plan      
Components of net periodic      
Service cost 0 0 0
Interest cost 0 0 0
Expected return on plan assets 1 1 1
Prior service cost(*) 0 0 0
Total change 1 1 1
Benefit payments:      
2025 1    
2026 1    
2027 1    
2028 1    
2029 1    
2030 to 2034 1    
Southern Company Gas | Pension plans      
Components of net periodic      
Service cost 28 24 34
Interest cost 42 42 28
Expected return on plan assets (85) (85) (91)
Recognized net loss(*) 0 (5) 8
Net amortization(*) 15 15 15
Prior service cost(*) (3) (3) (3)
Total change (3) (12) (9)
Benefit payments:      
2025 58    
2026 60    
2027 62    
2028 64    
2029 66    
2030 to 2034 346    
Southern Company Gas | Other Postretirement Benefits Plan      
Components of net periodic      
Service cost 1 1 1
Interest cost 8 9 5
Expected return on plan assets (13) (10) (9)
Prior service cost(*) 6 6 6
Total change 2 $ 6 $ 3
Benefit payments:      
2025 16    
2026 16    
2027 15    
2028 15    
2029 14    
2030 to 2034 $ 61    
v3.25.0.1
RETIREMENT BENEFITS - Fair Values of Pension Plan and Other Postretirement Benefit Plan Assets (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Liabilities:    
Target Allocation 100.00% 100.00%
Actual Allocation 100.00% 100.00%
Pension plans    
Assets:    
Plan assets $ 14,621 $ 14,760
Liabilities:    
Derivatives (33)  
Total $ 14,588  
Pension plans | Equity    
Liabilities:    
Target Allocation 41.00% 41.00%
Actual Allocation 41.00% 40.00%
Pension plans | Domestic equity    
Assets:    
Plan assets $ 2,930 $ 2,730
Pension plans | International equity    
Assets:    
Plan assets $ 2,991 $ 2,999
Pension plans | Fixed income    
Liabilities:    
Target Allocation 30.00% 30.00%
Actual Allocation 31.00% 32.00%
Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets $ 1,780 $ 1,973
Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 48 44
Pension plans | Corporate bonds    
Assets:    
Plan assets 1,715 1,724
Pension plans | Pooled funds    
Assets:    
Plan assets 792 777
Pension plans | Cash equivalents and other    
Assets:    
Plan assets 255 429
Pension plans | Real estate investments    
Assets:    
Plan assets $ 1,924 $ 2,053
Liabilities:    
Target Allocation 12.00% 12.00%
Actual Allocation 13.00% 14.00%
Pension plans | Special situations    
Assets:    
Plan assets $ 237 $ 245
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 2.00% 2.00%
Pension plans | Private equity    
Assets:    
Plan assets $ 1,797 $ 1,761
Liabilities:    
Target Allocation 9.00% 9.00%
Actual Allocation 12.00% 12.00%
Pension plans | Private Credit    
Assets:    
Plan assets $ 152 $ 25
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 1.00%  
Pension plans | Infrastructure    
Assets:    
Plan assets $ 0  
Liabilities:    
Target Allocation 2.00% 2.00%
Actual Allocation 0.00%  
Other postretirement benefit plans    
Assets:    
Plan assets $ 1,139 $ 1,096
Liabilities:    
Derivatives 1  
Total $ 1,138  
Target Allocation 100.00% 100.00%
Actual Allocation 100.00% 100.00%
Other postretirement benefit plans | Equity    
Liabilities:    
Target Allocation 61.00% 60.00%
Actual Allocation 62.00% 61.00%
Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets $ 192 $ 172
Other postretirement benefit plans | International equity    
Assets:    
Plan assets $ 137 $ 135
Other postretirement benefit plans | Fixed income    
Liabilities:    
Target Allocation 29.00% 30.00%
Actual Allocation 28.00% 28.00%
Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets $ 54 $ 57
Other postretirement benefit plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 1 2
Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 48 47
Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 99 92
Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 16 23
Other postretirement benefit plans | Trust-owned life insurance    
Assets:    
Plan assets 478 456
Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets $ 54 $ 57
Liabilities:    
Target Allocation 4.00% 4.00%
Actual Allocation 5.00% 6.00%
Other postretirement benefit plans | Special situations    
Assets:    
Plan assets $ 6 $ 6
Liabilities:    
Target Allocation 1.00% 1.00%
Actual Allocation 1.00% 1.00%
Other postretirement benefit plans | Private equity    
Assets:    
Plan assets $ 50 $ 48
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 4.00% 4.00%
Other postretirement benefit plans | Private Credit    
Assets:    
Plan assets $ 4 $ 1
Liabilities:    
Target Allocation 1.00% 1.00%
Actual Allocation 0.00%  
Other postretirement benefit plans | Infrastructure    
Assets:    
Plan assets $ 0  
Liabilities:    
Target Allocation 1.00% 1.00%
Actual Allocation 0.00%  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans    
Assets:    
Plan assets $ 4,670 $ 4,646
Liabilities:    
Derivatives 0  
Total 4,670  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Domestic equity    
Assets:    
Plan assets 2,095 1,959
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | International equity    
Assets:    
Plan assets 1,959 1,947
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Corporate bonds    
Assets:    
Plan assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Pooled funds    
Assets:    
Plan assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 255 371
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Real estate investments    
Assets:    
Plan assets 361 369
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Special situations    
Assets:    
Plan assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private equity    
Assets:    
Plan assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private Credit    
Assets:    
Plan assets 0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Infrastructure    
Assets:    
Plan assets 0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans    
Assets:    
Plan assets 175 170
Liabilities:    
Derivatives 0  
Total 175  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 94 85
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 54 53
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 16 21
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Trust-owned life insurance    
Assets:    
Plan assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 11 11
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Private Credit    
Assets:    
Plan assets 0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Infrastructure    
Assets:    
Plan assets 0  
Significant Other Observable Inputs (Level 2) | Pension plans    
Assets:    
Plan assets 6,202 6,399
Liabilities:    
Derivatives (33)  
Total 6,169  
Significant Other Observable Inputs (Level 2) | Pension plans | Domestic equity    
Assets:    
Plan assets 835 771
Significant Other Observable Inputs (Level 2) | Pension plans | International equity    
Assets:    
Plan assets 1,032 1,052
Significant Other Observable Inputs (Level 2) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 1,780 1,973
Significant Other Observable Inputs (Level 2) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 48 44
Significant Other Observable Inputs (Level 2) | Pension plans | Corporate bonds    
Assets:    
Plan assets 1,715 1,724
Significant Other Observable Inputs (Level 2) | Pension plans | Pooled funds    
Assets:    
Plan assets 792 777
Significant Other Observable Inputs (Level 2) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 0 58
Significant Other Observable Inputs (Level 2) | Pension plans | Real estate investments    
Assets:    
Plan assets 0 0
Significant Other Observable Inputs (Level 2) | Pension plans | Special situations    
Assets:    
Plan assets 0 0
Significant Other Observable Inputs (Level 2) | Pension plans | Private equity    
Assets:    
Plan assets 0 0
Significant Other Observable Inputs (Level 2) | Pension plans | Private Credit    
Assets:    
Plan assets 0  
Significant Other Observable Inputs (Level 2) | Pension plans | Infrastructure    
Assets:    
Plan assets 0  
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans    
Assets:    
Plan assets 861 825
Liabilities:    
Derivatives 1  
Total 860  
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 98 87
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 83 82
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 54 57
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 1 2
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 48 47
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 99 92
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 0 2
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Trust-owned life insurance    
Assets:    
Plan assets 478 456
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 0 0
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets 0 0
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets 0 0
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Private Credit    
Assets:    
Plan assets 0  
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Infrastructure    
Assets:    
Plan assets 0  
Net Asset Value as a Practical Expedient (NAV) | Pension plans    
Assets:    
Plan assets 3,749 3,715
Liabilities:    
Derivatives 0  
Total 3,749  
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Domestic equity    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | International equity    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Corporate bonds    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Pooled funds    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Real estate investments    
Assets:    
Plan assets 1,563 1,684
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Special situations    
Assets:    
Plan assets 237 245
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private equity    
Assets:    
Plan assets 1,797 1,761
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private Credit    
Assets:    
Plan assets 152 25
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Infrastructure    
Assets:    
Plan assets 0  
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans    
Assets:    
Plan assets 103 101
Liabilities:    
Derivatives 0  
Total 103  
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Trust-owned life insurance    
Assets:    
Plan assets 0 0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 43 46
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets 6 6
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets 50 48
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Private Credit    
Assets:    
Plan assets 4 1
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Infrastructure    
Assets:    
Plan assets $ 0  
Alabama Power    
Liabilities:    
Target Allocation 100.00%  
Actual Allocation 100.00%  
Alabama Power | Pension plans    
Assets:    
Plan assets $ 3,555 $ 3,579
Liabilities:    
Derivatives (8)  
Total $ 3,547  
Target Allocation 100.00% 100.00%
Actual Allocation 100.00% 100.00%
Alabama Power | Pension plans | Equity    
Liabilities:    
Target Allocation 41.00% 41.00%
Actual Allocation 41.00% 40.00%
Alabama Power | Pension plans | Domestic equity    
Assets:    
Plan assets $ 712 $ 663
Alabama Power | Pension plans | International equity    
Assets:    
Plan assets $ 727 $ 727
Alabama Power | Pension plans | Fixed income    
Liabilities:    
Target Allocation 30.00% 30.00%
Actual Allocation 31.00% 32.00%
Alabama Power | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets $ 433 $ 479
Alabama Power | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 12 11
Alabama Power | Pension plans | Corporate bonds    
Assets:    
Plan assets 417 418
Alabama Power | Pension plans | Pooled funds    
Assets:    
Plan assets 193 188
Alabama Power | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 62 104
Alabama Power | Pension plans | Real estate investments    
Assets:    
Plan assets $ 468 $ 497
Liabilities:    
Target Allocation 12.00% 12.00%
Actual Allocation 13.00% 14.00%
Alabama Power | Pension plans | Special situations    
Assets:    
Plan assets $ 57 $ 59
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 2.00% 2.00%
Alabama Power | Pension plans | Private equity    
Assets:    
Plan assets $ 437 $ 427
Liabilities:    
Target Allocation 9.00% 9.00%
Actual Allocation 12.00% 12.00%
Alabama Power | Pension plans | Private Credit    
Assets:    
Plan assets $ 37 $ 6
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 1.00%  
Alabama Power | Pension plans | Infrastructure    
Assets:    
Plan assets $ 0  
Liabilities:    
Target Allocation 2.00% 2.00%
Actual Allocation 0.00%  
Alabama Power | Other postretirement benefit plans    
Assets:    
Plan assets $ 418 $ 402
Liabilities:    
Target Allocation 100.00% 100.00%
Actual Allocation 100.00% 100.00%
Alabama Power | Other postretirement benefit plans | Equity    
Liabilities:    
Target Allocation 68.00% 67.00%
Actual Allocation 68.00% 66.00%
Alabama Power | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets $ 24 $ 22
Alabama Power | Other postretirement benefit plans | International equity    
Assets:    
Plan assets $ 25 $ 25
Alabama Power | Other postretirement benefit plans | Fixed income    
Liabilities:    
Target Allocation 23.00% 23.00%
Actual Allocation 24.00% 23.00%
Alabama Power | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets $ 14 $ 16
Alabama Power | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 14 14
Alabama Power | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 11 8
Alabama Power | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 2 3
Alabama Power | Other postretirement benefit plans | Trust-owned life insurance    
Assets:    
Plan assets 294 280
Alabama Power | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets $ 16 $ 17
Liabilities:    
Target Allocation 3.00% 4.00%
Actual Allocation 4.00% 6.00%
Alabama Power | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets $ 2 $ 2
Liabilities:    
Target Allocation 1.00% 1.00%
Actual Allocation 1.00% 1.00%
Alabama Power | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets $ 15 $ 15
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 3.00% 4.00%
Alabama Power | Other postretirement benefit plans | Private Credit    
Liabilities:    
Target Allocation   1.00%
Alabama Power | Other postretirement benefit plans | Infrastructure    
Liabilities:    
Target Allocation   1.00%
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans    
Assets:    
Plan assets $ 1,135 $ 1,127
Liabilities:    
Derivatives 0  
Total 1,135  
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Domestic equity    
Assets:    
Plan assets 509 476
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | International equity    
Assets:    
Plan assets 476 472
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Corporate bonds    
Assets:    
Plan assets 0 0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Pooled funds    
Assets:    
Plan assets 0 0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 62 90
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Real estate investments    
Assets:    
Plan assets 88 89
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Special situations    
Assets:    
Plan assets 0 0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private equity    
Assets:    
Plan assets 0 0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private Credit    
Assets:    
Plan assets 0  
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Infrastructure    
Assets:    
Plan assets 0  
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans    
Assets:    
Plan assets 38 38
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 17 16
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 16 16
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 0 0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 0 0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 2 3
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Trust-owned life insurance    
Assets:    
Plan assets 0 0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 3 3
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets 0 0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets 0 0
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans    
Assets:    
Plan assets 1,509 1,552
Liabilities:    
Derivatives (8)  
Total 1,501  
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Domestic equity    
Assets:    
Plan assets 203 187
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | International equity    
Assets:    
Plan assets 251 255
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 433 479
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 12 11
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Corporate bonds    
Assets:    
Plan assets 417 418
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Pooled funds    
Assets:    
Plan assets 193 188
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 0 14
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Real estate investments    
Assets:    
Plan assets 0 0
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Special situations    
Assets:    
Plan assets 0 0
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Private equity    
Assets:    
Plan assets 0 0
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Private Credit    
Assets:    
Plan assets 0  
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Infrastructure    
Assets:    
Plan assets 0  
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans    
Assets:    
Plan assets 349 333
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 7 6
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 9 9
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 14 16
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 14 14
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 11 8
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Trust-owned life insurance    
Assets:    
Plan assets 294 280
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 0 0
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets 0 0
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans    
Assets:    
Plan assets 911 900
Liabilities:    
Derivatives 0  
Total 911  
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Domestic equity    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | International equity    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Corporate bonds    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Pooled funds    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Real estate investments    
Assets:    
Plan assets 380 408
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Special situations    
Assets:    
Plan assets 57 59
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private equity    
Assets:    
Plan assets 437 427
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private Credit    
Assets:    
Plan assets 37 6
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Infrastructure    
Assets:    
Plan assets 0  
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans    
Assets:    
Plan assets 31 31
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Trust-owned life insurance    
Assets:    
Plan assets 0 0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 13 14
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets 2 2
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets $ 15 $ 15
Georgia Power    
Liabilities:    
Target Allocation 100.00% 100.00%
Actual Allocation 100.00% 100.00%
Georgia Power | Pension plans    
Assets:    
Plan assets $ 4,538 $ 4,615
Liabilities:    
Derivatives (10)  
Total $ 4,528  
Target Allocation 100.00%  
Actual Allocation 100.00%  
Georgia Power | Pension plans | Equity    
Liabilities:    
Target Allocation 41.00% 41.00%
Actual Allocation 41.00% 40.00%
Georgia Power | Pension plans | Domestic equity    
Assets:    
Plan assets $ 911 $ 852
Georgia Power | Pension plans | International equity    
Assets:    
Plan assets $ 928 $ 938
Georgia Power | Pension plans | Fixed income    
Liabilities:    
Target Allocation 30.00% 30.00%
Actual Allocation 31.00% 32.00%
Georgia Power | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets $ 552 $ 617
Georgia Power | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 15 14
Georgia Power | Pension plans | Corporate bonds    
Assets:    
Plan assets 532 539
Georgia Power | Pension plans | Pooled funds    
Assets:    
Plan assets 246 243
Georgia Power | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 79 134
Georgia Power | Pension plans | Real estate investments    
Assets:    
Plan assets $ 597 $ 642
Liabilities:    
Target Allocation 12.00% 12.00%
Actual Allocation 13.00% 14.00%
Georgia Power | Pension plans | Special situations    
Assets:    
Plan assets $ 73 $ 77
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 2.00% 2.00%
Georgia Power | Pension plans | Private equity    
Assets:    
Plan assets $ 558 $ 551
Liabilities:    
Target Allocation 9.00% 9.00%
Actual Allocation 12.00% 12.00%
Georgia Power | Pension plans | Private Credit    
Assets:    
Plan assets $ 47 $ 8
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 1.00% 0.00%
Georgia Power | Pension plans | Infrastructure    
Assets:    
Plan assets $ 0 $ 0
Liabilities:    
Target Allocation 2.00% 2.00%
Actual Allocation 0.00% 0.00%
Georgia Power | Other postretirement benefit plans    
Assets:    
Plan assets $ 420 $ 409
Liabilities:    
Target Allocation 100.00% 100.00%
Actual Allocation 100.00% 100.00%
Georgia Power | Other postretirement benefit plans | Equity    
Liabilities:    
Target Allocation 59.00% 58.00%
Actual Allocation 59.00% 57.00%
Georgia Power | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets $ 59 $ 53
Georgia Power | Other postretirement benefit plans | International equity    
Assets:    
Plan assets $ 57 $ 56
Georgia Power | Other postretirement benefit plans | Fixed income    
Liabilities:    
Target Allocation 35.00% 35.00%
Actual Allocation 33.00% 35.00%
Georgia Power | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets $ 14 $ 16
Georgia Power | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 14 14
Georgia Power | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 48 47
Georgia Power | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 10 13
Georgia Power | Other postretirement benefit plans | Trust-owned life insurance    
Assets:    
Plan assets 184 176
Georgia Power | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets $ 17 $ 18
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 4.00% 4.00%
Georgia Power | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets $ 2 $ 2
Liabilities:    
Target Allocation 1.00% 1.00%
Actual Allocation 1.00% 1.00%
Georgia Power | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets $ 15 $ 14
Liabilities:    
Target Allocation 2.00% 2.00%
Actual Allocation 3.00% 3.00%
Georgia Power | Other postretirement benefit plans | Private Credit    
Assets:    
Plan assets   $ 0
Liabilities:    
Target Allocation   1.00%
Actual Allocation   0.00%
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans    
Assets:    
Plan assets $ 1,451 $ 1,451
Liabilities:    
Derivatives 0  
Total 1,451  
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Domestic equity    
Assets:    
Plan assets 652 611
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | International equity    
Assets:    
Plan assets 608 609
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Corporate bonds    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Pooled funds    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 79 116
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Real estate investments    
Assets:    
Plan assets 112 115
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Special situations    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private equity    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private Credit    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Infrastructure    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans    
Assets:    
Plan assets 82 80
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 52 47
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 16 16
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 10 13
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Trust-owned life insurance    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 4 4
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets 0 0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Private Credit    
Assets:    
Plan assets   0
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans    
Assets:    
Plan assets 1,924 2,001
Liabilities:    
Derivatives (10)  
Total 1,914  
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Domestic equity    
Assets:    
Plan assets 259 241
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | International equity    
Assets:    
Plan assets 320 329
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 552 617
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 15 14
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Corporate bonds    
Assets:    
Plan assets 532 539
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Pooled funds    
Assets:    
Plan assets 246 243
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 0 18
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Real estate investments    
Assets:    
Plan assets 0 0
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Special situations    
Assets:    
Plan assets 0 0
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Private equity    
Assets:    
Plan assets 0 0
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Private Credit    
Assets:    
Plan assets 0 0
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Infrastructure    
Assets:    
Plan assets 0 0
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans    
Assets:    
Plan assets 308 299
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 7 6
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 41 40
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 14 16
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 14 14
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 48 47
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Trust-owned life insurance    
Assets:    
Plan assets 184 176
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 0 0
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets 0 0
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets 0 0
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Private Credit    
Assets:    
Plan assets   0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans    
Assets:    
Plan assets 1,163 1,163
Liabilities:    
Derivatives 0  
Total 1,163  
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Domestic equity    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | International equity    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Corporate bonds    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Pooled funds    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Real estate investments    
Assets:    
Plan assets 485 527
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Special situations    
Assets:    
Plan assets 73 77
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private equity    
Assets:    
Plan assets 558 551
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private Credit    
Assets:    
Plan assets 47 8
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Infrastructure    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans    
Assets:    
Plan assets 30 30
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Trust-owned life insurance    
Assets:    
Plan assets 0 0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 13 14
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets 2 2
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets $ 15 14
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Private Credit    
Assets:    
Plan assets   0
Mississippi Power    
Liabilities:    
Target Allocation 100.00%  
Actual Allocation 100.00%  
Mississippi Power | Pension plans    
Assets:    
Plan assets $ 667 $ 675
Liabilities:    
Derivatives (2)  
Total $ 665  
Target Allocation 100.00% 100.00%
Actual Allocation 100.00% 100.00%
Mississippi Power | Pension plans | Equity    
Liabilities:    
Target Allocation 41.00% 41.00%
Actual Allocation 41.00% 40.00%
Mississippi Power | Pension plans | Domestic equity    
Assets:    
Plan assets $ 135 $ 124
Mississippi Power | Pension plans | International equity    
Assets:    
Plan assets $ 136 $ 137
Mississippi Power | Pension plans | Fixed income    
Liabilities:    
Target Allocation 30.00% 30.00%
Actual Allocation 31.00% 32.00%
Mississippi Power | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets $ 81 $ 90
Mississippi Power | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 2 2
Mississippi Power | Pension plans | Corporate bonds    
Assets:    
Plan assets 78 79
Mississippi Power | Pension plans | Pooled funds    
Assets:    
Plan assets 36 36
Mississippi Power | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 12 20
Mississippi Power | Pension plans | Real estate investments    
Assets:    
Plan assets $ 87 $ 94
Liabilities:    
Target Allocation 12.00% 12.00%
Actual Allocation 13.00% 14.00%
Mississippi Power | Pension plans | Special situations    
Assets:    
Plan assets $ 11 $ 11
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 2.00% 2.00%
Mississippi Power | Pension plans | Private equity    
Assets:    
Plan assets $ 82 $ 81
Liabilities:    
Target Allocation 9.00% 9.00%
Actual Allocation 12.00% 12.00%
Mississippi Power | Pension plans | Private Credit    
Assets:    
Plan assets $ 7 $ 1
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 1.00% 0.00%
Mississippi Power | Pension plans | Infrastructure    
Assets:    
Plan assets $ 0 $ 0
Liabilities:    
Target Allocation 2.00% 2.00%
Actual Allocation 0.00% 0.00%
Mississippi Power | Other postretirement benefit plans    
Assets:    
Plan assets $ 23 $ 24
Liabilities:    
Target Allocation 100.00% 100.00%
Actual Allocation 100.00% 100.00%
Mississippi Power | Other postretirement benefit plans | Equity    
Liabilities:    
Target Allocation 34.00% 34.00%
Actual Allocation 32.00% 33.00%
Mississippi Power | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets $ 4 $ 4
Mississippi Power | Other postretirement benefit plans | International equity    
Assets:    
Plan assets $ 4 $ 4
Mississippi Power | Other postretirement benefit plans | Fixed income    
Liabilities:    
Target Allocation 43.00% 43.00%
Actual Allocation 44.00% 44.00%
Mississippi Power | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets $ 7 $ 7
Mississippi Power | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 2 2
Mississippi Power | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 1 1
Mississippi Power | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 1 1
Mississippi Power | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets $ 2 $ 3
Liabilities:    
Target Allocation 10.00% 10.00%
Actual Allocation 11.00% 11.00%
Mississippi Power | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets $ 0 $ 0
Liabilities:    
Target Allocation 2.00% 2.00%
Actual Allocation 2.00% 2.00%
Mississippi Power | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets $ 2 $ 2
Liabilities:    
Target Allocation 7.00% 7.00%
Actual Allocation 10.00% 10.00%
Mississippi Power | Other postretirement benefit plans | Private Credit    
Liabilities:    
Target Allocation   3.00%
Mississippi Power | Other postretirement benefit plans | Infrastructure    
Liabilities:    
Target Allocation   1.00%
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans    
Assets:    
Plan assets $ 214 $ 212
Liabilities:    
Derivatives 0  
Total 214  
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Domestic equity    
Assets:    
Plan assets 97 89
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | International equity    
Assets:    
Plan assets 89 89
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Corporate bonds    
Assets:    
Plan assets 0 0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Pooled funds    
Assets:    
Plan assets 0 0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 12 17
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Real estate investments    
Assets:    
Plan assets 16 17
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Special situations    
Assets:    
Plan assets 0 0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private equity    
Assets:    
Plan assets 0 0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private Credit    
Assets:    
Plan assets 0 0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Infrastructure    
Assets:    
Plan assets 0 0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans    
Assets:    
Plan assets 7 8
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 3 3
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 3 3
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 0 0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 0 0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 1 1
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 0 1
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets 0 0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets 0 0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans    
Assets:    
Plan assets 282 293
Liabilities:    
Derivatives (2)  
Total 280  
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Domestic equity    
Assets:    
Plan assets 38 35
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | International equity    
Assets:    
Plan assets 47 48
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 81 90
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 2 2
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Corporate bonds    
Assets:    
Plan assets 78 79
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Pooled funds    
Assets:    
Plan assets 36 36
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 0 3
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Real estate investments    
Assets:    
Plan assets 0 0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Special situations    
Assets:    
Plan assets 0 0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Private equity    
Assets:    
Plan assets 0 0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Private Credit    
Assets:    
Plan assets 0 0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Infrastructure    
Assets:    
Plan assets 0 0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans    
Assets:    
Plan assets 12 12
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 1 1
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 1 1
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 7 7
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 2 2
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 1 1
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 0 0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets 0 0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans    
Assets:    
Plan assets 171 170
Liabilities:    
Derivatives 0  
Total 171  
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Domestic equity    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | International equity    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Corporate bonds    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Pooled funds    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Real estate investments    
Assets:    
Plan assets 71 77
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Special situations    
Assets:    
Plan assets 11 11
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private equity    
Assets:    
Plan assets 82 81
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private Credit    
Assets:    
Plan assets 7 1
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Infrastructure    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans    
Assets:    
Plan assets 4 4
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 2 2
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Special situations    
Assets:    
Plan assets 0 0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets 2 2
Southern Power | Pension plans    
Assets:    
Plan assets $ 188 $ 187
Liabilities:    
Target Allocation 100.00% 100.00%
Actual Allocation 100.00% 100.00%
Southern Power | Pension plans | Equity    
Liabilities:    
Target Allocation 41.00% 41.00%
Actual Allocation 41.00% 40.00%
Southern Power | Pension plans | Domestic equity    
Assets:    
Plan assets $ 38 $ 34
Southern Power | Pension plans | International equity    
Assets:    
Plan assets $ 38 $ 38
Southern Power | Pension plans | Fixed income    
Liabilities:    
Target Allocation 30.00% 30.00%
Actual Allocation 31.00% 32.00%
Southern Power | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets $ 23 $ 25
Southern Power | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 1 1
Southern Power | Pension plans | Corporate bonds    
Assets:    
Plan assets 22 22
Southern Power | Pension plans | Pooled funds    
Assets:    
Plan assets 10 10
Southern Power | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 3 6
Southern Power | Pension plans | Real estate investments    
Assets:    
Plan assets $ 25 $ 26
Liabilities:    
Target Allocation 12.00% 12.00%
Actual Allocation 13.00% 14.00%
Southern Power | Pension plans | Special situations    
Assets:    
Plan assets $ 3 $ 3
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 2.00% 2.00%
Southern Power | Pension plans | Private equity    
Assets:    
Plan assets $ 23 $ 22
Liabilities:    
Target Allocation 9.00% 9.00%
Actual Allocation 12.00% 12.00%
Southern Power | Pension plans | Private Credit    
Assets:    
Plan assets $ 2 $ 0
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 1.00% 0.00%
Southern Power | Pension plans | Infrastructure    
Assets:    
Plan assets $ 0 $ 0
Liabilities:    
Target Allocation 2.00% 2.00%
Actual Allocation 0.00% 0.00%
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans    
Assets:    
Plan assets $ 60 $ 59
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Domestic equity    
Assets:    
Plan assets 27 24
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | International equity    
Assets:    
Plan assets 25 25
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Corporate bonds    
Assets:    
Plan assets 0 0
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Pooled funds    
Assets:    
Plan assets 0 0
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 3 5
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Real estate investments    
Assets:    
Plan assets 5 5
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Special situations    
Assets:    
Plan assets 0 0
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private equity    
Assets:    
Plan assets 0 0
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private Credit    
Assets:    
Plan assets 0 0
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Infrastructure    
Assets:    
Plan assets 0 0
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans    
Assets:    
Plan assets 80 82
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Domestic equity    
Assets:    
Plan assets 11 10
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | International equity    
Assets:    
Plan assets 13 13
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 23 25
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 1 1
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Corporate bonds    
Assets:    
Plan assets 22 22
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Pooled funds    
Assets:    
Plan assets 10 10
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 0 1
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Real estate investments    
Assets:    
Plan assets 0 0
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Special situations    
Assets:    
Plan assets 0 0
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Private equity    
Assets:    
Plan assets 0 0
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Private Credit    
Assets:    
Plan assets 0 0
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Infrastructure    
Assets:    
Plan assets 0 0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans    
Assets:    
Plan assets 48 46
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Domestic equity    
Assets:    
Plan assets 0 0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | International equity    
Assets:    
Plan assets 0 0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Corporate bonds    
Assets:    
Plan assets 0 0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Pooled funds    
Assets:    
Plan assets 0 0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Real estate investments    
Assets:    
Plan assets 20 21
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Special situations    
Assets:    
Plan assets 3 3
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private equity    
Assets:    
Plan assets 23 22
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private Credit    
Assets:    
Plan assets 2 0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Infrastructure    
Assets:    
Plan assets 0 0
Southern Company Gas | Pension plans    
Assets:    
Plan assets $ 983 $ 989
Liabilities:    
Target Allocation 100.00% 100.00%
Actual Allocation 100.00% 100.00%
Southern Company Gas | Pension plans | Equity    
Liabilities:    
Target Allocation 41.00% 41.00%
Actual Allocation 41.00% 40.00%
Southern Company Gas | Pension plans | Domestic equity    
Assets:    
Plan assets $ 198 $ 182
Southern Company Gas | Pension plans | International equity    
Assets:    
Plan assets $ 201 $ 201
Southern Company Gas | Pension plans | Fixed income    
Liabilities:    
Target Allocation 30.00% 30.00%
Actual Allocation 31.00% 32.00%
Southern Company Gas | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets $ 120 $ 132
Southern Company Gas | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 3 3
Southern Company Gas | Pension plans | Corporate bonds    
Assets:    
Plan assets 115 116
Southern Company Gas | Pension plans | Pooled funds    
Assets:    
Plan assets 53 52
Southern Company Gas | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 17 29
Southern Company Gas | Pension plans | Real estate investments    
Assets:    
Plan assets $ 129 $ 138
Liabilities:    
Target Allocation 12.00% 12.00%
Actual Allocation 13.00% 14.00%
Southern Company Gas | Pension plans | Special situations    
Assets:    
Plan assets $ 16 $ 16
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 2.00% 2.00%
Southern Company Gas | Pension plans | Private equity    
Assets:    
Plan assets $ 121 $ 118
Liabilities:    
Target Allocation 9.00% 9.00%
Actual Allocation 12.00% 12.00%
Southern Company Gas | Pension plans | Private Credit    
Assets:    
Plan assets $ 10 $ 2
Liabilities:    
Target Allocation 3.00% 3.00%
Actual Allocation 1.00%  
Southern Company Gas | Pension plans | Infrastructure    
Assets:    
Plan assets $ 0  
Liabilities:    
Target Allocation 2.00% 2.00%
Actual Allocation 0.00%  
Southern Company Gas | Other postretirement benefit plans    
Assets:    
Plan assets $ 138 $ 127
Liabilities:    
Target Allocation 100.00% 100.00%
Actual Allocation 100.00% 100.00%
Southern Company Gas | Other postretirement benefit plans | Equity    
Liabilities:    
Target Allocation 72.00% 72.00%
Actual Allocation 73.00% 72.00%
Southern Company Gas | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets $ 77 $ 69
Southern Company Gas | Other postretirement benefit plans | International equity    
Assets:    
Plan assets $ 24 $ 24
Southern Company Gas | Other postretirement benefit plans | Fixed income    
Liabilities:    
Target Allocation 26.00% 26.00%
Actual Allocation 25.00% 26.00%
Southern Company Gas | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets $ 1 $ 1
Southern Company Gas | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 1 1
Southern Company Gas | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 32 29
Southern Company Gas | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 1 1
Southern Company Gas | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets $ 1 $ 1
Liabilities:    
Target Allocation 1.00% 1.00%
Actual Allocation 1.00% 1.00%
Southern Company Gas | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets $ 1 $ 1
Liabilities:    
Target Allocation 1.00% 1.00%
Actual Allocation 1.00% 1.00%
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans    
Assets:    
Plan assets $ 315 $ 310
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Domestic equity    
Assets:    
Plan assets 142 130
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | International equity    
Assets:    
Plan assets 132 130
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Corporate bonds    
Assets:    
Plan assets 0 0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Pooled funds    
Assets:    
Plan assets 0 0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 17 25
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Real estate investments    
Assets:    
Plan assets 24 25
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Special situations    
Assets:    
Plan assets 0 0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private equity    
Assets:    
Plan assets 0 0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private Credit    
Assets:    
Plan assets 0  
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Infrastructure    
Assets:    
Plan assets 0  
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans    
Assets:    
Plan assets 3 5
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 1 2
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 1 2
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 0 0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 0 0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 1 1
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 0 0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets 0 0
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans    
Assets:    
Plan assets 416 430
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Domestic equity    
Assets:    
Plan assets 56 52
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | International equity    
Assets:    
Plan assets 69 71
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 120 132
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 3 3
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Corporate bonds    
Assets:    
Plan assets 115 116
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Pooled funds    
Assets:    
Plan assets 53 52
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 0 4
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Real estate investments    
Assets:    
Plan assets 0 0
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Special situations    
Assets:    
Plan assets 0 0
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Private equity    
Assets:    
Plan assets 0 0
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Private Credit    
Assets:    
Plan assets 0  
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Infrastructure    
Assets:    
Plan assets 0  
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans    
Assets:    
Plan assets 133 120
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 76 67
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 23 22
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 1 1
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 1 1
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 32 29
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 0 0
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans    
Assets:    
Plan assets 252 249
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Domestic equity    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | International equity    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Mortgage- and asset-backed securities    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Corporate bonds    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Pooled funds    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Real estate investments    
Assets:    
Plan assets 105 113
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Special situations    
Assets:    
Plan assets 16 16
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private equity    
Assets:    
Plan assets 121 118
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private Credit    
Assets:    
Plan assets 10 2
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Infrastructure    
Assets:    
Plan assets 0  
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans    
Assets:    
Plan assets 2 2
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Domestic equity    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | International equity    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Corporate bonds    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Pooled funds    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Cash equivalents and other    
Assets:    
Plan assets 0 0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Real estate investments    
Assets:    
Plan assets 1 1
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Private equity    
Assets:    
Plan assets $ 1 $ 1
v3.25.0.1
RETIREMENT BENEFITS - 401K Plan Matching Contributions (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]      
Defined contribution plan, cost $ 137 $ 131 $ 124
Alabama Power      
Defined Benefit Plan Disclosure [Line Items]      
Defined contribution plan, cost 29 28 26
Georgia Power      
Defined Benefit Plan Disclosure [Line Items]      
Defined contribution plan, cost 31 31 29
Mississippi Power      
Defined Benefit Plan Disclosure [Line Items]      
Defined contribution plan, cost 5 5 5
Southern Power      
Defined Benefit Plan Disclosure [Line Items]      
Defined contribution plan, cost 3 3 3
Southern Company Gas      
Defined Benefit Plan Disclosure [Line Items]      
Defined contribution plan, cost $ 20 $ 18 $ 17
v3.25.0.1
STOCK COMPENSATION - Schedule of Employees Participating in Stock-Based Compensation Programs (Details)
Dec. 31, 2024
employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of employees 1,154
Alabama Power  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of employees 158
Georgia Power  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of employees 161
Mississippi Power  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of employees 36
Southern Power  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of employees 36
Southern Company Gas  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of employees 183
v3.25.0.1
STOCK COMPENSATION - Performance Shares Narrative (Details)
$ / shares in Units, shares in Millions, $ in Millions
 1 Months Ended 12 Months Ended
Feb. 19, 2025
$ / shares
shares
Feb. 29, 2024
shares
Feb. 28, 2023
$ / shares
Dec. 31, 2024
USD ($)
type
$ / shares
shares
Dec. 31, 2023
$ / shares
shares
Dec. 31, 2022
$ / shares
Performance Shares            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting period of performance share units issued under performance share plan       3 years 3 years  
Minimum percentage of transfer performance shares to common stock based on actual total shareholder return       0.00%    
Maximum percentage of transfer performance shares to common stock based on actual total shareholder return       200.00%    
Number of types of PSUs | type       2    
Performance share units, unvested (in shares)       2.3 2.4  
Shares issued (in shares)   2.3        
Share price (in USD per share) | $ / shares     $ 66.95      
Equity instrument, granted (in shares)       1.1    
Equity instruments, vested (in shares)       1.2    
Unrecognized compensation cost | $       $ 33    
Total unrecognized compensation cost related to award, weighted average period       19 months    
Performance Shares | Subsequent Event            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Shares issued (in shares) 2.0          
Share price (in USD per share) | $ / shares $ 83.87          
EPS-based and ROE-based Performance Share Units            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting period of performance share units issued under performance share plan       3 years    
Equity instrument granted in period, weighted average grant date fair value (in dollars per share) | $ / shares       $ 69.67 $ 68.93 $ 66.87
v3.25.0.1
STOCK COMPENSATION - Performance Shares, Assumptions Used (Details) - Performance Shares - $ / shares
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected volatility 19.10% 30.00% 29.60%
Interest rate 4.00% 3.80% 1.70%
Weighted average grant-date fair value (in dollars per share) $ 80.99 $ 76.83 $ 79.69
v3.25.0.1
STOCK COMPENSATION - Performance Shares, Compensation Costs and Related Tax Benefit (Details) - Performance Shares - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Compensation cost recognized in income $ 102 $ 107 $ 101
Tax benefit of compensation cost recognized in income $ 27 $ 28 $ 26
v3.25.0.1
STOCK COMPENSATION - Restricted Stock Units Narrative (Details) - Restricted Stock Units (RSUs) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Equity instrument granted in period, weighted average grant date fair value (in dollars per share) $ 70.49 $ 68.95 $ 67.20
Award requisite service period 3 years    
Total unrecognized compensation cost related to award, weighted average period 19 months    
Restricted stock units, unvested (in shares) 0.9 0.9  
Equity instrument, granted (in shares) 0.5    
Vested or forfeited (in shares) 0.5    
Total compensation cost for award recognized in income $ 30 $ 30 $ 26
Total compensation cost for award recognized in income, tax benefit $ 8 $ 8 $ 7
One-year vesting period      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Total unrecognized compensation cost related to award, weighted average period 1 year    
Two-year vesting period      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Total unrecognized compensation cost related to award, weighted average period 2 years    
Three-year vesting period      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Total unrecognized compensation cost related to award, weighted average period 3 years    
v3.25.0.1
STOCK COMPENSATION - Stock Options Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Cash received from issuance related to option exercise $ 14 $ 28 $ 75
v3.25.0.1
STOCK COMPENSATION - Aggregate Intrinsic Value for Options Exercised (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]      
Intrinsic value of options exercised $ 10 $ 18 $ 49
Tax benefit of options exercised $ 2 $ 4 $ 12
v3.25.0.1
FAIR VALUE MEASUREMENTS - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Assets:    
Derivative asset $ 45 $ 32
Liabilities:    
Derivative liability 554 659
Collateral already posted, aggregate fair value 17 62
Recurring    
Assets:    
Cash equivalents and restricted cash 552 268
Other investments 48 44
Total 3,349 2,806
Liabilities:    
Contingent consideration 19 19
Other 24  
Total 659 776
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Cash equivalents and restricted cash 533 253
Other investments 9 9
Total 1,594 1,238
Liabilities:    
Contingent consideration 3 3
Other 0  
Total 8 49
Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Cash equivalents and restricted cash 19 15
Other investments 31 27
Total 1,557 1,382
Liabilities:    
Contingent consideration 0 0
Other 13  
Total 624 711
Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Cash equivalents and restricted cash 0 0
Other investments 8 8
Total 8 8
Liabilities:    
Contingent consideration 16 16
Other 11  
Total 27 16
Recurring | Fair Value Measured at Net Asset Value Per Share (NAV)    
Assets:    
Total 190 178
Alabama Power    
Assets:    
Derivative asset 7 5
Liabilities:    
Derivative liability 23 100
Collateral already posted, aggregate fair value 0  
Alabama Power | Recurring    
Assets:    
Cash equivalents and restricted cash 353 134
Other investments 31 27
Total 1,795 1,435
Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Cash equivalents and restricted cash 334 119
Other investments 0 0
Total 952 715
Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Cash equivalents and restricted cash 19 15
Other investments 31 27
Total 653 542
Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Cash equivalents and restricted cash 0 0
Other investments 0 0
Total 0 0
Alabama Power | Recurring | Fair Value Measured at Net Asset Value Per Share (NAV)    
Assets:    
Total 190 178
Georgia Power    
Assets:    
Derivative asset 4 2
Liabilities:    
Derivative liability 27 113
Georgia Power | Recurring    
Assets:    
Cash equivalents and restricted cash 35  
Total 1,290 1,176
Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Cash equivalents and restricted cash 35  
Total 453 371
Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Cash equivalents and restricted cash 0  
Total 837 805
Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Cash equivalents and restricted cash 0  
Total 0 0
Mississippi Power    
Assets:    
Derivative asset 2 1
Liabilities:    
Derivative liability 17 47
Mississippi Power | Recurring    
Assets:    
Cash equivalents and restricted cash   17
Total   32
Mississippi Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Cash equivalents and restricted cash   17
Total   17
Mississippi Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Cash equivalents and restricted cash   0
Total   15
Mississippi Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Cash equivalents and restricted cash   0
Total   0
Southern Power    
Assets:    
Derivative asset 4 3
Liabilities:    
Derivative liability 51 27
Other   13
Collateral already posted, aggregate fair value 0  
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Liabilities:    
Other   0
Southern Power | Significant Other Observable Inputs (Level 2)    
Liabilities:    
Other   13
Southern Power | Significant Unobservable Inputs (Level 3)    
Liabilities:    
Other   0
Southern Power | Recurring    
Assets:    
Cash equivalents and restricted cash 51  
Total 55  
Liabilities:    
Contingent consideration 19  
Other 24  
Total 94 59
Southern Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Cash equivalents and restricted cash 51  
Total 51  
Liabilities:    
Contingent consideration 3  
Other 0  
Total 3 3
Southern Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Cash equivalents and restricted cash 0  
Total 4  
Liabilities:    
Contingent consideration 0  
Other 13  
Total 64 40
Southern Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Cash equivalents and restricted cash 0  
Total 0  
Liabilities:    
Contingent consideration 16  
Other 11  
Total 27 16
Southern Company Gas    
Assets:    
Derivative asset 28 21
Liabilities:    
Derivative liability 84 87
Collateral already posted, aggregate fair value 17 62
Southern Company Gas | Recurring    
Assets:    
Cash equivalents and restricted cash 22  
Total 82 26
Liabilities:    
Total 95 137
Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Cash equivalents and restricted cash 22  
Total 38 9
Liabilities:    
Total 5 46
Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Cash equivalents and restricted cash 0  
Total 44 17
Liabilities:    
Total 90 91
Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Cash equivalents and restricted cash 0  
Total 0 0
Liabilities:    
Total 0 0
Energy-related derivatives | Recurring    
Assets:    
Derivative asset 89 55
Liabilities:    
Derivative liability 129 358
Energy-related derivatives | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivative asset 12 6
Liabilities:    
Derivative liability 5 46
Energy-related derivatives | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivative asset 77 49
Liabilities:    
Derivative liability 124 312
Energy-related derivatives | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivative asset 0 0
Liabilities:    
Derivative liability 0 0
Energy-related derivatives | Alabama Power | Recurring    
Assets:    
Derivative asset 26 15
Liabilities:    
Derivative liability 42 110
Energy-related derivatives | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivative asset 0 0
Liabilities:    
Derivative liability 0 0
Energy-related derivatives | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivative asset 26 15
Liabilities:    
Derivative liability 42 110
Energy-related derivatives | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivative asset 0 0
Liabilities:    
Derivative liability 0 0
Energy-related derivatives | Georgia Power | Recurring    
Assets:    
Derivative asset 19 13
Liabilities:    
Derivative liability 42 124
Energy-related derivatives | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivative asset 0 0
Liabilities:    
Derivative liability 0 0
Energy-related derivatives | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivative asset 19 13
Liabilities:    
Derivative liability 42 124
Energy-related derivatives | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivative asset 0 0
Liabilities:    
Derivative liability 0 0
Energy-related derivatives | Mississippi Power | Recurring    
Assets:    
Derivative asset 19 15
Liabilities:    
Derivative liability 34 61
Energy-related derivatives | Mississippi Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivative asset 0 0
Liabilities:    
Derivative liability 0 0
Energy-related derivatives | Mississippi Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivative asset 19 15
Liabilities:    
Derivative liability 34 61
Energy-related derivatives | Mississippi Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivative asset 0 0
Liabilities:    
Derivative liability 0 0
Energy-related derivatives | Southern Power | Recurring    
Assets:    
Derivative asset 4 3
Liabilities:    
Derivative liability   5
Energy-related derivatives | Southern Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivative asset 0 0
Liabilities:    
Derivative liability   0
Energy-related derivatives | Southern Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivative asset 4 3
Liabilities:    
Derivative liability   5
Energy-related derivatives | Southern Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivative asset 0 0
Liabilities:    
Derivative liability   0
Energy-related derivatives | Southern Company Gas | Recurring    
Assets:    
Derivative asset 21 9
Liabilities:    
Derivative liability 11 58
Energy-related derivatives | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivative asset 12 6
Liabilities:    
Derivative liability 5 46
Energy-related derivatives | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivative asset 9 3
Liabilities:    
Derivative liability 6 12
Energy-related derivatives | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivative asset 0 0
Liabilities:    
Derivative liability 0 0
Interest rate derivatives | Recurring    
Liabilities:    
Derivative liability 269 264
Interest rate derivatives | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Liabilities:    
Derivative liability 0 0
Interest rate derivatives | Recurring | Significant Other Observable Inputs (Level 2)    
Liabilities:    
Derivative liability 269 264
Interest rate derivatives | Recurring | Significant Unobservable Inputs (Level 3)    
Liabilities:    
Derivative liability 0 0
Interest rate derivatives | Southern Company Gas | Recurring    
Liabilities:    
Derivative liability 84 79
Interest rate derivatives | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Liabilities:    
Derivative liability 0 0
Interest rate derivatives | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)    
Liabilities:    
Derivative liability 84 79
Interest rate derivatives | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)    
Liabilities:    
Derivative liability 0 0
Foreign currency derivatives | Recurring    
Liabilities:    
Derivative liability 218 122
Foreign currency derivatives | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Liabilities:    
Derivative liability 0 0
Foreign currency derivatives | Recurring | Significant Other Observable Inputs (Level 2)    
Liabilities:    
Derivative liability 218 122
Foreign currency derivatives | Recurring | Significant Unobservable Inputs (Level 3)    
Liabilities:    
Derivative liability 0 0
Foreign currency derivatives | Southern Power | Recurring    
Liabilities:    
Derivative liability 51 22
Contingent consideration   19
Foreign currency derivatives | Southern Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Liabilities:    
Derivative liability 0 0
Contingent consideration   3
Foreign currency derivatives | Southern Power | Recurring | Significant Other Observable Inputs (Level 2)    
Liabilities:    
Derivative liability 51 22
Contingent consideration   0
Foreign currency derivatives | Southern Power | Recurring | Significant Unobservable Inputs (Level 3)    
Liabilities:    
Derivative liability 0 0
Contingent consideration   16
Domestic equity | Recurring    
Assets:    
Nuclear decommissioning trusts 1,099 980
Domestic equity | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 849 764
Domestic equity | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 250 216
Domestic equity | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Domestic equity | Alabama Power | Recurring    
Assets:    
Nuclear decommissioning trusts 700 651
Domestic equity | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 459 443
Domestic equity | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 241 208
Domestic equity | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Domestic equity | Georgia Power | Recurring    
Assets:    
Nuclear decommissioning trusts 391 322
Domestic equity | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 390 321
Domestic equity | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 1 1
Domestic equity | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Domestic equity | Southern Company Gas | Recurring    
Assets:    
Non-qualified deferred compensation trusts 8 7
Domestic equity | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Non-qualified deferred compensation trusts 0 0
Domestic equity | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Non-qualified deferred compensation trusts 8 7
Domestic equity | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Non-qualified deferred compensation trusts 0 0
Foreign equity | Recurring    
Assets:    
Nuclear decommissioning trusts 323 316
Foreign equity | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 148 145
Foreign equity | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 175 171
Foreign equity | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Foreign equity | Alabama Power | Recurring    
Assets:    
Nuclear decommissioning trusts 148 145
Foreign equity | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 148 145
Foreign equity | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 0 0
Foreign equity | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Foreign equity | Georgia Power | Recurring    
Assets:    
Nuclear decommissioning trusts 174 170
Foreign equity | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Foreign equity | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 174 170
Foreign equity | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Foreign equity | Southern Company Gas | Recurring    
Assets:    
Non-qualified deferred compensation trusts 1 1
Foreign equity | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Non-qualified deferred compensation trusts 0 0
Foreign equity | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Non-qualified deferred compensation trusts 1 1
Foreign equity | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Non-qualified deferred compensation trusts 0 0
U.S. Treasury and government agency securities | Recurring    
Assets:    
Nuclear decommissioning trusts 371 369
Investments, available for sale: 9  
U.S. Treasury and government agency securities | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Investments, available for sale: 2  
U.S. Treasury and government agency securities | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 371 369
Investments, available for sale: 7  
U.S. Treasury and government agency securities | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Investments, available for sale: 0  
U.S. Treasury and government agency securities | Alabama Power | Recurring    
Assets:    
Nuclear decommissioning trusts 16 20
U.S. Treasury and government agency securities | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
U.S. Treasury and government agency securities | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 16 20
U.S. Treasury and government agency securities | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
U.S. Treasury and government agency securities | Georgia Power | Recurring    
Assets:    
Nuclear decommissioning trusts 355 349
U.S. Treasury and government agency securities | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
U.S. Treasury and government agency securities | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 355 349
U.S. Treasury and government agency securities | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
U.S. Treasury and government agency securities | Southern Company Gas | Recurring    
Assets:    
Investments, available for sale: 9  
U.S. Treasury and government agency securities | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments, available for sale: 2  
U.S. Treasury and government agency securities | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments, available for sale: 7  
U.S. Treasury and government agency securities | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments, available for sale: 0  
Municipal bonds | Recurring    
Assets:    
Nuclear decommissioning trusts 47 48
Municipal bonds | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Municipal bonds | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 47 48
Municipal bonds | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Municipal bonds | Alabama Power | Recurring    
Assets:    
Nuclear decommissioning trusts 1 1
Municipal bonds | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Municipal bonds | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 1 1
Municipal bonds | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Municipal bonds | Georgia Power | Recurring    
Assets:    
Nuclear decommissioning trusts 46 47
Municipal bonds | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Municipal bonds | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 46 47
Municipal bonds | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Pooled funds – fixed income | Recurring    
Assets:    
Nuclear decommissioning trusts 7 6
Pooled funds – fixed income | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Pooled funds – fixed income | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 7 6
Pooled funds – fixed income | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Pooled funds – fixed income | Southern Company Gas | Recurring    
Assets:    
Non-qualified deferred compensation trusts 7 6
Pooled funds – fixed income | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Non-qualified deferred compensation trusts 0 0
Pooled funds – fixed income | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Non-qualified deferred compensation trusts 7 6
Pooled funds – fixed income | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Non-qualified deferred compensation trusts 0 0
Corporate bonds | Recurring    
Assets:    
Nuclear decommissioning trusts 452 389
Investments, available for sale: 3  
Corporate bonds | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Investments, available for sale: 1  
Corporate bonds | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 452 389
Investments, available for sale: 2  
Corporate bonds | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Investments, available for sale: 0  
Corporate bonds | Alabama Power | Recurring    
Assets:    
Nuclear decommissioning trusts 287 231
Corporate bonds | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Corporate bonds | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 287 231
Corporate bonds | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Corporate bonds | Georgia Power | Recurring    
Assets:    
Nuclear decommissioning trusts 165 158
Corporate bonds | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Corporate bonds | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 165 158
Corporate bonds | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Corporate bonds | Southern Company Gas | Recurring    
Assets:    
Investments, available for sale: 3  
Corporate bonds | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments, available for sale: 1  
Corporate bonds | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments, available for sale: 2  
Corporate bonds | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments, available for sale: 0  
Mortgage and asset backed securities | Recurring    
Assets:    
Nuclear decommissioning trusts 106 89
Investments, available for sale: 10  
Mortgage and asset backed securities | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Investments, available for sale: 0  
Mortgage and asset backed securities | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 106 89
Investments, available for sale: 10  
Mortgage and asset backed securities | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Investments, available for sale: 0  
Mortgage and asset backed securities | Alabama Power | Recurring    
Assets:    
Nuclear decommissioning trusts 31 25
Mortgage and asset backed securities | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Mortgage and asset backed securities | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 31 25
Mortgage and asset backed securities | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Mortgage and asset backed securities | Georgia Power | Recurring    
Assets:    
Nuclear decommissioning trusts 75 64
Mortgage and asset backed securities | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Mortgage and asset backed securities | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 75 64
Mortgage and asset backed securities | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Mortgage and asset backed securities | Southern Company Gas | Recurring    
Assets:    
Investments, available for sale: 10  
Mortgage and asset backed securities | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments, available for sale: 0  
Mortgage and asset backed securities | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments, available for sale: 10  
Mortgage and asset backed securities | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments, available for sale: 0  
Private equity | Recurring    
Assets:    
Nuclear decommissioning trusts 181 169
Private equity | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Private equity | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 0 0
Private equity | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Private equity | Recurring | Fair Value Measured at Net Asset Value Per Share (NAV)    
Assets:    
Nuclear decommissioning trusts 181 169
Private equity | Alabama Power | Recurring    
Assets:    
Nuclear decommissioning trusts 181 169
Private equity | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 0 0
Private equity | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 0 0
Private equity | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Private equity | Alabama Power | Recurring | Fair Value Measured at Net Asset Value Per Share (NAV)    
Assets:    
Nuclear decommissioning trusts 181 169
Cash and cash equivalents | Recurring    
Assets:    
Nuclear decommissioning trusts 1 3
Cash and cash equivalents | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 1 3
Cash and cash equivalents | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 0 0
Cash and cash equivalents | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Other | Recurring    
Assets:    
Nuclear decommissioning trusts 51 70
Other | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 39 58
Other | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 3 3
Other | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Other | Recurring | Fair Value Measured at Net Asset Value Per Share (NAV)    
Assets:    
Nuclear decommissioning trusts 9 9
Other | Alabama Power | Recurring    
Assets:    
Nuclear decommissioning trusts 21 17
Other | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 11 8
Other | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 1 0
Other | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Other | Alabama Power | Recurring | Fair Value Measured at Net Asset Value Per Share (NAV)    
Assets:    
Nuclear decommissioning trusts 9 9
Other | Georgia Power | Recurring    
Assets:    
Nuclear decommissioning trusts 30 53
Other | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Nuclear decommissioning trusts 28 50
Other | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Nuclear decommissioning trusts 2 3
Other | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Nuclear decommissioning trusts 0 0
Other | Southern Power | Recurring    
Liabilities:    
Derivative liability   13
Other | Southern Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Liabilities:    
Derivative liability   0
Other | Southern Power | Recurring | Significant Other Observable Inputs (Level 2)    
Liabilities:    
Derivative liability   13
Other | Southern Power | Recurring | Significant Unobservable Inputs (Level 3)    
Liabilities:    
Derivative liability   0
Cash and cash equivalents | Southern Company Gas | Recurring    
Assets:    
Non-qualified deferred compensation trusts 1 3
Cash and cash equivalents | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Non-qualified deferred compensation trusts 1 3
Cash and cash equivalents | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)    
Assets:    
Non-qualified deferred compensation trusts 0 0
Cash and cash equivalents | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)    
Assets:    
Non-qualified deferred compensation trusts $ 0 $ 0
v3.25.0.1
FAIR VALUE MEASUREMENTS - Narrative (Details) - Alabama Power - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Fair Value, Option, Quantitative Disclosures [Line Items]    
Alternative investment $ 190 $ 178
Unfunded commitments $ 78 $ 87
v3.25.0.1
FAIR VALUE MEASUREMENTS - Financial Instruments, Carrying Amount Not Equal to Fair Value (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Carrying amount    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt $ 63,200 $ 59,400
Fair value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt 57,700 55,000
Alabama Power | Carrying amount    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt 11,200 11,200
Alabama Power | Fair value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt 9,800 10,100
Georgia Power | Carrying amount    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt 18,100 16,500
Georgia Power | Fair value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt 16,200 15,100
Mississippi Power | Carrying amount    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt 1,700 1,600
Mississippi Power | Fair value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt 1,500 1,400
Southern Power | Carrying amount    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt 2,700 2,700
Southern Power | Fair value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt 2,600 2,600
Southern Company Gas | Carrying amount    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt 8,500 7,800
Southern Company Gas | Fair value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt $ 7,400 $ 6,800
v3.25.0.1
DERIVATIVES - Energy-Related Derivative Contracts (Details) - Energy-related, Natural Gas
MMBTU in Millions
Dec. 31, 2024
MMBTU
Derivative [Line Items]  
Net Purchased mmBtu 431.0
Alabama Power  
Derivative [Line Items]  
Net Purchased mmBtu 123.0
Georgia Power  
Derivative [Line Items]  
Net Purchased mmBtu 116.0
Mississippi Power  
Derivative [Line Items]  
Net Purchased mmBtu 103.0
Southern Power  
Derivative [Line Items]  
Net Purchased mmBtu 6.0
Southern Company Gas  
Derivative [Line Items]  
Net Purchased mmBtu 83.0
Long | Not Designated as Hedging Instrument | Southern Company Gas  
Derivative [Line Items]  
Derivative nonmonetary notional amount net long short position volume 90.0
Short | Not Designated as Hedging Instrument | Southern Company Gas  
Derivative [Line Items]  
Derivative nonmonetary notional amount net long short position volume 7.0
v3.25.0.1
DERIVATIVES - Narrative (Details)
MMBTU in Millions
 12 Months Ended
Dec. 31, 2024
USD ($)
MMBTU
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Derivative [Line Items]      
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU 15    
Estimated pre-tax gains (losses) that will be reclassified from OCI to interest expense for the next 12-month period $ (13,000,000)    
Collateral already posted, aggregate fair value 17,000,000 $ 62,000,000  
Derivative liability 554,000,000 659,000,000  
Interest rate derivatives      
Derivative [Line Items]      
Derivative liability 72,000,000    
Interest rate derivatives | Cash Flow Hedging      
Derivative [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI 23,000,000 (12,000,000) $ 46,000,000
Energy-related derivatives | Cash Flow Hedging      
Derivative [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI $ (7,000,000) (81,000,000) 3,000,000
Alabama Power      
Derivative [Line Items]      
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU 4    
Collateral already posted, aggregate fair value $ 0    
Derivative liability 23,000,000 100,000,000  
Alabama Power | Energy-related derivatives | Cash Flow Hedging      
Derivative [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI $ 0 0 0
Georgia Power      
Derivative [Line Items]      
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU 6    
Derivative liability $ 27,000,000 113,000,000  
Georgia Power | Cash Flow Hedging      
Derivative [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI $ 24,000,000 (2,000,000) 31,000,000
Mississippi Power      
Derivative [Line Items]      
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU 2    
Derivative liability $ 17,000,000 47,000,000  
Mississippi Power | Cash Flow Hedging      
Derivative [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI $ 7,000,000 0 0
Southern Power      
Derivative [Line Items]      
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU 3    
Estimated pre-tax gains (losses) that will be reclassified from OCI to interest expense for the next 12-month period $ (25,000,000)    
Collateral already posted, aggregate fair value 0    
Derivative liability 51,000,000 27,000,000  
Southern Power | Interest rate derivatives      
Derivative [Line Items]      
Derivative liability 24,000,000    
Southern Power | Energy-related derivatives | Cash Flow Hedging      
Derivative [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI (1,000,000) (18,000,000) (15,000,000)
Registrants | Derivative Counterparties      
Derivative [Line Items]      
Collateral already posted, aggregate fair value 0    
Southern Company Gas      
Derivative [Line Items]      
Collateral already posted, aggregate fair value 17,000,000 62,000,000  
Derivative liability 84,000,000 87,000,000  
Southern Company Gas | Interest rate derivatives | Cash Flow Hedging      
Derivative [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI (5,000,000) 0 0
Southern Company Gas | Energy-related derivatives | Cash Flow Hedging      
Derivative [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI (6,000,000) $ (63,000,000) $ 18,000,000
Traditional Electric Operating Companies      
Derivative [Line Items]      
Estimated pre-tax gains (losses) that will be reclassified from OCI to interest expense for the next 12-month period $ 0    
v3.25.0.1
DERIVATIVES - Interest Rate Derivatives (Details) - Interest rate derivatives
$ in Millions
 12 Months Ended
Dec. 31, 2024
USD ($)
Derivative [Line Items]  
Notional Amount $ 1,900
Fair Value Gain (Loss) December 31, 2024 (269)
Southern Company | Fair Value Hedges of Existing Debt | Date one  
Derivative [Line Items]  
Notional Amount $ 400
Weighted Average Interest Rate Paid 0.80%
Interest Rate Received 1.75%
Fair Value Gain (Loss) December 31, 2024 $ (42)
Southern Company | Fair Value Hedges of Existing Debt | Date 2  
Derivative [Line Items]  
Notional Amount $ 1,000
Weighted Average Interest Rate Paid 2.48%
Interest Rate Received 3.70%
Fair Value Gain (Loss) December 31, 2024 $ (143)
Southern Company Gas | Fair Value Hedges of Existing Debt  
Derivative [Line Items]  
Notional Amount $ 500
Weighted Average Interest Rate Paid 0.49%
Interest Rate Received 1.75%
Fair Value Gain (Loss) December 31, 2024 $ (84)
v3.25.0.1
DERIVATIVES - Foreign Currency Derivatives (Details)
€ in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2024
USD ($)
Dec. 31, 2024
EUR (€)
Dec. 31, 2023
USD ($)
Foreign currency derivatives | Cash Flow Hedges of Forecasted Debt      
Derivative [Line Items]      
Pay Notional $ 2,040    
Receive Notional | €   € 1,750  
Fair Value Gain (Loss) December 31, 2024 (218)    
Southern Power      
Derivative [Line Items]      
Fair Value Gain (Loss) December 31, 2024 (45)   $ (12)
Southern Power | Foreign currency derivatives | Cash Flow Hedges of Forecasted Debt      
Derivative [Line Items]      
Pay Notional $ 564    
Pay Rate 3.78%    
Receive Notional | €   500  
Receive Rate 1.85%    
Southern Power | Foreign currency derivatives | Date | Cash Flow Hedges of Forecasted Debt      
Derivative [Line Items]      
Fair Value Gain (Loss) December 31, 2024 $ (51)    
Southern Company | Foreign currency derivatives | Cash Flow Hedges of Forecasted Debt      
Derivative [Line Items]      
Fair Value Gain (Loss) December 31, 2024 (167)    
Southern Company | Foreign currency derivatives | Date | Fair Value Hedges of Existing Debt      
Derivative [Line Items]      
Pay Notional $ 1,476    
Pay Rate 3.39%    
Receive Notional | €   € 1,250  
Receive Rate 1.88%    
v3.25.0.1
DERIVATIVES - Derivative Financial Statement Presentation and Amounts With Balance Sheet Offsetting (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized $ 89 $ 55
Derivative asset, gross amount offset (44) (23)
Derivative asset, net amounts recognized in the balance sheets 45 32
Derivative liability, gross amounts recognized 615 744
Derivative liability, gross amounts offset $ (61) $ (85)
Derivative Liability Statement Of Financial Position Extensible Enumeration Not Disclosed Flag Net amounts recognized in the Balance Sheets(b) Net amounts recognized in the Balance Sheets(b)
Derivative liability, gross amounts recognized in balance sheets $ 554 $ 659
Derivative asset, statement of financial position, extensible enumeration, not disclosed, flag Net amounts recognized in the Balance Sheets(b) Net amounts recognized in the Balance Sheets(b)
Collateral already posted, aggregate fair value $ 17 $ 62
Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 6 9
Derivative liability, gross amounts recognized 3 10
Energy-related derivatives | Other deferred charges and assets | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 1 1
Energy-related derivatives | Other deferred credits and liabilities | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 0 2
Energy-related derivatives | Assets from risk management activities | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 5 8
Energy-related derivatives | Other current liabilities | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 3 8
Interest rate derivatives    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized in balance sheets 72  
Alabama Power    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amount offset (19) (10)
Derivative asset, net amounts recognized in the balance sheets 7 5
Derivative liability, gross amounts offset (19) (10)
Derivative liability, gross amounts recognized in balance sheets 23 100
Collateral already posted, aggregate fair value 0  
Georgia Power    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 19 13
Derivative asset, gross amount offset (15) (11)
Derivative asset, net amounts recognized in the balance sheets 4 2
Derivative liability, gross amounts recognized 42 124
Derivative liability, gross amounts offset (15) (11)
Derivative liability, gross amounts recognized in balance sheets 27 113
Georgia Power | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 0 1
Derivative liability, gross amounts recognized 1 0
Georgia Power | Energy-related derivatives | Other deferred charges and assets | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 0 1
Georgia Power | Energy-related derivatives | Other deferred credits and liabilities | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 0 0
Georgia Power | Energy-related derivatives | Other current liabilities | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 1 0
Georgia Power | Energy-related derivatives | Other current assets | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 0 0
Mississippi Power    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amount offset (17) (14)
Derivative asset, net amounts recognized in the balance sheets 2 1
Derivative liability, gross amounts offset (17) (14)
Derivative liability, gross amounts recognized in balance sheets 17 47
Southern Power    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, net amounts recognized in the balance sheets 4 3
Derivative liability, gross amounts recognized in balance sheets 51 27
Collateral already posted, aggregate fair value 0  
Southern Power | Interest rate derivatives    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized in balance sheets 24  
Southern Company Gas    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 21 9
Derivative asset, gross amount offset 7 12
Derivative asset, net amounts recognized in the balance sheets 28 21
Derivative liability, gross amounts recognized 94 137
Derivative liability, gross amounts offset (10) (50)
Derivative liability, gross amounts recognized in balance sheets 84 87
Collateral already posted, aggregate fair value 17 62
Southern Company Gas | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 6 8
Derivative liability, gross amounts recognized 2 10
Southern Company Gas | Energy-related derivatives | Other deferred charges and assets | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 1 1
Southern Company Gas | Energy-related derivatives | Other deferred credits and liabilities | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 0 2
Southern Company Gas | Energy-related derivatives | Assets from risk management activities | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 5 7
Southern Company Gas | Energy-related derivatives | Other current liabilities | Not Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 2 8
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 75 43
Derivative liability, gross amounts recognized 122 315
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 42 31
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 40 117
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Assets from risk management activities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 33 12
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 82 198
Hedging Instruments for Regulatory Purposes | Alabama Power | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 26 15
Derivative liability, gross amounts recognized 42 110
Hedging Instruments for Regulatory Purposes | Alabama Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 15 9
Hedging Instruments for Regulatory Purposes | Alabama Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 12 41
Hedging Instruments for Regulatory Purposes | Alabama Power | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 30 69
Hedging Instruments for Regulatory Purposes | Alabama Power | Energy-related derivatives | Other current assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 11 6
Hedging Instruments for Regulatory Purposes | Georgia Power | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 19 12
Derivative liability, gross amounts recognized 41 124
Hedging Instruments for Regulatory Purposes | Georgia Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 13 10
Hedging Instruments for Regulatory Purposes | Georgia Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 9 42
Hedging Instruments for Regulatory Purposes | Georgia Power | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 32 82
Hedging Instruments for Regulatory Purposes | Georgia Power | Energy-related derivatives | Other current assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 6 2
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 19 15
Derivative liability, gross amounts recognized 34 61
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 14 12
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 19 34
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 15 27
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Other current assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 5 3
Hedging Instruments for Regulatory Purposes | Southern Company Gas | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 1 0
Hedging Instruments for Regulatory Purposes | Southern Company Gas | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 0 4
Hedging Instruments for Regulatory Purposes | Southern Company Gas | Energy-related derivatives | Assets from risk management activities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 11 1
Hedging Instruments for Regulatory Purposes | Southern Company Gas | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 5 20
Cash Flow and Fair Value Hedging | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 8 3
Derivative liability, gross amounts recognized 490 419
Cash Flow and Fair Value Hedging | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 4 3
Cash Flow and Fair Value Hedging | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 0 4
Cash Flow and Fair Value Hedging | Energy-related derivatives | Assets from risk management activities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 4 0
Cash Flow and Fair Value Hedging | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 3 29
Cash Flow and Fair Value Hedging | Interest rate derivatives | Other deferred charges and assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 0 0
Cash Flow and Fair Value Hedging | Interest rate derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 208 190
Cash Flow and Fair Value Hedging | Interest rate derivatives | Assets from risk management activities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 0 0
Cash Flow and Fair Value Hedging | Interest rate derivatives | Other current liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 61 74
Cash Flow and Fair Value Hedging | Foreign currency derivatives | Other deferred charges and assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 0 0
Cash Flow and Fair Value Hedging | Foreign currency derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 182 88
Cash Flow and Fair Value Hedging | Foreign currency derivatives | Assets from risk management activities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 0 0
Cash Flow and Fair Value Hedging | Foreign currency derivatives | Other current liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 36 34
Cash Flow and Fair Value Hedging | Southern Power | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 4 3
Derivative liability, gross amounts recognized 51 27
Cash Flow and Fair Value Hedging | Southern Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 3 3
Cash Flow and Fair Value Hedging | Southern Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 0 0
Cash Flow and Fair Value Hedging | Southern Power | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 0 5
Cash Flow and Fair Value Hedging | Southern Power | Energy-related derivatives | Other current assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 1 0
Cash Flow and Fair Value Hedging | Southern Power | Foreign currency derivatives | Other deferred charges and assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 0 0
Cash Flow and Fair Value Hedging | Southern Power | Foreign currency derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 40 11
Cash Flow and Fair Value Hedging | Southern Power | Foreign currency derivatives | Other current liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 11 11
Cash Flow and Fair Value Hedging | Southern Power | Foreign currency derivatives | Other current assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 0 0
Cash Flow and Fair Value Hedging | Southern Company Gas | Energy-related derivatives | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 4 0
Derivative liability, gross amounts recognized 87 107
Cash Flow and Fair Value Hedging | Southern Company Gas | Energy-related derivatives | Assets from risk management activities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 3 0
Cash Flow and Fair Value Hedging | Southern Company Gas | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 3 24
Cash Flow and Fair Value Hedging | Southern Company Gas | Interest rate derivatives | Other deferred charges and assets | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 0 0
Cash Flow and Fair Value Hedging | Southern Company Gas | Interest rate derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized 67 59
Cash Flow and Fair Value Hedging | Southern Company Gas | Interest rate derivatives | Assets from risk management activities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative asset, gross amounts recognized 0 0
Cash Flow and Fair Value Hedging | Southern Company Gas | Interest rate derivatives | Other current liabilities | Designated as Hedging Instrument    
Fair value of energy-related derivatives and interest rate derivatives    
Derivative liability, gross amounts recognized $ 17 $ 20
v3.25.0.1
DERIVATIVES - Schedule of Unrealized Gain (Loss) Recognized in the Balance Sheet (Details) - Energy-related derivatives - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) $ (50) $ (257)
Other regulatory assets, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (61) (180)
Other regulatory assets, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (5) (87)
Other regulatory liabilities, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 8 9
Other regulatory liabilities, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 8 1
Alabama Power    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (16) (95)
Alabama Power | Other regulatory assets, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (23) (67)
Alabama Power | Other regulatory assets, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 0 (32)
Alabama Power | Other regulatory liabilities, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 4 4
Alabama Power | Other regulatory liabilities, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 3 0
Georgia Power    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (22) (112)
Georgia Power | Other regulatory assets, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (26) (80)
Georgia Power | Other regulatory assets, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 0 (33)
Georgia Power | Other regulatory liabilities, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 0 0
Georgia Power | Other regulatory liabilities, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 4 1
Mississippi Power    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (15) (46)
Mississippi Power | Other regulatory assets, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (11) (25)
Mississippi Power | Other regulatory assets, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (5) (22)
Mississippi Power | Other regulatory liabilities, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 0 1
Mississippi Power | Other regulatory liabilities, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 1 0
Southern Company Gas    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 3 (4)
Southern Company Gas | Other regulatory assets, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (1) (8)
Southern Company Gas | Other regulatory assets, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 0 0
Southern Company Gas | Other regulatory liabilities, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 4 4
Southern Company Gas | Other regulatory liabilities, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) $ 0 $ 0
v3.25.0.1
DERIVATIVES - Pre-Tax Effects of Derivatives Designated as Hedges on AOCI (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI $ (8) $ (58) $ (80)
Energy-related derivatives | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI (7) (81) 3
Interest rate derivatives | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI 23 (12) 46
Foreign currency derivatives | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI (40) 14 (105)
Foreign currency derivatives | Fair Value Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI 16 21 (24)
Georgia Power | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI 24 (2) 31
Mississippi Power | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI 7 0 0
Southern Power      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI (41) (4) (120)
Southern Power | Energy-related derivatives | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI (1) (18) (15)
Southern Power | Foreign currency derivatives | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI (40) 14 (105)
Southern Company Gas      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI (11) (63) 18
Southern Company Gas | Energy-related derivatives | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI (6) (63) 18
Southern Company Gas | Interest rate derivatives | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (Loss) From Derivatives Recognized in OCI $ (5) $ 0 $ 0
v3.25.0.1
DERIVATIVES - Pre-Tax Effects of Derivatives Designated as Hedges on Income (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Derivative Instruments, Gain (Loss) [Line Items]      
Depreciation and amortization $ 4,755 $ 4,525 $ 3,663
Interest expense, net of amounts capitalized (2,743) (2,446) (2,022)
Other income (expense), net 530 553 500
Natural gas      
Derivative Instruments, Gain (Loss) [Line Items]      
Cost of sales 1,196 1,644 3,004
Energy-related derivatives | Cost of Sales | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative (40) (44) 37
Energy-related derivatives | Operating Expense | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on hedges (2) (2) 0
Energy-related derivatives | Depreciation and Amortization | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative (6) (23) (5)
Interest rate derivatives | Interest Expense | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative (16) (35) (25)
Interest rate derivatives | Interest Expense | Fair Value Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative (4) 37 (291)
Foreign currency derivatives | Interest Expense | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative (12) (11) (19)
Foreign currency derivatives | Other Income (Expense) | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative (33) 19 (83)
Foreign currency fair value hedges 2 69 (106)
Amount excluded from effectiveness testing recognized in earnings (16) (21) 24
Southern Power      
Derivative Instruments, Gain (Loss) [Line Items]      
Depreciation and amortization 522 504 516
Interest expense, net of amounts capitalized (117) (129) (138)
Other income (expense), net 13 12 7
Southern Power | Energy-related derivatives | Depreciation and Amortization | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative (6) (23) (5)
Southern Power | Foreign currency derivatives | Interest Expense | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative (12) (11) (19)
Southern Power | Foreign currency derivatives | Other Income (Expense) | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative (33) 19 (83)
Southern Company Gas      
Derivative Instruments, Gain (Loss) [Line Items]      
Cost of sales 1,196 1,644 3,004
Depreciation and amortization 650 582 559
Interest expense, net of amounts capitalized (341) (310) (263)
Other income (expense), net 66 57 53
Southern Company Gas | Energy-related derivatives | Operating Expense | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on hedges (2) (2) 0
Southern Company Gas | Interest rate derivatives | Interest Expense | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on hedges (1) (19) (4)
Southern Company Gas | Interest rate derivatives | Interest Expense | Fair Value Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on hedges (5) 6 (86)
Southern Company Gas | Foreign currency derivatives | Other Income (Expense) | Cash Flow Hedging      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative $ (40) $ (44) $ 37
v3.25.0.1
DERIVATIVES - Cumulative Basis Adjustments for Fair Value Hedges (Details) - Long-term debt - Fair Value Hedging - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Derivative Instruments, Gain (Loss) [Line Items]    
Carrying Amount of the Hedged Item $ (2,936) $ (3,024)
Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item 242 235
Southern Company Gas    
Derivative Instruments, Gain (Loss) [Line Items]    
Carrying Amount of the Hedged Item (422) (427)
Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item $ 75 $ 70
v3.25.0.1
DERIVATIVES - Pre-Tax Effects of Derivatives Not Designated as Hedging (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Energy-related derivatives | Natural gas revenues      
Derivative Instruments, Gain (Loss) [Line Items]      
Derivative instruments not designated as hedging instruments, gain (loss), net $ 0 $ 0 $ (11)
Energy-related derivatives | Cost of natural gas      
Derivative Instruments, Gain (Loss) [Line Items]      
Derivative instruments not designated as hedging instruments, gain (loss), net 94 59 (65)
Energy-related derivatives | Cost of natural gas | Not Designated as Hedging Instrument | Southern Company Gas      
Derivative Instruments, Gain (Loss) [Line Items]      
Derivative instruments not designated as hedging instruments, gain (loss), net 94 59 (76)
Weather derivatives      
Derivative Instruments, Gain (Loss) [Line Items]      
Derivative instruments not designated as hedging instruments, gain (loss), net $ 12 $ 15 $ (7)
v3.25.0.1
ACQUISITIONS AND DISPOSITIONS - Alabama Power Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Business Acquisition [Line Items]      
Capital expenditures related to qualifying projects $ 8,955 $ 9,095 $ 7,923
Alabama Power      
Business Acquisition [Line Items]      
Capital expenditures related to qualifying projects $ 1,881 $ 2,022 2,016
Alabama Power | Calhoun Generating Station      
Business Acquisition [Line Items]      
Purchase price     179
Capital expenditures related to qualifying projects     $ 171
v3.25.0.1
ACQUISITIONS AND DISPOSITIONS - Southern Power Narrative (Details) - SOUTHERN POWER CO
$ in Millions
 1 Months Ended 12 Months Ended
Nov. 30, 2024
MW
Dec. 31, 2024
USD ($)
MW
Dec. 31, 2023
USD ($)
Kay Wind Facility      
Asset Acquisition [Line Items]      
Approximate Nameplate Capacity (MW) 299    
PPA Contract Period 20 years    
Nameplate Capacity, Amount Repowered 200    
South Cheyenne Solar Facility      
Asset Acquisition [Line Items]      
Approximate Nameplate Capacity (MW)   150  
PPA Contract Period   20 years  
Millers Branch Solar Development Phase 1      
Asset Acquisition [Line Items]      
Approximate Nameplate Capacity (MW)   200  
PPA Contract Period   20 years  
Millers Branch Solar Development Phase 2      
Asset Acquisition [Line Items]      
Approximate Nameplate Capacity (MW)   180  
PPA Contract Period   15 years  
Millers Branch      
Asset Acquisition [Line Items]      
Cost of construction | $   $ 292  
South Cheyenne Solar Facility and Millers Branch Solar Development      
Asset Acquisition [Line Items]      
Payments to acquire businesses | $     $ 193
v3.25.0.1
ACQUISITIONS AND DISPOSITIONS - Schedule of Asset Acquisitions (Details) - South Cheyenne Solar Facility - Southern Power
 12 Months Ended
Dec. 31, 2024
MW
Asset Acquisition [Line Items]  
Approximate Nameplate Capacity (MW) 150
PPA Contract Period 20 years
v3.25.0.1
ACQUISITIONS AND DISPOSITIONS - Schedule of Construction Projects (Details) - Southern Power - MW
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2022
Dec. 31, 2021
Garland Solar Storage      
Business Acquisition [Line Items]      
Approximate Nameplate Capacity (MW)   88 88
PPA Contract Period   20 years  
Nameplate capacity placed in service (in MWs)   15 73
Tranquility Solar Storage      
Business Acquisition [Line Items]      
Approximate Nameplate Capacity (MW)   72 72
PPA Contract Period   20 years  
Nameplate capacity placed in service (in MWs)     32
Tranquillity Solar Storage      
Business Acquisition [Line Items]      
Nameplate capacity placed in service (in MWs)   40  
Millers Branch Solar Development Phase 1      
Business Acquisition [Line Items]      
Approximate Nameplate Capacity (MW) 200    
PPA Contract Period 20 years    
Millers Branch Solar Development Phase 2      
Business Acquisition [Line Items]      
Approximate Nameplate Capacity (MW) 180    
PPA Contract Period 15 years    
Millers Branch Solar Development Phase 3      
Business Acquisition [Line Items]      
Approximate Nameplate Capacity (MW) 132    
PPA Contract Period 15 years    
South Cheyenne Solar Facility      
Business Acquisition [Line Items]      
Approximate Nameplate Capacity (MW) 150    
PPA Contract Period 20 years    
v3.25.0.1
ACQUISITIONS AND DISPOSITIONS - GAS Acquisitions and Dispositions Narrative (Details) - Disposal Group, Disposed of by Sale, Not Discontinued Operations - Natural Gas Storage Facilities - Southern Company Gas
$ in Millions
 3 Months Ended
Dec. 31, 2022
USD ($)
Sep. 30, 2022
USD ($)
storageFacility
Business Acquisition [Line Items]    
Number of natural gas storage facilities sold | storageFacility   2
Consideration for sale   $ 186
Gain (loss) on dispositions $ (131)  
Gain (loss) on dispositions, after tax $ (99)  
v3.25.0.1
SEGMENT AND RELATED INFORMATION - Narrative (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2024
USD ($)
segment
state
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Segment Reporting Information [Line Items]      
Total operating revenues $ 26,764 $ 24,828 $ 25,941
Total operating revenues 26,724 25,253 29,279
Southern Power      
Segment Reporting Information [Line Items]      
Total operating revenues 1,445 1,630 2,805
Total operating revenues $ 2,014 2,189 3,369
Number of reportable segments | segment 1    
Southern Company Gas      
Segment Reporting Information [Line Items]      
Total operating revenues $ 4,340 4,598 5,905
Total operating revenues $ 4,456 4,702 5,962
Number of reportable segments | segment 3    
Number of states in which entity operates | state 4    
Southern Natural Gas Company, LLC | Southern Company Gas      
Segment Reporting Information [Line Items]      
Ownership percentage, equity method investment 50.00%    
Dalton Pipeline | Southern Company Gas      
Segment Reporting Information [Line Items]      
Ownership percentage, equity method investment 50.00%    
Wholesale revenues, affiliates | Southern Power      
Segment Reporting Information [Line Items]      
Total operating revenues $ 371 $ 537 $ 875
v3.25.0.1
SEGMENT AND RELATED INFORMATION - Financial Data for Business Segments (Details)
$ in Millions
 1 Months Ended 3 Months Ended 12 Months Ended
Nov. 30, 2024
MW
Sep. 30, 2024
USD ($)
Jun. 30, 2024
USD ($)
Dec. 31, 2023
USD ($)
Jun. 30, 2023
USD ($)
Dec. 31, 2022
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Segment Reporting Information [Line Items]                  
Total operating revenues             $ 26,724 $ 25,253 $ 29,279
Other segment items             13,995 13,954 19,426
Depreciation and amortization             4,755 4,525 3,663
Earnings from equity method investments             139 144 151
Interest expense             2,743 2,446 2,022
Income taxes (benefit)             969 496 795
Segment net income (loss)             4,401 3,976 3,524
Goodwill       $ 5,161   $ 5,161 5,161 5,161 5,161
Total assets       139,331   134,891 145,180 139,331 134,891
Segment and Related Information (Textual) [Abstract]                  
Estimated loss on Plant Vogtle Units 3 and 4             (21) (68) 183
Southern Company Gas                  
Segment Reporting Information [Line Items]                  
Total operating revenues             4,456 4,702 5,962
Operating Segments                  
Segment Reporting Information [Line Items]                  
Total operating revenues             26,059 24,700 28,835
Other segment items             13,342 13,405 18,793
Depreciation and amortization             4,684 4,447 3,588
Earnings from equity method investments             154 139 148
Interest expense             1,713 1,584 1,330
Income taxes (benefit)             1,261 794 1,028
Segment net income (loss)             5,213 4,609 4,244
Goodwill       5,017   5,017 5,017 5,017 5,017
Total assets       137,728   132,904 143,382 137,728 132,904
Operating Segments | Electric Utilities                  
Segment Reporting Information [Line Items]                  
Total operating revenues             21,603 19,998 22,873
Other segment items             10,729 10,281 14,257
Depreciation and amortization             4,034 3,865 3,029
Earnings from equity method investments             8 (1) 0
Interest expense             1,372 1,274 1,067
Income taxes (benefit)             1,003 583 848
Segment net income (loss)             4,473 3,994 3,672
Goodwill       2   2 2 2 2
Total assets       112,645   108,283 117,205 112,645 108,283
Operating Segments | Traditional Electric Operating Companies                  
Segment Reporting Information [Line Items]                  
Total operating revenues             19,977 18,358 20,408
Other segment items             10,057 9,643 12,820
Depreciation and amortization             3,512 3,361 2,513
Earnings from equity method investments             8 (1) 0
Interest expense             1,255 1,145 929
Income taxes (benefit)             1,016 571 828
Segment net income (loss)             4,145 3,637 3,318
Goodwill       0   0 0 0 0
Total assets       100,429   95,861 105,577 100,429 95,861
Operating Segments | Southern Power                  
Segment Reporting Information [Line Items]                  
Total operating revenues             2,014 2,189 3,369
Other segment items             1,060 1,187 2,341
Depreciation and amortization             522 504 516
Earnings from equity method investments             0 0 0
Interest expense             117 129 138
Income taxes (benefit)             (13) 12 20
Segment net income (loss)             328 357 354
Goodwill       2   2 2 2 2
Total assets       12,761   13,081 12,653 12,761 13,081
Operating Segments | Southern Company Gas                  
Segment Reporting Information [Line Items]                  
Total operating revenues             4,456 4,702 5,962
Other segment items             2,613 3,124 4,536
Depreciation and amortization             650 582 559
Earnings from equity method investments             146 140 148
Interest expense             341 310 263
Income taxes (benefit)             258 211 180
Segment net income (loss)             740 615 572
Goodwill       5,015   5,015 5,015 5,015 5,015
Total assets       25,083   24,621 26,177 25,083 24,621
Eliminations                  
Segment Reporting Information [Line Items]                  
Total operating revenues             (178) (165) (149)
Other segment items             (149) (150) (138)
Depreciation and amortization             0 0 0
Earnings from equity method investments             2 0 0
Interest expense             0 (17) (2)
Income taxes (benefit)             0 0 0
Segment net income (loss)             (27) 2 (9)
Goodwill       0   0 0 0 0
Total assets       (843)   (678) (573) (843) (678)
Eliminations | Electric Utilities                  
Segment Reporting Information [Line Items]                  
Total operating revenues             (388) (549) (904)
Other segment items             (388) (549) (904)
Depreciation and amortization             0 0 0
Earnings from equity method investments             0 0 0
Interest expense             0 0 0
Income taxes (benefit)             0 0 0
Segment net income (loss)             0 0 0
Goodwill       0   0 0 0 0
Total assets       (545)   (659) (1,025) (545) (659)
All Other                  
Segment Reporting Information [Line Items]                  
Total operating revenues             843 718 593
Other segment items             802 699 771
Depreciation and amortization             71 78 75
Earnings from equity method investments             (17) 5 3
Interest expense             1,030 879 694
Income taxes (benefit)             (292) (298) (233)
Segment net income (loss)             (785) (635) (711)
Goodwill       144   144 144 144 144
Total assets       2,446   2,665 2,371 2,446 2,665
Georgia Power                  
Segment Reporting Information [Line Items]                  
Total operating revenues             11,331 10,118 11,584
Depreciation and amortization             1,774 1,681 1,430
Interest expense             725 626 485
Income taxes (benefit)             603 448 370
Total assets       56,817     61,255 56,817  
Segment and Related Information (Textual) [Abstract]                  
Estimated loss on Plant Vogtle Units 3 and 4     $ (21)       (21) (68) 183
Estimated loss on Plant Vogtle Units 3 and 4, net of tax     $ (16)            
Georgia Power | Traditional Electric Operating Companies | Plant Vogtle Units 3 and 4                  
Segment and Related Information (Textual) [Abstract]                  
Estimated loss on Plant Vogtle Units 3 and 4             (21) (68) 183
Estimated loss on Plant Vogtle Units 3 and 4, net of tax             (16) (50) 137
Southern Power                  
Segment Reporting Information [Line Items]                  
Total operating revenues             2,014 2,189 3,369
Depreciation and amortization             522 504 516
Interest expense             117 129 138
Income taxes (benefit)             (13) 12 20
Segment net income (loss)             328 357 354
Total assets       12,761     12,653 12,761  
Segment and Related Information (Textual) [Abstract]                  
Litigation settlement             18    
Amount awarded from other party             9    
Gain (loss) on dispositions             0 20 2
Southern Power | Kay Wind Facility                  
Segment and Related Information (Textual) [Abstract]                  
Pre-tax accelerated depreciation             9    
Accelerated depreciation, net of tax             7    
Approximate Nameplate Capacity (MW) | MW 299                
Southern Company Gas                  
Segment Reporting Information [Line Items]                  
Total operating revenues             4,456 4,702 5,962
Other segment items             2,613 3,124 4,536
Depreciation and amortization             650 582 559
Earnings from equity method investments             146 140 148
Interest expense             341 310 263
Income taxes (benefit)             258 211 180
Segment net income (loss)             740 615 572
Goodwill       5,015     5,015 5,015  
Total assets       25,083   24,621 26,177 25,083 24,621
Segment and Related Information (Textual) [Abstract]                  
Impairment charges             0 0 131
Estimated loss on regulatory disallowance             0 (96) 0
Southern Company Gas | Operating Segments                  
Segment Reporting Information [Line Items]                  
Total operating revenues             4,447 4,685 5,937
Other segment items             2,598 3,109 4,401
Depreciation and amortization             649 581 537
Earnings from equity method investments             146 140 148
Interest expense             349 310 259
Income taxes (benefit)             244 195 217
Segment net income (loss)             753 630 671
Total assets       26,055   25,233 27,336 26,055 25,233
Southern Company Gas | Eliminations                  
Segment Reporting Information [Line Items]                  
Total operating revenues             (14) (19) (30)
Other segment items             (14) (19) (30)
Depreciation and amortization             0 0 0
Earnings from equity method investments             0 0 0
Interest expense             0 0 0
Income taxes (benefit)             0 0 0
Segment net income (loss)             0 0 0
Total assets       (10,647)   (9,555) (11,206) (10,647) (9,555)
Southern Company Gas | All Other                  
Segment Reporting Information [Line Items]                  
Total operating revenues             23 36 55
Other segment items             29 34 165
Depreciation and amortization             1 1 22
Earnings from equity method investments             0 0 0
Interest expense             (8) 0 4
Income taxes (benefit)             14 16 (37)
Segment net income (loss)             (13) (15) (99)
Total assets       9,675   8,943 10,047 9,675 8,943
Nicor Gas                  
Segment and Related Information (Textual) [Abstract]                  
Estimated loss on regulatory disallowance       (58) $ (38)   96    
Estimated loss on regulatory disallowance, after tax       (44) $ (28)   72    
Alabama Power                  
Segment Reporting Information [Line Items]                  
Total operating revenues             7,554 7,050 7,817
Depreciation and amortization             1,459 1,401 875
Interest expense             448 425 382
Income taxes (benefit)             360 81 423
Segment net income (loss)             1,403 1,370 $ 1,340
Total assets       $ 35,780     36,538 $ 35,780  
Segment and Related Information (Textual) [Abstract]                  
Impairment charges   $ 36              
Impairment charges, after tax   $ 27              
Spare Parts | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Southern Power                  
Segment and Related Information (Textual) [Abstract]                  
Gain on sale             16    
Gain on sale, after tax             $ 12    
Natural Gas Storage Facilities | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Southern Company Gas                  
Segment and Related Information (Textual) [Abstract]                  
Gain (loss) on dispositions           (131)      
Gain (loss) on dispositions, after tax           $ (99)      
v3.25.0.1
SEGMENT AND RELATED INFORMATION - Electric Utilities' Revenues (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Revenue from External Customer [Line Items]      
Total operating revenues $ 26,724 $ 25,253 $ 29,279
Wholesale electric revenues      
Revenue from External Customer [Line Items]      
Total operating revenues 2,431 2,467 3,641
Electric Utilities      
Revenue from External Customer [Line Items]      
Total operating revenues 21,603 19,998 22,873
Electric Utilities | Retail electric revenues      
Revenue from External Customer [Line Items]      
Total operating revenues 17,790 16,343 18,197
Electric Utilities | Wholesale electric revenues      
Revenue from External Customer [Line Items]      
Total operating revenues 2,431 2,467 3,641
Electric Utilities | Other      
Revenue from External Customer [Line Items]      
Total operating revenues $ 1,382 $ 1,188 $ 1,035
v3.25.0.1
SEGMENT AND RELATED INFORMATION - Traditional Electric Companies (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Sep. 30, 2024
Jun. 30, 2024
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Segment Reporting Information [Line Items]          
Total operating revenues     $ 26,724 $ 25,253 $ 29,279
Total utility operations and maintenance     6,539 6,093 6,824
Other segment items     13,995 13,954 19,426
Depreciation and amortization     4,755 4,525 3,663
Interest expense     2,743 2,446 2,022
Income taxes (benefit)     969 496 795
Net Income     4,260 3,849 3,428
Estimated Loss On Plant Vogtle Units 3 And 4     (21) (68) 183
Alabama Power          
Segment Reporting Information [Line Items]          
Total operating revenues     7,554 7,050 7,817
Total utility operations and maintenance     1,895 1,769 1,935
Depreciation and amortization     1,459 1,401 875
Interest expense     448 425 382
Income taxes (benefit)     360 81 423
Net Income     1,403 1,370 1,351
Impairment charges $ 36        
Impairment charges, after tax $ 27        
Alabama Power | Reportable Segment          
Segment Reporting Information [Line Items]          
Total operating revenues     7,554 7,050 7,817
Rate RSE expenses     1,480 1,421 1,645
Rate CNP Compliance expenses     279 254 237
Total utility operations and maintenance     1,759 1,675 1,882
Other segment items     2,125 2,098 2,915
Depreciation and amortization     1,459 1,401 875
Interest expense     448 425 382
Income taxes (benefit)     360 81 423
Net Income     1,403 1,370 1,340
Capital expenditures     2,114 2,159 2,206
Georgia Power          
Segment Reporting Information [Line Items]          
Total operating revenues     11,331 10,118 11,584
Total utility operations and maintenance     2,372 2,083 2,349
Depreciation and amortization     1,774 1,681 1,430
Interest expense     725 626 485
Income taxes (benefit)     603 448 370
Net Income     2,543 2,080 1,813
Estimated Loss On Plant Vogtle Units 3 And 4   $ (21) (21) (68) 183
Estimated loss on Plant Vogtle Units 3 and 4, net of tax   (16)      
Georgia Power | Reportable Segment          
Segment Reporting Information [Line Items]          
Total operating revenues     11,331 10,118 11,584
Total utility operations and maintenance     2,210 1,901 2,237
Other segment items     3,476 3,382 5,249
Depreciation and amortization     1,774 1,681 1,430
Interest expense     725 626 485
Income taxes (benefit)     603 448 370
Net Income     2,543 2,080 1,813
Capital expenditures     5,355 5,394 4,219
Georgia Power | Traditional Electric Operating Companies | Plant Vogtle Units 3 and 4          
Segment Reporting Information [Line Items]          
Estimated Loss On Plant Vogtle Units 3 And 4     (21) (68) 183
Estimated loss on Plant Vogtle Units 3 and 4, net of tax     (16) (50) 137
Southern Company And Georgia Power | Disposal Group, Held-for-sale, Not Discontinued Operations          
Segment Reporting Information [Line Items]          
Gain on sale   114      
Gain on sale, after tax   $ 84      
Mississippi Power          
Segment Reporting Information [Line Items]          
Total operating revenues     1,463 1,474 1,694
Total utility operations and maintenance     370 362 376
Depreciation and amortization     193 190 181
Interest expense     77 71 56
Income taxes (benefit)     47 36 37
Net Income     199 188 164
Mississippi Power | Reportable Segment          
Segment Reporting Information [Line Items]          
Other segment items     $ 900 $ 1,000 $ 1,300
v3.25.0.1
SEGMENT AND RELATED INFORMATION - Southern Power (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2024
USD ($)
segment
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Segment Reporting Information [Line Items]      
Other segment items $ 13,995 $ 13,954 $ 19,426
Total operating revenues $ 26,724 25,253 29,279
SOUTHERN POWER CO      
Segment Reporting Information [Line Items]      
Number of reportable segments | segment 1    
Total operating revenues $ 2,014 2,189 3,369
SOUTHERN POWER CO | Wholesale revenues, affiliates      
Segment Reporting Information [Line Items]      
Total operating revenues $ 371 537 875
Alabama Power      
Segment Reporting Information [Line Items]      
Number of reportable segments | segment 1    
Total operating revenues $ 7,554 7,050 7,817
Alabama Power | Wholesale revenues, affiliates      
Segment Reporting Information [Line Items]      
Total operating revenues $ 139 60 202
Georgia Power      
Segment Reporting Information [Line Items]      
Number of reportable segments | segment 1    
Total operating revenues $ 11,331 10,118 11,584
Mississippi Power      
Segment Reporting Information [Line Items]      
Number of reportable segments | segment 1    
Total operating revenues $ 1,463 1,474 1,694
Mississippi Power | Wholesale revenues, affiliates      
Segment Reporting Information [Line Items]      
Total operating revenues 218 200 460
Reportable Segment | SOUTHERN POWER CO      
Segment Reporting Information [Line Items]      
Other segment items 1,100 1,200 2,300
Reportable Segment | Alabama Power      
Segment Reporting Information [Line Items]      
Other segment items 2,125 2,098 2,915
Total operating revenues 7,554 7,050 7,817
Reportable Segment | Georgia Power      
Segment Reporting Information [Line Items]      
Other segment items 3,476 3,382 5,249
Total operating revenues 11,331 10,118 11,584
Reportable Segment | Mississippi Power      
Segment Reporting Information [Line Items]      
Other segment items $ 900 $ 1,000 $ 1,300
v3.25.0.1
SEGMENT AND RELATED INFORMATION - Gas Revenues (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2023
Jun. 30, 2023
Dec. 31, 2022
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Segment Reporting Information [Line Items]            
Operating revenues       $ 26,724 $ 25,253 $ 29,279
Other segment items       13,995 13,954 19,426
Depreciation and amortization       4,755 4,525 3,663
Earnings from equity method investments       139 144 151
Interest expense       2,743 2,446 2,022
Income taxes (benefit)       969 496 795
Segment net income (loss)       4,401 3,976 3,524
Total assets $ 139,331   $ 134,891 145,180 139,331 134,891
Southern Company Gas            
Segment Reporting Information [Line Items]            
Operating revenues       4,456 4,702 5,962
Other segment items       2,613 3,124 4,536
Depreciation and amortization       650 582 559
Earnings from equity method investments       146 140 148
Interest expense       341 310 263
Income taxes (benefit)       258 211 180
Segment net income (loss)       740 615 572
Total assets 25,083   24,621 26,177 25,083 24,621
Estimated loss on regulatory disallowance       0 (96) 0
Southern Company Gas | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Natural Gas Storage Facilities            
Segment Reporting Information [Line Items]            
Gain on dispositions, net     (131)      
Gain (loss) on dispositions, after tax     (99)      
Nicor Gas            
Segment Reporting Information [Line Items]            
Estimated loss on regulatory disallowance (58) $ (38)   96    
Estimated loss on regulatory disallowance, after tax (44) $ (28)   72    
Operating Segments            
Segment Reporting Information [Line Items]            
Operating revenues       26,059 24,700 28,835
Other segment items       13,342 13,405 18,793
Depreciation and amortization       4,684 4,447 3,588
Earnings from equity method investments       154 139 148
Interest expense       1,713 1,584 1,330
Income taxes (benefit)       1,261 794 1,028
Segment net income (loss)       5,213 4,609 4,244
Total assets 137,728   132,904 143,382 137,728 132,904
Operating Segments | Southern Company Gas            
Segment Reporting Information [Line Items]            
Operating revenues       4,447 4,685 5,937
Other segment items       2,598 3,109 4,401
Depreciation and amortization       649 581 537
Earnings from equity method investments       146 140 148
Interest expense       349 310 259
Income taxes (benefit)       244 195 217
Segment net income (loss)       753 630 671
Total assets 26,055   25,233 27,336 26,055 25,233
All Other            
Segment Reporting Information [Line Items]            
Operating revenues       843 718 593
Other segment items       802 699 771
Depreciation and amortization       71 78 75
Earnings from equity method investments       (17) 5 3
Interest expense       1,030 879 694
Income taxes (benefit)       (292) (298) (233)
Segment net income (loss)       (785) (635) (711)
Total assets 2,446   2,665 2,371 2,446 2,665
All Other | Southern Company Gas            
Segment Reporting Information [Line Items]            
Operating revenues       23 36 55
Other segment items       29 34 165
Depreciation and amortization       1 1 22
Earnings from equity method investments       0 0 0
Interest expense       (8) 0 4
Income taxes (benefit)       14 16 (37)
Segment net income (loss)       (13) (15) (99)
Total assets 9,675   8,943 10,047 9,675 8,943
Eliminations            
Segment Reporting Information [Line Items]            
Operating revenues       (178) (165) (149)
Other segment items       (149) (150) (138)
Depreciation and amortization       0 0 0
Earnings from equity method investments       2 0 0
Interest expense       0 (17) (2)
Income taxes (benefit)       0 0 0
Segment net income (loss)       (27) 2 (9)
Total assets (843)   (678) (573) (843) (678)
Eliminations | Southern Company Gas            
Segment Reporting Information [Line Items]            
Operating revenues       (14) (19) (30)
Other segment items       (14) (19) (30)
Depreciation and amortization       0 0 0
Earnings from equity method investments       0 0 0
Interest expense       0 0 0
Income taxes (benefit)       0 0 0
Segment net income (loss)       0 0 0
Total assets (10,647)   (9,555) (11,206) (10,647) (9,555)
Gas distribution operations | Operating Segments | Southern Company Gas            
Segment Reporting Information [Line Items]            
Operating revenues       3,899 4,105 5,267
Other segment items       2,236 2,702 3,907
Depreciation and amortization       630 561 516
Earnings from equity method investments       0 0 0
Interest expense       311 275 229
Income taxes (benefit)       172 126 145
Segment net income (loss)       550 441 470
Total assets 22,906   22,040 24,067 22,906 22,040
Gas Pipeline Investments | Operating Segments | Southern Company Gas            
Segment Reporting Information [Line Items]            
Operating revenues       32 32 32
Other segment items       6 5 6
Depreciation and amortization       5 5 5
Earnings from equity method investments       146 140 148
Interest expense       35 32 27
Income taxes (benefit)       31 32 35
Segment net income (loss)       101 98 107
Total assets 1,534   1,577 1,573 1,534 1,577
Gas marketing services | Operating Segments | Southern Company Gas            
Segment Reporting Information [Line Items]            
Operating revenues       516 548 638
Other segment items       356 402 488
Depreciation and amortization       14 15 16
Earnings from equity method investments       0 0 0
Interest expense       3 3 3
Income taxes (benefit)       41 37 37
Segment net income (loss)       102 91 94
Total assets 1,615   1,616 1,696 1,615 1,616
Southern Company Gas            
Segment Reporting Information [Line Items]            
Operating revenues       4,456 4,702 5,962
Southern Company Gas | Gas distribution operations            
Segment Reporting Information [Line Items]            
Operating revenues       3,899 4,090 5,240
Southern Company Gas | Gas marketing services            
Segment Reporting Information [Line Items]            
Operating revenues       516 548 638
Southern Company Gas | Other Gas Revenue            
Segment Reporting Information [Line Items]            
Operating revenues       41 64 84
Southern Company Gas | Operating Segments            
Segment Reporting Information [Line Items]            
Operating revenues       4,456 4,702 5,962
Other segment items       2,613 3,124 4,536
Depreciation and amortization       650 582 559
Earnings from equity method investments       146 140 148
Interest expense       341 310 263
Income taxes (benefit)       258 211 180
Segment net income (loss)       740 615 572
Total assets $ 25,083   $ 24,621 $ 26,177 $ 25,083 $ 24,621
v3.25.0.1
VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Provision for uncollectible accounts:      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period $ 68 $ 71 $ 78
Charged to Income 119 87 71
Charged to Other Accounts (1) 3 (1)
Deductions 112 93 77
Balance at End of Period 74 68 71
Provision for uncollectible accounts: | Alabama Power      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period 16 14 14
Charged to Income 26 16 10
Charged to Other Accounts 0 0 0
Deductions 20 14 10
Balance at End of Period 22 16 14
Provision for uncollectible accounts: | Georgia Power      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period 4 3 2
Charged to Income 51 26 21
Charged to Other Accounts 0 0 0
Deductions 40 25 20
Balance at End of Period 15 4 3
Provision for uncollectible accounts: | Mississippi Power      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period 1 1 1
Charged to Income 2 2 1
Charged to Other Accounts 0 0 1
Deductions 2 2 2
Balance at End of Period 1 1 1
Provision for uncollectible accounts: | Southern Power      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period 1 1 5
Charged to Income (1) 0 (2)
Charged to Other Accounts 0 0 0
Deductions 0 0 2
Balance at End of Period 0 1 1
Provision for uncollectible accounts: | Southern Company Gas      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period 44 50 39
Charged to Income 39 43 55
Charged to Other Accounts (1) 3 0
Deductions 49 52 44
Balance at End of Period 33 44 50
Tax valuation allowance (net state)      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period 168 207 169
Charged to Income 97 (14) 68
Charged to Other Accounts 3 (25) (30)
Deductions 0 0 0
Balance at End of Period 268 168 207
Tax valuation allowance (net state) | Georgia Power      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period 60 98 58
Charged to Income 97 (15) 70
Charged to Other Accounts (33) (23) (30)
Deductions 0 0 0
Balance at End of Period 124 60 98
Tax valuation allowance (net state) | Mississippi Power      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period 32 32 32
Charged to Income 0 0 0
Charged to Other Accounts 0 0 0
Deductions 0 0 0
Balance at End of Period 32 32 32
Tax valuation allowance (net state) | Southern Power      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period 21 21 21
Charged to Income 0 0 0
Charged to Other Accounts 0 0 0
Deductions 0 0 0
Balance at End of Period 21 21 21
Tax valuation allowance (net state) | Southern Company Gas      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period 5 7 7
Charged to Income 0 0 0
Charged to Other Accounts (1) (2) 0
Deductions 0 0 0
Balance at End of Period $ 4 $ 5 $ 7