SOUTHERN CO, 10-Q filed on 7/30/2026
Quarterly Report
v3.26.1
Cover Page
 6 Months Ended
Jun. 30, 2026
shares
Document Information [Line Items]  
Document Type 10-Q
Document Quarterly Report true
Document Period End Date Jun. 30, 2026
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 Current Reporting Status Yes
Entity Interactive Data Current Yes
Entity Filer Category Large Accelerated Filer
Entity Small Business false
Entity Emerging Growth Company false
Entity Shell Company false
Entity Common Stock, Shares Outstanding (in shares) 1,150,362,966
Entity Central Index Key 0000092122
Amendment Flag false
Document Fiscal Year Focus 2026
Document Fiscal Period Focus Q2
Current Fiscal Year End Date --12-31
Common Stock, par value $0.01 per share  
Document Information [Line Items]  
Title of 12(b) Security Common Stock, par value $0.01 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
2025 Series A Corporate Units  
Document Information [Line Items]  
Title of 12(b) Security 2025 Series A Corporate Units
Trading Symbol SOMN
Security Exchange Name NYSE
ALABAMA POWER CO  
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 Current Reporting Status Yes
Entity Interactive Data Current Yes
Entity Filer Category Non-accelerated Filer
Entity Small Business false
Entity Emerging Growth Company false
Entity Shell Company false
Entity Common Stock, Shares Outstanding (in shares) 30,537,500
Entity Central Index Key 0000003153
GEORGIA POWER CO  
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 Current Reporting Status Yes
Entity Interactive Data Current Yes
Entity Filer Category Non-accelerated Filer
Entity Small Business false
Entity Emerging Growth Company false
Entity Shell Company false
Entity Common Stock, Shares Outstanding (in shares) 9,261,500
Entity Central Index Key 0000041091
GEORGIA POWER CO | 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 CO  
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 Current Reporting Status Yes
Entity Interactive Data Current Yes
Entity Filer Category Non-accelerated Filer
Entity Small Business false
Entity Emerging Growth Company false
Entity Shell Company false
Entity Common Stock, Shares Outstanding (in shares) 1,121,000
Entity Central Index Key 0000066904
SOUTHERN POWER CO  
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 Current Reporting Status Yes
Entity Interactive Data Current Yes
Entity Filer Category Non-accelerated Filer
Entity Small Business false
Entity Emerging Growth Company false
Entity Shell Company false
Entity Common Stock, Shares Outstanding (in shares) 1,000
Entity Central Index Key 0001160661
SOUTHERN POWER CO | 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 Co 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 725 W. Peachtree Street, 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 584-4000
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
Entity Shell Company false
Entity Common Stock, Shares Outstanding (in shares) 100
Entity Central Index Key 0001004155
v3.26.1
Condensed Consolidated Statements of Income (Unaudited) - Southern - USD ($)
shares in Millions, $ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Operating Revenues:        
Total operating revenues $ 6,977 $ 6,973 $ 15,374 $ 14,748
Operating Expenses:        
Other operations and maintenance 1,705 1,685 3,359 3,305
Depreciation and amortization 1,434 1,323 2,854 2,608
Taxes other than income taxes 367 403 831 848
Total operating expenses 5,201 5,209 11,580 10,974
Operating Income 1,776 1,764 3,794 3,774
Other Income and (Expense):        
Allowance for equity funds used during construction 128 80 248 153
Earnings from equity method investments 86 10 136 43
Interest expense, net of amounts capitalized (796) (874) (1,573) (1,588)
Other income (expense), net 181 162 336 310
Total other income and (expense) (401) (622) (853) (1,082)
Earnings Before Income Taxes 1,375 1,142 2,941 2,692
Income taxes 187 289 414 569
Consolidated Net Income 1,188 853 2,527 2,123
Net income (loss) attributable to noncontrolling interests 14 (27) (4) (91)
Consolidated Net Income Attributable to Southern Company $ 1,174 $ 880 $ 2,531 $ 2,214
Earnings per share -        
Basic (in dollars per share) $ 1.03 $ 0.80 $ 2.24 $ 2.01
Diluted (in dollars per share) $ 1.03 $ 0.79 $ 2.23 $ 2.00
Average number of shares of common stock outstanding — (in millions)        
Basic (in shares) 1,137 1,101 1,130 1,100
Diluted (in shares) 1,141 1,108 1,134 1,107
Retail electric revenues        
Operating Revenues:        
Total operating revenues $ 4,745 $ 4,758 $ 9,385 $ 9,358
Wholesale electric revenues        
Operating Revenues:        
Total operating revenues 699 681 1,664 1,425
Other electric revenues        
Operating Revenues:        
Total operating revenues 242 220 507 463
Natural Gas        
Operating Revenues:        
Total operating revenues 966 979 3,157 2,818
Other revenues        
Operating Revenues:        
Total operating revenues 325 335 661 684
Operating Expenses:        
Total cost of sales 176 167 357 366
Fuel        
Operating Expenses:        
Total cost of sales 1,054 1,116 2,544 2,408
Purchased power        
Operating Expenses:        
Total cost of sales 288 260 532 510
Natural gas        
Operating Expenses:        
Total cost of sales 177 255 1,103 929
Alternative revenue programs        
Operating Revenues:        
Total operating revenues $ 4 $ (9) $ 2 $ (28)
v3.26.1
Condensed Consolidated Statements of Income (Unaudited) - Southern (Parenthetical) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Total operating revenues $ 6,977 $ 6,973 $ 15,374 $ 14,748
Alternative revenue programs        
Total operating revenues $ 4 $ (9) $ 2 $ (28)
v3.26.1
Condensed Consolidated Statements of Comprehensive Income (Unaudited) - Southern - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Statement of Comprehensive Income [Abstract]        
Consolidated Net Income $ 1,188 $ 853 $ 2,527 $ 2,123
Qualifying hedges:        
Changes in fair value, net of tax (13) 35 (16) 49
Reclassification adjustment for amounts included in net income, net of tax 7 (31) 11 (43)
Pension and other postretirement benefit plans:        
Benefit plan net gain (loss), net of tax 0 0 1 1
Total other comprehensive income (loss) (5) 4 (3) 7
Comprehensive Income 1,183 857 2,524 2,130
Comprehensive income (loss) attributable to noncontrolling interests 14 (27) (4) (91)
Consolidated Comprehensive Income Attributable to Company $ 1,169 $ 884 $ 2,528 $ 2,221
v3.26.1
Condensed Consolidated Statements of Comprehensive Income (Unaudited) - Southern (Parenthetical) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Statement of Comprehensive Income [Abstract]        
Changes in fair value, tax $ (4) $ 11 $ (4) $ 16
Qualifying hedges, reclassification adjustment, tax 3 (10) 4 (14)
Benefit plan net gain (loss), tax 0 0 0 0
Reclassification adjustment for amounts included in net income, tax $ 0 $ 0 $ 0 $ 0
v3.26.1
Condensed Consolidated Statements of Cash Flows (Unaudited) - Southern - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Operating Activities:    
Consolidated Net Income $ 2,527 $ 2,123
Adjustments to reconcile net income to net cash provided from operating activities —    
Depreciation and amortization, total 3,176 2,860
Deferred income taxes 310 453
Allowance for equity funds used during construction (248) (153)
Pension, postretirement, and other employee benefits (277) (253)
Settlement of asset retirement obligations (283) (285)
Stock based compensation expense 112 102
Storm damage cost recovery – long-term (139) (238)
Other, net (87) 76
Changes in certain current assets and liabilities —    
Receivables 116 (130)
Retail fuel cost under recovery 188 158
Prepayments (96) (109)
Materials and supplies (178) 35
Natural gas for sale, net of temporary LIFO liquidation 197 233
Other current assets (60) 61
Accounts payable (403) (695)
Accrued taxes (221) (245)
Accrued compensation (459) (421)
Other current liabilities 105 (141)
Net cash provided from operating activities 4,280 3,431
Investing Activities:    
Property additions (6,639) (5,456)
Contributions in aid of construction 313 219
Nuclear decommissioning trust fund purchases (994) (777)
Nuclear decommissioning trust fund sales 994 777
Cost of removal, net of salvage (349) (304)
Other investing activities (83) (193)
Net cash used for investing activities (6,758) (5,734)
Financing Activities:    
Increase in notes payable, net 1,415  
Proceeds —    
Long-term debt 4,790 6,319
Short-term borrowings 350 200
Common stock 2,596 62
Redemptions and repurchases —    
Long-term debt (3,085) (2,254)
Short-term borrowings (350) 0
Distributions to noncontrolling interests (76) (66)
Payment of common stock dividends (1,579) (1,494)
Other financing activities (233) (150)
Net cash provided from financing activities 3,828 2,467
Net Change in Cash, Cash Equivalents, and Restricted Cash 1,350 164
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period 1,640 1,101
Cash, Cash Equivalents, and Restricted Cash at End of Period 2,990 1,265
Supplemental Cash Flow Information:    
Interest, net of amounts capitalized 1,472 1,287
Income taxes, net (excludes credit transfers) 146 199
Noncash transactions —    
Accrued property additions at end of period 1,409 1,091
Right-of-use assets obtained under operating leases 107 114
Right-of-use assets obtained under finance leases 5 14
Issuance of common stock under dividend reinvestment plan $ 109 $ 112
v3.26.1
Condensed Consolidated Statements of Cash Flows (Unaudited) - Southern (Parenthetical) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Statement of Cash Flows [Abstract]    
Net cash paid for capitalized interest $ 100 $ 61
v3.26.1
Condensed Consolidated Balance Sheets (Unaudited) - Southern - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Current Assets:    
Cash and cash equivalents $ 2,984 $ 1,639
Receivables —    
Customer accounts 2,301 2,251
Unbilled revenues 938 931
Under recovered fuel clause revenues 227 316
Other accounts and notes 580 655
Accumulated provision for uncollectible accounts (98) (84)
Materials and supplies 2,380 2,202
Fossil fuel for generation 728 735
Natural gas for sale 198 396
Prepaid expenses 370 327
Regulatory assets – asset retirement obligations 353 353
Other regulatory assets 916 709
Other current assets 501 487
Total current assets 12,378 10,917
Property, Plant, and Equipment:    
In service 151,437 146,114
Less: Accumulated depreciation 45,868 43,483
Plant in service, net of depreciation 105,569 102,631
Other utility plant, net 0 307
Nuclear fuel, at amortized cost 902 897
Construction work in progress 11,874 10,534
Total property, plant, and equipment 118,345 114,369
Other Property and Investments:    
Goodwill 5,161 5,161
Nuclear decommissioning trusts, at fair value 3,110 2,947
Equity investments in unconsolidated subsidiaries 1,428 1,318
Other intangible assets, net of amortization 287 300
Miscellaneous property and investments 701 714
Total other property and investments 10,687 10,440
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 1,369 1,358
Deferred charges related to income taxes 1,094 948
Prepaid pension costs 3,544 3,257
Unamortized loss on reacquired debt 179 187
Deferred under recovered fuel clause revenues 151 252
Regulatory assets – asset retirement obligations, deferred 5,042 5,129
Other regulatory assets, deferred 7,577 7,427
Other deferred charges and assets 1,661 1,436
Total deferred charges and other assets 20,617 19,994
Total Assets 162,027 155,720
Current Liabilities:    
Securities due within one year 4,694 6,220
Notes payable 2,132 722
Accounts payable 3,374 3,710
Customer deposits 487 475
Accrued taxes —    
Accrued income taxes 70 22
Other accrued taxes 695 982
Accrued interest 812 807
Accrued compensation 927 1,418
Asset retirement obligations 658 662
Liabilities from risk management activities, net of collateral 151 118
Operating lease obligations 207 197
Natural gas cost over recovery 191 158
Other regulatory liabilities 190 240
Other current liabilities 1,146 1,157
Total current liabilities 15,734 16,888
Long-term Debt 68,756 65,649
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 12,628 12,133
Deferred credits related to income taxes 4,611 4,712
Accumulated deferred ITCs 2,066 2,002
Employee benefit obligations 1,029 980
Operating lease obligations, deferred 1,298 1,287
Asset retirement obligations, deferred 8,917 8,939
Other cost of removal obligations 2,084 2,036
Other regulatory liabilities, deferred 712 722
Other deferred credits and liabilities 1,850 1,505
Total deferred credits and other liabilities 35,195 34,316
Total Liabilities 119,685 116,853
Total Stockholders' Equity 42,342 38,867
Total Liabilities and Stockholders' Equity $ 162,027 $ 155,720
v3.26.1
Condensed Consolidated Balance Sheets (Unaudited) - Southern (Parenthetical) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Statement of Financial Position [Abstract]    
Other intangible assets, amortization $ 457 $ 444
v3.26.1
Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - Southern - USD ($)
shares in Millions, $ in Millions
Total
Common Stock
Treasury
Paid-In Capital
Retained Earnings
Accumulated Other Comprehensive Income (Loss)
Noncontrolling Interests
Beginning balance (in shares) at Dec. 31, 2024   1,098          
Beginning balance (in shares) at Dec. 31, 2024     (1)        
Beginning balance at Dec. 31, 2024 $ 36,674 $ 5,446 $ (59) $ 14,149 $ 13,750 $ (78) $ 3,466
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income (loss) 1,270       1,334   (64)
Other comprehensive income 3         3  
Stock issued (in shares)   2          
Stock issued 85 $ 7   78      
Stock-based compensation 5     5      
Cash dividends on common stock (791)       (791)    
Capital contributions from noncontrolling interests 19           19
Distributions to noncontrolling interests (37)           (37)
Other (5)   $ (2) (1) (2)    
Ending balance (in shares) at Mar. 31, 2025   1,100          
Ending balance (in shares) at Mar. 31, 2025     (1)        
Ending balance at Mar. 31, 2025 37,223 $ 5,453 $ (61) 14,231 14,291 (75) 3,384
Beginning balance (in shares) at Dec. 31, 2024   1,098          
Beginning balance (in shares) at Dec. 31, 2024     (1)        
Beginning balance at Dec. 31, 2024 36,674 $ 5,446 $ (59) 14,149 13,750 (78) 3,466
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income (loss) 2,123            
Other comprehensive income 7            
Ending balance (in shares) at Jun. 30, 2025   1,101          
Ending balance (in shares) at Jun. 30, 2025     (1)        
Ending balance at Jun. 30, 2025 37,342 $ 5,458 $ (62) 14,332 14,357 (71) 3,328
Beginning balance (in shares) at Mar. 31, 2025   1,100          
Beginning balance (in shares) at Mar. 31, 2025     (1)        
Beginning balance at Mar. 31, 2025 37,223 $ 5,453 $ (61) 14,231 14,291 (75) 3,384
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income (loss) 853       880   (27)
Other comprehensive income 4         4  
Stock issued (in shares)   1          
Stock issued 89 $ 5   84      
Stock-based compensation 11     11      
Cash dividends on common stock (815)       (815)    
Capital contributions from noncontrolling interests 4           4
Distributions to noncontrolling interests (33)           (33)
Other 6   $ (1) 6 1    
Ending balance (in shares) at Jun. 30, 2025   1,101          
Ending balance (in shares) at Jun. 30, 2025     (1)        
Ending balance at Jun. 30, 2025 37,342 $ 5,458 $ (62) 14,332 14,357 (71) 3,328
Beginning balance (in shares) at Dec. 31, 2025   1,120          
Beginning balance (in shares) at Dec. 31, 2025     (1)        
Beginning balance at Dec. 31, 2025 38,867 $ 5,554 $ (59) 15,740 14,856 (75) 2,851
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income (loss) 1,338       1,356   (18)
Other comprehensive income 2         2  
Stock issued (in shares)   8          
Stock issued 589 $ 34   555      
Stock-based compensation (9)     (9)      
Cash dividends on common stock (830)       (830)    
Capital contributions from noncontrolling interests 4           4
Distributions to noncontrolling interests (46)           (46)
Other (3)   $ (1) (1)     (1)
Ending balance (in shares) at Mar. 31, 2026   1,128          
Ending balance (in shares) at Mar. 31, 2026     (1)        
Ending balance at Mar. 31, 2026 39,912 $ 5,588 $ (60) 16,285 15,382 (73) 2,790
Beginning balance (in shares) at Dec. 31, 2025   1,120          
Beginning balance (in shares) at Dec. 31, 2025     (1)        
Beginning balance at Dec. 31, 2025 38,867 $ 5,554 $ (59) 15,740 14,856 (75) 2,851
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income (loss) 2,527            
Other comprehensive income (3)            
Ending balance (in shares) at Jun. 30, 2026   1,151          
Ending balance (in shares) at Jun. 30, 2026     (1)        
Ending balance at Jun. 30, 2026 42,342 $ 11 $ (61) 23,998 15,700 (78) 2,772
Beginning balance (in shares) at Mar. 31, 2026   1,128          
Beginning balance (in shares) at Mar. 31, 2026     (1)        
Beginning balance at Mar. 31, 2026 39,912 $ 5,588 $ (60) 16,285 15,382 (73) 2,790
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income (loss) 1,188       1,174   14
Other comprehensive income (5)         (5)  
Change in par value 0 $ (5,577)   5,577      
Stock issued (in shares)   23          
Stock issued 2,116     2,116      
Stock-based compensation 15     15      
Cash dividends on common stock (858)       (858)    
Distributions to noncontrolling interests (32)           (32)
Other 6   $ (1) 5 2    
Ending balance (in shares) at Jun. 30, 2026   1,151          
Ending balance (in shares) at Jun. 30, 2026     (1)        
Ending balance at Jun. 30, 2026 $ 42,342 $ 11 $ (61) $ 23,998 $ 15,700 $ (78) $ 2,772
v3.26.1
Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - Southern (Parenthetical) - $ / shares
 3 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Jun. 30, 2025
Mar. 31, 2025
Statement of Stockholders' Equity [Abstract]        
Cash dividends (in dollars per share) $ 0.76 $ 0.74 $ 0.74 $ 0.72
Common stock, par value (in dollars per share) $ 0.01 $ 5.00    
v3.26.1
Condensed Statements of Income (Unaudited) - APC - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Operating Revenues:        
Total operating revenues $ 6,977 $ 6,973 $ 15,374 $ 14,748
Operating Expenses:        
Other operations and maintenance 1,705 1,685 3,359 3,305
Depreciation and amortization 1,434 1,323 2,854 2,608
Taxes other than income taxes 367 403 831 848
Total operating expenses 5,201 5,209 11,580 10,974
Operating Income 1,776 1,764 3,794 3,774
Other Income and (Expense):        
Allowance for equity funds used during construction 128 80 248 153
Interest expense, net of amounts capitalized (796) (874) (1,573) (1,588)
Other income (expense), net 181 162 336 310
Total other income and (expense) (401) (622) (853) (1,082)
Earnings Before Income Taxes 1,375 1,142 2,941 2,692
Income taxes (benefit) 187 289 414 569
Consolidated Net Income Attributable to Southern Company 1,174 880 2,531 2,214
Retail revenues        
Operating Revenues:        
Total operating revenues 4,745 4,758 9,385 9,358
Other revenues        
Operating Revenues:        
Total operating revenues 325 335 661 684
Operating Expenses:        
Total cost of sales 176 167 357 366
Fuel        
Operating Expenses:        
Total cost of sales 1,054 1,116 2,544 2,408
Purchased power, non-affiliates        
Operating Expenses:        
Total cost of sales 288 260 532 510
Alabama Power        
Operating Revenues:        
Total operating revenues 1,963 1,968 4,055 3,980
Operating Expenses:        
Other operations and maintenance 415 472 808 935
Depreciation and amortization 385 371 766 741
Taxes other than income taxes 118 120 251 250
Total operating expenses 1,370 1,421 2,851 2,894
Operating Income 593 547 1,204 1,086
Other Income and (Expense):        
Allowance for equity funds used during construction 18 18 37 36
Interest expense, net of amounts capitalized (117) (116) (232) (225)
Other income (expense), net 78 47 116 84
Total other income and (expense) (21) (51) (79) (105)
Earnings Before Income Taxes 572 496 1,125 981
Income taxes (benefit) 135 115 263 226
Consolidated Net Income Attributable to Southern Company 437 381 862 755
Alabama Power | Retail revenues        
Operating Revenues:        
Total operating revenues 1,710 1,718 3,438 3,441
Alabama Power | Wholesale revenues, non-affiliates        
Operating Revenues:        
Total operating revenues 85 98 202 189
Alabama Power | Wholesale revenues, affiliates        
Operating Revenues:        
Total operating revenues 55 36 174 105
Alabama Power | Other revenues        
Operating Revenues:        
Total operating revenues 113 116 241 245
Alabama Power | Fuel        
Operating Expenses:        
Total cost of sales 336 337 764 723
Alabama Power | Purchased power, non-affiliates        
Operating Expenses:        
Total cost of sales 63 54 136 124
Alabama Power | Purchased power, affiliates        
Operating Expenses:        
Total cost of sales $ 53 $ 67 $ 126 $ 121
v3.26.1
Condensed Statements of Comprehensive Income (Unaudited) - APC - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Net income $ 1,174 $ 880 $ 2,531 $ 2,214
Qualifying hedges:        
Changes in fair value, net of tax (13) 35 (16) 49
Reclassification adjustment for amounts included in net income, net of tax 7 (31) 11 (43)
Consolidated Comprehensive Income Attributable to Company 1,169 884 2,528 2,221
Alabama Power        
Net income 437 381 862 755
Qualifying hedges:        
Changes in fair value, net of tax (2) 0 (2) 0
Reclassification adjustment for amounts included in net income, net of tax 0 0 0 1
Total other comprehensive income (loss) (2) 0 (2) 1
Consolidated Comprehensive Income Attributable to Company $ 435 $ 381 $ 860 $ 756
v3.26.1
Condensed Statements of Comprehensive Income (Unaudited) - APC (Parenthetical) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Changes in fair value, tax $ (4) $ 11 $ (4) $ 16
Qualifying hedges, reclassification adjustment, tax 3 (10) 4 (14)
Alabama Power        
Changes in fair value, tax 0 0 0 0
Qualifying hedges, reclassification adjustment, tax $ 0 $ 0 $ 0 $ 0
v3.26.1
Condensed Statements of Cash Flows (Unaudited) - APC - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Operating Activities:    
Net income $ 2,531 $ 2,214
Adjustments to reconcile net income to net cash provided from operating activities —    
Depreciation and amortization, total 3,176 2,860
Deferred income taxes 310 453
Pension, postretirement, and other employee benefits (277) (253)
Settlement of asset retirement obligations (283) (285)
Other, net (87) 76
Changes in certain current assets and liabilities —    
Receivables 116 (130)
Prepayments (96) (109)
Other current assets (60) 61
Accounts payable (403) (695)
Accrued taxes (221) (245)
Accrued compensation (459) (421)
Other current liabilities 105 (141)
Net cash provided from operating activities 4,280 3,431
Investing Activities:    
Property additions (6,639) (5,456)
Contributions in aid of construction 313 219
Nuclear decommissioning trust fund purchases (994) (777)
Nuclear decommissioning trust fund sales 994 777
Cost of removal, net of salvage (349) (304)
Other investing activities (83) (193)
Net cash used for investing activities (6,758) (5,734)
Proceeds —    
Payment of common stock dividends (1,579) (1,494)
Other financing activities (233) (150)
Net cash provided from financing activities 3,828 2,467
Net Change in Cash, Cash Equivalents, and Restricted Cash 1,350 164
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period 1,640 1,101
Cash, Cash Equivalents, and Restricted Cash at End of Period 2,990 1,265
Supplemental Cash Flow Information:    
Interest, net of amounts capitalized 1,472 1,287
Income taxes, net (excludes credit transfers) 146 199
Noncash transactions —    
Accrued property additions at end of period 1,409 1,091
Right-of-use assets obtained under finance leases 5 14
Alabama Power    
Operating Activities:    
Net income 862 755
Adjustments to reconcile net income to net cash provided from operating activities —    
Depreciation and amortization, total 867 803
Deferred income taxes 88 116
Pension, postretirement, and other employee benefits (115) (89)
Settlement of asset retirement obligations (114) (120)
Retail fuel cost under recovery – long-term (66) (62)
Other, net (57) (44)
Changes in certain current assets and liabilities —    
Receivables (6) (94)
Prepayments (66) (89)
Other current assets (21) (8)
Accounts payable (277) (251)
Accrued taxes 72 25
Accrued compensation (111) (93)
Customer refunds 2 (110)
Other current liabilities 20 (61)
Net cash provided from operating activities 1,078 678
Investing Activities:    
Property additions (958) (1,065)
Contributions in aid of construction 157 31
Nuclear decommissioning trust fund purchases (307) (270)
Nuclear decommissioning trust fund sales 307 270
Cost of removal, net of salvage (95) (92)
Other investing activities 18 (43)
Net cash used for investing activities (878) (1,169)
Proceeds —    
Senior notes 0 600
Other long-term debt 0 4
Redemptions — Senior notes 0 (250)
Other long-term debt (45) 0
Capital contributions from parent company 276 562
Payment of common stock dividends (601) (609)
Other financing activities 6 (7)
Net cash provided from financing activities (364) 300
Net Change in Cash, Cash Equivalents, and Restricted Cash (164) (191)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period 566 585
Cash, Cash Equivalents, and Restricted Cash at End of Period 402 394
Supplemental Cash Flow Information:    
Interest, net of amounts capitalized 229 205
Income taxes, net (excludes credit transfers) 217 217
Noncash transactions —    
Accrued property additions at end of period 131 116
Right-of-use assets obtained under operating leases 11 7
Right-of-use assets obtained under finance leases $ 3 $ 1
v3.26.1
Condensed Statements of Cash Flows (Unaudited) - APC (Parenthetical) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Net cash paid for capitalized interest $ 100 $ 61
Alabama Power    
Net cash paid for capitalized interest $ 11 $ 10
v3.26.1
Condensed Balance Sheets (Unaudited) - APC - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Current Assets:    
Cash and cash equivalents $ 2,984 $ 1,639
Receivables —    
Customer accounts and affiliated 2,301 2,251
Unbilled revenues 938 931
Other accounts and notes 580 655
Accumulated provision for uncollectible accounts (98) (84)
Fossil fuel stock 728 735
Materials and supplies 2,380 2,202
Prepaid expenses 370 327
Other regulatory assets 916 709
Other current assets 501 487
Total current assets 12,378 10,917
Property, Plant, and Equipment:    
In service 151,437 146,114
Less: Accumulated depreciation 45,868 43,483
Plant in service, net of depreciation 105,569 102,631
Other utility plant, net 0 307
Nuclear fuel, at amortized cost 902 897
Construction work in progress 11,874 10,534
Total property, plant, and equipment 118,345 114,369
Other Property and Investments:    
Nuclear decommissioning trusts, at fair value 3,110 2,947
Equity investments in unconsolidated subsidiaries 1,428 1,318
Miscellaneous property and investments 701 714
Total other property and investments 10,687 10,440
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 1,369 1,358
Deferred charges related to income taxes 1,094 948
Regulatory assets – asset retirement obligations 5,042 5,129
Other regulatory assets, deferred 7,577 7,427
Other deferred charges and assets 1,661 1,436
Total deferred charges and other assets 20,617 19,994
Total Assets 162,027 155,720
Current Liabilities:    
Securities due within one year 4,694 6,220
Accounts payable —    
Customer deposits 487 475
Accrued interest 812 807
Accrued compensation 927 1,418
Asset retirement obligations 658 662
Other regulatory liabilities 190 240
Other current liabilities 1,146 1,157
Total current liabilities 15,734 16,888
Long-term Debt 68,756 65,649
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 12,628 12,133
Deferred credits related to income taxes 4,611 4,712
Accumulated deferred ITCs 2,066 2,002
Employee benefit obligations 1,029 980
Operating lease obligations 1,298 1,287
Asset retirement obligations, deferred 8,917 8,939
Other regulatory liabilities, deferred 712 722
Other deferred credits and liabilities 1,850 1,505
Total deferred credits and other liabilities 35,195 34,316
Total Liabilities 119,685 116,853
Total Liabilities and Stockholders' Equity 162,027 155,720
Alabama Power    
Current Assets:    
Cash and cash equivalents 402 566
Receivables —    
Unbilled revenues 216 189
Other accounts and notes 84 113
Accumulated provision for uncollectible accounts (23) (23)
Fossil fuel stock 294 303
Materials and supplies 746 732
Prepaid expenses 152 86
Other regulatory assets 372 344
Other current assets 84 80
Total current assets 3,034 2,986
Property, Plant, and Equipment:    
In service 40,731 38,915
Less: Accumulated depreciation 14,001 12,816
Plant in service, net of depreciation 26,730 26,099
Other utility plant, net 0 307
Nuclear fuel, at amortized cost 276 290
Construction work in progress 1,386 1,441
Total property, plant, and equipment 28,392 28,137
Other Property and Investments:    
Nuclear decommissioning trusts, at fair value 1,653 1,542
Equity investments in unconsolidated subsidiaries 53 48
Miscellaneous property and investments 123 123
Total other property and investments 1,829 1,713
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 89 86
Deferred charges related to income taxes 263 261
Prepaid pension and other postretirement benefit costs 1,061 1,016
Regulatory assets – asset retirement obligations 1,454 1,518
Other regulatory assets, deferred 2,146 1,982
Other deferred charges and assets 411 425
Total deferred charges and other assets 5,424 5,288
Total Assets 38,679 38,124
Current Liabilities:    
Securities due within one year 303 625
Accounts payable —    
Customer deposits 115 113
Accrued taxes 187 105
Accrued interest 137 134
Accrued compensation 185 275
Asset retirement obligations 261 256
Other regulatory liabilities 58 89
Other current liabilities 148 135
Total current liabilities 2,079 2,602
Long-term Debt 11,670 11,388
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 4,351 4,209
Deferred credits related to income taxes 1,535 1,585
Accumulated deferred ITCs 105 115
Employee benefit obligations 138 152
Operating lease obligations 80 78
Asset retirement obligations, deferred 3,387 3,423
Other regulatory liabilities, deferred 216 252
Other deferred credits and liabilities 587 326
Total deferred credits and other liabilities 10,399 10,140
Total Liabilities 24,148 24,130
Total common stockholders' equity 14,531 13,994
Total Liabilities and Stockholders' Equity 38,679 38,124
Alabama Power | Nonrelated Party    
Receivables —    
Customer accounts and affiliated 587 470
Accounts payable —    
Affiliated and Other 422 576
Alabama Power | Related Party    
Receivables —    
Customer accounts and affiliated 120 126
Accounts payable —    
Affiliated and Other $ 263 $ 294
v3.26.1
Condensed Statements of Common Stockholders' Equity (Unaudited) - APC - USD ($)
shares in Millions, $ in Millions
Total
Common Stock
Paid-In Capital
Retained Earnings
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, 2024   1,098       31      
Beginning balance at Dec. 31, 2024         $ 13,088 $ 1,222 $ 7,657 $ 4,214 $ (5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income         375     375  
Capital contributions from parent company         527   527    
Other comprehensive income (loss)         1       1
Cash dividends on common stock $ (791)     $ (791) (305)     (305)  
Other (5)   $ (1) (2) (1)       (1)
Ending balance (in shares) at Mar. 31, 2025   1,100       31      
Ending balance at Mar. 31, 2025         13,685 $ 1,222 8,184 4,284 (5)
Beginning balance (in shares) at Dec. 31, 2024   1,098       31      
Beginning balance at Dec. 31, 2024         13,088 $ 1,222 7,657 4,214 (5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 2,214       755        
Other comprehensive income (loss)         1        
Ending balance (in shares) at Jun. 30, 2025   1,101       31      
Ending balance at Jun. 30, 2025         13,800 $ 1,222 8,222 4,360 (4)
Beginning balance (in shares) at Mar. 31, 2025   1,100       31      
Beginning balance at Mar. 31, 2025         13,685 $ 1,222 8,184 4,284 (5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 880       381     381  
Capital contributions from parent company         38   38    
Other comprehensive income (loss)         0        
Cash dividends on common stock (815)     (815) (304)     (304)  
Other 6   6 1 0     (1) 1
Ending balance (in shares) at Jun. 30, 2025   1,101       31      
Ending balance at Jun. 30, 2025         13,800 $ 1,222 8,222 4,360 (4)
Beginning balance (in shares) at Dec. 31, 2025   1,120       31      
Beginning balance at Dec. 31, 2025         13,994 $ 1,222 8,263 4,512 (3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income         425     425  
Capital contributions from parent company         226   226    
Cash dividends on common stock (830)     (830) (301)     (301)  
Other (3)   (1)            
Ending balance (in shares) at Mar. 31, 2026   1,128       31      
Ending balance at Mar. 31, 2026         14,344 $ 1,222 8,489 4,636 (3)
Beginning balance (in shares) at Dec. 31, 2025   1,120       31      
Beginning balance at Dec. 31, 2025         13,994 $ 1,222 8,263 4,512 (3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 2,531       862        
Other comprehensive income (loss)         (2)        
Ending balance (in shares) at Jun. 30, 2026   1,151       31      
Ending balance at Jun. 30, 2026         14,531 $ 1,222 8,542 4,772 (5)
Beginning balance (in shares) at Mar. 31, 2026   1,128       31      
Beginning balance at Mar. 31, 2026         14,344 $ 1,222 8,489 4,636 (3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 1,174       437     437  
Capital contributions from parent company         53   53    
Other comprehensive income (loss)         (2)       (2)
Cash dividends on common stock (858)     (858) (300)     (300)  
Other $ 6   $ 5 $ 2 (1)     (1)  
Ending balance (in shares) at Jun. 30, 2026   1,151       31      
Ending balance at Jun. 30, 2026         $ 14,531 $ 1,222 $ 8,542 $ 4,772 $ (5)
v3.26.1
Condensed Statements of Income (Unaudited) - GPC - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Operating Revenues:        
Total operating revenues $ 6,977 $ 6,973 $ 15,374 $ 14,748
Operating Expenses:        
Other operations and maintenance 1,705 1,685 3,359 3,305
Depreciation and amortization 1,434 1,323 2,854 2,608
Taxes other than income taxes 367 403 831 848
Total operating expenses 5,201 5,209 11,580 10,974
Operating Income 1,776 1,764 3,794 3,774
Other Income and (Expense):        
Allowance for equity funds used during construction 128 80 248 153
Interest expense, net of amounts capitalized (796) (874) (1,573) (1,588)
Other income (expense), net 181 162 336 310
Total other income and (expense) (401) (622) (853) (1,082)
Earnings Before Income Taxes 1,375 1,142 2,941 2,692
Income taxes (benefit) 187 289 414 569
Consolidated Net Income Attributable to Southern Company 1,174 880 2,531 2,214
Retail revenues        
Operating Revenues:        
Total operating revenues 4,745 4,758 9,385 9,358
Wholesale revenues        
Operating Revenues:        
Total operating revenues 699 681 1,664 1,425
Other revenues        
Operating Revenues:        
Total operating revenues 325 335 661 684
Operating Expenses:        
Total cost of sales 176 167 357 366
Fuel        
Operating Expenses:        
Total cost of sales 1,054 1,116 2,544 2,408
Purchased power, non-affiliates        
Operating Expenses:        
Total cost of sales 288 260 532 510
GEORGIA POWER CO        
Operating Revenues:        
Total operating revenues 3,133 3,110 6,276 6,148
Operating Expenses:        
Other operations and maintenance 667 645 1,341 1,283
Depreciation and amortization 503 512 987 1,015
Taxes other than income taxes 138 173 313 342
Total operating expenses 2,129 2,183 4,510 4,441
Operating Income 1,004 927 1,766 1,707
Other Income and (Expense):        
Allowance for equity funds used during construction 104 56 201 104
Interest expense, net of amounts capitalized (228) (198) (431) (385)
Other income (expense), net 50 58 108 112
Total other income and (expense) (74) (84) (122) (169)
Earnings Before Income Taxes 930 843 1,644 1,538
Income taxes (benefit) 151 236 236 334
Consolidated Net Income Attributable to Southern Company 779 607 1,408 1,204
GEORGIA POWER CO | Retail revenues        
Operating Revenues:        
Total operating revenues 2,753 2,765 5,391 5,395
GEORGIA POWER CO | Wholesale revenues        
Operating Revenues:        
Total operating revenues 120 107 347 250
GEORGIA POWER CO | Other revenues        
Operating Revenues:        
Total operating revenues 260 238 538 503
GEORGIA POWER CO | Fuel        
Operating Expenses:        
Total cost of sales 466 476 1,067 1,000
GEORGIA POWER CO | Purchased power, non-affiliates        
Operating Expenses:        
Total cost of sales 171 180 329 340
GEORGIA POWER CO | Purchased power, affiliates        
Operating Expenses:        
Total cost of sales $ 184 $ 197 $ 473 $ 461
v3.26.1
Condensed Statements of Comprehensive Income (Unaudited) - GPC - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Net income $ 1,174 $ 880 $ 2,531 $ 2,214
Qualifying hedges:        
Changes in fair value, net of tax (13) 35 (16) 49
Reclassification adjustment for amounts included in net income, net of tax 7 (31) 11 (43)
Consolidated Comprehensive Income Attributable to Company 1,169 884 2,528 2,221
GEORGIA POWER CO        
Net income 779 607 1,408 1,204
Qualifying hedges:        
Changes in fair value, net of tax 0 4 0 2
Reclassification adjustment for amounts included in net income, net of tax 0 0 0 1
Total other comprehensive income (loss) 0 4 0 3
Consolidated Comprehensive Income Attributable to Company $ 779 $ 611 $ 1,408 $ 1,207
v3.26.1
Condensed Statements of Comprehensive Income (Unaudited) - GPC (Parenthetical) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Changes in fair value, tax $ (4) $ 11 $ (4) $ 16
Qualifying hedges, reclassification adjustment, tax 3 (10) 4 (14)
GEORGIA POWER CO        
Changes in fair value, tax 0 1 0 1
Qualifying hedges, reclassification adjustment, tax $ 0 $ 0 $ 0 $ 0
v3.26.1
Condensed Statements of Cash Flows (Unaudited) - GPC - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Operating Activities:    
Net income $ 2,531 $ 2,214
Adjustments to reconcile net income to net cash provided from operating activities —    
Depreciation and amortization, total 3,176 2,860
Deferred income taxes 310 453
Allowance for equity funds used during construction (248) (153)
Pension, postretirement, and other employee benefits (277) (253)
Settlement of asset retirement obligations (283) (285)
Storm damage cost recovery – long-term (139) (238)
Other, net (87) 76
Changes in certain current assets and liabilities —    
Receivables 116 (130)
Retail fuel cost under recovery 188 158
Materials and supplies (178) 35
Other current assets (60) 61
Accounts payable (403) (695)
Accrued taxes (221) (245)
Other current liabilities 105 (141)
Net cash provided from operating activities 4,280 3,431
Investing Activities:    
Property additions (6,639) (5,456)
Contributions in aid of construction 313 219
Nuclear decommissioning trust fund purchases (994) (777)
Nuclear decommissioning trust fund sales 994 777
Cost of removal, net of salvage (349) (304)
Other investing activities (83) (193)
Net cash used for investing activities (6,758) (5,734)
Financing Activities:    
Increase in notes payable, net 1,415  
Proceeds —    
Short-term borrowings 350 200
Redemptions and repurchases —    
Short-term borrowings (350) 0
Payment of common stock dividends (1,579) (1,494)
Other financing activities (233) (150)
Net cash provided from financing activities 3,828 2,467
Net Change in Cash, Cash Equivalents, and Restricted Cash 1,350 164
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period 1,640 1,101
Cash, Cash Equivalents, and Restricted Cash at End of Period 2,990 1,265
Supplemental Cash Flow Information:    
Interest, net of amounts capitalized 1,472 1,287
Income taxes, net (excludes credit transfers) 146 199
Noncash transactions —    
Accrued property additions at end of period 1,409 1,091
Right-of-use assets obtained under operating leases 107 114
Right-of-use assets obtained under finance leases 5 14
GEORGIA POWER CO    
Operating Activities:    
Net income 1,408 1,204
Adjustments to reconcile net income to net cash provided from operating activities —    
Depreciation and amortization, total 1,128 1,167
Deferred income taxes 25 238
Allowance for equity funds used during construction (201) (104)
Pension, postretirement, and other employee benefits (127) (128)
Settlement of asset retirement obligations (147) (149)
Storm damage cost recovery – long-term (139) (238)
Other, net (23) (39)
Changes in certain current assets and liabilities —    
Receivables (210) (270)
Retail fuel cost under recovery 210 186
Materials and supplies (132) 16
Other current assets (36) (11)
Accounts payable 48 (396)
Accrued taxes (207) (196)
Other current liabilities (20) 55
Net cash provided from operating activities 1,577 1,335
Investing Activities:    
Property additions (4,233) (3,090)
Contributions in aid of construction 141 99
Nuclear decommissioning trust fund purchases (687) (507)
Nuclear decommissioning trust fund sales 687 507
Cost of removal, net of salvage (194) (152)
Other investing activities (26) (75)
Net cash used for investing activities (4,312) (3,218)
Financing Activities:    
Increase in notes payable, net 70 285
Proceeds —    
Proceeds — Senior notes 1,300 1,600
Short-term borrowings 250 200
FFB loan 1,016 0
Redemptions and repurchases —    
Redemptions — Senior notes (325) (700)
Short-term borrowings (250) 0
FFB loan (43) (43)
Other long-term debt (400) 0
Capital contributions from parent company 2,463 1,671
Payment of common stock dividends (1,287) (1,105)
Other financing activities (46) (49)
Net cash provided from financing activities 2,748 1,859
Net Change in Cash, Cash Equivalents, and Restricted Cash 13 (24)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period 59 118
Cash, Cash Equivalents, and Restricted Cash at End of Period 72 94
Supplemental Cash Flow Information:    
Interest, net of amounts capitalized 392 341
Income taxes, net (excludes credit transfers) 118 25
Noncash transactions —    
Accrued property additions at end of period 1,050 699
Right-of-use assets obtained under operating leases 23 28
Right-of-use assets obtained under finance leases $ 1,400 $ 13
v3.26.1
Condensed Statements of Cash Flows (Unaudited) - GPC (Parenthetical) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Net cash paid for capitalized interest $ 100 $ 61
GEORGIA POWER CO    
Net cash paid for capitalized interest $ 61 $ 33
v3.26.1
Condensed Balance Sheets (Unaudited) - GPC - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Current Assets:    
Cash and cash equivalents $ 2,984 $ 1,639
Receivables —    
Customer accounts, net and Affiliated 2,301 2,251
Unbilled revenues 938 931
Other accounts and notes 580 655
Fossil fuel stock 728 735
Materials and supplies 2,380 2,202
Regulatory assets – asset retirement obligations 353 353
Other regulatory assets 916 709
Other current assets 501 487
Total current assets 12,378 10,917
Property, Plant, and Equipment:    
In service 151,437 146,114
Less: Accumulated depreciation 45,868 43,483
Plant in service, net of depreciation 105,569 102,631
Nuclear fuel, at amortized cost 902 897
Construction work in progress 11,874 10,534
Total property, plant, and equipment 118,345 114,369
Other Property and Investments:    
Nuclear decommissioning trusts, at fair value 3,110 2,947
Equity investments in unconsolidated subsidiaries 1,428 1,318
Miscellaneous property and investments 701 714
Total other property and investments 10,687 10,440
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 1,369 1,358
Deferred charges related to income taxes 1,094 948
Prepaid pension costs 3,544 3,257
Deferred under recovered fuel clause revenues 151 252
Regulatory assets – asset retirement obligations, deferred 5,042 5,129
Other regulatory assets, deferred 7,577 7,427
Other deferred charges and assets 1,661 1,436
Total deferred charges and other assets 20,617 19,994
Total Assets 162,027 155,720
Current Liabilities:    
Securities due within one year 4,694 6,220
Notes payable 2,132 722
Accounts payable —    
Customer deposits 487 475
Accrued interest 812 807
Accrued compensation 927 1,418
Operating lease obligations 207 197
Asset retirement obligations 658 662
Other regulatory liabilities 190 240
Other current liabilities 1,146 1,157
Total current liabilities 15,734 16,888
Long-term Debt 68,756 65,649
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 12,628 12,133
Deferred credits related to income taxes 4,611 4,712
Accumulated deferred ITCs 2,066 2,002
Employee benefit obligations 1,029 980
Operating lease obligations, deferred 1,298 1,287
Asset retirement obligations, deferred 8,917 8,939
Other deferred credits and liabilities 1,850 1,505
Total deferred credits and other liabilities 35,195 34,316
Total Liabilities 119,685 116,853
Total Liabilities and Stockholders' Equity 162,027 155,720
GEORGIA POWER CO    
Current Assets:    
Cash and cash equivalents 72 59
Receivables —    
Unbilled revenues 577 346
Under recovered retail fuel clause revenues 161 310
Joint owner accounts 76 195
Other accounts and notes 127 61
Fossil fuel stock 364 362
Materials and supplies 1,130 994
Regulatory assets – asset retirement obligations 222 222
Other regulatory assets 500 335
Other current assets 288 285
Total current assets 4,626 4,258
Property, Plant, and Equipment:    
In service 63,226 59,458
Less: Accumulated depreciation 16,442 15,957
Plant in service, net of depreciation 46,784 43,501
Nuclear fuel, at amortized cost 626 606
Construction work in progress 8,215 6,764
Total property, plant, and equipment 55,625 50,871
Other Property and Investments:    
Nuclear decommissioning trusts, at fair value 1,457 1,405
Equity investments in unconsolidated subsidiaries 39 40
Miscellaneous property and investments 229 231
Total other property and investments 1,725 1,676
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 881 1,120
Deferred charges related to income taxes 805 660
Prepaid pension costs 1,180 1,099
Deferred under recovered fuel clause revenues 151 212
Regulatory assets – asset retirement obligations, deferred 3,360 3,382
Other regulatory assets, deferred 4,034 4,032
Other deferred charges and assets 984 767
Total deferred charges and other assets 11,395 11,272
Total Assets 73,371 68,077
Current Liabilities:    
Securities due within one year 1,548 1,370
Notes payable 230 160
Accounts payable —    
Customer deposits 277 267
Accrued taxes 471 678
Accrued interest 236 234
Accrued compensation 217 327
Operating lease obligations 132 170
Asset retirement obligations 350 360
Other regulatory liabilities 29 52
Other current liabilities 346 332
Total current liabilities 6,496 6,670
Long-term Debt 22,857 20,122
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 4,902 4,811
Deferred credits related to income taxes 2,207 2,225
Accumulated deferred ITCs 461 354
Employee benefit obligations 192 189
Operating lease obligations, deferred 761 960
Asset retirement obligations, deferred 5,193 5,167
Other deferred credits and liabilities 682 545
Total deferred credits and other liabilities 14,398 14,251
Total Liabilities 43,751 41,043
Total common stockholders' equity 29,620 27,034
Total Liabilities and Stockholders' Equity 73,371 68,077
GEORGIA POWER CO | Nonrelated Party    
Receivables —    
Customer accounts, net and Affiliated 1,014 993
Accounts payable —    
Affiliated and Other 1,756 1,728
GEORGIA POWER CO | Related Party    
Receivables —    
Customer accounts, net and Affiliated 95 96
Accounts payable —    
Affiliated and Other $ 904 $ 992
v3.26.1
Condensed Statements of Common Stockholders' Equity (Unaudited) - GPC - USD ($)
shares in Millions, $ in Millions
Total
Common Stock
Paid-In Capital
Retained Earnings
GEORGIA POWER CO
GEORGIA POWER CO
Common Stock
GEORGIA POWER CO
Paid-In Capital
GEORGIA POWER CO
Retained Earnings
GEORGIA POWER CO
Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2024   1,098       9      
Beginning balance at Dec. 31, 2024         $ 23,681 $ 398 $ 19,708 $ 3,562 $ 13
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income         596     596  
Capital contributions from parent company         702   702    
Other comprehensive income         (1)       (1)
Cash dividends on common stock $ (791)     $ (791) (552)     (552)  
Other (5)   $ (1) (2)          
Ending balance (in shares) at Mar. 31, 2025   1,100       9      
Ending balance at Mar. 31, 2025         24,426 $ 398 20,410 3,606 12
Beginning balance (in shares) at Dec. 31, 2024   1,098       9      
Beginning balance at Dec. 31, 2024         23,681 $ 398 19,708 3,562 13
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 2,214       1,204        
Other comprehensive income         3        
Ending balance (in shares) at Jun. 30, 2025   1,101       9      
Ending balance at Jun. 30, 2025         25,457 $ 398 21,382 3,661 16
Beginning balance (in shares) at Mar. 31, 2025   1,100       9      
Beginning balance at Mar. 31, 2025         24,426 $ 398 20,410 3,606 12
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 880       607     607  
Capital contributions from parent company         972   972    
Other comprehensive income         4       4
Cash dividends on common stock (815)     (815) (553)     (553)  
Other 6   6 1 1     1  
Ending balance (in shares) at Jun. 30, 2025   1,101       9      
Ending balance at Jun. 30, 2025         25,457 $ 398 21,382 3,661 16
Beginning balance (in shares) at Dec. 31, 2025   1,120       9      
Beginning balance at Dec. 31, 2025         27,034 $ 398 22,416 4,204 16
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income         628     628  
Capital contributions from parent company         1,500   1,500    
Cash dividends on common stock (830)     (830) (644)     (644)  
Other (3)   (1)   1     1  
Ending balance (in shares) at Mar. 31, 2026   1,128       9      
Ending balance at Mar. 31, 2026         28,519 $ 398 23,916 4,189 16
Beginning balance (in shares) at Dec. 31, 2025   1,120       9      
Beginning balance at Dec. 31, 2025         27,034 $ 398 22,416 4,204 16
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 2,531       1,408        
Other comprehensive income         0        
Ending balance (in shares) at Jun. 30, 2026   1,151       9      
Ending balance at Jun. 30, 2026         29,620 $ 398 24,881 4,325 16
Beginning balance (in shares) at Mar. 31, 2026   1,128       9      
Beginning balance at Mar. 31, 2026         28,519 $ 398 23,916 4,189 16
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 1,174       779     779  
Capital contributions from parent company         965   965    
Other comprehensive income         0        
Cash dividends on common stock (858)     (858) (643)     (643)  
Other $ 6   $ 5 $ 2          
Ending balance (in shares) at Jun. 30, 2026   1,151       9      
Ending balance at Jun. 30, 2026         $ 29,620 $ 398 $ 24,881 $ 4,325 $ 16
v3.26.1
Condensed Statements of Income and Comprehensive Income (Unaudited) - MPC - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Operating Revenues:        
Total operating revenues $ 6,977 $ 6,973 $ 15,374 $ 14,748
Operating Expenses:        
Other operations and maintenance 1,705 1,685 3,359 3,305
Depreciation and amortization 1,434 1,323 2,854 2,608
Taxes other than income taxes 367 403 831 848
Total operating expenses 5,201 5,209 11,580 10,974
Operating Income 1,776 1,764 3,794 3,774
Other Income and (Expense):        
Interest expense, net of amounts capitalized (796) (874) (1,573) (1,588)
Other income (expense), net 181 162 336 310
Total other income and (expense) (401) (622) (853) (1,082)
Earnings Before Income Taxes 1,375 1,142 2,941 2,692
Income taxes (benefit) 187 289 414 569
Consolidated Net Income Attributable to Southern Company 1,174 880 2,531 2,214
Retail revenues        
Operating Revenues:        
Total operating revenues 4,745 4,758 9,385 9,358
Other revenues        
Operating Revenues:        
Total operating revenues 325 335 661 684
Operating Expenses:        
Fuel and purchased power 176 167 357 366
Mississippi Power        
Operating Revenues:        
Total operating revenues 403 400 875 821
Operating Expenses:        
Other operations and maintenance 107 82 194 166
Depreciation and amortization 58 52 113 105
Taxes other than income taxes 36 36 72 69
Total operating expenses 323 313 707 649
Operating Income 80 87 168 172
Other Income and (Expense):        
Interest expense, net of amounts capitalized (21) (20) (41) (40)
Other income (expense), net 9 9 19 16
Total other income and (expense) (12) (11) (22) (24)
Earnings Before Income Taxes 68 76 146 148
Income taxes (benefit) 16 17 34 34
Consolidated Net Income Attributable to Southern Company 52 59 112 114
Mississippi Power | Retail revenues        
Operating Revenues:        
Total operating revenues 283 274 556 522
Mississippi Power | Wholesale revenues, non-affiliates        
Operating Revenues:        
Total operating revenues 74 62 162 133
Mississippi Power | Wholesale revenues, affiliates        
Operating Revenues:        
Total operating revenues 35 55 131 136
Mississippi Power | Other revenues        
Operating Revenues:        
Total operating revenues 11 9 26 30
Mississippi Power | Fuel and purchased power        
Operating Expenses:        
Fuel and purchased power $ 122 $ 143 $ 328 $ 309
v3.26.1
Condensed Statements of Cash Flows (Unaudited) - MPC - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Operating Activities:    
Net income $ 2,531 $ 2,214
Adjustments to reconcile net income to net cash provided from operating activities —    
Depreciation and amortization, total 3,176 2,860
Deferred income taxes 310 453
Pension, postretirement, and other employee benefits (277) (253)
Settlement of asset retirement obligations (283) (285)
Other, net (87) 76
Changes in certain current assets and liabilities —    
Receivables 116 (130)
Retail fuel cost under recovery 188 158
Other current assets (60) 61
Accounts payable (403) (695)
Accrued taxes (221) (245)
Accrued compensation (459) (421)
Other current liabilities 105 (141)
Net cash provided from operating activities 4,280 3,431
Investing Activities:    
Property additions (6,639) (5,456)
Contributions in aid of construction 313 219
Cost of removal, net of salvage (349) (304)
Other investing activities (83) (193)
Net cash used for investing activities (6,758) (5,734)
Financing Activities:    
Increase in notes payable, net 1,415  
Increase (decrease) in notes payable, net   (150)
Payment of common stock dividends (1,579) (1,494)
Other financing activities (233) (150)
Net cash provided from financing activities 3,828 2,467
Net Change in Cash, Cash Equivalents, and Restricted Cash 1,350 164
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period 1,640 1,101
Cash, Cash Equivalents, and Restricted Cash at End of Period 2,990 1,265
Supplemental Cash Flow Information:    
Interest 1,472 1,287
Income taxes, net (excludes credit transfers) 146 199
Noncash transactions —    
Accrued property additions at end of period 1,409 1,091
Right-of-use assets obtained under operating leases 107 114
Mississippi Power    
Operating Activities:    
Net income 112 114
Adjustments to reconcile net income to net cash provided from operating activities —    
Depreciation and amortization, total 125 115
Deferred income taxes 14 4
Pension, postretirement, and other employee benefits (9) (8)
Settlement of asset retirement obligations (12) (7)
Other, net (3) (7)
Changes in certain current assets and liabilities —    
Receivables (11) (26)
Retail fuel cost under recovery (14) (28)
Fossil fuel stock 0 20
Other current assets (8) 8
Accounts payable (23) (22)
Accrued taxes (57) (49)
Accrued compensation (21) (22)
Wholesale fuel cost over recovery 0 (15)
Other current liabilities 0 1
Net cash provided from operating activities 93 78
Investing Activities:    
Property additions (185) (166)
Contributions in aid of construction 4 57
Cost of removal, net of salvage (18) (17)
Payments pursuant to LTSAs (11) (11)
Other investing activities 1 (8)
Net cash used for investing activities (209) (145)
Financing Activities:    
Increase in notes payable, net 38 18
Proceeds — Senior notes 75 100
Capital contributions from parent company 97 57
Payment of common stock dividends (96) (97)
Other financing activities (2) (2)
Net cash provided from financing activities 112 76
Net Change in Cash, Cash Equivalents, and Restricted Cash (4) 9
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period 26 13
Cash, Cash Equivalents, and Restricted Cash at End of Period 22 22
Supplemental Cash Flow Information:    
Interest 40 37
Income taxes, net (excludes credit transfers) 23 21
Noncash transactions —    
Accrued property additions at end of period 42 30
Right-of-use assets obtained under operating leases $ 3 $ 0
v3.26.1
Condensed Balance Sheets (Unaudited) - MPC - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Current Assets:    
Cash and cash equivalents $ 2,984 $ 1,639
Receivables —    
Customer accounts, net and Affiliated 2,301 2,251
Unbilled revenues 938 931
Other accounts and notes 580 655
Fossil fuel stock 728 735
Materials and supplies 2,380 2,202
Other regulatory assets 916 709
Other current assets 501 487
Total current assets 12,378 10,917
Property, Plant, and Equipment:    
In service 151,437 146,114
Less: Accumulated depreciation 45,868 43,483
Plant in service, net of depreciation 105,569 102,631
Construction work in progress 11,874 10,534
Total property, plant, and equipment 118,345 114,369
Other Property and Investments:    
Total other property and investments 10,687 10,440
Deferred Charges and Other Assets:    
Deferred charges related to income taxes 1,094 948
Prepaid pension costs 3,544 3,257
Deferred under recovered fuel clause revenues 151 252
Regulatory assets – asset retirement obligations 5,042 5,129
Other regulatory assets, deferred 7,577 7,427
Other deferred charges and assets 1,661 1,436
Total deferred charges and other assets 20,617 19,994
Total Assets 162,027 155,720
Current Liabilities:    
Securities due within one year 4,694 6,220
Notes payable 2,132 722
Accounts payable —    
Accrued compensation 927 1,418
Asset retirement obligations 658 662
Other regulatory liabilities 190 240
Other current liabilities 1,146 1,157
Total current liabilities 15,734 16,888
Long-term Debt 68,756 65,649
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 12,628 12,133
Deferred credits related to income taxes 4,611 4,712
Employee benefit obligations 1,029 980
Asset retirement obligations, deferred 8,917 8,939
Other cost of removal obligations 2,084 2,036
Other regulatory liabilities, deferred 712 722
Other deferred credits and liabilities 1,850 1,505
Total deferred credits and other liabilities 35,195 34,316
Total Liabilities 119,685 116,853
Total Liabilities and Stockholders' Equity 162,027 155,720
Mississippi Power    
Current Assets:    
Cash and cash equivalents 22 26
Receivables —    
Unbilled revenues 48 44
Under recovered retail fuel clause revenues 55 0
Other accounts and notes 18 22
Fossil fuel stock 46 46
Materials and supplies 102 101
Other regulatory assets 58 49
Other current assets 14 10
Total current assets 450 374
Property, Plant, and Equipment:    
In service 6,111 5,972
Less: Accumulated depreciation 2,020 1,922
Plant in service, net of depreciation 4,091 4,050
Construction work in progress 223 238
Total property, plant, and equipment 4,314 4,288
Other Property and Investments:    
Total other property and investments 140 143
Deferred Charges and Other Assets:    
Deferred charges related to income taxes 24 25
Prepaid pension costs 162 151
Deferred under recovered fuel clause revenues 0 40
Regulatory assets – asset retirement obligations 228 229
Other regulatory assets, deferred 259 255
Accumulated deferred income taxes 59 66
Other deferred charges and assets 81 66
Total deferred charges and other assets 813 832
Total Assets 5,717 5,637
Current Liabilities:    
Securities due within one year 141 66
Notes payable 38 0
Accounts payable —    
Accrued taxes 70 125
Accrued compensation 30 49
Asset retirement obligations 18 21
Other regulatory liabilities 24 20
Other current liabilities 97 92
Total current liabilities 559 520
Long-term Debt 1,720 1,720
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 501 491
Deferred credits related to income taxes 192 211
Employee benefit obligations 66 67
Asset retirement obligations, deferred 97 103
Other cost of removal obligations 103 115
Other regulatory liabilities, deferred 137 141
Other deferred credits and liabilities 40 80
Total deferred credits and other liabilities 1,136 1,208
Total Liabilities 3,415 3,448
Total common stockholders' equity 2,302 2,189
Total Liabilities and Stockholders' Equity 5,717 5,637
Mississippi Power | Nonrelated Party    
Receivables —    
Customer accounts, net and Affiliated 60 50
Accounts payable —    
Affiliated and Other 69 77
Mississippi Power | Related Party    
Receivables —    
Customer accounts, net and Affiliated 27 26
Accounts payable —    
Affiliated and Other $ 72 $ 70
v3.26.1
Condensed Statements of Common Stockholders' Equity (Unaudited) - MPC - USD ($)
shares in Millions, $ in Millions
Total
Common Stock
Paid-In Capital
Retained Earnings
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, 2024   1,098       1      
Beginning balance at Dec. 31, 2024         $ 2,089 $ 38 $ 4,791 $ (2,745) $ 5
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income         55     55  
Capital contributions from parent company         51   51    
Cash dividends on common stock $ (791)     $ (791) (48)     (48)  
Other (5)   $ (1) (2) (1)       (1)
Ending balance (in shares) at Mar. 31, 2025   1,100       1      
Ending balance at Mar. 31, 2025         2,146 $ 38 4,842 (2,738) 4
Beginning balance (in shares) at Dec. 31, 2024   1,098       1      
Beginning balance at Dec. 31, 2024         2,089 $ 38 4,791 (2,745) 5
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 2,214       114        
Ending balance (in shares) at Jun. 30, 2025   1,101       1      
Ending balance at Jun. 30, 2025         2,164 $ 38 4,849 (2,727) 4
Beginning balance (in shares) at Mar. 31, 2025   1,100       1      
Beginning balance at Mar. 31, 2025         2,146 $ 38 4,842 (2,738) 4
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 880       59     59  
Capital contributions from parent company         7   7    
Cash dividends on common stock (815)     (815) (49)     (49)  
Other 6   6 1 1     1  
Ending balance (in shares) at Jun. 30, 2025   1,101       1      
Ending balance at Jun. 30, 2025         2,164 $ 38 4,849 (2,727) 4
Beginning balance (in shares) at Dec. 31, 2025   1,120       1      
Beginning balance at Dec. 31, 2025         2,189 $ 38 4,871 (2,724) 4
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income         60     60  
Capital contributions from parent company         90   90    
Cash dividends on common stock (830)     (830) (48)     (48)  
Other (3)   (1)            
Ending balance (in shares) at Mar. 31, 2026   1,128       1      
Ending balance at Mar. 31, 2026         2,291 $ 38 4,961 (2,712) 4
Beginning balance (in shares) at Dec. 31, 2025   1,120       1      
Beginning balance at Dec. 31, 2025         2,189 $ 38 4,871 (2,724) 4
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 2,531       112        
Ending balance (in shares) at Jun. 30, 2026   1,151       1      
Ending balance at Jun. 30, 2026         2,302 $ 38 4,968 (2,708) 4
Beginning balance (in shares) at Mar. 31, 2026   1,128       1      
Beginning balance at Mar. 31, 2026         2,291 $ 38 4,961 (2,712) 4
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Net income 1,174       52     52  
Capital contributions from parent company         7   7    
Cash dividends on common stock (858)     (858) (48)     (48)  
Other $ 6   $ 5 $ 2          
Ending balance (in shares) at Jun. 30, 2026   1,151       1      
Ending balance at Jun. 30, 2026         $ 2,302 $ 38 $ 4,968 $ (2,708) $ 4
v3.26.1
Condensed Consolidated Statements of Income (Loss) (Unaudited) - SPC - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Operating Revenues:        
Total operating revenues $ 6,977 $ 6,973 $ 15,374 $ 14,748
Operating Expenses:        
Other operations and maintenance 1,705 1,685 3,359 3,305
Depreciation and amortization 1,434 1,323 2,854 2,608
Taxes other than income taxes 367 403 831 848
Total operating expenses 5,201 5,209 11,580 10,974
Operating Income 1,776 1,764 3,794 3,774
Other Income and (Expense):        
Interest expense, net of amounts capitalized (796) (874) (1,573) (1,588)
Other income (expense), net 181 162 336 310
Total other income and (expense) (401) (622) (853) (1,082)
Earnings Before Income Taxes 1,375 1,142 2,941 2,692
Income taxes (benefit) 187 289 414 569
Consolidated Net Income 1,188 853 2,527 2,123
Net income (loss) attributable to noncontrolling interests 14 (27) (4) (91)
Consolidated Net Income Attributable to Southern Company 1,174 880 2,531 2,214
Other revenues        
Operating Revenues:        
Total operating revenues 325 335 661 684
Operating Expenses:        
Total cost of sales 176 167 357 366
Fuel        
Operating Expenses:        
Total cost of sales 1,054 1,116 2,544 2,408
Purchased power        
Operating Expenses:        
Total cost of sales 288 260 532 510
SOUTHERN POWER CO        
Operating Revenues:        
Total operating revenues 535 546 1,216 1,113
Operating Expenses:        
Other operations and maintenance 139 135 278 257
Depreciation and amortization 280 177 558 329
Taxes other than income taxes 13 13 25 25
Total operating expenses 597 503 1,338 1,025
Operating Income (62) 43 (122) 88
Other Income and (Expense):        
Interest expense, net of amounts capitalized (28) (24) (55) (50)
Other income (expense), net 2 3 4 6
Total other income and (expense) (26) (21) (51) (44)
Earnings Before Income Taxes (88) 22 (173) 44
Income taxes (benefit) (77) (2) (147) (3)
Consolidated Net Income (11) 24 (26) 47
Net income (loss) attributable to noncontrolling interests 14 (27) (4) (91)
Consolidated Net Income Attributable to Southern Company (25) 51 (22) 138
SOUTHERN POWER CO | Wholesale revenues, non-affiliates        
Operating Revenues:        
Total operating revenues 439 424 1,016 870
SOUTHERN POWER CO | Wholesale revenues, affiliates        
Operating Revenues:        
Total operating revenues 92 114 192 229
SOUTHERN POWER CO | Other revenues        
Operating Revenues:        
Total operating revenues 4 8 8 14
SOUTHERN POWER CO | Fuel        
Operating Expenses:        
Total cost of sales 129 147 383 355
SOUTHERN POWER CO | Purchased power        
Operating Expenses:        
Total cost of sales $ 36 $ 31 $ 94 $ 59
v3.26.1
Condensed Consolidated Statements of Comprehensive Income (Unaudited) - SPC - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Net income $ 1,188 $ 853 $ 2,527 $ 2,123
Qualifying hedges:        
Changes in fair value, net of tax (13) 35 (16) 49
Reclassification adjustment for amounts included in net income, net of tax 7 (31) 11 (43)
Total other comprehensive income (loss) (5) 4 (3) 7
Comprehensive Income 1,183 857 2,524 2,130
Comprehensive income (loss) attributable to noncontrolling interests 14 (27) (4) (91)
Consolidated Comprehensive Income Attributable to Company 1,169 884 2,528 2,221
SOUTHERN POWER CO        
Net income (11) 24 (26) 47
Qualifying hedges:        
Changes in fair value, net of tax (7) 35 (14) 52
Reclassification adjustment for amounts included in net income, net of tax 4 (33) 13 (48)
Total other comprehensive income (loss) (3) 2 (1) 4
Comprehensive Income (14) 26 (27) 51
Comprehensive income (loss) attributable to noncontrolling interests 14 (27) (4) (91)
Consolidated Comprehensive Income Attributable to Company $ (28) $ 53 $ (23) $ 142
v3.26.1
Condensed Consolidated Statements of Comprehensive Income (Unaudited) - SPC (Parenthetical) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Changes in fair value, tax $ (4) $ 11 $ (4) $ 16
Reclassification adjustment for amounts included in net income, tax 3 (10) 4 (14)
SOUTHERN POWER CO        
Changes in fair value, tax (2) 11 (5) 17
Reclassification adjustment for amounts included in net income, tax $ 1 $ (10) $ 4 $ (15)
v3.26.1
Condensed Consolidated Statements of Cash Flows (Unaudited) - SPC - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Operating Activities:    
Net income $ 2,527 $ 2,123
Adjustments to reconcile net income to net cash provided from operating activities —    
Depreciation and amortization, total 3,176 2,860
Deferred income taxes 310 453
Other, net (87) 76
Changes in certain current assets and liabilities —    
Receivables 116 (130)
Other current assets (60) 61
Accounts payable (403) (695)
Accrued compensation (459) (421)
Other current liabilities 105 (141)
Net cash provided from operating activities 4,280 3,431
Investing Activities:    
Property additions (6,639) (5,456)
Other investing activities (83) (193)
Net cash used for investing activities (6,758) (5,734)
Financing Activities:    
Increase (decrease) in notes payable, net   (150)
Increase in notes payable, net 1,415  
Distributions to noncontrolling interests (76) (66)
Payment of common stock dividends (1,579) (1,494)
Other financing activities (233) (150)
Net cash provided from financing activities 3,828 2,467
Net Change in Cash, Cash Equivalents, and Restricted Cash 1,350 164
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period 1,640 1,101
Cash, Cash Equivalents, and Restricted Cash at End of Period 2,990 1,265
Supplemental Cash Flow Information:    
Interest, net of amounts capitalized 1,472 1,287
Income taxes, net (excludes credit transfers) 146 199
Noncash transactions —    
Accrued property additions at end of period 1,409 1,091
Right-of-use assets obtained under operating leases 107 114
SOUTHERN POWER CO    
Operating Activities:    
Net income (26) 47
Adjustments to reconcile net income to net cash provided from operating activities —    
Depreciation and amortization, total 568 340
Deferred income taxes (75) (2)
Utilization of federal tax credit carryforward 130 0
Amortization of ITCs (29) (29)
Loss on damaged equipment 22 0
Other, net (9) (18)
Changes in certain current assets and liabilities —    
Receivables (47) (69)
Income taxes receivable (39) (2)
Other current assets (24) 2
Accounts payable (19) (20)
Accrued compensation (11) (11)
Other current liabilities 8 (6)
Net cash provided from operating activities 449 232
Investing Activities:    
Property additions (399) (392)
Payments pursuant to LTSAs (28) (26)
Other investing activities 10 0
Net cash used for investing activities (417) (418)
Financing Activities:    
Increase (decrease) in notes payable, net (135)  
Increase in notes payable, net   201
Proceeds — Senior notes 600 0
Redemptions — Senior notes (564) 0
Capital contributions from parent company 465 146
Capital contributions from noncontrolling interests 4 23
Distributions to noncontrolling interests (76) (66)
Payment of common stock dividends (143) (139)
Other financing activities (10) (4)
Net cash provided from financing activities 141 161
Net Change in Cash, Cash Equivalents, and Restricted Cash 173 (25)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period 105 168
Cash, Cash Equivalents, and Restricted Cash at End of Period 278 143
Supplemental Cash Flow Information:    
Interest, net of amounts capitalized 61 59
Income taxes, net (excludes credit transfers) (61) 52
Noncash transactions —    
Accrued property additions at end of period 66 60
Right-of-use assets obtained under operating leases $ 0 $ 2
v3.26.1
Condensed Consolidated Statements of Cash Flows (Unaudited) - SPC (Parenthetical) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Net cash paid for capitalized interest $ 100 $ 61
SOUTHERN POWER CO    
Net cash paid for capitalized interest $ 21 $ 8
v3.26.1
Condensed Consolidated Balance Sheets (Unaudited) - SPC - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Current Assets:    
Cash and cash equivalents $ 2,984 $ 1,639
Receivables —    
Customer accounts, net and Affiliated 2,301 2,251
Other 580 655
Materials and supplies 2,380 2,202
Other current assets 501 487
Total current assets 12,378 10,917
Property, Plant, and Equipment:    
In service 151,437 146,114
Less: Accumulated depreciation 45,868 43,483
Plant in service, net of depreciation 105,569 102,631
Construction work in progress 11,874 10,534
Total property, plant, and equipment 118,345 114,369
Other Property and Investments:    
Total other property and investments 10,687 10,440
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 1,369 1,358
Other deferred charges and assets 1,661 1,436
Total deferred charges and other assets 20,617 19,994
Total Assets 162,027 155,720
Current Liabilities:    
Securities due within one year 4,694 6,220
Notes payable 2,132 722
Accounts payable —    
Accrued interest 812 807
Operating lease obligations 207 197
Other current liabilities 1,146 1,157
Total current liabilities 15,734 16,888
Long-term Debt 68,756 65,649
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 12,628 12,133
Accumulated deferred ITCs 2,066 2,002
Operating lease obligations, deferred 1,298 1,287
Other deferred credits and liabilities 1,850 1,505
Total deferred credits and other liabilities 35,195 34,316
Total Liabilities 119,685 116,853
Total Stockholders' Equity (See accompanying statements) 42,342 38,867
Total Liabilities and Stockholders' Equity 162,027 155,720
SOUTHERN POWER CO    
Current Assets:    
Cash and cash equivalents 278 105
Receivables —    
Other 52 16
Materials and supplies 136 132
Prepaid income taxes 52 8
Other current assets 61 81
Total current assets 814 528
Property, Plant, and Equipment:    
In service 15,339 15,034
Less: Accumulated depreciation 5,564 5,214
Plant in service, net of depreciation 9,775 9,820
Construction work in progress 944 1,080
Total property, plant, and equipment 10,719 10,900
Other Property and Investments:    
Intangible assets, net of amortization 194 203
Net investment in sales-type leases 133 137
Total other property and investments 327 340
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 474 479
Prepaid LTSAs 198 170
Other deferred charges and assets 248 240
Total deferred charges and other assets 920 889
Total Assets 12,780 12,657
Current Liabilities:    
Securities due within one year 0 587
Notes payable 0 138
Accounts payable —    
Accrued taxes 21 9
Accrued interest 32 38
Operating lease obligations 31 31
Other current liabilities 75 92
Total current liabilities 336 1,076
Long-term Debt 2,950 2,353
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 655 579
Accumulated deferred ITCs 1,354 1,383
Operating lease obligations, deferred 505 510
Other deferred credits and liabilities 238 235
Total deferred credits and other liabilities 2,752 2,707
Total Liabilities 6,038 6,136
Total Stockholders' Equity (See accompanying statements) 6,742 6,521
Total Liabilities and Stockholders' Equity 12,780 12,657
SOUTHERN POWER CO | Nonrelated Party    
Receivables —    
Customer accounts, net and Affiliated 193 151
Accounts payable —    
Affiliated and Other 101 93
SOUTHERN POWER CO | Related Party    
Receivables —    
Customer accounts, net and Affiliated 42 35
Accounts payable —    
Affiliated and Other $ 76 $ 88
v3.26.1
Condensed Consolidated Balance Sheets (Unaudited) - SPC (Parenthetical) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Other intangible assets, amortization $ 457 $ 444
SOUTHERN POWER CO    
Other intangible assets, amortization $ 198 $ 188
v3.26.1
Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - SPC - USD ($)
$ in Millions
Total
Paid-In Capital
Retained Earnings
Accumulated Other Comprehensive Income (Loss)
Noncontrolling Interests
SOUTHERN POWER CO
SOUTHERN POWER CO
Total Common Stockholder's Equity
SOUTHERN POWER CO
Paid-In Capital
SOUTHERN POWER CO
Retained Earnings
SOUTHERN POWER CO
Accumulated Other Comprehensive Income (Loss)
SOUTHERN POWER CO
Noncontrolling Interests
Beginning 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
Increase (Decrease) in Stockholders' Equity [Roll Forward]                      
Net income (loss) 1,270   1,334   (64) 23 87   87   (64)
Capital contributions from parent company           130 130 130      
Other comprehensive income 3     3   2 2     2  
Cash dividends on common stock (791)   (791)     (70) (70)   (70)    
Capital contributions from noncontrolling interests 19       19 19         19
Distributions to noncontrolling interests (37)       (37) (37)         (37)
Other (5) (1) (2)                
Ending balance at Mar. 31, 2025 37,223 14,231 14,291 (75) 3,384 6,749 3,365 1,436 1,929 0 3,384
Beginning 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
Increase (Decrease) in Stockholders' Equity [Roll Forward]                      
Net income (loss) 2,123         47          
Other comprehensive income 7         4          
Ending balance at Jun. 30, 2025 37,342 14,332 14,357 (71) 3,328 6,692 3,364 1,452 1,910 2 3,328
Beginning balance at Mar. 31, 2025 37,223 14,231 14,291 (75) 3,384 6,749 3,365 1,436 1,929 0 3,384
Increase (Decrease) in Stockholders' Equity [Roll Forward]                      
Net income (loss) 853   880   (27) 24 51   51   (27)
Capital contributions from parent company           16 16 16      
Other comprehensive income 4     4   2 2     2  
Cash dividends on common stock (815)   (815)     (69) (69)   (69)    
Capital contributions from noncontrolling interests 4       4 4         4
Distributions to noncontrolling interests (33)       (33) (33)         (33)
Other 6 6 1     (1) (1)   (1)    
Ending balance at Jun. 30, 2025 37,342 14,332 14,357 (71) 3,328 6,692 3,364 1,452 1,910 2 3,328
Beginning balance at Dec. 31, 2025 38,867 15,740 14,856 (75) 2,851 6,521 3,670 1,912 1,758 0 2,851
Increase (Decrease) in Stockholders' Equity [Roll Forward]                      
Net income (loss) 1,338   1,356   (18) (14) 4   4   (18)
Other comprehensive income 2     2   2 2     2  
Cash dividends on common stock (830)   (830)     (72) (72)   (72)    
Capital contributions from noncontrolling interests 4       4 4         4
Distributions to noncontrolling interests (46)       (46) (46)         (46)
Other (3) (1)     (1) (1)   (1) 1   (1)
Ending balance at Mar. 31, 2026 39,912 16,285 15,382 (73) 2,790 6,394 3,604 1,911 1,691 2 2,790
Beginning balance at Dec. 31, 2025 38,867 15,740 14,856 (75) 2,851 6,521 3,670 1,912 1,758 0 2,851
Increase (Decrease) in Stockholders' Equity [Roll Forward]                      
Net income (loss) 2,527         (26)          
Other comprehensive income (3)         (1)          
Ending balance at Jun. 30, 2026 42,342 23,998 15,700 (78) 2,772 6,742 3,970 2,377 1,594 (1) 2,772
Beginning balance at Mar. 31, 2026 39,912 16,285 15,382 (73) 2,790 6,394 3,604 1,911 1,691 2 2,790
Increase (Decrease) in Stockholders' Equity [Roll Forward]                      
Net income (loss) 1,188   1,174   14 (11) (25)   (25)   14
Capital contributions from parent company           465 465 465      
Other comprehensive income (5)     (5)   (3) (3)     (3)  
Cash dividends on common stock (858)   (858)     (71) (71)   (71)    
Distributions to noncontrolling interests (32)       (32) (32)         (32)
Other 6 5 2     0   1 (1)    
Ending balance at Jun. 30, 2026 $ 42,342 $ 23,998 $ 15,700 $ (78) $ 2,772 $ 6,742 $ 3,970 $ 2,377 $ 1,594 $ (1) $ 2,772
v3.26.1
Condensed Consolidated Statements of Income (Unaudited) - GAS - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Operating Revenues:        
Total operating revenues $ 6,977 $ 6,973 $ 15,374 $ 14,748
Operating Expenses:        
Other operations and maintenance 1,705 1,685 3,359 3,305
Depreciation and amortization 1,434 1,323 2,854 2,608
Taxes other than income taxes 367 403 831 848
Total operating expenses 5,201 5,209 11,580 10,974
Operating Income 1,776 1,764 3,794 3,774
Other Income and (Expense):        
Earnings from equity method investments 86 10 136 43
Interest expense, net of amounts capitalized (796) (874) (1,573) (1,588)
Other income (expense), net 181 162 336 310
Total other income and (expense) (401) (622) (853) (1,082)
Earnings Before Income Taxes 1,375 1,142 2,941 2,692
Income taxes (benefit) 187 289 414 569
Consolidated Net Income Attributable to Southern Company 1,174 880 2,531 2,214
SOUTHERN Co GAS        
Operating Revenues:        
Total operating revenues $ 966 $ 979 $ 3,157 $ 2,818
Revenue, Product and Service [Extensible Enumeration] Natural gas Natural gas Natural gas Natural gas
Operating Expenses:        
Total cost of sales $ 177 $ 255 $ 1,103 $ 929
Cost, Product and Service [Extensible Enumeration] Natural gas Natural gas Natural gas Natural gas
Other operations and maintenance $ 341 $ 301 $ 683 $ 617
Depreciation and amortization 185 172 369 341
Taxes other than income taxes 61 61 166 158
Total operating expenses 764 789 2,321 2,045
Operating Income 202 190 836 773
Other Income and (Expense):        
Earnings from equity method investments 32 23 78 62
Interest expense, net of amounts capitalized (101) (92) (206) (183)
Other income (expense), net 25 18 41 34
Total other income and (expense) (44) (51) (87) (87)
Earnings Before Income Taxes 158 139 749 686
Income taxes (benefit) 32 33 176 162
Consolidated Net Income Attributable to Southern Company $ 126 $ 106 $ 573 $ 524
v3.26.1
Condensed Consolidated Statements of Income (Unaudited) - GAS (Parenthetical) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
SOUTHERN Co GAS        
Revenue taxes collected $ 25 $ 27 $ 95 $ 90
v3.26.1
Condensed Consolidated Statements of Comprehensive Income (Unaudited) - GAS - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Net income $ 1,174 $ 880 $ 2,531 $ 2,214
Qualifying hedges:        
Changes in fair value, net of tax (13) 35 (16) 49
Reclassification adjustment for amounts included in net income, net of tax 7 (31) 11 (43)
Pension and other postretirement benefit plans:        
Reclassification adjustment for amounts included in net income, net of tax 1 0 1 0
Consolidated Comprehensive Income Attributable to Company 1,169 884 2,528 2,221
SOUTHERN Co GAS        
Net income 126 106 573 524
Qualifying hedges:        
Changes in fair value, net of tax (3) (6) 2 6
Reclassification adjustment for amounts included in net income, net of tax 2 (1) (4) 0
Pension and other postretirement benefit plans:        
Reclassification adjustment for amounts included in net income, net of tax 0 0 (1) (1)
Total other comprehensive income (loss) (1) (7) (3) 5
Consolidated Comprehensive Income Attributable to Company $ 125 $ 99 $ 570 $ 529
v3.26.1
Condensed Consolidated Statements of Comprehensive Income (Unaudited) - GAS (Parenthetical) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Changes in fair value, tax $ (4) $ 11 $ (4) $ 16
Qualifying hedges, reclassification adjustment, tax 3 (10) 4 (14)
Reclassification adjustment for amounts included in net income, tax 0 0 0 0
SOUTHERN Co GAS        
Changes in fair value, tax (1) (2) 1 2
Qualifying hedges, reclassification adjustment, tax 1 0 (2) 0
Reclassification adjustment for amounts included in net income, tax $ 0 $ 0 $ 0 $ 0
v3.26.1
Condensed Consolidated Statements of Cash Flows (Unaudited) - GAS - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Operating Activities:    
Net income $ 2,531 $ 2,214
Adjustments to reconcile net income to net cash provided from operating activities —    
Depreciation and amortization, total 3,176 2,860
Deferred income taxes 310 453
Other, net (87) 76
Changes in certain current assets and liabilities —    
Receivables 116 (130)
Natural gas for sale, net of temporary LIFO liquidation 197 233
Other current assets (60) 61
Accounts payable (403) (695)
Accrued compensation (459) (421)
Other current liabilities 105 (141)
Net cash provided from operating activities 4,280 3,431
Investing Activities:    
Property additions (6,639) (5,456)
Contributions in aid of construction 313 219
Cost of removal, net of salvage (349) (304)
Other investing activities (83) (193)
Net cash used for investing activities (6,758) (5,734)
Financing Activities:    
Increase (decrease) in notes payable, net   (150)
Increase in notes payable, net 1,415  
Payment of common stock dividends (1,579) (1,494)
Other financing activities (233) (150)
Net cash provided from financing activities 3,828 2,467
Net Change in Cash, Cash Equivalents, and Restricted Cash 1,350 164
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period 1,640 1,101
Cash, Cash Equivalents, and Restricted Cash at End of Period 2,990 1,265
Supplemental Cash Flow Information:    
Interest, net of amounts capitalized 1,472 1,287
Income taxes, net (excludes credit transfers) 146 199
Noncash transactions —    
Accrued property additions at end of period 1,409 1,091
Right-of-use assets obtained under operating leases 107 114
SOUTHERN Co GAS    
Operating Activities:    
Net income 573 524
Adjustments to reconcile net income to net cash provided from operating activities —    
Depreciation and amortization, total 366 338
Deferred income taxes 89 67
Other, net 40 26
Changes in certain current assets and liabilities —    
Receivables 427 209
Natural gas for sale, net of temporary LIFO liquidation 197 233
Other current assets (12) 37
Accounts payable (152) (105)
Accrued compensation (39) (44)
Natural gas cost over recovery 34 (87)
Other current liabilities (15) 12
Net cash provided from operating activities 1,508 1,210
Investing Activities:    
Property additions (799) (704)
Contributions in aid of construction 11 27
Cost of removal, net of salvage (39) (42)
Change in construction payables, net 26 15
Capital contributions to unconsolidated subsidiaries (93) (31)
Other investing activities 5 0
Net cash used for investing activities (889) (735)
Financing Activities:    
Increase (decrease) in notes payable, net (190)  
Increase in notes payable, net   16
Proceeds — Other long-term debt 500 0
Redemptions — Senior notes (350) 0
Redemptions - First mortgage bonds (100) 0
Return of capital to parent company 0 (23)
Capital contributions from parent company 22 22
Payment of common stock dividends (281) (297)
Other financing activities (17) (12)
Net cash provided from financing activities (416) (294)
Net Change in Cash, Cash Equivalents, and Restricted Cash 203 181
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period 15 44
Cash, Cash Equivalents, and Restricted Cash at End of Period 218 225
Supplemental Cash Flow Information:    
Interest, net of amounts capitalized 201 185
Income taxes, net (excludes credit transfers) 55 66
Noncash transactions —    
Accrued property additions at end of period 138 101
Right-of-use assets obtained under operating leases 1 60
Return of capital to parent company $ 0 $ 33
v3.26.1
Condensed Consolidated Statements of Cash Flows (Unaudited) - GAS (Parenthetical) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Net cash paid for capitalized interest $ 100 $ 61
SOUTHERN Co GAS    
Net cash paid for capitalized interest $ 7 $ 9
v3.26.1
Condensed Consolidated Balance Sheets (Unaudited) - GAS - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Current Assets:    
Cash and cash equivalents $ 2,984 $ 1,639
Receivables —    
Customer accounts 2,301 2,251
Unbilled revenues 938 931
Other accounts and notes 580 655
Accumulated provision for uncollectible accounts (98) (84)
Materials and supplies 2,380 2,202
Natural gas for sale 198 396
Prepaid expenses 370 327
Other regulatory assets 916 709
Other current assets 501 487
Total current assets 12,378 10,917
Property, Plant, and Equipment:    
In service 151,437 146,114
Less: Accumulated depreciation 45,868 43,483
Plant in service, net of depreciation 105,569 102,631
Construction work in progress 11,874 10,534
Total property, plant, and equipment 118,345 114,369
Other Property and Investments:    
Goodwill 5,161 5,161
Equity investments in unconsolidated subsidiaries 1,428 1,318
Other intangible assets, net of amortization 287 300
Miscellaneous property and investments 701 714
Total other property and investments 10,687 10,440
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 1,369 1,358
Other regulatory assets, deferred 7,577 7,427
Other deferred charges and assets 1,661 1,436
Total deferred charges and other assets 20,617 19,994
Total Assets 162,027 155,720
Current Liabilities:    
Securities due within one year 4,694 6,220
Notes payable 2,132 722
Accounts payable —    
Customer deposits 487 475
Accrued interest 812 807
Accrued compensation 927 1,418
Natural gas cost over recovery 191 158
Other regulatory liabilities 190 240
Other current liabilities 1,146 1,157
Total current liabilities 15,734 16,888
Long-term Debt 68,756 65,649
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 12,628 12,133
Deferred credits related to income taxes 4,611 4,712
Employee benefit obligations 1,029 980
Operating lease obligations 1,298 1,287
Other cost of removal obligations 2,084 2,036
Other deferred credits and liabilities 1,850 1,505
Total deferred credits and other liabilities 35,195 34,316
Total Liabilities 119,685 116,853
Total Liabilities and Stockholders' Equity 162,027 155,720
SOUTHERN Co GAS    
Current Assets:    
Cash and cash equivalents 214 15
Receivables —    
Customer accounts 326 490
Unbilled revenues 85 341
Other accounts and notes 61 57
Accumulated provision for uncollectible accounts (65) (50)
Materials and supplies 61 62
Natural gas for sale 198 396
Prepaid expenses 35 26
Other regulatory assets 117 114
Other current assets 49 66
Total current assets 1,081 1,517
Property, Plant, and Equipment:    
In service 24,726 24,098
Less: Accumulated depreciation 6,489 6,273
Plant in service, net of depreciation 18,237 17,825
Construction work in progress 969 863
Total property, plant, and equipment 19,206 18,688
Other Property and Investments:    
Goodwill 5,015 5,015
Equity investments in unconsolidated subsidiaries 1,254 1,182
Other intangible assets, net of amortization 1 3
Miscellaneous property and investments 25 24
Total other property and investments 6,295 6,224
Deferred Charges and Other Assets:    
Operating lease right-of-use assets, net of amortization 80 85
Prepaid pension and other postretirement benefit costs 301 229
Other regulatory assets, deferred 508 517
Other deferred charges and assets 133 127
Total deferred charges and other assets 1,022 958
Total Assets 27,604 27,387
Current Liabilities:    
Securities due within one year 80 531
Notes payable 235 425
Accounts payable —    
Customer deposits 75 75
Accrued taxes 111 107
Accrued interest 102 100
Accrued compensation 98 137
Natural gas cost over recovery 191 158
Other regulatory liabilities 36 36
Other current liabilities 96 110
Total current liabilities 1,538 2,302
Long-term Debt 9,224 8,743
Deferred Credits and Other Liabilities:    
Accumulated deferred income taxes 2,059 1,971
Deferred credits related to income taxes 667 681
Employee benefit obligations 135 78
Operating lease obligations 120 123
Other cost of removal obligations 1,981 1,921
Accrued environmental remediation 201 207
Other deferred credits and liabilities 238 234
Total deferred credits and other liabilities 5,401 5,215
Total Liabilities 16,163 16,260
Total common stockholders' equity 11,441 11,127
Total Liabilities and Stockholders' Equity 27,604 27,387
SOUTHERN Co GAS | Related Party    
Accounts payable —    
Affiliated and Other 75 70
SOUTHERN Co GAS | Nonrelated Party    
Accounts payable —    
Affiliated and Other $ 439 $ 553
v3.26.1
Condensed Consolidated Balance Sheets (Unaudited) - GAS (Parenthetical) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Other intangible assets, amortization $ 457 $ 444
SOUTHERN Co GAS    
Other intangible assets, amortization $ 181 $ 179
v3.26.1
Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - GAS - USD ($)
$ in Millions
Total
Paid-In Capital
Retained Earnings
SOUTHERN Co GAS
SOUTHERN Co GAS
Paid-In Capital
SOUTHERN Co GAS
Retained Earnings
SOUTHERN Co GAS
Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2024       $ 10,996 $ 10,863 $ 85 $ 48
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income       418   418  
Return of capital to parent company       (56) (56)    
Capital contributions from parent company       3 3    
Other comprehensive income       12     12
Cash dividends on common stock $ (791)   $ (791) (149)   (149)  
Other (5) $ (1) (2) 1   1  
Ending balance at Mar. 31, 2025       11,225 10,810 355 60
Beginning balance at Dec. 31, 2024       10,996 10,863 85 48
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income 2,214     524      
Other comprehensive income       5      
Ending balance at Jun. 30, 2025       11,198 10,833 312 53
Beginning balance at Mar. 31, 2025       11,225 10,810 355 60
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income 880     106   106  
Capital contributions from parent company       23 23    
Other comprehensive income       (7)     (7)
Cash dividends on common stock (815)   (815) (148)   (148)  
Other 6 6 1 (1)   (1)  
Ending balance at Jun. 30, 2025       11,198 10,833 312 53
Beginning balance at Dec. 31, 2025       11,127 10,854 222 51
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income       447   447  
Capital contributions from parent company       1 1    
Other comprehensive income       (2)     (2)
Cash dividends on common stock (830)   (830) (141)   (141)  
Other (3) (1)   1   1  
Ending balance at Mar. 31, 2026       11,433 10,855 529 49
Beginning balance at Dec. 31, 2025       11,127 10,854 222 51
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income 2,531     573      
Other comprehensive income       (3)      
Ending balance at Jun. 30, 2026       11,441 10,879 514 48
Beginning balance at Mar. 31, 2026       11,433 10,855 529 49
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income 1,174     126   126  
Capital contributions from parent company       24 24    
Other comprehensive income       (1)     (1)
Cash dividends on common stock (858)   (858) (140)   (140)  
Other $ 6 $ 5 $ 2 (1)   (1)  
Ending balance at Jun. 30, 2026       $ 11,441 $ 10,879 $ 514 $ 48
v3.26.1
Introduction
 6 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Introduction INTRODUCTION
The condensed quarterly financial statements of each Registrant included herein have been prepared by such Registrant, without audit, pursuant to the rules and regulations of the SEC. The Condensed Balance Sheets at December 31, 2025 have been derived from the audited financial statements of each Registrant. In the opinion of each Registrant's management, the information regarding such Registrant furnished herein reflects all adjustments, which, except as otherwise disclosed, are of a normal recurring nature, necessary to present fairly the results of operations for the periods ended June 30, 2026 and 2025. Certain information and disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations, although each Registrant believes that the disclosures regarding such Registrant are adequate to make the information presented not misleading. Disclosures which would substantially duplicate the disclosures in the Form 10-K and details which have not changed significantly in amount or composition since the filing of the Form 10-K are generally omitted from this Quarterly Report on Form 10-Q unless specifically required by GAAP. Therefore, these Condensed Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the Form 10-K. Due to the seasonal variations in the demand for energy and other factors, operating results for the periods presented are not necessarily indicative of the operating results to be expected for the full year.
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 year data presented in the financial statements have been reclassified to conform to the current year presentation. These reclassifications had no impact on the overall results of operations, financial position, or cash flows of any Registrant.
Goodwill and Other Intangible Assets
Goodwill at both June 30, 2026 and December 31, 2025 was as follows:
Goodwill
(in millions)
Southern Company$5,161 
Southern Company Gas:
Gas distribution operations$4,034 
Gas marketing services981 
Southern Company Gas total$5,015 
Goodwill is not amortized but is subject to an annual impairment test during the fourth quarter of each year, or more frequently if goodwill impairment indicators exist.
Other intangible assets were as follows:
At June 30, 2026At December 31, 2025
Gross
Carrying
Amount		Accumulated
Amortization		Other
Intangible
Assets,
Net		Gross
Carrying
Amount		Accumulated
Amortization		Other
Intangible
Assets,
Net
(in millions)(in millions)
Southern Company
Subject to amortization:
Customer relationships$212 $(192)$20 $212 $(189)$23 
Trade names64 (64)— 64 (64)— 
PPA fair value adjustments390 (198)192 390 (188)202 
Other3 (3)— 3 (3)— 
Total subject to amortization$669 $(457)$212 $669 $(444)$225 
Not subject to amortization:
FCC licenses75 — 75 75 — 75 
Total other intangible assets$744 $(457)$287 $744 $(444)$300 
Southern Power(*)
PPA fair value adjustments$390 $(198)$192 $390 $(188)$202 
Southern Company Gas(*)
Gas marketing services
Customer relationships$156 $(155)$1 $156 $(153)$3 
Trade names26 (26)— 26 (26)— 
Total other intangible assets$182 $(181)$1 $182 $(179)$3 
(*)All subject to amortization.
Amortization associated with other intangible assets was as follows:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
(in millions)
Southern Company(a)
$7 $8 $13 $16 
Southern Power(b)
5 5 10 10 
Southern Company Gas
Gas marketing services1 1 2 3 
(a)Includes $5 million for the three months ended June 30, 2026 and 2025 and $10 million for the six months ended June 30, 2026 and 2025 recorded as a reduction to operating revenues.
(b)Recorded as a reduction to operating revenues.
Cash, Cash Equivalents, and Restricted Cash
The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed balance sheets that total to the amount shown in the condensed statements of cash flows for the applicable Registrants:
Southern CompanySouthern
Company Gas
(in millions)
At June 30, 2026
Cash and cash equivalents$2,984 $214 
Restricted cash(a):
Other current assets
5 4 
Total cash, cash equivalents, and restricted cash(b)
$2,990 $218 
At December 31, 2025
Cash and cash equivalents$1,639 $15 
Restricted cash(a):
Other current assets
1 — 
Total cash, cash equivalents, and restricted cash(b)
$1,640 $15 
(a)For Southern Company Gas, reflects funds held to support letters of credit. For Southern Company, also reflects collateral of $1 million for life insurance and long-term disability insurance, which was included at Southern Holdings.
(b)Total may not add due to rounding.
Natural Gas for Sale
With the exception of Nicor Gas, Southern Company Gas records natural gas inventories on a weighted average cost basis. For any declines in market prices below the weighted average cost considered to be non-temporary, an adjustment is recorded to reduce the value of natural gas inventories to market value. 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.
Southern Company Gas recorded no material adjustments to natural gas inventories for either period presented. Nicor Gas' inventory decrements that occurred during the year have been restored as of June 30, 2026.
Asset Retirement Obligations
See BUSINESS – "Regulation – Federal Power Act" in Item 1 and Note 6 to the financial statements in Item 8 of the Form 10-K for additional information.
On April 16, 2026, the FERC issued a surrender order for Georgia Power's Langdale and Riverview hydroelectric projects, which includes dam removal obligations and other post-dam removal activities. As a result, in June 2026, Georgia Power recorded AROs of $46 million.
v3.26.1
Regulatory Matters
 6 Months Ended
Jun. 30, 2026
Regulated Operations [Abstract]  
Regulatory Matters REGULATORY MATTERS
See Note 2 to the financial statements in Item 8 of the Form 10-K for additional information relating to regulatory matters.
The recovery balances for retail fuel and storm/property damage for the traditional electric operating companies and natural gas cost for Southern Company Gas at June 30, 2026 and December 31, 2025 were as follows:
Recovery/Regulatory ClauseBalance Sheet LocationAt June 30, 2026At December 31, 2025
(in millions)
Alabama Power
Rate ECR
Other regulatory assets, current
$7 $— 
Other regulatory assets, deferred212 146 
NDROther regulatory liabilities, deferred29 60 
Georgia Power
Fuel cost recovery
Receivables – under recovered retail fuel clause revenues
$161 $310 
Deferred under recovered retail fuel clause revenues151 212 
Storm damage recoveryOther regulatory assets, current187 31 
Other regulatory assets, deferred784 880 
Mississippi Power
Fuel cost recovery(*)
Receivables – under recovered retail fuel clause revenues$55 $— 
Deferred under recovered retail fuel clause revenues— 40 
Property damage reserveOther regulatory liabilities, deferred56 57 
Southern Company Gas
Natural gas cost recoveryNatural gas cost over recovery$191 $158 
(*)Mississippi Power also has wholesale MRA and Market Based (MB) fuel cost recovery factors. At June 30, 2026 and December 31, 2025, wholesale MRA fuel cost under recovery was $10 million and $6 million, respectively, and was included in customer accounts receivable, net on Mississippi Power's balance sheets. The wholesale MB fuel cost recovery was immaterial for both periods presented.
Alabama Power
Power to the People Act
In December 2025, the Alabama PSC issued a consent order to keep retail rates stable through 2027. On April 2, 2026, the State of Alabama enacted legislation providing that retail base rates established and in place on October 1, 2026 may not be increased before January 1, 2029 for utilities that are regulated by the Alabama PSC and that provide retail electric service. The ultimate outcome of this matter cannot be determined at this time.
Reliability Reserve Accounting Order
In accordance with the notification provided to the Alabama PSC through its annual Rate RSE filing indicating plans to use $60 million of the reliability reserve, Alabama Power utilized $40 million of its reliability reserve during the first six months of 2026 for reliability-related transmission, distribution, and generation expenses. At June 30, 2026, Alabama Power's reliability reserve balance was $144 million.
Environmental Accounting Order
As a result of the planned conversion of Plant Barry Unit 5 from coal to natural gas, the unit's net book value no longer meets the criteria to be considered probable of abandonment, and, in the first quarter 2026, approximately $307 million was reclassified from other utility plant, net to plant in service on Alabama Power's and Southern Company's balance sheets.
Georgia Power
Integrated Resource Plans
Certification Requests
On March 25, 2026, Georgia Interfaith Power & Light, Park Avenue Baptist Church, Unitarian Universalist Church of Savannah, Sierra Club, Adrien Webber, and Southern Alliance for Clean Energy filed a petition with the Fulton County Superior Court appealing the Georgia PSC's December 19, 2025 approval of Georgia Power's request for certification of resources totaling 9,885 MWs (2025 All-Source Certification). The petition requests a reversal of the 2025 All-Source Certification, including a decertification of at least 757 MWs of resources. Georgia Power intervened in the proceeding, and both the Georgia PSC and Georgia Power filed motions to dismiss on April 24, 2026 and June 23, 2026, respectively. Georgia Power believes the appeal has no merit; however, the ultimate outcome of this matter cannot be determined at this time.
On June 2, 2026, the FERC approved two affiliate PPAs with Southern Power procured under the 2022 IRP. These affiliate PPAs began in June 2026 with capacities of 638 MWs and 74 MWs. See Note (F) under "Georgia Power Lease Modification" for additional information.
2025 IRP
Pursuant to the final order for Georgia Power's 2025 IRP, on June 9, 2026, Georgia Power initiated a request for proposals for 2,000 MWs to 6,000 MWs of capacity resources with projected CODs or delivery commencement dates in 2032 and 2033.
Fuel Cost Recovery
On each of March 13, 2026, April 15, 2026, and May 14, 2026, Georgia Power filed an Interim Fuel Rider (IFR) notification and plan informing the Georgia PSC that Georgia Power's under recovered fuel balance accumulated since May 31, 2023 exceeded $200 million, as established in a Georgia PSC stipulation approved in 2023, as of February 28, 2026, March 31, 2026, and April 30, 2026, respectively. Georgia Power did not propose a fuel cost recovery rate change pursuant to these IFR notifications and plans.
On May 28, 2026, the Georgia PSC approved a stipulation among Georgia Power, the staff of the Georgia PSC, and certain intervenors to decrease annual fuel billings by 12.9%, or approximately $394 million, effective June 1, 2026. Under the approved stipulation, Georgia Power is required to file for an adjustment to its fuel cost recovery rates under an IFR 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, 2026 exceeds $300 million. Within 30 days of the filing, the Georgia PSC will approve, modify, or reject any proposed fuel cost recovery rate adjustment. Georgia Power is scheduled to file its next fuel case no later than February 28, 2029. Changes in fuel rates have no significant effect on Georgia Power's net income but impact the related operating cash flows.
Storm Damage Recovery
On May 28, 2026, the Georgia PSC approved a stipulation among Georgia Power, the staff of the Georgia PSC, and certain intervenors regarding Georgia Power's recovery of storm restoration costs. Under the stipulation, the Georgia PSC approved the following:
•Recovery of $31 million annually for storm restoration costs incurred after December 31, 2025.
•Recovery of Georgia Power's adjusted regulatory asset balance totaling $869 million, as determined through the proceedings and stipulation, related to storm damage as of December 31, 2025 over a period of 67 months from June 1, 2026 through December 31, 2031, or $156 million annually.
Additionally, the stipulation provided for the treatment of the Internal Revenue Code §45U PTCs generated from Georgia Power's nuclear generating facilities in 2024 and 2025, in which Georgia Power agreed to use $77 million of these tax credits for the benefit of customers.
Construction
At June 30, 2026, Georgia Power had recorded approximately $4.4 billion of combined capital costs, excluding AFUDC, for the projects reflected in the table below approved by the Georgia PSC through the 2023 IRP Update and certification requests in September and December 2025 authorized through its 2022 IRP. The total certified amounts related to these projects are approximately $19.5 billion, excluding AFUDC. The ultimate outcome of these matters cannot be determined at this time.
Resource/Project
Approximate Nameplate Capacity
(MW)
Actual/Projected COD
Projects Under Construction at June 30, 2026
Battery Energy Storage
McGrau Ford Phase 2
265
Third quarter 2026
McGrau Ford Phase 1265Fourth quarter 2026
Hammond Phase 158
Fourth quarter 2026
Hammond Phase 2193Fourth quarter 2030
Twiggs County200Fourth quarter 2027
Wadley260Fourth quarter 2027
Bowen Phase 1
250Fourth quarter 2028
Bowen Phase 2
250Fourth quarter 2029
South Hall250Fourth quarter 2028
Wansley
500Fourth quarter 2028
Yates Phase 1
320Fourth quarter 2028
Yates Phase 2
250Fourth quarter 2028
Thomson500Fourth quarter 2029
McIntosh
250Fourth quarter 2030
Solar with Battery Energy Storage
Laurens County 200Fourth quarter 2028
Plant Mitchell 150Fourth quarter 2028
Combined Cycle
Plant Bowen Unit 7741Fourth quarter 2029
Plant Bowen Unit 8741Second quarter 2030
Plant Wansley Unit 10727Fourth quarter 2029
Plant Wansley Unit 11727Second quarter 2030
Plant McIntosh Unit 12757Fourth quarter 2030
Combustion Turbine
Plant Yates Unit 8(*)
442Fourth quarter 2026
Plant Yates Unit 9(*)
442Second quarter 2027
Plant Yates Unit 10(*)
442Third quarter 2027
Projects Completed During the Six Months Ended June 30, 2026
Battery Energy Storage
Robins
128March 2026
Moody50April 2026
Mississippi Power
Performance Evaluation Plan
On June 18, 2026, the Mississippi PSC approved Mississippi Power's annual retail PEP Evaluation Report for 2026, resulting in an annual increase in revenues of approximately 1.8%, or $20 million, primarily due to increases in investment and depreciation. In accordance with the PEP rate schedule, the increase became effective with the first billing cycle of January 2026.
Integrated Resource Plans
On March 9, 2026, in compliance with its IRP requirements, Mississippi Power submitted its mid-point update to its 2024 IRP to the Mississippi PSC, indicating that the retirement dates of Plant Daniel Unit 2 and Plant Watson Unit 4 will extend beyond 2028.
On July 7, 2026, the Mississippi PSC approved a request from Mississippi Power to convert either Plant Daniel Unit 1 or Unit 2 from a coal-fired unit to a natural gas-fired unit. Conversion of the declared unit is projected to be completed in 2029.
The remaining net book value of Plant Daniel Units 1 and 2 was approximately $481 million at June 30, 2026, and Mississippi Power is continuing to depreciate these units using approved rates. Until a unit is declared to be converted, Mississippi Power is unable to determine what portion of the net book value will remain in service upon a unit conversion. Mississippi Power expects to reclassify the remaining net book value of assets no longer in service upon a unit conversion or retirement to a regulatory asset to be amortized over a period to be determined by the Mississippi PSC in future proceedings, consistent with a 2020 order. The ultimate outcome of this matter cannot be determined at this time.
Environmental Compliance Overview Plan
On April 14, 2026, the Mississippi PSC approved Mississippi Power's annual ECO Plan filing for 2026, resulting in a $2 million annual increase in revenues effective with the first billing cycle of May 2026.
Ad Valorem Tax Adjustment
On June 12, 2026, Mississippi Power submitted its annual ad valorem tax adjustment filing for 2026 to the Mississippi PSC, which requested a $7 million annual increase in revenues. The ultimate outcome of this matter cannot be determined at this time.
System Restoration Rider
On June 18, 2026, the Mississippi PSC approved Mississippi Power's annual SRR filing for 2026, with no change in retail rates. Mississippi Power's minimum annual SRR accrual increased from $13.5 million to $13.7 million.
Reliability Reserve Accounting Order
On March 16, 2026, through its annual PEP Evaluation Report, Mississippi Power notified the Mississippi PSC of its intent to use a portion of its $59 million retail reliability reserve balance during 2026. On June 18, 2026, the Mississippi PSC approved the annual PEP filing which allowed for the use of approximately $7 million of the reliability reserve balance, which Mississippi Power utilized for reliability-related generation, transmission, and distribution expenses during the first six months of 2026. At June 30, 2026, Mississippi Power's retail reliability reserve balance was $52 million. See "Performance Evaluation Plan" herein for information regarding Mississippi Power's annual PEP filing.
Excess Accumulated Deferred Income Tax Accounting Order
On June 18, 2026, the Mississippi PSC approved approximately $21 million associated with certain federal excess accumulated deferred income taxes resulting from the Tax Reform Legislation to be credited back to customers over an 18-month period starting with the first billing cycle of July 2026.
Southern Company Gas
Rate Proceedings
On June 16, 2026, in connection with Nicor Gas' 2023 general base rate case proceeding, the Illinois Appellate Court determined that the Illinois Commission did not provide sufficient support for its disallowance of $43 million of Nicor Gas' planned capital investments that were expected to be completed by December 31, 2024. As the disallowance related to planned capital investments for which costs had not yet been incurred, it was not included in the pre-tax charge to income recorded in 2023. This matter remains subject to further proceedings before the Illinois Commission and had no impact on the current period financial statements.
On July 21, 2026, Nicor Gas filed a petition for leave to appeal with the Illinois Supreme Court related to the capital structure approved in Nicor Gas' 2023 general base rate case proceeding. The Illinois Supreme Court is expected to rule on the petition on September 30, 2026.
The ultimate outcome of these matters cannot be determined at this time.
v3.26.1
Contingencies
 6 Months Ended
Jun. 30, 2026
Commitments and Contingencies Disclosure [Abstract]  
Contingencies CONTINGENCIES
See Note 3 to the financial statements in Item 8 of the Form 10-K for information relating to various lawsuits and other contingencies.
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
In July 2025, a purported class action complaint was filed in the U.S. District Court for the District of Maryland against two nuclear consulting companies and all U.S. commercial nuclear power operators, or affiliated entities, including Southern Company. The purported class of plaintiffs includes all persons employed in nuclear power generation by the defendants, including nuclear operators, nuclear engineers, and nuclear technicians, from May 1, 2003 to the present. The complaint alleges that, since at least May 2003, the nuclear power industry conspired to fix and suppress employee compensation for nuclear power generation employees in violation of federal antitrust law. Although not named as defendants, other entities are accused of having participated in the conspiracy alleged by the plaintiffs. The plaintiffs seek to recover, among other relief, unspecified monetary damages, including treble damages and attorneys' fees, and injunctive relief. In October 2025, Southern Company moved to dismiss the complaint. In November 2025, the plaintiffs filed an amended complaint naming Southern Nuclear, among others, as a defendant. In December 2025, Southern Company and Southern Nuclear filed a motion to dismiss the amended complaint. An adverse outcome could have a material impact on Southern Company's financial statements.
Alabama Power
In 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.
Later in 2022, Alabama Power filed a motion to dismiss the case. In 2024, the lawsuit was dismissed without prejudice by the U.S. District Court judge. Later in 2024, the U.S. District Court judge denied a motion to reconsider filed by the plaintiff, and 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. On May 18, 2026, the U.S. Court of Appeals for the Eleventh Circuit overturned the dismissal and remanded the case to the U.S. District Court for further proceedings.
In 2023, the EPA issued a Notice of Potential Violations (NOPV) associated with Alabama Power's plan to close the Plant Barry surface impoundment. In 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.
In July 2025, Coosa Riverkeeper filed a citizen suit in the U.S. District Court for the Northern District of Alabama alleging that Alabama Power's closure of the Plant Gadsden surface impoundment utilizing a closure-in-place methodology violates the RCRA and regulations governing CCR. Among other relief requested, Coosa Riverkeeper seeks declaratory judgment that Alabama Power is in violation of the RCRA and regulations governing CCR, and preliminary and injunctive relief to require Alabama Power to close the CCR unit and operate a groundwater monitoring system in a different manner to satisfy the RCRA and the regulations governing CCR requirements. In September 2025, Alabama Power filed a motion to dismiss the citizen suit.
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 to the financial statements in Item 8 of the Form 10-K for a discussion of Alabama Power's ARO liabilities.
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 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. These regulatory mechanisms are adjusted annually or as necessary within limits approved by the state PSCs or other applicable state regulatory agencies.
Georgia Power's environmental remediation liability was $15 million and $14 million at June 30, 2026 and December 31, 2025, respectively. 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.
Southern Company Gas' environmental remediation liability was $215 million and $227 million at June 30, 2026 and December 31, 2025, respectively, based on the estimated cost of environmental investigation and remediation at known former manufactured gas plant operating sites.
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.
v3.26.1
Revenue from Contracts with Customers and Lease Income
 6 Months Ended
Jun. 30, 2026
Revenue from Contract with Customer [Abstract]  
Revenue from Contracts with Customers and Lease Income REVENUE FROM CONTRACTS WITH CUSTOMERS AND LEASE INCOME
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 to the financial statements under "Affiliate Transactions" and "Revenues" in Item 8 of the Form 10-K for additional information. See "Lease Income" herein and Note (J) 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 three and six months ended June 30, 2026 and 2025:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Three Months Ended June 30, 2026
Operating revenues
Retail electric revenues
Residential$2,007 $720 $1,208 $79 $— $— 
Commercial1,757 501 1,166 90 — — 
Industrial1,021 441 471 109 — — 
Other29 3 24 2 — — 
Total retail electric revenues4,814 1,665 2,869 280 — — 
Natural gas distribution revenues
Residential353 — — — — 353 
Commercial89 — — — — 89 
Transportation358 — — — — 358 
Industrial 6 — — — — 6 
Other67 — — — — 67 
Total natural gas distribution revenues873 — — — — 873 
Wholesale electric revenues
PPA energy revenues301 47 40 8 218 — 
PPA capacity revenues145 18 32 25 89 — 
Non-PPA revenues64 55 19 80 43 — 
Total wholesale electric revenues510 120 91 113 350 — 
Other natural gas revenues
Gas marketing services73 — — — — 73 
Other
2 — — — — 2 
Total other natural gas revenues
75 — — — — 75 
Other revenues450 62 212 11 4 — 
Total revenue from contracts with customers6,722 1,847 3,172 404 354 948 
Other revenue sources(*)
255 116 (39)(1)181 18 
Total operating revenues$6,977 $1,963 $3,133 $403 $535 $966 
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Six Months Ended June 30, 2026
Operating revenues
Retail electric revenues
Residential$4,010 $1,493 $2,358 $159 $— $— 
Commercial3,419 978 2,269 172 — — 
Industrial1,962 855 909 198 — — 
Other61 6 50 5 — — 
Total retail electric revenues9,452 3,332 5,586 534 — — 
Natural gas distribution revenues
Residential1,380 — — — — 1,380 
Commercial342 — — — — 342 
Transportation798 — — — — 798 
Industrial 30 — — — — 30 
Other213 — — — — 213 
Total natural gas distribution revenues2,763 — — — — 2,763 
Wholesale electric revenues
PPA energy revenues796 93 104 11 610 — 
PPA capacity revenues294 36 76 46 172 — 
Non-PPA revenues156 175 63 250 88 — 
Total wholesale electric revenues1,246 304 243 307 870 — 
Other natural gas revenues
Gas marketing services355 — — — — 355 
Other
4 — — — — 4 
Total other natural gas revenues
359 — — — — 359 
Other revenues945 140 449 26 8 — 
Total revenue from contracts with customers14,765 3,776 6,278 867 878 3,122 
Other revenue sources(*)
609 279 (2)8 338 35 
Total operating revenues$15,374 $4,055 $6,276 $875 $1,216 $3,157 
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Three Months Ended June 30, 2025
Operating revenues
Retail electric revenues
Residential$2,021 $725 $1,217 $79 $— $— 
Commercial1,716 504 1,127 85 — — 
Industrial1,015 432 496 87 — — 
Other29 2 25 2 — — 
Total retail electric revenues4,781 1,663 2,865 253 — — 
Natural gas distribution revenues
Residential394 — — — — 394 
Commercial94 — — — — 94 
Transportation331 — — — — 331 
Industrial 7 — — — — 7 
Other60 — — — — 60 
Total natural gas distribution revenues886 — — — — 886 
Wholesale electric revenues
PPA energy revenues310 58 50 2 210 — 
PPA capacity revenues154 29 35 17 85 — 
Non-PPA revenues60 36 10 100 59 — 
Total wholesale electric revenues524 123 95 119 354 — 
Other natural gas revenues
Gas marketing services81 — — — — 81 
Other
5 — — — — 5 
Total other natural gas revenues
86 — — — — 86 
Other revenues457 67 206 9 8 — 
Total revenue from contracts with customers6,734 1,853 3,166 381 362 972 
Other revenue sources(*)
239 115 (56)19 184 7 
Total operating revenues$6,973 $1,968 $3,110 $400 $546 $979 
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Six Months Ended June 30, 2025
Operating revenues
Retail electric revenues
Residential$4,087 $1,531 $2,403 $153 $— $— 
Commercial3,327 986 2,181 160 — — 
Industrial1,930 822 940 168 — — 
Other61 4 52 5 — — 
Total retail electric revenues9,405 3,343 5,576 486 — — 
Natural gas distribution revenues
Residential1,239 — — — — 1,239 
Commercial292 — — — — 292 
Transportation737 — — — — 737 
Industrial 26 — — — — 26 
Other170 — — — — 170 
Total natural gas distribution revenues2,464 — — — — 2,464 
Wholesale electric revenues
PPA energy revenues723 112 134 5 491 — 
PPA capacity revenues299 57 74 34 169 — 
Non-PPA revenues136 106 19 233 121 — 
Total wholesale electric revenues1,158 275 227 272 781 — 
Other natural gas revenues
Gas marketing services337 — — — — 337 
Other
10 — — — — 10 
Total other natural gas revenues
347 — — — — 347 
Other revenues954 150 436 30 14 — 
Total revenue from contracts with customers14,328 3,768 6,239 788 795 2,811 
Other revenue sources(*)
420 212 (91)33 318 7 
Total operating revenues$14,748 $3,980 $6,148 $821 $1,113 $2,818 
(*)Other revenue sources relate to revenues from customers accounted for as derivatives and leases, alternative revenue programs primarily 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 June 30, 2026 and December 31, 2025:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Accounts Receivable
At June 30, 2026$3,155 $860 $1,549 $122 $136 $448 
At December 31, 20253,139 716 1,278 115 132 864 
Contract Assets
At June 30, 2026$354 $— $189 $4 $— $67 
At December 31, 2025294 3 160 — — 67 
Contract Liabilities
At June 30, 2026$329 $7 $123 $— $1 $— 
At December 31, 2025213 6 75 — 2 — 
Contract assets for Georgia Power primarily relate to unregulated service agreements, where payment is contingent on project completion, and retail customer fixed bill programs, where payment is contingent upon Georgia Power's continued performance and the customer's continued participation in the program over a one-year contract term. 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 received cash advances totaling approximately $68 million from a third-party financial institution to fund work performed. These advances have been accounted for as long-term debt on the balance sheets. See Note 1 to the financial statements under "Affiliate Transactions" in Item 8 of the Form 10-K for additional information regarding the construction contract. At June 30, 2026 and December 31, 2025, Southern Company's unregulated distributed generation business had contract assets of $92 million and $63 million, respectively, and contract liabilities of $199 million and $132 million, respectively, for outstanding performance obligations, all of which are expected to be satisfied within one year.
Revenues recognized in the three and six months ended June 30, 2026, which were included in contract liabilities at December 31, 2025, were $26 million and $80 million, respectively, for Southern Company, $7 million and $18 million, respectively, for Georgia Power, 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. 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 June 30, 2026 are expected to be recognized as follows:
2026 (remaining)2027202820292030Thereafter
(in millions)
Southern Company$668 $826 $472 $413 $416 $3,130 
Alabama Power7 5 4 3 1 6 
Georgia Power37 69 46 22 22 146 
Mississippi Power(*)
33 69 73 12 — — 
Southern Power(*)
184 349 389 393 393 2,978 
Southern Company Gas28 24 — — — — 
(*)Includes performance obligations related to affiliate PPAs with Georgia Power. See Note 1 to the financial statements under "Affiliate Transactions" in Item 8 of the Form 10-K for additional information.
Lease Income
Lease income for the three and six months ended June 30, 2026 and 2025 was as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
 (in millions)
Three Months Ended June 30, 2026
Lease income - interest income on sales-type leases$5 $— $— $3 $2 $— 
Lease income - operating leases34 3 7 1 27 9 
Variable lease income125 — — — 136 — 
Total lease income$164 $3 $7 $4 $165 $9 
Six Months Ended June 30, 2026
Lease income - interest income on sales-type leases$12 $— $— $7 $4 $— 
Lease income - operating leases69 6 15 2 64 18 
Variable lease income204 — — — 223 — 
Total lease income$285 $6 $15 $9 $291 $18 
Three Months Ended June 30, 2025
Lease income - interest income on sales-type leases$6 $— $— $4 $2 $— 
Lease income - operating leases33 2 7 1 37 9 
Variable lease income125 — — — 136 — 
Total lease income$164 $2 $7 $5 $175 $9 
Six Months Ended June 30, 2025
Lease income - interest income on sales-type leases$11 $— $— $7 $4 $— 
Lease income - operating leases66 3 14 1 73 18 
Variable lease income207 1 — — 225 — 
Total lease income$284 $4 $14 $8 $302 $18 
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.
v3.26.1
Consolidated Entities and Equity Method Investments
 6 Months Ended
Jun. 30, 2026
Regulated Operations [Abstract]  
Consolidated Entities and Equity Method Investments CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS
See Note 7 to the financial statements in Item 8 of the Form 10-K for additional information.
Southern Company
At June 30, 2026 and December 31, 2025, Southern Holdings had equity method investments totaling $156 million and $124 million, respectively, primarily related to investments in venture capital funds focused on energy and utility investments. The net earnings (losses) from these investments totaled $45 million and $(14) million for the three months ended June 30, 2026 and 2025, respectively, and $48 million and $(20) million for the six months ended June 30, 2026 and 2025, respectively.
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
At June 30, 2026 and December 31, 2025, SP Solar had total assets of $5.1 billion and $5.2 billion, respectively, total liabilities of $364 million and $360 million, respectively, and noncontrolling interests of $907 million and $918 million, respectively. 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.
Southern Power consolidates SP Solar, as the primary beneficiary, since it controls the most significant activities of the entity, including operating and maintaining its assets. Certain transfers and sales of the assets in the VIE 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 June 30, 2026 and December 31, 2025, the other VIEs had total assets of $1.5 billion and $1.6 billion, respectively, total liabilities of $259 million and $236 million, respectively, and noncontrolling interests of $563 million and $617 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.
Southern Company Gas
The carrying amounts of Southern Company Gas' equity method investments at June 30, 2026 and December 31, 2025 were as follows:
Investment BalanceAt June 30, 2026At December 31, 2025
(in millions)
SNG$1,220 $1,148 
Other34 34 
Total$1,254 $1,182 
The earnings from Southern Company Gas' equity method investment in SNG were $32 million and $23 million for the three months ended June 30, 2026 and 2025, respectively, and $77 million and $62 million for the six months ended June 30, 2026 and 2025, respectively. The earnings from Southern Company Gas' other equity method investments were immaterial for all periods presented.
v3.26.1
Financing and Leases
 6 Months Ended
Jun. 30, 2026
Debt Disclosure [Abstract]  
Financing and Leases FINANCING AND LEASES
Bank Credit Arrangements
See Note 8 to the financial statements under "Bank Credit Arrangements" in Item 8 of the Form 10-K for additional information.
At June 30, 2026, committed credit arrangements with banks were as follows:
Expires
Company20262027202820292031TotalUnusedExpires within
One Year
(in millions)
Southern Company parent(a)
$— $— $500 $— $2,500 $3,000 $2,999 $— 
Alabama Power(b)
15 — — 650 700 1,365 1,365 15 
Georgia Power(c)
— — — — 2,050 2,050 2,042 — 
Mississippi Power(a)
— — — 125 150 275 275 — 
Southern Power(a)(d)
— — — — 600 600 600 — 
Southern Company Gas(e)
— — — — 1,600 1,600 1,598 — 
SEGCO— 30 — — — 30 30 30 
Southern Company$15 $30 $500 $775 $7,600 $8,920 $8,909 $45 
(a)Arrangement expiring in 2031 represents a $3.25 billion combined arrangement for Southern Company, Mississippi Power, and Southern Power allowing for flexible sublimits. Pursuant to the combined facility, the allocations among Southern Company, Mississippi Power, and Southern Power may be adjusted.
(b)Includes $15 million expiring in 2026 at Alabama Property Company, a wholly-owned subsidiary of Alabama Power, of which $15 million was unused at June 30, 2026. Alabama Power is not party to this arrangement.
(c)Georgia Power had $26 million of letters of credit outstanding under an uncommitted letter of credit facility at June 30, 2026.
(d)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 2029, respectively, of which $17 million and $4 million, respectively, was unused at June 30, 2026. In addition, Southern Power Company had $23 million of letters of credit outstanding under an uncommitted letter of credit facility at June 30, 2026. Southern Power's subsidiaries are not parties to its bank credit arrangements or letter of credit facilities.
(e)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 2031. Southern Company Gas' committed credit arrangement expiring in 2031 also includes $800 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 2031, the allocations between Southern Company Gas Capital and Nicor Gas may be adjusted.
As reflected in the table above, in March 2026, (i) Southern Company, Mississippi Power, and Southern Power extended the maturity date of their $3.25 billion combined multi-year credit arrangement from 2030 to 2031, (ii)
Southern Company extended the maturity date of its multi-year credit agreement from 2027 to 2028, (iii) Georgia Power extended the maturity date of its multi-year credit arrangement from 2030 to 2031, and (iv) Mississippi Power extended the maturity date of its multi-year credit arrangement from 2027 to 2029. In May 2026, Alabama Power and Southern Company Gas Capital, along with Nicor Gas, extended the maturity date of each of their respective multi-year credit arrangements from 2030 to 2031. In May and June 2026, SEGCO amended its credit arrangements to extend the maturity dates from 2026 to 2027.
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. At June 30, 2026, 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 June 30, 2026, outstanding variable rate demand revenue bonds of the traditional electric operating companies with allocated liquidity support totaled approximately $1.5 billion (comprised of approximately $796 million at Alabama Power, $667 million at Georgia Power, and $58 million at Mississippi Power). In addition, at June 30, 2026, Georgia Power had approximately $210 million of fixed rate revenue bonds outstanding that are required to be remarketed within the next 12 months. 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.
DOE Loan Guarantee Borrowings
On February 20, 2026, pursuant to the loan guarantee program (DOE Loan Guarantee Program) established under Title XVII of the Energy Policy Act of 2005, as amended (Title XVII), Alabama Power entered into (i) a loan guarantee agreement, dated as of February 20, 2026 (Alabama Power LGA), between Alabama Power and the DOE, as guarantor, (ii) a note purchase agreement, dated as of February 20, 2026 (Alabama Power NPA), among Alabama Power, the FFB, and the Secretary of Energy, acting through the DOE, and (iii) future advance promissory notes, each dated February 20, 2026, made by Alabama Power to the FFB (each an Alabama Power FFB Note and, together with the Alabama Power NPA, the Alabama Power FFB Credit Facility Documents). The Alabama Power LGA and the Alabama Power FFB Credit Facility Documents are referred to herein together as the Alabama Power Loan Documents.
In addition, on February 20, 2026, pursuant to the DOE Loan Guarantee Program, Georgia Power entered into (i) a loan guarantee agreement, dated as of February 20, 2026 (Georgia Power LGA and, together with the Alabama Power LGA, the Loan Guarantee Agreements), between Georgia Power and the DOE, as guarantor, (ii) a note purchase agreement, dated as of February 20, 2026 (Georgia Power NPA), among Georgia Power, the FFB, and the Secretary of Energy, acting through the DOE, and (iii) future advance promissory notes, each dated February 20, 2026, made by Georgia Power to the FFB (each a Georgia Power FFB Note and, together with the Georgia Power NPA, the Georgia Power FFB Credit Facility Documents). The Georgia Power LGA and the Georgia Power FFB Credit Facility Documents are referred to herein together as the Georgia Power Loan Documents.
The Alabama Power FFB Credit Facility Documents provide for a multi-advance term loan facility under which Alabama Power may make term loan borrowings through the FFB (Alabama Power Credit Facility). The Georgia Power FFB Credit Facility Documents provide for a multi-advance term loan facility under which Georgia Power may make term loan borrowings through the FFB (Georgia Power Credit Facility and, together with the Alabama
Power Credit Facility, the Credit Facilities). Each of Alabama Power and Georgia Power is referred to herein as a Borrower in connection with its applicable Credit Facility.
Proceeds of advances made under each Credit Facility must be used for the purpose of reimbursing the applicable Borrower for a portion (up to 80%) of "eligible project costs" (as defined in the applicable Loan Guarantee Agreement) incurred by such Borrower for projects that are eligible for financing under the terms of the applicable Loan Guarantee Agreement and the DOE Loan Guarantee Program (Eligible Projects). Eligible Projects may include new gas generating units and upgrades associated with existing gas generating units; new transmission lines, substations, and transmission system upgrades; new stand-alone battery energy storage systems; hydropower refurbishment and upgrades; upgrades, uprates, and license extensions for existing nuclear facilities; coal-to-gas conversions; and grid enhancements.
The aggregate amount of advances under the Alabama Power Credit Facility may not exceed approximately $4.1 billion (Alabama Power Maximum Facility Amount). The aggregate amount of advances under the Georgia Power Credit Facility may not exceed approximately $22.4 billion (Georgia Power Maximum Facility Amount and, together with the Alabama Power Maximum Facility Amount, the Maximum Facility Amounts). Each Borrower may request advances under its applicable Credit Facility during an availability period (with respect to each Borrower, the "availability period") that will continue until the earliest of (i) September 15, 2033, (ii) the date total advances reach the applicable Maximum Facility Amount, or (iii) the termination of the obligation to fund further advances following an event of default under the applicable Loan Guarantee Agreement. In addition, the FFB's obligation to fund advances to Alabama Power will terminate if Alabama Power has failed to request an initial advance by February 20, 2031.
In March 2026, Georgia Power received initial advances under the Georgia Power Credit Facility in an amount of approximately $1.0 billion at an interest rate of 5.041% through the final maturity date of December 10, 2055.
Future advances under each of the Credit Facilities are subject to confirmation of investment grade credit ratings and satisfaction of customary conditions, as well as certification of compliance with the requirements of Title XVII, including accuracy of project-related representation and warranties, delivery of updated project-related information, and evidence of compliance with the prevailing wage requirements of the Davis-Bacon Act of 1931, as amended (DOE Program Requirements), compliance with the Cargo Preference Act of 1954, and certification from the DOE's consulting engineer that proceeds of the advances are used to reimburse for eligible project costs.
All borrowings under each of the Credit Facilities will be full recourse, senior unsecured obligations of the respective Borrower. Alabama Power is not a party to, and has no obligations with respect to, the Georgia Power Credit Facility. Georgia Power is not a party to, and has no obligations with respect to, the Alabama Power Credit Facility.
The final scheduled maturity date for all borrowings under each Credit Facility is December 10, 2055. Each advance will bear interest at a rate equal to the applicable U.S. Treasury rate plus a spread of 0.375%, which rate will be determined at the time of the advance. Principal payments for the Alabama Power Credit Facility are payable in three equal annual installments, beginning on December 10, 2053. Principal payments for the Georgia Power Credit Facility are payable in seven equal annual installments, beginning on December 10, 2049.
Under each of the Loan Guarantee Agreements, the DOE agreed to provide guarantees with respect to the obligations of Alabama Power and Georgia Power under the Alabama Power FFB Credit Facility Documents and Georgia Power FFB Credit Facility Documents, respectively. Under their respective Loan Guarantee Agreements, Alabama Power and Georgia Power are obligated to reimburse the DOE for any amounts the DOE is required to pay with respect to such guarantees. Alabama Power's and Georgia Power's reimbursement obligations to the DOE are full recourse, senior unsecured obligations of the respective Borrower.
Under each Loan Guarantee Agreement, the applicable Borrower is subject to customary affirmative and negative covenants and events of default. In addition, Alabama Power and Georgia Power are subject to project-related reporting requirements and other project-specific covenants and events of default.
Under each Loan Guarantee Agreement, the applicable Borrower will be required to prepay certain amounts outstanding under the applicable Credit Facility if (i) the applicable Borrower takes any action that causes an Eligible Project to cease to be an Eligible Project, (ii) certain "termination events" (as defined in the applicable Loan Guarantee Agreement) occur with respect to any Eligible Project of the applicable Borrower, (iii) eligible project costs recoverable in customer rates of the applicable Borrower are less than 95% of total advances made to the applicable Borrower under the applicable Credit Facility, with such amount tested on the third anniversary of the termination of the applicable availability period, or (iv) the applicable Borrower receives advances for certain preliminary costs and fails to satisfy the DOE Program Requirements. Any mandatory prepayment will be made in quarterly installments and, depending on the size of the required mandatory prepayment, will be payable over a period of one to three years (in the case of Alabama Power) or one to five years (in the case of Georgia Power). Any such mandatory prepayment will be at a prepayment price equal to 100% of the principal amount to be prepaid, plus accrued and unpaid interest to the date of prepayment.
In addition, if a "change of control" (as defined in the applicable Loan Guarantee Agreement) occurs with respect to the applicable Borrower, such Borrower will be required to offer to prepay all outstanding advances under its Credit Facility. Any such prepayment will be made with a make-whole premium or discount, as applicable.
Each Borrower will be permitted to voluntarily prepay all or a portion of any outstanding advances. Any such prepayment will be made with a make-whole premium or discount, as applicable.
Equity Distribution Agreement
See Note 8 to the financial statements under "Equity Distribution Agreement" in Item 8 of the Form 10-K for additional information.
In June 2026, Southern Company established a new at-the-market program and entered 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 initially priced forward sale contracts and collared forward sale contracts (2026 ATM Program). In connection with the establishment of the 2026 ATM Program, Southern Company terminated further sales under its prior at-the-market program established in 2024 (2024 ATM Program).
The table below reflects shares of Southern Company common stock sold and settled under separate initially priced forward sale contracts with forward purchasers during the six months ended June 30, 2026.
Shares Sold
Initial Forward Price per Share
To be Settled On or Before
Forward Price Per Share SettledShares Issued to SettleSettlement Date
Sold during 2025 (2024 ATM Program)
3,255,866$89.4692December 31, 2026$89.24433,255,866March 2, 2026
2,314,487$92.7805June 30, 2027$92.87232,314,487March 2, 2026
3,850,000$90.6617December 31, 2026$90.23623,850,000June 1, 2026
2,470,306$94.5394June 30, 2027$93.89132,470,306June 1, 2026
1,590,200$93.4524June 30, 2027$93.40381,590,200June 1, 2026
4,000,000$90.8141June 30, 2027$90.63584,000,000June 12, 2026
2,876,034$92.2437June 30, 2027$91.96642,876,034June 12, 2026
3,015,668$93.4521June 30, 2027$93.12903,015,668June 12, 2026
    3,130,641(a)
$88.2823December 31, 2026$88.06201,070,641June 16, 2026
2,346,903$91.1610June 30, 2027$90.94252,346,903June 16, 2026
911,448$94.2411June 30, 2027$93.9331911,448June 16, 2026
Sold during 2026 (2024 ATM Program)
1,467,305$96.3883March 31, 2028N/AN/AN/A
1,896,549$97.5815March 31, 2028N/AN/AN/A
1,903,317$95.5086March 31, 2028N/AN/AN/A
Sold during 2026 (2026 ATM Program)
1,713,535$93.2987June 30, 2028N/AN/AN/A
1,909,112$92.4821June 30, 2028N/AN/AN/A
1,994,083$95.1457June 30, 2028N/AN/AN/A
    600,094(b)
$95.9974June 30, 2028N/AN/AN/A
(a)The total number of shares sold under this forward sale contract is 3,130,641, of which 1,070,641 shares were settled during the six months ended June 30, 2026. The other 2,060,000 shares were settled in December 2025.
(b)The total number of shares sold under this forward sale contract is 1,940,548, of which the remaining 1,340,454 shares were sold subsequent to June 30, 2026. The initial forward price was determined after the completion of sales by the forward seller in July 2026.
As of June 30, 2026, Southern Company had entered into separate forward sale contracts with forward purchasers for a total of 49,885,779 shares of common stock under the 2024 ATM Program, all of which had been sold by the forward sellers, and 7,557,278 shares of common stock under the 2026 ATM Program, of which 6,216,824 shares had been sold by the forward sellers. Of these shares, 27,701,553 were settled during the six months ended June 30, 2026, all under the 2024 ATM Program, in the form of shares at the initial forward price adjusted for interest earned and dividends paid from the forward sale date to the settlement date. The net proceeds from the shares settled during the six months ended June 30, 2026 were approximately $2.5 billion.
As of June 30, 2026, the total number of shares sold remaining under the forward sale contracts subject to settlement at a future date is 11,483,995. Each initial forward price is subject to adjustment under certain circumstances as specified in the respective forward sales contracts. Southern Company may settle each of the forward transactions in shares, cash, or net shares.
Earnings per Share
For Southern Company, the difference in computing basic and diluted EPS is attributable to awards outstanding under stock-based compensation plans, forward sale contracts pursuant to the equity distribution agreement, convertible senior notes, and equity units. EPS dilution resulting from stock-based compensation plans, forward sale contracts, and the equity units is determined using the treasury stock method. EPS dilution resulting from the convertible senior notes is determined using the net share settlement method. See "Equity Distribution Agreement"
herein and Note 8 to the financial statements under "Convertible Senior Notes," "Equity Distribution Agreement," and "Equity Units" and Note 12 to the financial statements in Item 8 of the Form 10-K for additional information. Shares used to compute diluted EPS were as follows:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025

(in millions)
As reported shares1,137 1,101 1,130 1,100 
Effect of stock-based compensation3 6 3 6 
Effect of convertible senior notes
— 1 — 1 
Effect of forward sale contracts1 — 1 — 
Diluted shares1,141 1,108 1,134 1,107 
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.
Georgia Power Lease Modification
See Note 9 to the financial statements in Item 8 of the Form 10-K for information on Georgia Power's leases. In June 2026, Georgia Power recognized a lease modification related to an existing affiliate PPA with Southern Power which converted from an operating lease to a finance lease upon its approval by the FERC. As a result, Georgia Power removed from its balance sheet operating lease right-of-use assets, net of amortization of $179 million and lease obligations of $197 million maturing through 2030 and recorded finance lease right-of-use assets of $1.3 billion and lease obligations of $1.3 billion maturing through 2045. See Note (B) under "Georgia Power – Integrated Resource Plans – Certification Requests" for additional information.
v3.26.1
Income Taxes
 6 Months Ended
Jun. 30, 2026
Income Tax Disclosure [Abstract]  
Income Taxes INCOME TAXES
See Note 10 to the financial statements in Item 8 of the Form 10-K for additional tax information.
Cash Paid for Income Taxes
Alabama Power, Georgia Power, and Southern Power have 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. The discount is recorded as a reduction in tax credits recognized in the financial statements and does not have a material impact on results of operations. During the first six months of 2026, Alabama Power, Georgia Power, and Southern Power received cash of $39 million, $91 million, and $49 million, respectively, from credits transferred. The Southern Company system continues to explore the ability to efficiently monetize its tax credits through third-party transfer agreements.
During the first six months of 2026, pursuant to certain joint ownership agreements, Georgia Power paid $83 million to the other Vogtle Owners for advanced nuclear PTCs for Plant Vogtle Units 3 and 4. The gain was recognized as an income tax benefit and was 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.
Details of significant changes in the effective tax rate for the applicable Registrants are provided herein.
Southern Company
Southern Company's effective tax rate was 14.1% for the six months ended June 30, 2026 compared to 21.1% for the corresponding period in 2025. The effective tax rate decrease was primarily due to a decrease in charges to a
valuation allowance on certain state tax credit carryforwards at Georgia Power, an increase in federal PTCs at Southern Power, and an increase in amortization of federal PTCs at Georgia Power, partially offset by a decrease in the flowback of excess state deferred income taxes at Georgia Power.
Georgia Power
Georgia Power's effective tax rate was 14.3% for the six months ended June 30, 2026 compared to 21.7% for the corresponding period in 2025. The effective tax rate decrease was primarily due to a decrease in charges to a valuation allowance on certain state tax credit carryforwards and an increase in amortization of federal PTCs and ITCs, partially offset by a decrease in the flowback of excess state deferred income taxes.
Southern Power
Southern Power's effective tax benefit rate was (85.1)% for the six months ended June 30, 2026 compared to (7.0)% for the corresponding period in 2025. The effective tax benefit rate increase was primarily due to an increase in federal PTCs resulting from Southern Power's purchase of the noncontrolling membership interests in the SP Wind tax equity partnership, as well as a change in pre-tax earnings attributable to Southern Power, including the impact of accelerated depreciation related to wind repowering projects. See Note (K) under "Southern Power – Wind Repowering Projects" and Notes 5 and 15 to the financial statements under "Depreciation and Amortization – Southern Power" and "Southern Power – Purchase of Renewable Facility Interests," respectively, in Item 8 of the Form 10-K for additional information.
Southern Company Gas
Southern Company Gas' effective tax rate was 23.5% for the six months ended June 30, 2026 compared to 23.7% for the corresponding period in 2025. The effective tax rate decrease was primarily due to an increase in tax benefits related to certain state tax filing positions, offset by a decrease in the flowback of excess state deferred income taxes.
v3.26.1
Retirement Benefits
 6 Months Ended
Jun. 30, 2026
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 employees at PowerSecure. The qualified pension plan is funded in accordance with requirements of the Employee Retirement Income Security Act of 1974, as amended. No mandatory contributions to the qualified pension plan are anticipated for the year ending December 31, 2026. 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.
See Note 11 to the financial statements in Item 8 of the Form 10-K for additional information.
On each Registrant's condensed statements of income, the service cost component of net periodic benefit costs is included in other operations and maintenance expenses and all other components of net periodic benefit costs are included in other income (expense), net. Components of the net periodic benefit costs for the three and six months ended June 30, 2026 and 2025 are presented in the following tables.
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Three Months Ended June 30, 2026
Pension Plans
Service cost$69 $16 $16 $3 $1 $7 
Interest cost161 37 47 8 3 11 
Expected return on plan assets(322)(78)(100)(14)(4)(22)
Amortization:
Prior service costs— — 1 — — (1)
Net (gain) loss19 5 7 — (1)1 
Net periodic pension income$(73)$(20)$(29)$(3)$(1)$(4)
Postretirement Benefits
Service cost$3 $1 $1 $— $— $— 
Interest cost16 4 6 — — 2 
Expected return on plan assets(22)(8)(8)1 — (2)
Amortization:
Net gain(2)(1)— — — (2)
Net periodic postretirement benefit cost (income)$(5)$(4)$(1)$1 $— $(2)
Six Months Ended June 30, 2026
Pension Plans
Service cost$138 $31 $33 $6 $3 $14 
Interest cost323 75 94 15 5 22 
Expected return on plan assets(644)(157)(199)(29)(8)(43)
Amortization:
Prior service costs— — 1 — — (1)
Regulatory asset— — — — — 3 
Net (gain) loss37 10 13 1 (1)1 
Net periodic pension income$(146)$(41)$(58)$(7)$(1)$(4)
Postretirement Benefits
Service cost$6 $2 $2 $— $— $— 
Interest cost32 8 12 1 — 3 
Expected return on plan assets(45)(17)(16)— — (4)
Amortization:
Prior service costs1 — — — — — 
Net gain(4)(1)— — — (4)
Net periodic postretirement benefit cost (income)$(10)$(8)$(2)$1 $— $(5)
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Three Months Ended June 30, 2025
Pension Plans
Service cost$66 $15 $15 $2 $2 $7 
Interest cost166 38 49 8 3 11 
Expected return on plan assets(320)(78)(99)(14)(4)(22)
Amortization:
Prior service costs— — 1 — — (1)
Regulatory asset— — — — — 4 
Net (gain) loss10 4 3 — (2)— 
Net periodic pension income$(78)$(21)$(31)$(4)$(1)$(1)
Postretirement Benefits
Service cost$3 $1 $1 $— $— $— 
Interest cost18 4 7 — — 2 
Expected return on plan assets(22)(9)(8)— — (2)
Amortization:
Regulatory asset— — — — — 2 
Net (gain) loss(4)— (2)1 — (2)
Net periodic postretirement benefit cost (income)$(5)$(4)$(2)$1 $— $— 
Six Months Ended June 30, 2025
Pension Plans
Service cost$132 $30 $31 $5 $3 $13 
Interest cost332 77 98 15 5 22 
Expected return on plan assets(640)(156)(198)(29)(8)(43)
Amortization:
Prior service costs— — 1 — — (1)
Regulatory asset— — — — — 8 
Net (gain) loss19 6 7 1 (1)— 
Net periodic pension income$(157)$(43)$(61)$(8)$(1)$(1)
Postretirement Benefits
Service cost$6 $2 $2 $— $— $— 
Interest cost35 8 13 1 — 4 
Expected return on plan assets(45)(18)(16)— — (4)
Amortization:
Prior service costs1 — — — — — 
Regulatory asset— — — — — 3 
Net gain(7)— (2)— — (4)
Net periodic postretirement benefit cost (income)$(10)$(8)$(3)$1 $— $(1)
v3.26.1
Fair Value Measurements
 6 Months Ended
Jun. 30, 2026
Fair Value Disclosures [Abstract]  
Fair Value Measurements FAIR VALUE MEASUREMENTS
At June 30, 2026, 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
At June 30, 2026Quoted Prices
in Active
Markets for
Identical
Assets
(Level 1)		Significant
Other
Observable
Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Net Asset
Value as a
Practical
Expedient
(NAV)		Total
(in millions)
Southern Company
Assets:
Energy-related derivatives(a)
$8 $61 $— $— $69 
Interest rate derivatives— 5 — — 5 
Investments in trusts:(b)
Domestic equity1,030 293 — — 1,323 
Foreign equity199 256 — — 455 
U.S. Treasury and government agency securities— 410 — — 410 
Municipal bonds— 31 — — 31 
Pooled funds – fixed income— 4 — — 4 
Corporate bonds— 533 — — 533 
Mortgage- and asset-backed securities — 110 — — 110 
Private equity— — — 202 202 
Cash and cash equivalents1 — — — 1 
Other33 4 — 9 46 
Investments, available-for-sale:
U.S. Treasury and government agency securities1 12 — — 13 
Municipal bonds— 2 — — 2 
Corporate bonds— 4 — — 4 
Mortgage- and asset-backed securities— 3 — — 3 
Cash equivalents1,768 18 — — 1,786 
Other investments10 35 8 — 53 
Other— — 10 — 10 
Total$3,050 $1,781 $18 $211 $5,060 
Liabilities:
Energy-related derivatives(a)
$11 $155 $— $— $166 
Interest rate derivatives— 205 — — 205 
Foreign currency derivatives— 63 — — 63 
Contingent consideration— — 12 — 12 
Other— 13 11 — 24 
Total$11 $436 $23 $— $470 
Fair Value Measurements Using
At June 30, 2026Quoted Prices
in Active
Markets for
Identical
Assets
(Level 1)		Significant
Other
Observable
Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Net Asset
Value as a
Practical
Expedient
(NAV)		Total
(in millions)
Alabama Power
Assets:
Energy-related derivatives$— $27 $— $— $27 
Nuclear decommissioning trusts:(b)
Domestic equity569 282 — — 851 
Foreign equity199 — — — 199 
U.S. Treasury and government agency securities— 16 — — 16 
Municipal bonds— 1 — — 1 
Corporate bonds— 319 — — 319 
Mortgage- and asset-backed securities— 28 — — 28 
Private equity— — — 202 202 
Other14 2 — 9 25 
Cash equivalents40 18 — — 58 
Other investments— 35 — — 35 
Total$822 $728 $— $211 $1,761 
Liabilities:
Energy-related derivatives$— $58 $— $— $58 
Georgia Power
Assets:
Energy-related derivatives$— $14 $— $— $14 
Nuclear decommissioning trusts:(b)
Domestic equity461 1 — — 462 
Foreign equity— 254 — — 254 
U.S. Treasury and government agency securities— 394 — — 394 
Municipal bonds— 30 — — 30 
Corporate bonds— 214 — — 214 
Mortgage- and asset-backed securities— 82 — — 82 
Other19 2 — — 21 
Cash equivalents11 — — — 11 
Total$491 $991 $— $— $1,482 
Liabilities:
Energy-related derivatives$— $48 $— $— $48 
Fair Value Measurements Using
At June 30, 2026Quoted Prices
in Active
Markets for
Identical
Assets
(Level 1)		Significant
Other
Observable
Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Net Asset
Value as a
Practical
Expedient
(NAV)		Total
(in millions)
Mississippi Power
Assets:
Energy-related derivatives$— $14 $— $— $14 
Cash equivalents1 — — — 1 
Total$1 $14 $— $— $15 
Liabilities:
Energy-related derivatives$— $40 $— $— $40 
Southern Power
Assets:
Energy-related derivatives$— $3 $— $— $3 
Cash equivalents162 — — — 162 
Other— — 10 — 10 
Total$162 $3 $10 $— $175 
Liabilities:
Energy-related derivatives$— $4 $— $— $4 
Contingent consideration— — 12 — 12 
Other— 13 11 — 24 
Total$— $17 $23 $— $40 
Southern Company Gas
Assets:
Energy-related derivatives(a)
$8 $3 $— $— $11 
Non-qualified deferred compensation trusts:
Domestic equity— 10 — — 10 
Foreign equity— 2 — — 2 
Pooled funds – fixed income— 4 — — 4 
Cash and cash equivalents1 — — — 1 
Cash equivalents200 — — — 200 
Total$209 $19 $— $— $228 
Liabilities:
Energy-related derivatives(a)
$11 $5 $— $— $16 
Interest rate derivatives— 62 — — 62 
Total$11 $67 $— $— $78 
(a)Excludes cash collateral of $18 million.
(b)Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 to the financial statements under "Nuclear Decommissioning" in Item 8 of the Form 10-K for additional information.
Southern Company, Alabama Power, and Georgia Power continue to elect the option to fair value investment securities held in the nuclear decommissioning trust funds. The fair value of the funds, including reinvested interest and dividends and excluding the funds' expenses, increased (decreased) by the amounts shown in the table below for
the three and six months ended June 30, 2026 and 2025. The changes were recorded as a change to the regulatory assets and liabilities related to AROs for Georgia Power and Alabama Power, respectively.
Three Months Ended June 30,Six Months Ended June 30,
Fair value increases (decreases)2026202520262025
(in millions)
Southern Company $249 $165 $205 $159 
Alabama Power 156 99 126 86 
Georgia Power93 66 79 73 
Valuation Methodologies
The energy-related derivatives primarily consist of exchange-traded and over-the-counter 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 over-the-counter 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 (J) 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 to the financial statements under "Nuclear Decommissioning" in Item 8 of the Form 10-K for additional information.
Southern Company's investments, available for sale relate to a wholly-owned subsidiary that insures various risk exposures of Southern Company 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.
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.
At June 30, 2026, 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 $211 million and unfunded commitments related to the private market investments totaled $94 million. Private market investments include high-quality private equity funds across several market sectors, funds that invest in real estate assets, and private credit funds. Private market funds do not have redemption rights. Distributions from these funds will be received as the underlying investments in the funds are liquidated.
At June 30, 2026, other financial instruments for which the carrying amount did not equal fair value were as follows:
Southern
   Company(*)
Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power
Southern
Company
   Gas(*)
(in billions)
Long-term debt, including securities due within one year:
Carrying amount$72.7 $12.0 $22.3 $1.8 $3.0 $9.3 
Fair value68.0 10.7 20.7 1.7 2.9 8.4 
(*)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.
v3.26.1
Derivatives
 6 Months Ended
Jun. 30, 2026
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 (I) 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 to the financial statements under "Financial Instruments" in Item 8 of the Form 10-K 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 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 accumulated OCI 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 June 30, 2026, 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(*)
46920302029
Alabama Power15520292026
Georgia Power11720282026
Mississippi Power11420302026
Southern Power820302026
Southern Company Gas(*)
7520282029
(*)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 85 million mmBtu long natural gas positions and 10 million mmBtu short natural gas positions at June 30, 2026, 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 accumulated OCI to earnings for the 12-month period ending June 30, 2027 are immaterial for Southern Company, Alabama Power, Mississippi Power, 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 June 30, 2026, the following interest rate derivatives were outstanding:
Notional
Amount		Weighted
Average Interest
Rate Paid		Interest
Rate
Received		Hedge
Maturity
Date
Fair Value
Gain (Loss) at
June 30, 2026
 (in millions)   (in millions)
Fair Value Hedges of Existing Debt
Southern Company parent$400 
1-day SOFR + 0.80%
1.75%March 2028$(23)
Southern Company parent1,000 
1-day SOFR + 2.48%
3.70%April 2030(103)
Southern Company parent565 
1-day SOFR + 1.56%
6.50%March 2045(12)
Southern Company Gas500 
1-day SOFR + 0.49%
1.75%January 2031(62)
Southern Company$2,465 $(200)
For cash flow hedges of interest rate derivatives, the estimated pre-tax gains (losses) expected to be reclassified from accumulated OCI to interest expense for the 12-month period ending June 30, 2027 are immaterial for Southern Company, 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 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 June 30, 2026, the following foreign currency derivatives were outstanding:
Pay
Notional		Pay
Rate		Receive
Notional		Receive
Rate		Hedge
Maturity Date
Fair Value
Gain (Loss) at
June 30, 2026
(in millions)(in millions)(in millions)
Fair Value Hedges of Existing Debt
Southern Company parent$1,476 3.39%€1,250 1.88%September 2027$(63)
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. 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:
At June 30, 2026At December 31, 2025
Derivative Category and Balance Sheet LocationAssetsLiabilitiesAssetsLiabilities
(in millions)
Southern Company
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$28 $89 $24 $64 
Non-current
30 60 31 35 
Total derivatives designated as hedging instruments for regulatory purposes58 149 55 99 
Derivatives designated as hedging instruments in cash flow and fair value hedges
Energy-related derivatives:
Current3 12 1 6 
Non-current2 1 2 1 
Interest rate derivatives:
Current5 52 8 48 
Non-current— 153 — 139 
Foreign currency derivatives:
Current— 23 17 22 
Non-current— 40 4 — 
Total derivatives designated as hedging instruments in cash flow and fair value hedges10 281 32 216 
Energy-related derivatives not designated as hedging instruments
Current6 4 6 6 
Gross amounts recognized74 434 93 321 
Gross amounts offset(a)
(39)(57)(21)(54)
Net amounts recognized in the Balance Sheets(b)
$35 $377 $72 $267 
Alabama Power
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current$15 $31 $9 $18 
Non-current12 25 10 13 
Total derivatives designated as hedging instruments for regulatory purposes27 56 19 31 
Derivatives designated as hedging instruments in cash flow and fair value hedges
Energy-related derivatives:
Current— 2 — — 
Gross amounts recognized27 58 19 31 
Gross amounts offset(16)(16)(13)(13)
Net amounts recognized in the Balance Sheets$11 $42 $6 $18 
At June 30, 2026At December 31, 2025
Derivative Category and Balance Sheet LocationAssetsLiabilitiesAssetsLiabilities
(in millions)
Georgia Power
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current$5 $32 $7 $23 
Non-current7 16 10 10 
Total derivatives designated as hedging instruments for regulatory purposes12 48 17 33 
Energy-related derivatives not designated as hedging instruments
Current
2 — 1 — 
Gross amounts recognized14 48 18 33 
Gross amounts offset(11)(11)(14)(14)
Net amounts recognized in the Balance Sheets$3 $37 $4 $19 
Mississippi Power
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current$3 $21 $3 $15 
Non-current11 19 11 12 
Total derivatives designated as hedging instruments for regulatory purposes14 40 14 27 
Gross amounts offset(13)(13)(13)(13)
Net amounts recognized in the Balance Sheets$1 $27 $1 $14 
Southern Power
Derivatives designated as hedging instruments in cash flow hedges
Energy-related derivatives:
Current$1 $2 $1 $1 
Non-current2 1 2 — 
Foreign currency derivatives:
Current— — 17 — 
Total derivatives designated as hedging instruments in cash flow hedges
3 3 20 1 
Energy-related derivatives not designated as hedging instruments
Current
— 1 1 — 
Gross amounts recognized3 4 21 1 
Gross amounts offset(1)(1)— — 
Net amounts recognized in the Balance Sheets$2 $3 $21 $1 
At June 30, 2026At December 31, 2025
Derivative Category and Balance Sheet LocationAssetsLiabilitiesAssetsLiabilities
(in millions)
Southern Company Gas
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$5 $5 $5 $8 
Derivatives designated as hedging instruments in cash flow and fair value hedges
Energy-related derivatives:
Current2 8 — 5 
Non-current— — — 1 
Interest rate derivatives:
Current— 13 — 13 
Non-current— 49 — 46 
Total derivatives designated as hedging instruments in cash flow and fair value hedges2 70 — 65 
Energy-related derivatives not designated as hedging instruments
Current4 3 4 6 
Gross amounts recognized11 78 9 79 
Gross amounts offset(a)
6 (12)19 (14)
Net amounts recognized in the Balance Sheets(b)
$17 $66 $28 $65 
(a)Gross amounts offset includes cash collateral held on deposit in broker margin accounts of $18 million and $33 million at June 30, 2026 and December 31, 2025, respectively.
(b)Net amounts of derivative instruments outstanding exclude immaterial premium and intrinsic value associated with weather derivatives at June 30, 2026 and December 31, 2025.
At June 30, 2026 and December 31, 2025, the pre-tax effects of unrealized derivative gains (losses) arising from energy-related derivative instruments designated as regulatory hedging instruments and deferred were as follows:
Regulatory Hedge Unrealized Gain (Loss) Recognized in the Balance Sheets
Derivative Category and
Balance Sheet Location		Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern Company Gas
 (in millions)
At June 30, 2026:
Energy-related derivatives:
Other regulatory assets, current$(75)$(26)$(27)$(18)$(4)
Other regulatory assets, deferred(31)(13)(10)(8)— 
Other regulatory liabilities, current15 10 — — 5 
Total energy-related derivative gains (losses)$(91)$(29)$(37)$(26)$1 
At December 31, 2025:
Energy-related derivatives:
Other regulatory assets, current$(48)$(13)$(17)$(12)$(6)
Other regulatory assets, deferred(8)(5)(1)(2)— 
Other regulatory liabilities, current7 4 1 — 2 
Other regulatory liabilities, deferred4 2 1 1 — 
Total energy-related derivative gains (losses)$(45)$(12)$(16)$(13)$(4)
For the three and six months ended June 30, 2026 and 2025, the pre-tax effects of cash flow and fair value hedge accounting on accumulated OCI for the applicable Registrants were as follows:
Gain (Loss) From Derivatives Recognized in OCIThree Months Ended June 30,Six Months Ended June 30,
2026202520262025
(in millions)
Southern Company
Cash flow hedges:
Energy-related derivatives$(8)$(13)$1 $6 
Interest rate derivatives— 9 — 5 
Foreign currency derivatives(7)47 (19)67 
Fair value hedges(*):
Foreign currency derivatives— 3 (1)(13)
Total$(15)$46 $(19)$65 
Alabama Power
Cash flow hedges:
Energy-related derivatives$(2)$— $(2)$— 
Georgia Power
Cash flow hedges:
Interest rate derivatives$— $5 $— $3 
Southern Power
Cash flow hedges:
Energy-related derivatives$(2)$(1)$— $2 
Foreign currency derivatives(7)47 (19)67 
Total$(9)$46 $(19)$69 
Southern Company Gas
Cash flow hedges:
Energy-related derivatives$(4)$(12)$3 $4 
Interest rate derivatives— 4 — 4 
Total$(4)$(8)$3 $8 
(*)Represents amounts excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI.
For the three and six months ended June 30, 2026 and 2025, the pre-tax effects of cash flow and fair value hedge accounting on income were as follows:
Gain (Loss)
Statements of Income Location
Derivative Category
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
(in millions)
Southern Company
Fuel
Energy-related cash flow hedges
$(1)$— $2 $1 
Cost of natural gas
Energy-related cash flow hedges
(3)1 7 — 
Interest expense, net of amounts capitalized
Interest rate cash flow hedges
(2)(3)(5)(6)
Foreign currency cash flow hedges
(2)(2)(5)(5)
Interest rate fair value hedges
(41)29 (21)69 
Other income (expense), net
Foreign currency cash flow hedges
(2)45 (14)67 
Foreign currency fair value hedges
(13)115 (45)155 
Amount excluded from effectiveness testing recognized in earnings— (3)1 13 
Southern Power
Fuel
Energy-related cash flow hedges
$(1)$— $2 $1 
Interest expense, net of amounts capitalized
Foreign currency cash flow hedges
(2)(2)(5)(5)
Other income (expense), net
Foreign currency cash flow hedges
(2)45 (14)67 
Southern Company Gas
Cost of natural gas
Energy-related cash flow hedges
$(3)$1 $7 $— 
Interest expense, net of amounts capitalized
Interest rate fair value hedges
(32)3 (3)21 
At June 30, 2026 and December 31, 2025, the following amounts were recorded on the balance sheets related to cumulative basis adjustments for fair value hedges:
Carrying Amount of the Hedged
Item		Cumulative Amount of Fair Value
Hedging Adjustment included in
Carrying Amount of the Hedged
Item
Balance Sheet Location of Hedged ItemsAt June 30, 2026At December 31, 2025At June 30, 2026At December 31, 2025
(in millions)
Southern Company
Long-term debt$(3,687)$(3,742)$169 $156 
Southern Company Gas
Long-term debt$(442)$(446)$56 $51 
Pre-tax gains (losses) on energy-related derivatives not designated as hedging instruments were $7 million and $(14) million for the three months ended June 30, 2026 and 2025, respectively, and $2 million and $(6) million for the six months ended June 30, 2026 and 2025, respectively, and reflected in cost of natural gas on the statements of income of Southern Company and Southern Company Gas.
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 June 30, 2026, 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 $31 million at June 30, 2026. 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 June 30, 2026. 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 June 30, 2026, 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, which are netted with energy-related derivatives recognized in the balance sheets.
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.
The Registrants do not anticipate a material adverse effect on their respective financial statements as a result of counterparty nonperformance.
v3.26.1
Acquisitions and Dispositions
 6 Months Ended
Jun. 30, 2026
Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract]  
Acquisitions and Dispositions ACQUISITIONS AND DISPOSITIONS
See Note 15 to the financial statements in Item 8 of the Form 10-K for additional information.
Southern Power
Construction Projects
During the six months ended June 30, 2026, Southern Power completed construction of and placed in service the 200-MW first phase and continued construction of the 180-MW second phase and 132-MW third phase of the Millers Branch solar facility. At June 30, 2026, the total cost of construction incurred for the Millers Branch project
was $718 million, of which $408 million remains in CWIP. The ultimate outcome of these matters cannot be determined at this time.
Project
Facility		Resource
Approximate
Nameplate Capacity
(MW)
LocationActual/Projected
COD		PPA
Contract
Period
Projects Under Construction at June 30, 2026
Millers Branch
Phase IISolar180Haskell County, TXThird quarter 202615 years
Phase III
Solar
132Haskell County, TX
Fourth quarter 2026
15 years
Projects Completed During the Six Months Ended June 30, 2026
Millers Branch
Phase I
Solar200Haskell County, TXFebruary 202620 years
Wind Repowering Projects
During the six months ended June 30, 2026, Southern Power continued the development projects to repower the Kay, Grant, Grant Plains, Wake, and Bethel wind facilities. At June 30, 2026, the total cost of construction incurred related to the projects was $598 million, of which $409 million remains in CWIP. The repowered output of the facilities is contracted under new and amended PPAs. The ultimate outcome of these matters cannot be determined at this time.
Project FacilityResource
Approximate Nameplate
Capacity
(MW)
LocationActual/Projected
Completion Date
Projects Under Construction at June 30, 2026
Kay(a)
Wind
200
Kay County, OK
   July 2026(b)
Grant
Wind
152
Grant County, OK
Fourth quarter 2026
Grant Plains
Wind
147
Grant County, OK
Fourth quarter 2026
Wake
Wind
257
Crosby & Floyd Counties, TX
Second quarter 2027
BethelWind276Castro County, TXThird quarter 2027
(a)The facility has a total capacity of 299 MWs, of which 200 MWs was projected to be repowered and is contracted under a PPA.
(b)During the first six months of 2026 and subsequent to June 30, 2026, Southern Power placed all 200 MWs of repowered capacity in service.
Natural Gas Turbine Upgrade Projects
In the first quarter 2026, Southern Power committed to projects to upgrade certain turbines at its existing Franklin and Wansley natural gas facilities, located in Lee County, Alabama and Heard County, Georgia, respectively. The upgrades are projected to add up to 400 MWs of incremental capacity, with commercial operations projected to begin between the second quarter 2029 and the fourth quarter 2030. At June 30, 2026, the total cost of construction incurred related to the projects was $82 million, which is included in CWIP. The ultimate outcome of these matters cannot be determined at this time.
v3.26.1
Segment and Related Information
 6 Months Ended
Jun. 30, 2026
Segment Reporting [Abstract]  
Segment and Related Information SEGMENT AND RELATED INFORMATION
See Note 16 to the financial statements in Item 8 of the Form 10-K for additional information.
Southern Company
The primary businesses of the Southern Company system are electricity sales by the traditional electric operating companies and Southern Power and the distribution of natural gas by Southern Company Gas. The traditional electric operating companies are vertically integrated utilities providing electric service in three Southeastern states. Southern Power develops, constructs, acquires, owns, operates, and manages power generation assets, including battery energy storage projects, and sells electricity at market-based rates in the wholesale market. Southern Company Gas distributes natural gas through its natural gas distribution utilities and is involved in several other complementary businesses including gas pipeline investments and gas marketing services.
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 distribution 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. The "All Other" presentation includes the Southern Company parent entity, which does not allocate operating expenses to business segments, and operating segments below the quantitative threshold for separate disclosure. These operating segments include providing distributed energy and resilience solutions and deploying microgrids for commercial, industrial, governmental, and utility customers, as well as investments in telecommunications. Revenues from sales by Southern Power to the traditional electric operating companies were $92 million and $192 million for the three and six months ended June 30, 2026, respectively, and $114 million and $229 million for the three and six months ended June 30, 2025, respectively. All other inter-segment revenues were immaterial for all periods presented.
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 for the three and six months ended June 30, 2026 and 2025 was as follows:
Electric Utilities
Traditional
Electric Operating
Companies		Southern
Power		EliminationsTotalSouthern Company Gas
Total Reportable Segments
All
Other		EliminationsConsolidated
(in millions)
Three Months Ended June 30, 2026
Operating revenues$5,396 $535 $(105)$5,826 $966 $6,792 $223 $(38)$6,977 
Other segment items(a)
2,501 329 (78)2,752 554 3,306 193 (27)3,472 
Depreciation and amortization(b)
967 280 (15)1,232 185 1,417 17 — 1,434 
Earnings from equity method investments12 — — 12 32 44 42 — 86 
Interest expense
367 28 (12)383 101 484 312 — 796 
Income taxes (benefit)304 (77)— 227 32 259 (72)— 187 
Segment net income (loss)(b)(c)
$1,269 $(25)$— $1,244 $126 $1,370 $(185)$(11)$1,174 
Six Months Ended June 30, 2026
Operating revenues$10,878 $1,216 $(246)$11,848 $3,157 $15,005 $441 $(72)$15,374 
Other segment items(a)
5,360 772 (219)5,913 1,911 7,824 382 (68)8,138 
Depreciation and amortization(b)
1,908 558 (15)2,451 369 2,820 34 — 2,854 
Earnings from equity method investments11 — — 11 78 89 47 — 136 
Interest expense(d)
705 55 (12)748 206 954 619 — 1,573 
Income taxes (benefit)534 (147)— 387 176 563 (149)— 414 
Segment net income (loss)(b)(c)(d)
$2,382 $(22)$— $2,360 $573 $2,933 $(398)$(4)$2,531 
At June 30, 2026
Goodwill$— $2 $— $2 $5,015 $5,017 $144 $— $5,161 
Total assets120,194 12,780 (2,101)130,873 27,604 158,477 4,283 (733)162,027 
Electric Utilities
Traditional
Electric Operating
Companies		Southern
Power		EliminationsTotalSouthern Company Gas
Total Reportable Segments
All
Other		EliminationsConsolidated
(in millions)
Three Months Ended June 30, 2025
Operating revenues$5,380 $546 $(122)$5,804 $979 $6,783 $225 $(35)$6,973 
Other segment items(a)
2,674 296 (122)2,848 599 3,447 193 (23)3,617 
Depreciation and amortization(b)
957 177 — 1,134 172 1,306 17 — 1,323 
Earnings from equity method investments4 — — 4 23 27 (17)— 10 
Interest expense(d)
336 24 — 360 92 452 422 — 874 
Income taxes (benefit)370 (2)— 368 33 401 (112)— 289 
Segment net income (loss)(b)(c)(d)
$1,047 $51 $— $1,098 $106 $1,204 $(312)$(12)$880 
Six Months Ended June 30, 2025
Operating revenues$10,692 $1,113 $(245)$11,560 $2,818 $14,378 $454 $(84)$14,748 
Other segment items(a)
5,468 599 (245)5,822 1,670 7,492 401 (81)7,812 
Depreciation and amortization(b)
1,905 329 — 2,234 341 2,575 33 — 2,608 
Earnings from equity method investments2 — — 2 62 64 (21)— 43 
Interest expense(d)
652 50 — 702 183 885 703 — 1,588 
Income taxes (benefit)596 (3)— 593 162 755 (186)— 569 
Segment net income (loss)(b)(c)(d)
$2,073 $138 $— $2,211 $524 $2,735 $(518)$(3)$2,214 
At December 31, 2025
Goodwill$— $2 $— $2 $5,015 $5,017 $144 $— $5,161 
Total assets114,287 12,657 (915)126,029 27,387 153,416 2,829 (525)155,720 
(a)Primarily consists of fuel, purchased power, cost of natural gas, cost of other sales, other operations and maintenance expenses, taxes other than income taxes, AFUDC equity, non-service cost-related retirement benefits income, and net income (loss) attributable to noncontrolling interests.
(b)For Southern Power, includes accelerated depreciation related to the repowering of multiple wind facilities of $140 million ($109 million after tax) and $293 million ($228 million after tax) for the three and six months ended June 30, 2026, respectively, and $42 million ($31 million after tax, net of noncontrolling interest impacts) and $69 million ($51 million after tax, net of noncontrolling interest impacts) for the three and six months ended June 30, 2025. See Note (K) under "Southern Power – Wind Repowering Projects" and Notes 5 and 15 to the financial statements under "Depreciation and Amortization – Southern Power" and "Southern Power – Wind Repowering Projects," respectively, in Item 8 of the Form 10-K for additional information.
(c)Attributable to Southern Company.
(d)For All Other, includes pre-tax losses associated with the extinguishment of debt at the parent company of $11 million ($8 million after tax) for the six months ended June 30, 2026 and $129 million ($97 million after tax) for the three and six months ended June 30, 2025.
Traditional Electric Operating Companies
Each of the traditional electric operating companies' single reportable business segment is the sale of electricity.
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. See Note 2 to the financial statements under "Alabama Power" in Item 8 of the Form 10-K for additional information.
During the third and fourth quarters of 2025, Mississippi Power updated the information provided to its CODM. As a result, Mississippi Power identified certain operational and environmental compliance expenses as significant segment expenses and has recast prior period information to conform to the current period presentation.
Financial data for significant segment expenses and other segment information for the three and six months ended June 30, 2026 and 2025 was as follows:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
(in millions)
Alabama Power
Operating revenues$1,963 $1,968 $4,055 $3,980 
Utility operations and maintenance
Rate RSE expenses332 374 633 739 
Rate CNP Compliance expenses71 67 145 142 
Total utility operations and maintenance403 441 778 881 
Other segment items(a)
486 544 1,154 1,152 
Depreciation and amortization385 371 766 741 
Interest expense117 116 232 225 
Income taxes135 115 263 226 
Segment net income$437 $381 $862 $755 
Capital expenditures$501 $599 $1,019 $1,159 
Georgia Power
Operating revenues$3,133 $3,110 $6,276 $6,148 
Utility operations and maintenance586 568 1,164 1,104 
Other segment items(a)
886 989 2,050 2,106 
Depreciation and amortization503 512 987 1,015 
Interest expense228 198 431 385 
Income taxes151 236 236 334 
Segment net income$779 $607 $1,408 $1,204 
Capital expenditures$2,173 $1,676 $4,243 $3,313 
Mississippi Power
Operating revenues$403 $400 $875 $821 
Operational expenses(b)
80 65 144 122 
Environmental compliance expenses(c)
3 4 7 6 
Other segment items(a)
173 183 424 400 
Depreciation and amortization58 52 113 105 
Interest expense21 20 41 40 
Income taxes16 17 34 34 
Segment net income
$52 $59 $112 $114 
Capital expenditures$96 $126 $178 $199 
(a)Primarily consists of fuel, purchased power, expenses from unregulated products and services, losses (gains) on asset dispositions, amortization of cloud software, taxes other than income taxes, AFUDC equity, and non-service cost-related retirement benefits income. For Mississippi Power, includes employee benefit expenses. Also includes earnings from equity method investments, which were immaterial for all periods presented.
(b)Consists of certain operations and maintenance expenses related to PEP and the MRA tariff, including labor costs, materials, contract services, and other normal operational costs. See Note (B) under "Mississippi Power" and Note 2 to the financial statements under "Mississippi Power" in Item 8 of the Form 10-K for additional information regarding PEP and the MRA tariff.
(c)Consists of environmental compliance expenses related to ECO Plan and the MRA tariff. See Note (B) under "Mississippi Power" and Note 2 to the financial statements under "Mississippi Power" in Item 8 of the Form 10-K for additional information regarding ECO Plan and the MRA tariff.
Southern Power
Southern Power's single reportable business segment is the sale of electricity in the competitive wholesale market. 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.
Financial data for segment information for the three and six months ended June 30, 2026 and 2025 was as follows:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
(in millions)
Operating revenues
$535 $546 $1,216 $1,113 
Other segment items(a)
329 296 772 599 
Depreciation and amortization(b)
280 177 558 329 
Interest expense28 24 55 50 
Income taxes (benefit)(77)(2)(147)(3)
Segment net income (loss)(b)(c)
$(25)$51 $(22)$138 
(a)Primarily consists of fuel, purchased power, other operations and maintenance expenses, taxes other than income taxes, and net income (loss) attributable to noncontrolling interests.
(b)Includes accelerated depreciation related to the repowering of multiple wind facilities of $140 million ($109 million after tax) and $293 million ($228 million after tax) for the three and six months ended June 30, 2026, respectively, and $42 million ($31 million after tax, net of noncontrolling interest impacts) and $69 million ($51 million after tax, net of noncontrolling interest impacts) for the three and six months ended June 30, 2025 respectively. See Note (K) under "Southern Power – Wind Repowering Projects" and Notes 5 and 15 to the financial statements under "Depreciation and Amortization – Southern Power" and "Southern Power – Wind Repowering Projects," respectively, in Item 8 of the Form 10-K for additional information.
(c)Southern Power had no earnings from equity method investments for any period presented.
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."
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 Note 7 to the financial statements under "Southern Company Gas" in Item 8 of the Form 10-K for additional information.
The gas marketing services segment provides natural gas marketing to end-use customers primarily in Georgia through SouthStar.
The "All Other" presentation includes operating segments and subsidiaries that fall below the quantitative threshold for separate disclosure.
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 three and six months ended June 30, 2026 and 2025 was as follows:
Gas Distribution OperationsGas
Pipeline Investments		Gas Marketing Services
Total Reportable Segments
All
Other
EliminationsConsolidated
(in millions)
Three Months Ended June 30, 2026
Operating revenues$885 $8 $73 $966 $2 $(2)$966 
Other segment items(*)
496 1 54 551 5 (2)554 
Depreciation and amortization181 1 3 185 — — 185 
Earnings from equity method investments— 32 — 32 — — 32 
Interest expense90 9 1 100 1 — 101 
Income taxes (benefit)23 7 4 34 (2)— 32 
Segment net income (loss)$95 $22 $11 $128 $(2)$— $126 
Six Months Ended June 30, 2026
Operating revenues$2,785 $16 $358 $3,159 $4 $(6)$3,157 
Other segment items(*)
1,673 1 237 1,911 6 (6)1,911 
Depreciation and amortization360 2 5 367 2 — 369 
Earnings from equity method investments— 78 — 78 — — 78 
Interest expense181 18 2 201 5 — 206 
Income taxes (benefit)
139 18 32 189 (13)— 176 
Segment net income
$432 $55 $82 $569 $4 $— $573 
Total assets at June 30, 2026
$26,244 $1,546 $1,710 $29,500 $11,265 $(13,161)$27,604 
Three Months Ended June 30, 2025
Operating revenues$885 $8 $83 $976 $5 $(2)$979 
Other segment items(*)
526 1 68 595 6 (2)599 
Depreciation and amortization167 1 3 171 1 — 172 
Earnings from equity method investments— 23 — 23 — — 23 
Interest expense82 9 1 92 — — 92 
Income taxes19 5 3 27 6 — 33 
Segment net income (loss)$91 $15 $8 $114 $(8)$— $106 
Six Months Ended June 30, 2025
Operating revenues$2,454 $16 $345 $2,815 $9 $(6)$2,818 
Other segment items(*)
1,431 3 234 1,668 8 (6)1,670 
Depreciation and amortization330 3 7 340 1 — 341 
Earnings from equity method investments— 62 — 62 — — 62 
Interest expense164 18 1 183 — — 183 
Income taxes (benefit)
123 13 29 165 (3)— 162 
Segment net income$406 $41 $74 $521 $3 $— $524 
Total assets at December 31, 2025
$25,391 $1,475 $1,749 $28,615 $10,643 $(11,871)$27,387 
(*)Primarily consists of cost of natural gas, other operations and maintenance expenses, taxes other than income taxes, AFUDC equity, and non-service cost-related retirement benefits income.
v3.26.1
Insider Trading Arrangements
 3 Months Ended
Jun. 30, 2026
shares
Trading Arrangements, by Individual  
Material Terms of Trading Arrangement
The following table reports information regarding the adoption of "Rule 10b5-1 trading arrangements" or "non-Rule 10b5-1 trading arrangements," as defined in Item 408(a) of Regulation S-K, during the three months ended June 30, 2026 for Southern Company's directors and "officers," as defined in Rule 16a-1(f) under the Securities Exchange Act of 1934, as amended. There were no modifications or terminations of such trading arrangements during the three months ended June 30, 2026. Unless otherwise indicated, each trading arrangement listed below is a "Rule 10b5-1 trading arrangement," provides for the sale of shares of Southern Company's common stock, commences no earlier than the expiration of the cooling-off period required by Rule 10b5-1(c)(1)(ii)(B)(1) under the Securities Exchange Act of 1934, as amended, and terminates upon the earlier of the "Expiration Date" listed below or the completion of all sales. The Subsidiary Registrants had no reportable trading arrangements for the three months ended June 30, 2026.
Name
Title
Date of Adoption
Expiration Date
Aggregate Number of Shares Covered
Peter P. Sena IIIChairman, President, and Chief Executive Officer of Southern NuclearMay 5, 2026September 1, 20274,266
Non-Rule 10b5-1 Arrangement Adopted false
Rule 10b5-1 Arrangement Terminated false
Non-Rule 10b5-1 Arrangement Terminated false
Peter P. Sena III [Member]  
Trading Arrangements, by Individual  
Name Peter P. Sena III
Title Chairman, President, and Chief Executive Officer of Southern Nuclear
Rule 10b5-1 Arrangement Adopted true
Adoption Date May 5, 2026
Expiration Date September 1, 2027
Arrangement Duration 484 days
Aggregate Available 4,266
v3.26.1
Introduction (Policies)
 6 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Basis of Accounting
The condensed quarterly financial statements of each Registrant included herein have been prepared by such Registrant, without audit, pursuant to the rules and regulations of the SEC. The Condensed Balance Sheets at December 31, 2025 have been derived from the audited financial statements of each Registrant. In the opinion of each Registrant's management, the information regarding such Registrant furnished herein reflects all adjustments, which, except as otherwise disclosed, are of a normal recurring nature, necessary to present fairly the results of operations for the periods ended June 30, 2026 and 2025. Certain information and disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations, although each Registrant believes that the disclosures regarding such Registrant are adequate to make the information presented not misleading. Disclosures which would substantially duplicate the disclosures in the Form 10-K and details which have not changed significantly in amount or composition since the filing of the Form 10-K are generally omitted from this Quarterly Report on Form 10-Q unless specifically required by GAAP. Therefore, these Condensed Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the Form 10-K. Due to the seasonal variations in the demand for energy and other factors, operating results for the periods presented are not necessarily indicative of the operating results to be expected for the full year.
Reclassifications
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 year data presented in the financial statements have been reclassified to conform to the current year presentation. These reclassifications had no impact on the overall results of operations, financial position, or cash flows of any Registrant.
Goodwill
Goodwill is not amortized but is subject to an annual impairment test during the fourth quarter of each year, or more frequently if goodwill impairment indicators exist.
Natural Gas for Sale
With the exception of Nicor Gas, Southern Company Gas records natural gas inventories on a weighted average cost basis. For any declines in market prices below the weighted average cost considered to be non-temporary, an adjustment is recorded to reduce the value of natural gas inventories to market value. 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.
Valuation Methodologies
The energy-related derivatives primarily consist of exchange-traded and over-the-counter 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 over-the-counter 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 (J) 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 to the financial statements under "Nuclear Decommissioning" in Item 8 of the Form 10-K for additional information.
Southern Company's investments, available for sale relate to a wholly-owned subsidiary that insures various risk exposures of Southern Company 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.
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.
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 (I) 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 to the financial statements under "Financial Instruments" in Item 8 of the Form 10-K 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 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 accumulated OCI 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 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.
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. 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.
v3.26.1
Introduction (Tables)
 6 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Goodwill
Goodwill at both June 30, 2026 and December 31, 2025 was as follows:
Goodwill
(in millions)
Southern Company$5,161 
Southern Company Gas:
Gas distribution operations$4,034 
Gas marketing services981 
Southern Company Gas total$5,015 
Schedule of Other Intangible Assets, Indefinite-Lived
Other intangible assets were as follows:
At June 30, 2026At December 31, 2025
Gross
Carrying
Amount		Accumulated
Amortization		Other
Intangible
Assets,
Net		Gross
Carrying
Amount		Accumulated
Amortization		Other
Intangible
Assets,
Net
(in millions)(in millions)
Southern Company
Subject to amortization:
Customer relationships$212 $(192)$20 $212 $(189)$23 
Trade names64 (64)— 64 (64)— 
PPA fair value adjustments390 (198)192 390 (188)202 
Other3 (3)— 3 (3)— 
Total subject to amortization$669 $(457)$212 $669 $(444)$225 
Not subject to amortization:
FCC licenses75 — 75 75 — 75 
Total other intangible assets$744 $(457)$287 $744 $(444)$300 
Southern Power(*)
PPA fair value adjustments$390 $(198)$192 $390 $(188)$202 
Southern Company Gas(*)
Gas marketing services
Customer relationships$156 $(155)$1 $156 $(153)$3 
Trade names26 (26)— 26 (26)— 
Total other intangible assets$182 $(181)$1 $182 $(179)$3 
(*)All subject to amortization.
Schedule of Other Intangible Assets, Finite-Lived
Other intangible assets were as follows:
At June 30, 2026At December 31, 2025
Gross
Carrying
Amount		Accumulated
Amortization		Other
Intangible
Assets,
Net		Gross
Carrying
Amount		Accumulated
Amortization		Other
Intangible
Assets,
Net
(in millions)(in millions)
Southern Company
Subject to amortization:
Customer relationships$212 $(192)$20 $212 $(189)$23 
Trade names64 (64)— 64 (64)— 
PPA fair value adjustments390 (198)192 390 (188)202 
Other3 (3)— 3 (3)— 
Total subject to amortization$669 $(457)$212 $669 $(444)$225 
Not subject to amortization:
FCC licenses75 — 75 75 — 75 
Total other intangible assets$744 $(457)$287 $744 $(444)$300 
Southern Power(*)
PPA fair value adjustments$390 $(198)$192 $390 $(188)$202 
Southern Company Gas(*)
Gas marketing services
Customer relationships$156 $(155)$1 $156 $(153)$3 
Trade names26 (26)— 26 (26)— 
Total other intangible assets$182 $(181)$1 $182 $(179)$3 
(*)All subject to amortization.
Schedule of Amortization of Other Intangible Assets
Amortization associated with other intangible assets was as follows:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
(in millions)
Southern Company(a)
$7 $8 $13 $16 
Southern Power(b)
5 5 10 10 
Southern Company Gas
Gas marketing services1 1 2 3 
(a)Includes $5 million for the three months ended June 30, 2026 and 2025 and $10 million for the six months ended June 30, 2026 and 2025 recorded as a reduction to operating revenues.
(b)Recorded as a reduction to operating revenues.
Schedule of Restrictions on Cash and Cash Equivalents
The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed balance sheets that total to the amount shown in the condensed statements of cash flows for the applicable Registrants:
Southern CompanySouthern
Company Gas
(in millions)
At June 30, 2026
Cash and cash equivalents$2,984 $214 
Restricted cash(a):
Other current assets
5 4 
Total cash, cash equivalents, and restricted cash(b)
$2,990 $218 
At December 31, 2025
Cash and cash equivalents$1,639 $15 
Restricted cash(a):
Other current assets
1 — 
Total cash, cash equivalents, and restricted cash(b)
$1,640 $15 
(a)For Southern Company Gas, reflects funds held to support letters of credit. For Southern Company, also reflects collateral of $1 million for life insurance and long-term disability insurance, which was included at Southern Holdings.
(b)Total may not add due to rounding.
Schedule of Cash and Cash Equivalents
The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed balance sheets that total to the amount shown in the condensed statements of cash flows for the applicable Registrants:
Southern CompanySouthern
Company Gas
(in millions)
At June 30, 2026
Cash and cash equivalents$2,984 $214 
Restricted cash(a):
Other current assets
5 4 
Total cash, cash equivalents, and restricted cash(b)
$2,990 $218 
At December 31, 2025
Cash and cash equivalents$1,639 $15 
Restricted cash(a):
Other current assets
1 — 
Total cash, cash equivalents, and restricted cash(b)
$1,640 $15 
(a)For Southern Company Gas, reflects funds held to support letters of credit. For Southern Company, also reflects collateral of $1 million for life insurance and long-term disability insurance, which was included at Southern Holdings.
(b)Total may not add due to rounding.
v3.26.1
Regulatory Matters (Tables)
 6 Months Ended
Jun. 30, 2026
Regulated Operations [Abstract]  
Schedule of Cost Recovery Clauses
The recovery balances for retail fuel and storm/property damage for the traditional electric operating companies and natural gas cost for Southern Company Gas at June 30, 2026 and December 31, 2025 were as follows:
Recovery/Regulatory ClauseBalance Sheet LocationAt June 30, 2026At December 31, 2025
(in millions)
Alabama Power
Rate ECR
Other regulatory assets, current
$7 $— 
Other regulatory assets, deferred212 146 
NDROther regulatory liabilities, deferred29 60 
Georgia Power
Fuel cost recovery
Receivables – under recovered retail fuel clause revenues
$161 $310 
Deferred under recovered retail fuel clause revenues151 212 
Storm damage recoveryOther regulatory assets, current187 31 
Other regulatory assets, deferred784 880 
Mississippi Power
Fuel cost recovery(*)
Receivables – under recovered retail fuel clause revenues$55 $— 
Deferred under recovered retail fuel clause revenues— 40 
Property damage reserveOther regulatory liabilities, deferred56 57 
Southern Company Gas
Natural gas cost recoveryNatural gas cost over recovery$191 $158 
(*)Mississippi Power also has wholesale MRA and Market Based (MB) fuel cost recovery factors. At June 30, 2026 and December 31, 2025, wholesale MRA fuel cost under recovery was $10 million and $6 million, respectively, and was included in customer accounts receivable, net on Mississippi Power's balance sheets. The wholesale MB fuel cost recovery was immaterial for both periods presented.
Schedule of Construction Projects
Resource/Project
Approximate Nameplate Capacity
(MW)
Actual/Projected COD
Projects Under Construction at June 30, 2026
Battery Energy Storage
McGrau Ford Phase 2
265
Third quarter 2026
McGrau Ford Phase 1265Fourth quarter 2026
Hammond Phase 158
Fourth quarter 2026
Hammond Phase 2193Fourth quarter 2030
Twiggs County200Fourth quarter 2027
Wadley260Fourth quarter 2027
Bowen Phase 1
250Fourth quarter 2028
Bowen Phase 2
250Fourth quarter 2029
South Hall250Fourth quarter 2028
Wansley
500Fourth quarter 2028
Yates Phase 1
320Fourth quarter 2028
Yates Phase 2
250Fourth quarter 2028
Thomson500Fourth quarter 2029
McIntosh
250Fourth quarter 2030
Solar with Battery Energy Storage
Laurens County 200Fourth quarter 2028
Plant Mitchell 150Fourth quarter 2028
Combined Cycle
Plant Bowen Unit 7741Fourth quarter 2029
Plant Bowen Unit 8741Second quarter 2030
Plant Wansley Unit 10727Fourth quarter 2029
Plant Wansley Unit 11727Second quarter 2030
Plant McIntosh Unit 12757Fourth quarter 2030
Combustion Turbine
Plant Yates Unit 8(*)
442Fourth quarter 2026
Plant Yates Unit 9(*)
442Second quarter 2027
Plant Yates Unit 10(*)
442Third quarter 2027
Projects Completed During the Six Months Ended June 30, 2026
Battery Energy Storage
Robins
128March 2026
Moody50April 2026
(*)Pursuant to the 2023 IRP Update, cost recovery over the certified amount is limited.
v3.26.1
Revenue from Contracts with Customers and Lease Income (Tables)
 6 Months Ended
Jun. 30, 2026
Revenue from Contract with Customer [Abstract]  
Schedule of Disaggregation of Revenue
The following table disaggregates revenue from contracts with customers for the three and six months ended June 30, 2026 and 2025:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Three Months Ended June 30, 2026
Operating revenues
Retail electric revenues
Residential$2,007 $720 $1,208 $79 $— $— 
Commercial1,757 501 1,166 90 — — 
Industrial1,021 441 471 109 — — 
Other29 3 24 2 — — 
Total retail electric revenues4,814 1,665 2,869 280 — — 
Natural gas distribution revenues
Residential353 — — — — 353 
Commercial89 — — — — 89 
Transportation358 — — — — 358 
Industrial 6 — — — — 6 
Other67 — — — — 67 
Total natural gas distribution revenues873 — — — — 873 
Wholesale electric revenues
PPA energy revenues301 47 40 8 218 — 
PPA capacity revenues145 18 32 25 89 — 
Non-PPA revenues64 55 19 80 43 — 
Total wholesale electric revenues510 120 91 113 350 — 
Other natural gas revenues
Gas marketing services73 — — — — 73 
Other
2 — — — — 2 
Total other natural gas revenues
75 — — — — 75 
Other revenues450 62 212 11 4 — 
Total revenue from contracts with customers6,722 1,847 3,172 404 354 948 
Other revenue sources(*)
255 116 (39)(1)181 18 
Total operating revenues$6,977 $1,963 $3,133 $403 $535 $966 
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Six Months Ended June 30, 2026
Operating revenues
Retail electric revenues
Residential$4,010 $1,493 $2,358 $159 $— $— 
Commercial3,419 978 2,269 172 — — 
Industrial1,962 855 909 198 — — 
Other61 6 50 5 — — 
Total retail electric revenues9,452 3,332 5,586 534 — — 
Natural gas distribution revenues
Residential1,380 — — — — 1,380 
Commercial342 — — — — 342 
Transportation798 — — — — 798 
Industrial 30 — — — — 30 
Other213 — — — — 213 
Total natural gas distribution revenues2,763 — — — — 2,763 
Wholesale electric revenues
PPA energy revenues796 93 104 11 610 — 
PPA capacity revenues294 36 76 46 172 — 
Non-PPA revenues156 175 63 250 88 — 
Total wholesale electric revenues1,246 304 243 307 870 — 
Other natural gas revenues
Gas marketing services355 — — — — 355 
Other
4 — — — — 4 
Total other natural gas revenues
359 — — — — 359 
Other revenues945 140 449 26 8 — 
Total revenue from contracts with customers14,765 3,776 6,278 867 878 3,122 
Other revenue sources(*)
609 279 (2)8 338 35 
Total operating revenues$15,374 $4,055 $6,276 $875 $1,216 $3,157 
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Three Months Ended June 30, 2025
Operating revenues
Retail electric revenues
Residential$2,021 $725 $1,217 $79 $— $— 
Commercial1,716 504 1,127 85 — — 
Industrial1,015 432 496 87 — — 
Other29 2 25 2 — — 
Total retail electric revenues4,781 1,663 2,865 253 — — 
Natural gas distribution revenues
Residential394 — — — — 394 
Commercial94 — — — — 94 
Transportation331 — — — — 331 
Industrial 7 — — — — 7 
Other60 — — — — 60 
Total natural gas distribution revenues886 — — — — 886 
Wholesale electric revenues
PPA energy revenues310 58 50 2 210 — 
PPA capacity revenues154 29 35 17 85 — 
Non-PPA revenues60 36 10 100 59 — 
Total wholesale electric revenues524 123 95 119 354 — 
Other natural gas revenues
Gas marketing services81 — — — — 81 
Other
5 — — — — 5 
Total other natural gas revenues
86 — — — — 86 
Other revenues457 67 206 9 8 — 
Total revenue from contracts with customers6,734 1,853 3,166 381 362 972 
Other revenue sources(*)
239 115 (56)19 184 7 
Total operating revenues$6,973 $1,968 $3,110 $400 $546 $979 
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Six Months Ended June 30, 2025
Operating revenues
Retail electric revenues
Residential$4,087 $1,531 $2,403 $153 $— $— 
Commercial3,327 986 2,181 160 — — 
Industrial1,930 822 940 168 — — 
Other61 4 52 5 — — 
Total retail electric revenues9,405 3,343 5,576 486 — — 
Natural gas distribution revenues
Residential1,239 — — — — 1,239 
Commercial292 — — — — 292 
Transportation737 — — — — 737 
Industrial 26 — — — — 26 
Other170 — — — — 170 
Total natural gas distribution revenues2,464 — — — — 2,464 
Wholesale electric revenues
PPA energy revenues723 112 134 5 491 — 
PPA capacity revenues299 57 74 34 169 — 
Non-PPA revenues136 106 19 233 121 — 
Total wholesale electric revenues1,158 275 227 272 781 — 
Other natural gas revenues
Gas marketing services337 — — — — 337 
Other
10 — — — — 10 
Total other natural gas revenues
347 — — — — 347 
Other revenues954 150 436 30 14 — 
Total revenue from contracts with customers14,328 3,768 6,239 788 795 2,811 
Other revenue sources(*)
420 212 (91)33 318 7 
Total operating revenues$14,748 $3,980 $6,148 $821 $1,113 $2,818 
(*)Other revenue sources relate to revenues from customers accounted for as derivatives and leases, alternative revenue programs primarily 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.
Schedule of Contract Balances
The following table reflects the closing balances of receivables, contract assets, and contract liabilities related to revenues from contracts with customers at June 30, 2026 and December 31, 2025:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Accounts Receivable
At June 30, 2026$3,155 $860 $1,549 $122 $136 $448 
At December 31, 20253,139 716 1,278 115 132 864 
Contract Assets
At June 30, 2026$354 $— $189 $4 $— $67 
At December 31, 2025294 3 160 — — 67 
Contract Liabilities
At June 30, 2026$329 $7 $123 $— $1 $— 
At December 31, 2025213 6 75 — 2 — 
Schedule of Remaining Performance Obligations Revenues from contracts with customers related to these performance obligations remaining at June 30, 2026 are expected to be recognized as follows:
2026 (remaining)2027202820292030Thereafter
(in millions)
Southern Company$668 $826 $472 $413 $416 $3,130 
Alabama Power7 5 4 3 1 6 
Georgia Power37 69 46 22 22 146 
Mississippi Power(*)
33 69 73 12 — — 
Southern Power(*)
184 349 389 393 393 2,978 
Southern Company Gas28 24 — — — — 
(*)Includes performance obligations related to affiliate PPAs with Georgia Power. See Note 1 to the financial statements under "Affiliate Transactions" in Item 8 of the Form 10-K for additional information.
Schedule of Lease Income
Lease income for the three and six months ended June 30, 2026 and 2025 was as follows:
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
 (in millions)
Three Months Ended June 30, 2026
Lease income - interest income on sales-type leases$5 $— $— $3 $2 $— 
Lease income - operating leases34 3 7 1 27 9 
Variable lease income125 — — — 136 — 
Total lease income$164 $3 $7 $4 $165 $9 
Six Months Ended June 30, 2026
Lease income - interest income on sales-type leases$12 $— $— $7 $4 $— 
Lease income - operating leases69 6 15 2 64 18 
Variable lease income204 — — — 223 — 
Total lease income$285 $6 $15 $9 $291 $18 
Three Months Ended June 30, 2025
Lease income - interest income on sales-type leases$6 $— $— $4 $2 $— 
Lease income - operating leases33 2 7 1 37 9 
Variable lease income125 — — — 136 — 
Total lease income$164 $2 $7 $5 $175 $9 
Six Months Ended June 30, 2025
Lease income - interest income on sales-type leases$11 $— $— $7 $4 $— 
Lease income - operating leases66 3 14 1 73 18 
Variable lease income207 1 — — 225 — 
Total lease income$284 $4 $14 $8 $302 $18 
v3.26.1
Consolidated Entities and Equity Method Investments (Tables)
 6 Months Ended
Jun. 30, 2026
Regulated Operations [Abstract]  
Schedule of Equity Method Investments
The carrying amounts of Southern Company Gas' equity method investments at June 30, 2026 and December 31, 2025 were as follows:
Investment BalanceAt June 30, 2026At December 31, 2025
(in millions)
SNG$1,220 $1,148 
Other34 34 
Total$1,254 $1,182 
v3.26.1
Financing and Leases (Tables)
 6 Months Ended
Jun. 30, 2026
Debt Disclosure [Abstract]  
Schedule of Credit Arrangements
At June 30, 2026, committed credit arrangements with banks were as follows:
Expires
Company20262027202820292031TotalUnusedExpires within
One Year
(in millions)
Southern Company parent(a)
$— $— $500 $— $2,500 $3,000 $2,999 $— 
Alabama Power(b)
15 — — 650 700 1,365 1,365 15 
Georgia Power(c)
— — — — 2,050 2,050 2,042 — 
Mississippi Power(a)
— — — 125 150 275 275 — 
Southern Power(a)(d)
— — — — 600 600 600 — 
Southern Company Gas(e)
— — — — 1,600 1,600 1,598 — 
SEGCO— 30 — — — 30 30 30 
Southern Company$15 $30 $500 $775 $7,600 $8,920 $8,909 $45 
(a)Arrangement expiring in 2031 represents a $3.25 billion combined arrangement for Southern Company, Mississippi Power, and Southern Power allowing for flexible sublimits. Pursuant to the combined facility, the allocations among Southern Company, Mississippi Power, and Southern Power may be adjusted.
(b)Includes $15 million expiring in 2026 at Alabama Property Company, a wholly-owned subsidiary of Alabama Power, of which $15 million was unused at June 30, 2026. Alabama Power is not party to this arrangement.
(c)Georgia Power had $26 million of letters of credit outstanding under an uncommitted letter of credit facility at June 30, 2026.
(d)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 2029, respectively, of which $17 million and $4 million, respectively, was unused at June 30, 2026. In addition, Southern Power Company had $23 million of letters of credit outstanding under an uncommitted letter of credit facility at June 30, 2026. Southern Power's subsidiaries are not parties to its bank credit arrangements or letter of credit facilities.
(e)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 2031. Southern Company Gas' committed credit arrangement expiring in 2031 also includes $800 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 2031, the allocations between Southern Company Gas Capital and Nicor Gas may be adjusted.
Schedule of Forward Contracts Indexed to Issuer's Equity
The table below reflects shares of Southern Company common stock sold and settled under separate initially priced forward sale contracts with forward purchasers during the six months ended June 30, 2026.
Shares Sold
Initial Forward Price per Share
To be Settled On or Before
Forward Price Per Share SettledShares Issued to SettleSettlement Date
Sold during 2025 (2024 ATM Program)
3,255,866$89.4692December 31, 2026$89.24433,255,866March 2, 2026
2,314,487$92.7805June 30, 2027$92.87232,314,487March 2, 2026
3,850,000$90.6617December 31, 2026$90.23623,850,000June 1, 2026
2,470,306$94.5394June 30, 2027$93.89132,470,306June 1, 2026
1,590,200$93.4524June 30, 2027$93.40381,590,200June 1, 2026
4,000,000$90.8141June 30, 2027$90.63584,000,000June 12, 2026
2,876,034$92.2437June 30, 2027$91.96642,876,034June 12, 2026
3,015,668$93.4521June 30, 2027$93.12903,015,668June 12, 2026
    3,130,641(a)
$88.2823December 31, 2026$88.06201,070,641June 16, 2026
2,346,903$91.1610June 30, 2027$90.94252,346,903June 16, 2026
911,448$94.2411June 30, 2027$93.9331911,448June 16, 2026
Sold during 2026 (2024 ATM Program)
1,467,305$96.3883March 31, 2028N/AN/AN/A
1,896,549$97.5815March 31, 2028N/AN/AN/A
1,903,317$95.5086March 31, 2028N/AN/AN/A
Sold during 2026 (2026 ATM Program)
1,713,535$93.2987June 30, 2028N/AN/AN/A
1,909,112$92.4821June 30, 2028N/AN/AN/A
1,994,083$95.1457June 30, 2028N/AN/AN/A
    600,094(b)
$95.9974June 30, 2028N/AN/AN/A
(a)The total number of shares sold under this forward sale contract is 3,130,641, of which 1,070,641 shares were settled during the six months ended June 30, 2026. The other 2,060,000 shares were settled in December 2025.
(b)The total number of shares sold under this forward sale contract is 1,940,548, of which the remaining 1,340,454 shares were sold subsequent to June 30, 2026. The initial forward price was determined after the completion of sales by the forward seller in July 2026.
Schedule of Shares Used to Compute Diluted Earnings Per Share Shares used to compute diluted EPS were as follows:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025

(in millions)
As reported shares1,137 1,101 1,130 1,100 
Effect of stock-based compensation3 6 3 6 
Effect of convertible senior notes
— 1 — 1 
Effect of forward sale contracts1 — 1 — 
Diluted shares1,141 1,108 1,134 1,107 
v3.26.1
Retirement Benefits (Tables)
 6 Months Ended
Jun. 30, 2026
Retirement Benefits [Abstract]  
Schedule of Pension Plans and Postretirement Plans Components of the net periodic benefit costs for the three and six months ended June 30, 2026 and 2025 are presented in the following tables.
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Three Months Ended June 30, 2026
Pension Plans
Service cost$69 $16 $16 $3 $1 $7 
Interest cost161 37 47 8 3 11 
Expected return on plan assets(322)(78)(100)(14)(4)(22)
Amortization:
Prior service costs— — 1 — — (1)
Net (gain) loss19 5 7 — (1)1 
Net periodic pension income$(73)$(20)$(29)$(3)$(1)$(4)
Postretirement Benefits
Service cost$3 $1 $1 $— $— $— 
Interest cost16 4 6 — — 2 
Expected return on plan assets(22)(8)(8)1 — (2)
Amortization:
Net gain(2)(1)— — — (2)
Net periodic postretirement benefit cost (income)$(5)$(4)$(1)$1 $— $(2)
Six Months Ended June 30, 2026
Pension Plans
Service cost$138 $31 $33 $6 $3 $14 
Interest cost323 75 94 15 5 22 
Expected return on plan assets(644)(157)(199)(29)(8)(43)
Amortization:
Prior service costs— — 1 — — (1)
Regulatory asset— — — — — 3 
Net (gain) loss37 10 13 1 (1)1 
Net periodic pension income$(146)$(41)$(58)$(7)$(1)$(4)
Postretirement Benefits
Service cost$6 $2 $2 $— $— $— 
Interest cost32 8 12 1 — 3 
Expected return on plan assets(45)(17)(16)— — (4)
Amortization:
Prior service costs1 — — — — — 
Net gain(4)(1)— — — (4)
Net periodic postretirement benefit cost (income)$(10)$(8)$(2)$1 $— $(5)
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Three Months Ended June 30, 2025
Pension Plans
Service cost$66 $15 $15 $2 $2 $7 
Interest cost166 38 49 8 3 11 
Expected return on plan assets(320)(78)(99)(14)(4)(22)
Amortization:
Prior service costs— — 1 — — (1)
Regulatory asset— — — — — 4 
Net (gain) loss10 4 3 — (2)— 
Net periodic pension income$(78)$(21)$(31)$(4)$(1)$(1)
Postretirement Benefits
Service cost$3 $1 $1 $— $— $— 
Interest cost18 4 7 — — 2 
Expected return on plan assets(22)(9)(8)— — (2)
Amortization:
Regulatory asset— — — — — 2 
Net (gain) loss(4)— (2)1 — (2)
Net periodic postretirement benefit cost (income)$(5)$(4)$(2)$1 $— $— 
Six Months Ended June 30, 2025
Pension Plans
Service cost$132 $30 $31 $5 $3 $13 
Interest cost332 77 98 15 5 22 
Expected return on plan assets(640)(156)(198)(29)(8)(43)
Amortization:
Prior service costs— — 1 — — (1)
Regulatory asset— — — — — 8 
Net (gain) loss19 6 7 1 (1)— 
Net periodic pension income$(157)$(43)$(61)$(8)$(1)$(1)
Postretirement Benefits
Service cost$6 $2 $2 $— $— $— 
Interest cost35 8 13 1 — 4 
Expected return on plan assets(45)(18)(16)— — (4)
Amortization:
Prior service costs1 — — — — — 
Regulatory asset— — — — — 3 
Net gain(7)— (2)— — (4)
Net periodic postretirement benefit cost (income)$(10)$(8)$(3)$1 $— $(1)
v3.26.1
Fair Value Measurements (Tables)
 6 Months Ended
Jun. 30, 2026
Fair Value Disclosures [Abstract]  
Schedule of Assets and Liabilities Measured at Fair Value
At June 30, 2026, 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
At June 30, 2026Quoted Prices
in Active
Markets for
Identical
Assets
(Level 1)		Significant
Other
Observable
Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Net Asset
Value as a
Practical
Expedient
(NAV)		Total
(in millions)
Southern Company
Assets:
Energy-related derivatives(a)
$8 $61 $— $— $69 
Interest rate derivatives— 5 — — 5 
Investments in trusts:(b)
Domestic equity1,030 293 — — 1,323 
Foreign equity199 256 — — 455 
U.S. Treasury and government agency securities— 410 — — 410 
Municipal bonds— 31 — — 31 
Pooled funds – fixed income— 4 — — 4 
Corporate bonds— 533 — — 533 
Mortgage- and asset-backed securities — 110 — — 110 
Private equity— — — 202 202 
Cash and cash equivalents1 — — — 1 
Other33 4 — 9 46 
Investments, available-for-sale:
U.S. Treasury and government agency securities1 12 — — 13 
Municipal bonds— 2 — — 2 
Corporate bonds— 4 — — 4 
Mortgage- and asset-backed securities— 3 — — 3 
Cash equivalents1,768 18 — — 1,786 
Other investments10 35 8 — 53 
Other— — 10 — 10 
Total$3,050 $1,781 $18 $211 $5,060 
Liabilities:
Energy-related derivatives(a)
$11 $155 $— $— $166 
Interest rate derivatives— 205 — — 205 
Foreign currency derivatives— 63 — — 63 
Contingent consideration— — 12 — 12 
Other— 13 11 — 24 
Total$11 $436 $23 $— $470 
Fair Value Measurements Using
At June 30, 2026Quoted Prices
in Active
Markets for
Identical
Assets
(Level 1)		Significant
Other
Observable
Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Net Asset
Value as a
Practical
Expedient
(NAV)		Total
(in millions)
Alabama Power
Assets:
Energy-related derivatives$— $27 $— $— $27 
Nuclear decommissioning trusts:(b)
Domestic equity569 282 — — 851 
Foreign equity199 — — — 199 
U.S. Treasury and government agency securities— 16 — — 16 
Municipal bonds— 1 — — 1 
Corporate bonds— 319 — — 319 
Mortgage- and asset-backed securities— 28 — — 28 
Private equity— — — 202 202 
Other14 2 — 9 25 
Cash equivalents40 18 — — 58 
Other investments— 35 — — 35 
Total$822 $728 $— $211 $1,761 
Liabilities:
Energy-related derivatives$— $58 $— $— $58 
Georgia Power
Assets:
Energy-related derivatives$— $14 $— $— $14 
Nuclear decommissioning trusts:(b)
Domestic equity461 1 — — 462 
Foreign equity— 254 — — 254 
U.S. Treasury and government agency securities— 394 — — 394 
Municipal bonds— 30 — — 30 
Corporate bonds— 214 — — 214 
Mortgage- and asset-backed securities— 82 — — 82 
Other19 2 — — 21 
Cash equivalents11 — — — 11 
Total$491 $991 $— $— $1,482 
Liabilities:
Energy-related derivatives$— $48 $— $— $48 
Fair Value Measurements Using
At June 30, 2026Quoted Prices
in Active
Markets for
Identical
Assets
(Level 1)		Significant
Other
Observable
Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Net Asset
Value as a
Practical
Expedient
(NAV)		Total
(in millions)
Mississippi Power
Assets:
Energy-related derivatives$— $14 $— $— $14 
Cash equivalents1 — — — 1 
Total$1 $14 $— $— $15 
Liabilities:
Energy-related derivatives$— $40 $— $— $40 
Southern Power
Assets:
Energy-related derivatives$— $3 $— $— $3 
Cash equivalents162 — — — 162 
Other— — 10 — 10 
Total$162 $3 $10 $— $175 
Liabilities:
Energy-related derivatives$— $4 $— $— $4 
Contingent consideration— — 12 — 12 
Other— 13 11 — 24 
Total$— $17 $23 $— $40 
Southern Company Gas
Assets:
Energy-related derivatives(a)
$8 $3 $— $— $11 
Non-qualified deferred compensation trusts:
Domestic equity— 10 — — 10 
Foreign equity— 2 — — 2 
Pooled funds – fixed income— 4 — — 4 
Cash and cash equivalents1 — — — 1 
Cash equivalents200 — — — 200 
Total$209 $19 $— $— $228 
Liabilities:
Energy-related derivatives(a)
$11 $5 $— $— $16 
Interest rate derivatives— 62 — — 62 
Total$11 $67 $— $— $78 
(a)Excludes cash collateral of $18 million.
(b)Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 to the financial statements under "Nuclear Decommissioning" in Item 8 of the Form 10-K for additional information.
Schedule of Increase (Decrease) In Fair Value Of Funds The changes were recorded as a change to the regulatory assets and liabilities related to AROs for Georgia Power and Alabama Power, respectively.
Three Months Ended June 30,Six Months Ended June 30,
Fair value increases (decreases)2026202520262025
(in millions)
Southern Company $249 $165 $205 $159 
Alabama Power 156 99 126 86 
Georgia Power93 66 79 73 
Schedule of Financial Instruments for which Carrying Amount Did Not Equal Fair Value
At June 30, 2026, other financial instruments for which the carrying amount did not equal fair value were as follows:
Southern
   Company(*)
Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power
Southern
Company
   Gas(*)
(in billions)
Long-term debt, including securities due within one year:
Carrying amount$72.7 $12.0 $22.3 $1.8 $3.0 $9.3 
Fair value68.0 10.7 20.7 1.7 2.9 8.4 
(*)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.
v3.26.1
Derivatives (Tables)
 6 Months Ended
Jun. 30, 2026
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Schedule of Energy-Related Derivatives
At June 30, 2026, 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(*)
46920302029
Alabama Power15520292026
Georgia Power11720282026
Mississippi Power11420302026
Southern Power820302026
Southern Company Gas(*)
7520282029
(*)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 85 million mmBtu long natural gas positions and 10 million mmBtu short natural gas positions at June 30, 2026, which is also included in Southern Company's total volume.
Schedule of Interest Rate Derivatives
At June 30, 2026, the following interest rate derivatives were outstanding:
Notional
Amount		Weighted
Average Interest
Rate Paid		Interest
Rate
Received		Hedge
Maturity
Date
Fair Value
Gain (Loss) at
June 30, 2026
 (in millions)   (in millions)
Fair Value Hedges of Existing Debt
Southern Company parent$400 
1-day SOFR + 0.80%
1.75%March 2028$(23)
Southern Company parent1,000 
1-day SOFR + 2.48%
3.70%April 2030(103)
Southern Company parent565 
1-day SOFR + 1.56%
6.50%March 2045(12)
Southern Company Gas500 
1-day SOFR + 0.49%
1.75%January 2031(62)
Southern Company$2,465 $(200)
Schedule of Foreign Currency Derivatives
At June 30, 2026, the following foreign currency derivatives were outstanding:
Pay
Notional		Pay
Rate		Receive
Notional		Receive
Rate		Hedge
Maturity Date
Fair Value
Gain (Loss) at
June 30, 2026
(in millions)(in millions)(in millions)
Fair Value Hedges of Existing Debt
Southern Company parent$1,476 3.39%€1,250 1.88%September 2027$(63)
Schedule of Derivative Category and Balance Sheet Location
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:
At June 30, 2026At December 31, 2025
Derivative Category and Balance Sheet LocationAssetsLiabilitiesAssetsLiabilities
(in millions)
Southern Company
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$28 $89 $24 $64 
Non-current
30 60 31 35 
Total derivatives designated as hedging instruments for regulatory purposes58 149 55 99 
Derivatives designated as hedging instruments in cash flow and fair value hedges
Energy-related derivatives:
Current3 12 1 6 
Non-current2 1 2 1 
Interest rate derivatives:
Current5 52 8 48 
Non-current— 153 — 139 
Foreign currency derivatives:
Current— 23 17 22 
Non-current— 40 4 — 
Total derivatives designated as hedging instruments in cash flow and fair value hedges10 281 32 216 
Energy-related derivatives not designated as hedging instruments
Current6 4 6 6 
Gross amounts recognized74 434 93 321 
Gross amounts offset(a)
(39)(57)(21)(54)
Net amounts recognized in the Balance Sheets(b)
$35 $377 $72 $267 
Alabama Power
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current$15 $31 $9 $18 
Non-current12 25 10 13 
Total derivatives designated as hedging instruments for regulatory purposes27 56 19 31 
Derivatives designated as hedging instruments in cash flow and fair value hedges
Energy-related derivatives:
Current— 2 — — 
Gross amounts recognized27 58 19 31 
Gross amounts offset(16)(16)(13)(13)
Net amounts recognized in the Balance Sheets$11 $42 $6 $18 
At June 30, 2026At December 31, 2025
Derivative Category and Balance Sheet LocationAssetsLiabilitiesAssetsLiabilities
(in millions)
Georgia Power
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current$5 $32 $7 $23 
Non-current7 16 10 10 
Total derivatives designated as hedging instruments for regulatory purposes12 48 17 33 
Energy-related derivatives not designated as hedging instruments
Current
2 — 1 — 
Gross amounts recognized14 48 18 33 
Gross amounts offset(11)(11)(14)(14)
Net amounts recognized in the Balance Sheets$3 $37 $4 $19 
Mississippi Power
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current$3 $21 $3 $15 
Non-current11 19 11 12 
Total derivatives designated as hedging instruments for regulatory purposes14 40 14 27 
Gross amounts offset(13)(13)(13)(13)
Net amounts recognized in the Balance Sheets$1 $27 $1 $14 
Southern Power
Derivatives designated as hedging instruments in cash flow hedges
Energy-related derivatives:
Current$1 $2 $1 $1 
Non-current2 1 2 — 
Foreign currency derivatives:
Current— — 17 — 
Total derivatives designated as hedging instruments in cash flow hedges
3 3 20 1 
Energy-related derivatives not designated as hedging instruments
Current
— 1 1 — 
Gross amounts recognized3 4 21 1 
Gross amounts offset(1)(1)— — 
Net amounts recognized in the Balance Sheets$2 $3 $21 $1 
At June 30, 2026At December 31, 2025
Derivative Category and Balance Sheet LocationAssetsLiabilitiesAssetsLiabilities
(in millions)
Southern Company Gas
Energy-related derivatives designated as hedging instruments for regulatory purposes
Current
$5 $5 $5 $8 
Derivatives designated as hedging instruments in cash flow and fair value hedges
Energy-related derivatives:
Current2 8 — 5 
Non-current— — — 1 
Interest rate derivatives:
Current— 13 — 13 
Non-current— 49 — 46 
Total derivatives designated as hedging instruments in cash flow and fair value hedges2 70 — 65 
Energy-related derivatives not designated as hedging instruments
Current4 3 4 6 
Gross amounts recognized11 78 9 79 
Gross amounts offset(a)
6 (12)19 (14)
Net amounts recognized in the Balance Sheets(b)
$17 $66 $28 $65 
(a)Gross amounts offset includes cash collateral held on deposit in broker margin accounts of $18 million and $33 million at June 30, 2026 and December 31, 2025, respectively.
(b)Net amounts of derivative instruments outstanding exclude immaterial premium and intrinsic value associated with weather derivatives at June 30, 2026 and December 31, 2025.
Schedule of Pre-tax Effects of Unrealized Derivative Gains (Losses)
At June 30, 2026 and December 31, 2025, the pre-tax effects of unrealized derivative gains (losses) arising from energy-related derivative instruments designated as regulatory hedging instruments and deferred were as follows:
Regulatory Hedge Unrealized Gain (Loss) Recognized in the Balance Sheets
Derivative Category and
Balance Sheet Location		Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern Company Gas
 (in millions)
At June 30, 2026:
Energy-related derivatives:
Other regulatory assets, current$(75)$(26)$(27)$(18)$(4)
Other regulatory assets, deferred(31)(13)(10)(8)— 
Other regulatory liabilities, current15 10 — — 5 
Total energy-related derivative gains (losses)$(91)$(29)$(37)$(26)$1 
At December 31, 2025:
Energy-related derivatives:
Other regulatory assets, current$(48)$(13)$(17)$(12)$(6)
Other regulatory assets, deferred(8)(5)(1)(2)— 
Other regulatory liabilities, current7 4 1 — 2 
Other regulatory liabilities, deferred4 2 1 1 — 
Total energy-related derivative gains (losses)$(45)$(12)$(16)$(13)$(4)
Schedule of Pre-Tax Effects of Hedging on AOCI
For the three and six months ended June 30, 2026 and 2025, the pre-tax effects of cash flow and fair value hedge accounting on accumulated OCI for the applicable Registrants were as follows:
Gain (Loss) From Derivatives Recognized in OCIThree Months Ended June 30,Six Months Ended June 30,
2026202520262025
(in millions)
Southern Company
Cash flow hedges:
Energy-related derivatives$(8)$(13)$1 $6 
Interest rate derivatives— 9 — 5 
Foreign currency derivatives(7)47 (19)67 
Fair value hedges(*):
Foreign currency derivatives— 3 (1)(13)
Total$(15)$46 $(19)$65 
Alabama Power
Cash flow hedges:
Energy-related derivatives$(2)$— $(2)$— 
Georgia Power
Cash flow hedges:
Interest rate derivatives$— $5 $— $3 
Southern Power
Cash flow hedges:
Energy-related derivatives$(2)$(1)$— $2 
Foreign currency derivatives(7)47 (19)67 
Total$(9)$46 $(19)$69 
Southern Company Gas
Cash flow hedges:
Energy-related derivatives$(4)$(12)$3 $4 
Interest rate derivatives— 4 — 4 
Total$(4)$(8)$3 $8 
(*)Represents amounts excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI.
Schedule of Pre-Tax Effects of Cash Flow and Fair Value Hedging on Income
For the three and six months ended June 30, 2026 and 2025, the pre-tax effects of cash flow and fair value hedge accounting on income were as follows:
Gain (Loss)
Statements of Income Location
Derivative Category
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
(in millions)
Southern Company
Fuel
Energy-related cash flow hedges
$(1)$— $2 $1 
Cost of natural gas
Energy-related cash flow hedges
(3)1 7 — 
Interest expense, net of amounts capitalized
Interest rate cash flow hedges
(2)(3)(5)(6)
Foreign currency cash flow hedges
(2)(2)(5)(5)
Interest rate fair value hedges
(41)29 (21)69 
Other income (expense), net
Foreign currency cash flow hedges
(2)45 (14)67 
Foreign currency fair value hedges
(13)115 (45)155 
Amount excluded from effectiveness testing recognized in earnings— (3)1 13 
Southern Power
Fuel
Energy-related cash flow hedges
$(1)$— $2 $1 
Interest expense, net of amounts capitalized
Foreign currency cash flow hedges
(2)(2)(5)(5)
Other income (expense), net
Foreign currency cash flow hedges
(2)45 (14)67 
Southern Company Gas
Cost of natural gas
Energy-related cash flow hedges
$(3)$1 $7 $— 
Interest expense, net of amounts capitalized
Interest rate fair value hedges
(32)3 (3)21 
Schedule of Cumulative Basis Adjustments for Fair Value Hedges
At June 30, 2026 and December 31, 2025, the following amounts were recorded on the balance sheets related to cumulative basis adjustments for fair value hedges:
Carrying Amount of the Hedged
Item		Cumulative Amount of Fair Value
Hedging Adjustment included in
Carrying Amount of the Hedged
Item
Balance Sheet Location of Hedged ItemsAt June 30, 2026At December 31, 2025At June 30, 2026At December 31, 2025
(in millions)
Southern Company
Long-term debt$(3,687)$(3,742)$169 $156 
Southern Company Gas
Long-term debt$(442)$(446)$56 $51 
v3.26.1
Acquisitions and Dispositions (Tables)
 6 Months Ended
Jun. 30, 2026
Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract]  
Schedule of Asset Acquisitions
Project
Facility		Resource
Approximate
Nameplate Capacity
(MW)
LocationActual/Projected
COD		PPA
Contract
Period
Projects Under Construction at June 30, 2026
Millers Branch
Phase IISolar180Haskell County, TXThird quarter 202615 years
Phase III
Solar
132Haskell County, TX
Fourth quarter 2026
15 years
Projects Completed During the Six Months Ended June 30, 2026
Millers Branch
Phase I
Solar200Haskell County, TXFebruary 202620 years
Project FacilityResource
Approximate Nameplate
Capacity
(MW)
LocationActual/Projected
Completion Date
Projects Under Construction at June 30, 2026
Kay(a)
Wind
200
Kay County, OK
   July 2026(b)
Grant
Wind
152
Grant County, OK
Fourth quarter 2026
Grant Plains
Wind
147
Grant County, OK
Fourth quarter 2026
Wake
Wind
257
Crosby & Floyd Counties, TX
Second quarter 2027
BethelWind276Castro County, TXThird quarter 2027
(a)The facility has a total capacity of 299 MWs, of which 200 MWs was projected to be repowered and is contracted under a PPA.
(b)During the first six months of 2026 and subsequent to June 30, 2026, Southern Power placed all 200 MWs of repowered capacity in service.
v3.26.1
Segment and Related Information (Tables)
 6 Months Ended
Jun. 30, 2026
Segment Reporting [Abstract]  
Schedule of Financial Data for Business Segments
Financial data for business segments for the three and six months ended June 30, 2026 and 2025 was as follows:
Electric Utilities
Traditional
Electric Operating
Companies		Southern
Power		EliminationsTotalSouthern Company Gas
Total Reportable Segments
All
Other		EliminationsConsolidated
(in millions)
Three Months Ended June 30, 2026
Operating revenues$5,396 $535 $(105)$5,826 $966 $6,792 $223 $(38)$6,977 
Other segment items(a)
2,501 329 (78)2,752 554 3,306 193 (27)3,472 
Depreciation and amortization(b)
967 280 (15)1,232 185 1,417 17 — 1,434 
Earnings from equity method investments12 — — 12 32 44 42 — 86 
Interest expense
367 28 (12)383 101 484 312 — 796 
Income taxes (benefit)304 (77)— 227 32 259 (72)— 187 
Segment net income (loss)(b)(c)
$1,269 $(25)$— $1,244 $126 $1,370 $(185)$(11)$1,174 
Six Months Ended June 30, 2026
Operating revenues$10,878 $1,216 $(246)$11,848 $3,157 $15,005 $441 $(72)$15,374 
Other segment items(a)
5,360 772 (219)5,913 1,911 7,824 382 (68)8,138 
Depreciation and amortization(b)
1,908 558 (15)2,451 369 2,820 34 — 2,854 
Earnings from equity method investments11 — — 11 78 89 47 — 136 
Interest expense(d)
705 55 (12)748 206 954 619 — 1,573 
Income taxes (benefit)534 (147)— 387 176 563 (149)— 414 
Segment net income (loss)(b)(c)(d)
$2,382 $(22)$— $2,360 $573 $2,933 $(398)$(4)$2,531 
At June 30, 2026
Goodwill$— $2 $— $2 $5,015 $5,017 $144 $— $5,161 
Total assets120,194 12,780 (2,101)130,873 27,604 158,477 4,283 (733)162,027 
Electric Utilities
Traditional
Electric Operating
Companies		Southern
Power		EliminationsTotalSouthern Company Gas
Total Reportable Segments
All
Other		EliminationsConsolidated
(in millions)
Three Months Ended June 30, 2025
Operating revenues$5,380 $546 $(122)$5,804 $979 $6,783 $225 $(35)$6,973 
Other segment items(a)
2,674 296 (122)2,848 599 3,447 193 (23)3,617 
Depreciation and amortization(b)
957 177 — 1,134 172 1,306 17 — 1,323 
Earnings from equity method investments4 — — 4 23 27 (17)— 10 
Interest expense(d)
336 24 — 360 92 452 422 — 874 
Income taxes (benefit)370 (2)— 368 33 401 (112)— 289 
Segment net income (loss)(b)(c)(d)
$1,047 $51 $— $1,098 $106 $1,204 $(312)$(12)$880 
Six Months Ended June 30, 2025
Operating revenues$10,692 $1,113 $(245)$11,560 $2,818 $14,378 $454 $(84)$14,748 
Other segment items(a)
5,468 599 (245)5,822 1,670 7,492 401 (81)7,812 
Depreciation and amortization(b)
1,905 329 — 2,234 341 2,575 33 — 2,608 
Earnings from equity method investments2 — — 2 62 64 (21)— 43 
Interest expense(d)
652 50 — 702 183 885 703 — 1,588 
Income taxes (benefit)596 (3)— 593 162 755 (186)— 569 
Segment net income (loss)(b)(c)(d)
$2,073 $138 $— $2,211 $524 $2,735 $(518)$(3)$2,214 
At December 31, 2025
Goodwill$— $2 $— $2 $5,015 $5,017 $144 $— $5,161 
Total assets114,287 12,657 (915)126,029 27,387 153,416 2,829 (525)155,720 
(a)Primarily consists of fuel, purchased power, cost of natural gas, cost of other sales, other operations and maintenance expenses, taxes other than income taxes, AFUDC equity, non-service cost-related retirement benefits income, and net income (loss) attributable to noncontrolling interests.
(b)For Southern Power, includes accelerated depreciation related to the repowering of multiple wind facilities of $140 million ($109 million after tax) and $293 million ($228 million after tax) for the three and six months ended June 30, 2026, respectively, and $42 million ($31 million after tax, net of noncontrolling interest impacts) and $69 million ($51 million after tax, net of noncontrolling interest impacts) for the three and six months ended June 30, 2025. See Note (K) under "Southern Power – Wind Repowering Projects" and Notes 5 and 15 to the financial statements under "Depreciation and Amortization – Southern Power" and "Southern Power – Wind Repowering Projects," respectively, in Item 8 of the Form 10-K for additional information.
(c)Attributable to Southern Company.
(d)For All Other, includes pre-tax losses associated with the extinguishment of debt at the parent company of $11 million ($8 million after tax) for the six months ended June 30, 2026 and $129 million ($97 million after tax) for the three and six months ended June 30, 2025.
Financial data for significant segment expenses and other segment information for the three and six months ended June 30, 2026 and 2025 was as follows:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
(in millions)
Alabama Power
Operating revenues$1,963 $1,968 $4,055 $3,980 
Utility operations and maintenance
Rate RSE expenses332 374 633 739 
Rate CNP Compliance expenses71 67 145 142 
Total utility operations and maintenance403 441 778 881 
Other segment items(a)
486 544 1,154 1,152 
Depreciation and amortization385 371 766 741 
Interest expense117 116 232 225 
Income taxes135 115 263 226 
Segment net income$437 $381 $862 $755 
Capital expenditures$501 $599 $1,019 $1,159 
Georgia Power
Operating revenues$3,133 $3,110 $6,276 $6,148 
Utility operations and maintenance586 568 1,164 1,104 
Other segment items(a)
886 989 2,050 2,106 
Depreciation and amortization503 512 987 1,015 
Interest expense228 198 431 385 
Income taxes151 236 236 334 
Segment net income$779 $607 $1,408 $1,204 
Capital expenditures$2,173 $1,676 $4,243 $3,313 
Mississippi Power
Operating revenues$403 $400 $875 $821 
Operational expenses(b)
80 65 144 122 
Environmental compliance expenses(c)
3 4 7 6 
Other segment items(a)
173 183 424 400 
Depreciation and amortization58 52 113 105 
Interest expense21 20 41 40 
Income taxes16 17 34 34 
Segment net income
$52 $59 $112 $114 
Capital expenditures$96 $126 $178 $199 
(a)Primarily consists of fuel, purchased power, expenses from unregulated products and services, losses (gains) on asset dispositions, amortization of cloud software, taxes other than income taxes, AFUDC equity, and non-service cost-related retirement benefits income. For Mississippi Power, includes employee benefit expenses. Also includes earnings from equity method investments, which were immaterial for all periods presented.
(b)Consists of certain operations and maintenance expenses related to PEP and the MRA tariff, including labor costs, materials, contract services, and other normal operational costs. See Note (B) under "Mississippi Power" and Note 2 to the financial statements under "Mississippi Power" in Item 8 of the Form 10-K for additional information regarding PEP and the MRA tariff.
(c)Consists of environmental compliance expenses related to ECO Plan and the MRA tariff. See Note (B) under "Mississippi Power" and Note 2 to the financial statements under "Mississippi Power" in Item 8 of the Form 10-K for additional information regarding ECO Plan and the MRA tariff.
Financial data for segment information for the three and six months ended June 30, 2026 and 2025 was as follows:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
(in millions)
Operating revenues
$535 $546 $1,216 $1,113 
Other segment items(a)
329 296 772 599 
Depreciation and amortization(b)
280 177 558 329 
Interest expense28 24 55 50 
Income taxes (benefit)(77)(2)(147)(3)
Segment net income (loss)(b)(c)
$(25)$51 $(22)$138 
(a)Primarily consists of fuel, purchased power, other operations and maintenance expenses, taxes other than income taxes, and net income (loss) attributable to noncontrolling interests.
(b)Includes accelerated depreciation related to the repowering of multiple wind facilities of $140 million ($109 million after tax) and $293 million ($228 million after tax) for the three and six months ended June 30, 2026, respectively, and $42 million ($31 million after tax, net of noncontrolling interest impacts) and $69 million ($51 million after tax, net of noncontrolling interest impacts) for the three and six months ended June 30, 2025 respectively. See Note (K) under "Southern Power – Wind Repowering Projects" and Notes 5 and 15 to the financial statements under "Depreciation and Amortization – Southern Power" and "Southern Power – Wind Repowering Projects," respectively, in Item 8 of the Form 10-K for additional information.
(c)Southern Power had no earnings from equity method investments for any period presented.
Financial data for business segments for the three and six months ended June 30, 2026 and 2025 was as follows:
Gas Distribution OperationsGas
Pipeline Investments		Gas Marketing Services
Total Reportable Segments
All
Other
EliminationsConsolidated
(in millions)
Three Months Ended June 30, 2026
Operating revenues$885 $8 $73 $966 $2 $(2)$966 
Other segment items(*)
496 1 54 551 5 (2)554 
Depreciation and amortization181 1 3 185 — — 185 
Earnings from equity method investments— 32 — 32 — — 32 
Interest expense90 9 1 100 1 — 101 
Income taxes (benefit)23 7 4 34 (2)— 32 
Segment net income (loss)$95 $22 $11 $128 $(2)$— $126 
Six Months Ended June 30, 2026
Operating revenues$2,785 $16 $358 $3,159 $4 $(6)$3,157 
Other segment items(*)
1,673 1 237 1,911 6 (6)1,911 
Depreciation and amortization360 2 5 367 2 — 369 
Earnings from equity method investments— 78 — 78 — — 78 
Interest expense181 18 2 201 5 — 206 
Income taxes (benefit)
139 18 32 189 (13)— 176 
Segment net income
$432 $55 $82 $569 $4 $— $573 
Total assets at June 30, 2026
$26,244 $1,546 $1,710 $29,500 $11,265 $(13,161)$27,604 
Three Months Ended June 30, 2025
Operating revenues$885 $8 $83 $976 $5 $(2)$979 
Other segment items(*)
526 1 68 595 6 (2)599 
Depreciation and amortization167 1 3 171 1 — 172 
Earnings from equity method investments— 23 — 23 — — 23 
Interest expense82 9 1 92 — — 92 
Income taxes19 5 3 27 6 — 33 
Segment net income (loss)$91 $15 $8 $114 $(8)$— $106 
Six Months Ended June 30, 2025
Operating revenues$2,454 $16 $345 $2,815 $9 $(6)$2,818 
Other segment items(*)
1,431 3 234 1,668 8 (6)1,670 
Depreciation and amortization330 3 7 340 1 — 341 
Earnings from equity method investments— 62 — 62 — — 62 
Interest expense164 18 1 183 — — 183 
Income taxes (benefit)
123 13 29 165 (3)— 162 
Segment net income$406 $41 $74 $521 $3 $— $524 
Total assets at December 31, 2025
$25,391 $1,475 $1,749 $28,615 $10,643 $(11,871)$27,387 
(*)Primarily consists of cost of natural gas, other operations and maintenance expenses, taxes other than income taxes, AFUDC equity, and non-service cost-related retirement benefits income.
v3.26.1
Introduction - Schedule of Goodwill (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Goodwill [Line Items]    
Goodwill $ 5,161 $ 5,161
SOUTHERN Co GAS    
Goodwill [Line Items]    
Goodwill 5,015 5,015
SOUTHERN Co GAS | Gas distribution operations    
Goodwill [Line Items]    
Goodwill 4,034 4,034
SOUTHERN Co GAS | Gas marketing services    
Goodwill [Line Items]    
Goodwill $ 981 $ 981
v3.26.1
Introduction - Schedule of Other Intangible Assets (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Subject to amortization:    
Gross Carrying Amount $ 669 $ 669
Accumulated Amortization (457) (444)
Other Intangible Assets, Net 212 225
Not subject to amortization:    
FCC licenses 75 75
Total other intangible assets    
Gross Carrying Amount 744 744
Accumulated Amortization (457) (444)
Other Intangible Assets, Net 287 300
Customer relationships    
Subject to amortization:    
Gross Carrying Amount 212 212
Accumulated Amortization (192) (189)
Other Intangible Assets, Net 20 23
Total other intangible assets    
Accumulated Amortization (192) (189)
Trade names    
Subject to amortization:    
Gross Carrying Amount 64 64
Accumulated Amortization (64) (64)
Other Intangible Assets, Net 0 0
Total other intangible assets    
Accumulated Amortization (64) (64)
PPA fair value adjustments    
Subject to amortization:    
Gross Carrying Amount 390 390
Accumulated Amortization (198) (188)
Other Intangible Assets, Net 192 202
Total other intangible assets    
Accumulated Amortization (198) (188)
Other    
Subject to amortization:    
Gross Carrying Amount 3 3
Accumulated Amortization (3) (3)
Other Intangible Assets, Net 0 0
Total other intangible assets    
Accumulated Amortization (3) (3)
SOUTHERN POWER CO    
Subject to amortization:    
Accumulated Amortization (198) (188)
Total other intangible assets    
Accumulated Amortization (198) (188)
SOUTHERN POWER CO | PPA fair value adjustments    
Subject to amortization:    
Gross Carrying Amount 390 390
Accumulated Amortization (198) (188)
Other Intangible Assets, Net 192 202
Total other intangible assets    
Accumulated Amortization (198) (188)
SOUTHERN Co GAS    
Subject to amortization:    
Gross Carrying Amount 182 182
Accumulated Amortization (181) (179)
Other Intangible Assets, Net 1 3
Total other intangible assets    
Accumulated Amortization (181) (179)
Other Intangible Assets, Net 1 3
SOUTHERN Co GAS | Customer relationships    
Subject to amortization:    
Gross Carrying Amount 156 156
Accumulated Amortization (155) (153)
Other Intangible Assets, Net 1 3
Total other intangible assets    
Accumulated Amortization (155) (153)
SOUTHERN Co GAS | Trade names    
Subject to amortization:    
Gross Carrying Amount 26 26
Accumulated Amortization (26) (26)
Other Intangible Assets, Net 0 0
Total other intangible assets    
Accumulated Amortization $ (26) $ (26)
v3.26.1
Introduction - Schedule of Amortization of Other Intangible Assets (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Intangible Asset, Finite-Lived [Line Items]        
Amortization of intangible assets $ 7 $ 8 $ 13 $ 16
Decrease in operating revenues 5 5 10 10
SOUTHERN POWER CO        
Intangible Asset, Finite-Lived [Line Items]        
Amortization of intangible assets 5 5 10 10
SOUTHERN Co GAS        
Intangible Asset, Finite-Lived [Line Items]        
Amortization of intangible assets $ 1 $ 1 $ 2 $ 3
v3.26.1
Introduction - Schedule of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Dec. 31, 2024
Restricted Cash and Cash Equivalent Item [Line Items]        
Cash and cash equivalents $ 2,984 $ 1,639    
Restricted cash:        
Total cash, cash equivalents, and restricted cash 2,990 1,640 $ 1,265 $ 1,101
Other current assets        
Restricted cash:        
Restricted cash 5 1    
GEORGIA POWER CO        
Restricted Cash and Cash Equivalent Item [Line Items]        
Cash and cash equivalents 72 59    
Restricted cash:        
Total cash, cash equivalents, and restricted cash 72 59 94 118
SOUTHERN POWER CO        
Restricted Cash and Cash Equivalent Item [Line Items]        
Cash and cash equivalents 278 105    
Restricted cash:        
Total cash, cash equivalents, and restricted cash 278 105 143 168
SOUTHERN Co GAS        
Restricted Cash and Cash Equivalent Item [Line Items]        
Cash and cash equivalents 214 15    
Restricted cash:        
Total cash, cash equivalents, and restricted cash 218 15 $ 225 $ 44
SOUTHERN Co GAS | Other current assets        
Restricted cash:        
Restricted cash 4 0    
Southern Holdings Company | Collateral For Life Insurance And Long-Term Disability Insurance        
Restricted cash:        
Restricted cash $ 1 $ 1    
v3.26.1
Introduction - Asset Retirement Obligations (Details)
$ in Millions
 1 Months Ended
Jun. 30, 2026
USD ($)
GEORGIA POWER CO  
Schedule of Asset Retirement Obligation [Line Items]  
ARO liabilities $ 46
v3.26.1
Regulatory Matters - Schedule of Cost Recovery Clauses (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
ALABAMA POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsCurrent    
Loss Contingencies [Line Items]    
Rate ECR $ 7 $ 0
ALABAMA POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsDeferred    
Loss Contingencies [Line Items]    
Rate ECR 212 146
ALABAMA POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryLiabilitiesDeferred    
Loss Contingencies [Line Items]    
Liability for Unpaid Claims and Claims Adjustment Expense, Net 29 60
GEORGIA POWER CO | Balance Sheet Location [Axis]: us-gaap:DeferredCosts    
Loss Contingencies [Line Items]    
Fuel cost recovery 151 212
GEORGIA POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsCurrent | Property Damage Reserve Asset    
Loss Contingencies [Line Items]    
Regulatory asset balance related to storm damage 187 31
GEORGIA POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsDeferred | Property Damage Reserve Asset    
Loss Contingencies [Line Items]    
Regulatory asset balance related to storm damage 784 880
GEORGIA POWER CO | Balance Sheet Location [Axis]: so:UnderRecoveredFuelClauseRevenuesReceivablesCurrent    
Loss Contingencies [Line Items]    
Fuel cost recovery 161 310
MISSISSIPPI POWER CO | Wholesale MB    
Loss Contingencies [Line Items]    
Fuel cost recovery 0 0
MISSISSIPPI POWER CO | Balance Sheet Location [Axis]: us-gaap:AccountsReceivableGrossCurrent | Wholesale MRA    
Loss Contingencies [Line Items]    
Fuel cost recovery 10 6
MISSISSIPPI POWER CO | Balance Sheet Location [Axis]: us-gaap:DeferredCosts    
Loss Contingencies [Line Items]    
Fuel cost recovery 0 40
MISSISSIPPI POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryLiabilitiesDeferred | Retail electric revenues    
Loss Contingencies [Line Items]    
Property damage reserve 56 57
MISSISSIPPI POWER CO | Balance Sheet Location [Axis]: so:UnderRecoveredFuelClauseRevenuesReceivablesCurrent    
Loss Contingencies [Line Items]    
Fuel cost recovery 55 0
SOUTHERN Co GAS | Balance Sheet Location [Axis]: so:NaturalGasCostOverRecoveryShortTerm    
Loss Contingencies [Line Items]    
Natural gas cost under recovery $ 191 $ 158
v3.26.1
Regulatory Matters - Alabama Power (Details) - USD ($)
$ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2026
Mar. 31, 2026
Dec. 31, 2025
Loss Contingencies [Line Items]        
In service $ 151,437     $ 146,114
ALABAMA POWER CO        
Loss Contingencies [Line Items]        
In service 40,731     38,915
ALABAMA POWER CO | Plant Barry Unit 5        
Loss Contingencies [Line Items]        
In service     $ 307  
SOUTHERN POWER CO        
Loss Contingencies [Line Items]        
In service 15,339     $ 15,034
SOUTHERN POWER CO | Plant Barry Unit 5        
Loss Contingencies [Line Items]        
In service     $ 307  
Reliability Reserve Liability | ALABAMA POWER CO        
Loss Contingencies [Line Items]        
Remaining net book value 144      
Reliability reserve expense $ 40      
Reliability Reserve Liability | ALABAMA POWER CO | Scenario, Forecast        
Loss Contingencies [Line Items]        
Reliability reserve expense   $ 60    
v3.26.1
Regulatory Matters - Georgia Power (Details) - GEORGIA POWER CO
$ in Millions
 1 Months Ended 6 Months Ended
Jun. 09, 2026
MW
Jun. 02, 2026
project
MW
May 28, 2026
USD ($)
Mar. 25, 2026
MW
Jan. 01, 2026
USD ($)
Dec. 31, 2025
USD ($)
Dec. 19, 2025
MW
May 14, 2025
USD ($)
May 31, 2023
USD ($)
Jun. 30, 2026
USD ($)
MW
Public Utilities, General Disclosures [Line Items]                    
Capital costs | $                   $ 4,400
Total certified amounts | $                   $ 19,500
Approved capacity increase (in MWs)             9,885      
Generating capacity petitioned for decertification (at least)       757            
Approved affiliate PPAs | project   2                
Requested revenues increase (decrease) percentage     (12.90%)              
Requested rate increase amount | $     $ (394)              
Fuel cost recovery rate adjustment period     30 days              
Storm damage reserves | $         $ 31 $ 156        
Recovery period           67 months        
Regulatory liability | $     $ 77     $ 869        
First PPA                    
Public Utilities, General Disclosures [Line Items]                    
Approved capacity increase (in MWs)   638                
Second PPA                    
Public Utilities, General Disclosures [Line Items]                    
Approved capacity increase (in MWs)   74                
Plant Bowen Unit 8                    
Public Utilities, General Disclosures [Line Items]                    
Approximate nameplate capacity                   741
Plant Wansley Unit 10                    
Public Utilities, General Disclosures [Line Items]                    
Approximate nameplate capacity                   727
Minimum                    
Public Utilities, General Disclosures [Line Items]                    
Approved capacity increase (in MWs) 2,000                  
Maximum                    
Public Utilities, General Disclosures [Line Items]                    
Approved rate increase (decrease) | $               $ 200    
Approved capacity increase (in MWs) 6,000                  
Requested rate increase amount | $                 $ 300  
Approved rate increase (decrease)                 40.00%  
v3.26.1
Regulatory Matters - Georgia Power, Projects Under Construction (Details) - GEORGIA POWER CO
Jun. 30, 2026
MW
McGrau Ford Phase 2  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 265
McGrau Ford Phase 1  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 265
Hammond Phase 1  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 58
Hammond Phase 2  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 193
Twiggs County  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 200
Wadley  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 260
Plant Bowen, Phase 1  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 250
Plant Bowen, Phase 2  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 250
South Hall  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 250
Plant Wansley  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 500
Plant Yates, Phase 1  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 320
Plant Yates, Phase 2  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 250
Thomson  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 500
Plant McIntosh  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 250
Laurens County  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 200
Plant Mitchell  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 150
Plant Bowen Unit 7  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 741
Plant Bowen Unit 8  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 741
Plant Wansley Unit 10  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 727
Plant Wansley Unit 11  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 727
Plant McIntosh Unit 12  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 757
Plant Yates Unit 8  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 442
Plant Yates Unit 9  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 442
Plant Yates Unit 10  
Public Utilities, General Disclosures [Line Items]  
Approximate nameplate capacity 442
Robins  
Public Utilities, General Disclosures [Line Items]  
Nameplate capacity placed in service 128
Moody  
Public Utilities, General Disclosures [Line Items]  
Nameplate capacity placed in service 50
v3.26.1
Regulatory Matters - Mississippi Power (Details) - MISSISSIPPI POWER CO - USD ($)
$ in Millions
Jun. 18, 2026
Jun. 12, 2026
Apr. 14, 2026
Mar. 02, 2026
Jun. 30, 2026
Mar. 16, 2026
Loss Contingencies [Line Items]            
Deferred Income Taxes, Excess Accumulated Amount $ 21.0          
Deferred Income Taxes, Excess Accumulated Amount, Period 18 months          
Plant Daniel Units 1 and 2            
Loss Contingencies [Line Items]            
Remaining net book value         $ 481.0  
Reliability Reserve Liability            
Loss Contingencies [Line Items]            
Reliability reserve expense $ 7.0          
Remaining net book value         $ 52.0 $ 59.0
Mississippi PSC PEP Filing            
Loss Contingencies [Line Items]            
Approved rate increase (decrease) $ 20.0          
Approved rate increase (decrease) 1.80%          
Mississippi PSC            
Loss Contingencies [Line Items]            
Approved rate increase (decrease)     $ 2.0      
Mississippi PSC SRR Filing            
Loss Contingencies [Line Items]            
Approved rate increase (decrease)       $ 13.7    
Minimum annual accrual, amount       $ 13.5    
Ad Valorem Tax Adjustment            
Loss Contingencies [Line Items]            
Requested rate increase amount   $ 7.0        
v3.26.1
Regulatory Matters - Southern Company Gas (Details)
$ in Millions
Jun. 16, 2026
USD ($)
Nicor Gas | Investing In Illinois Qualifying Infrastructure Plant  
Public Utilities, General Disclosures [Line Items]  
Capital expenditures disallowed $ 43
v3.26.1
Contingencies - Environmental Remediation (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
GEORGIA POWER CO    
Loss Contingencies [Line Items]    
Environmental remediation liability, current and former sites $ 15 $ 14
SOUTHERN Co GAS    
Loss Contingencies [Line Items]    
Environmental remediation liability, current and former sites $ 215 $ 227
v3.26.1
Revenue from Contracts with Customers and Lease Income - Schedule of Disaggregation of Revenue (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers $ 6,722 $ 6,734 $ 14,765 $ 14,328
Total operating revenues 6,977 6,973 15,374 14,748
Residential        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 2,007 2,021 4,010 4,087
Commercial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 1,757 1,716 3,419 3,327
Industrial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 1,021 1,015 1,962 1,930
Other        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 29 29 61 61
Retail electric revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 4,814 4,781 9,452 9,405
Natural gas distribution revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 873 886 2,763 2,464
Residential        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 353 394 1,380 1,239
Commercial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 89 94 342 292
Transportation        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 358 331 798 737
Industrial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 6 7 30 26
Other        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 67 60 213 170
Wholesale electric revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 510 524 1,246 1,158
PPA energy revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 301 310 796 723
PPA capacity revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 145 154 294 299
Non-PPA revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 64 60 156 136
Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 75 86 359 347
Gas marketing services        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 73 81 355 337
Other        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 2 5 4 10
Other revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 450 457 945 954
Other revenue sources        
Disaggregation of Revenue [Line Items]        
Other revenues 255 239 609 420
ALABAMA POWER CO        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 1,847 1,853 3,776 3,768
Total operating revenues 1,963 1,968 4,055 3,980
ALABAMA POWER CO | Residential        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 720 725 1,493 1,531
ALABAMA POWER CO | Commercial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 501 504 978 986
ALABAMA POWER CO | Industrial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 441 432 855 822
ALABAMA POWER CO | Other        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 3 2 6 4
ALABAMA POWER CO | Retail electric revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 1,665 1,663 3,332 3,343
ALABAMA POWER CO | Wholesale electric revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 120 123 304 275
ALABAMA POWER CO | PPA energy revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 47 58 93 112
ALABAMA POWER CO | PPA capacity revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 18 29 36 57
ALABAMA POWER CO | Non-PPA revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 55 36 175 106
ALABAMA POWER CO | Other revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 62 67 140 150
ALABAMA POWER CO | Other revenue sources        
Disaggregation of Revenue [Line Items]        
Other revenues 116 115 279 212
GEORGIA POWER CO        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 3,172 3,166 6,278 6,239
Total operating revenues 3,133 3,110 6,276 6,148
GEORGIA POWER CO | Residential        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 1,208 1,217 2,358 2,403
GEORGIA POWER CO | Commercial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 1,166 1,127 2,269 2,181
GEORGIA POWER CO | Industrial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 471 496 909 940
GEORGIA POWER CO | Other        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 24 25 50 52
GEORGIA POWER CO | Retail electric revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 2,869 2,865 5,586 5,576
GEORGIA POWER CO | Wholesale electric revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 91 95 243 227
GEORGIA POWER CO | PPA energy revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 40 50 104 134
GEORGIA POWER CO | PPA capacity revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 32 35 76 74
GEORGIA POWER CO | Non-PPA revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 19 10 63 19
GEORGIA POWER CO | Other revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 212 206 449 436
GEORGIA POWER CO | Other revenue sources        
Disaggregation of Revenue [Line Items]        
Other revenues (39) (56) (2) (91)
MISSISSIPPI POWER CO        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 404 381 867 788
Total operating revenues 403 400 875 821
MISSISSIPPI POWER CO | Residential        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 79 79 159 153
MISSISSIPPI POWER CO | Commercial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 90 85 172 160
MISSISSIPPI POWER CO | Industrial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 109 87 198 168
MISSISSIPPI POWER CO | Other        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 2 2 5 5
MISSISSIPPI POWER CO | Retail electric revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 280 253 534 486
MISSISSIPPI POWER CO | Wholesale electric revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 113 119 307 272
MISSISSIPPI POWER CO | PPA energy revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 8 2 11 5
MISSISSIPPI POWER CO | PPA capacity revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 25 17 46 34
MISSISSIPPI POWER CO | Non-PPA revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 80 100 250 233
MISSISSIPPI POWER CO | Other revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 11 9 26 30
MISSISSIPPI POWER CO | Other revenue sources        
Disaggregation of Revenue [Line Items]        
Other revenues (1) 19 8 33
SOUTHERN POWER CO        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 354 362 878 795
Total operating revenues 535 546 1,216 1,113
SOUTHERN POWER CO | Residential        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
SOUTHERN POWER CO | Commercial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
SOUTHERN POWER CO | Industrial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
SOUTHERN POWER CO | Other        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
SOUTHERN POWER CO | Retail electric revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
SOUTHERN POWER CO | Wholesale electric revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 350 354 870 781
SOUTHERN POWER CO | PPA energy revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 218 210 610 491
SOUTHERN POWER CO | PPA capacity revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 89 85 172 169
SOUTHERN POWER CO | Non-PPA revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 43 59 88 121
SOUTHERN POWER CO | Other revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 4 8 8 14
SOUTHERN POWER CO | Other revenue sources        
Disaggregation of Revenue [Line Items]        
Other revenues 181 184 338 318
SOUTHERN Co GAS        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 948 972 3,122 2,811
Total operating revenues 966 979 3,157 2,818
SOUTHERN Co GAS | Natural gas distribution revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 873 886 2,763 2,464
SOUTHERN Co GAS | Residential        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 353 394 1,380 1,239
SOUTHERN Co GAS | Commercial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 89 94 342 292
SOUTHERN Co GAS | Transportation        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 358 331 798 737
SOUTHERN Co GAS | Industrial        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 6 7 30 26
SOUTHERN Co GAS | Other        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 67 60 213 170
SOUTHERN Co GAS | Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 75 86 359 347
SOUTHERN Co GAS | Gas marketing services        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 73 81 355 337
SOUTHERN Co GAS | Other        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 2 5 4 10
SOUTHERN Co GAS | Other revenues        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
SOUTHERN Co GAS | Other revenue sources        
Disaggregation of Revenue [Line Items]        
Other revenues $ 18 $ 7 $ 35 $ 7
v3.26.1
Revenue from Contracts with Customers and Lease Income - Schedule of Contract Balances (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2026
Dec. 31, 2025
Disaggregation of Revenue [Line Items]      
Accounts Receivable $ 3,155 $ 3,155 $ 3,139
Contract Assets 354 354 294
Contract Liabilities 329 329 213
Revenue from contracts with customers recognized 26 80  
ALABAMA POWER CO      
Disaggregation of Revenue [Line Items]      
Accounts Receivable 860 860 716
Contract Assets 0 0 3
Contract Liabilities 7 7 6
Revenue from contracts with customers recognized 0 0  
GEORGIA POWER CO      
Disaggregation of Revenue [Line Items]      
Accounts Receivable 1,549 1,549 1,278
Contract Assets 189 189 160
Contract Liabilities 123 123 75
Revenue from contracts with customers recognized 7 18  
MISSISSIPPI POWER CO      
Disaggregation of Revenue [Line Items]      
Accounts Receivable 122 122 115
Contract Assets 4 4 0
Contract Liabilities 0 0 0
Revenue from contracts with customers recognized 0 0  
SOUTHERN POWER CO      
Disaggregation of Revenue [Line Items]      
Accounts Receivable 136 136 132
Contract Assets 0 0 0
Contract Liabilities 1 1 2
Revenue from contracts with customers recognized 0 0  
SOUTHERN Co GAS      
Disaggregation of Revenue [Line Items]      
Accounts Receivable 448 448 864
Contract Assets 67 67 67
Contract Liabilities 0 0 $ 0
Revenue from contracts with customers recognized $ 0 $ 0  
v3.26.1
Revenue from Contracts with Customers and Lease Income - Narrative (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2026
Dec. 31, 2025
Disaggregation of Revenue [Line Items]      
Contract liabilities $ 329 $ 329 $ 213
Contract assets 354 354 294
Revenue from contracts with customers recognized 26 80  
GEORGIA POWER CO      
Disaggregation of Revenue [Line Items]      
Contract liabilities 123 123 75
Contract assets 189 189 160
Revenue from contracts with customers recognized 7 18  
SOUTHERN Co GAS      
Disaggregation of Revenue [Line Items]      
Contract liabilities 0 0 0
Contract assets 67 67 67
Revenue from contracts with customers recognized 0 0  
ALABAMA POWER CO      
Disaggregation of Revenue [Line Items]      
Contract liabilities 7 7 6
Contract assets 0 0 3
Revenue from contracts with customers recognized 0 0  
MISSISSIPPI POWER CO      
Disaggregation of Revenue [Line Items]      
Contract liabilities 0 0 0
Contract assets 4 4 0
Revenue from contracts with customers recognized 0 0  
SOUTHERN POWER CO      
Disaggregation of Revenue [Line Items]      
Contract liabilities 1 1 2
Contract assets 0 0 0
Revenue from contracts with customers recognized 0 $ 0  
Retail Customer Fixed Bill Programs | GEORGIA POWER CO      
Disaggregation of Revenue [Line Items]      
Contract term   1 year  
Energy Efficiency Enhancement And Upgrade | SOUTHERN Co GAS      
Disaggregation of Revenue [Line Items]      
Contract liabilities 68 $ 68  
Unregulated Distributed Generation      
Disaggregation of Revenue [Line Items]      
Contract liabilities 199 199 132
Contract assets $ 92 $ 92 $ 63
v3.26.1
Revenue from Contracts with Customers and Lease Income - Schedule of Remaining Performance Obligations (Details)
$ in Millions
Jun. 30, 2026
USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-07-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 668
Performance obligation, expected timing of satisfaction 6 months
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 $ 826
Performance obligation, 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 $ 472
Performance obligation, 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 $ 413
Performance obligation, 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 $ 416
Performance obligation, expected timing of satisfaction 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2031-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 3,130
Performance obligation, expected timing of satisfaction
ALABAMA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-07-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 7
Performance obligation, expected timing of satisfaction 6 months
ALABAMA POWER CO | 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 $ 5
Performance obligation, expected timing of satisfaction 1 year
ALABAMA POWER CO | 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 $ 4
Performance obligation, expected timing of satisfaction 1 year
ALABAMA POWER CO | 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 $ 3
Performance obligation, expected timing of satisfaction 1 year
ALABAMA POWER CO | 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 $ 1
Performance obligation, expected timing of satisfaction 1 year
ALABAMA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2031-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 6
Performance obligation, expected timing of satisfaction
GEORGIA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-07-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 37
Performance obligation, expected timing of satisfaction 6 months
GEORGIA POWER CO | 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
Performance obligation, expected timing of satisfaction 1 year
GEORGIA POWER CO | 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 $ 46
Performance obligation, expected timing of satisfaction 1 year
GEORGIA POWER CO | 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 $ 22
Performance obligation, expected timing of satisfaction 1 year
GEORGIA POWER CO | 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 $ 22
Performance obligation, expected timing of satisfaction 1 year
GEORGIA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2031-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 146
Performance obligation, expected timing of satisfaction
MISSISSIPPI POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-07-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 33
Performance obligation, expected timing of satisfaction 6 months
MISSISSIPPI POWER CO | 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
Performance obligation, expected timing of satisfaction 1 year
MISSISSIPPI POWER CO | 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
Performance obligation, expected timing of satisfaction 1 year
MISSISSIPPI POWER CO | 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 $ 12
Performance obligation, expected timing of satisfaction 1 year
MISSISSIPPI POWER CO | 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
Performance obligation, expected timing of satisfaction 1 year
MISSISSIPPI POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2031-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
Performance obligation, expected timing of satisfaction
SOUTHERN POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-07-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 184
Performance obligation, expected timing of satisfaction 6 months
SOUTHERN POWER CO | 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 $ 349
Performance obligation, expected timing of satisfaction 1 year
SOUTHERN POWER CO | 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 $ 389
Performance obligation, expected timing of satisfaction 1 year
SOUTHERN POWER CO | 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 $ 393
Performance obligation, expected timing of satisfaction 1 year
SOUTHERN POWER CO | 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 $ 393
Performance obligation, expected timing of satisfaction 1 year
SOUTHERN POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2031-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 2,978
Performance obligation, expected timing of satisfaction
SOUTHERN Co GAS | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-07-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 28
SOUTHERN Co 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 24
SOUTHERN Co 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
SOUTHERN Co 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
SOUTHERN Co 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
SOUTHERN Co GAS | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2031-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 0
v3.26.1
Revenue from Contracts with Customers and Lease Income - Schedule of Lease Income (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Lessor, Lease, Description [Line Items]        
Lease income - interest income on sales-type leases $ 5 $ 6 $ 12 $ 11
Lease income - operating leases 34 33 69 66
Variable lease income 125 125 204 207
Total lease income 164 164 285 284
ALABAMA POWER CO        
Lessor, Lease, Description [Line Items]        
Lease income - interest income on sales-type leases 0 0 0 0
Lease income - operating leases 3 2 6 3
Variable lease income 0 0 0 1
Total lease income 3 2 6 4
GEORGIA POWER CO        
Lessor, Lease, Description [Line Items]        
Lease income - interest income on sales-type leases 0 0 0 0
Lease income - operating leases 7 7 15 14
Variable lease income 0 0 0 0
Total lease income 7 7 15 14
MISSISSIPPI POWER CO        
Lessor, Lease, Description [Line Items]        
Lease income - interest income on sales-type leases 3 4 7 7
Lease income - operating leases 1 1 2 1
Variable lease income 0 0 0 0
Total lease income 4 5 9 8
SOUTHERN POWER CO        
Lessor, Lease, Description [Line Items]        
Lease income - interest income on sales-type leases 2 2 4 4
Lease income - operating leases 27 37 64 73
Variable lease income 136 136 223 225
Total lease income 165 175 291 302
SOUTHERN Co GAS        
Lessor, Lease, Description [Line Items]        
Lease income - interest income on sales-type leases 0 0 0 0
Lease income - operating leases 9 9 18 18
Variable lease income 0 0 0 0
Total lease income $ 9 $ 9 $ 18 $ 18
v3.26.1
Consolidated Entities and Equity Method Investments - Narrative (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Schedule of Equity Method Investments [Line Items]          
Equity investments in unconsolidated subsidiaries $ 1,428   $ 1,428   $ 1,318
Earnings from equity method investments 86 $ 10 136 $ 43  
Assets 162,027   162,027   155,720
Liabilities 119,685   119,685   116,853
Southern Holdings Company          
Schedule of Equity Method Investments [Line Items]          
Equity investments in unconsolidated subsidiaries 156   156   124
Earnings from equity method investments 45 (14) 48 (20)  
SOUTHERN POWER CO          
Schedule of Equity Method Investments [Line Items]          
Earnings from equity method investments     0 0  
Assets 12,780   12,780   12,657
Liabilities 6,038   6,038   6,136
SOUTHERN Co GAS          
Schedule of Equity Method Investments [Line Items]          
Equity investments in unconsolidated subsidiaries 1,254   1,254   1,182
Earnings from equity method investments 32 23 78 62  
Assets 27,604   27,604   27,387
Liabilities 16,163   16,163   16,260
SOUTHERN Co GAS | Other          
Schedule of Equity Method Investments [Line Items]          
Equity investments in unconsolidated subsidiaries 34   34   34
Earnings from equity method investments 0 $ 0 $ 0 $ 0  
SP Solar Holdings I, LP | SOUTHERN POWER CO          
Schedule of Equity Method Investments [Line Items]          
Distribution made to limited partner, cash distributions paid, percentage     67.00%    
SP Solar Holdings I, LP | Financial Investors          
Schedule of Equity Method Investments [Line Items]          
Distribution made to limited partner, cash distributions paid, percentage     33.00%    
Variable Interest Entity, Primary Beneficiary | SP Solar Holdings I, LP | SOUTHERN POWER CO          
Schedule of Equity Method Investments [Line Items]          
Assets 5,100   $ 5,100   5,200
Liabilities 364   364   360
Noncontrolling interests related to other partners' interests 907   907   918
Variable Interest Entity, Primary Beneficiary | Other Variable Interest Entities | SOUTHERN POWER CO          
Schedule of Equity Method Investments [Line Items]          
Assets 1,500   1,500   1,600
Liabilities 259   259   236
Noncontrolling interests related to other partners' interests $ 563   $ 563   $ 617
v3.26.1
Consolidated Entities and Equity Method Investments - Schedule of Equity Method Investments (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Schedule of Equity Method Investments [Line Items]    
Investment Balance $ 1,428 $ 1,318
SOUTHERN Co GAS    
Schedule of Equity Method Investments [Line Items]    
Investment Balance 1,254 1,182
SOUTHERN Co GAS | SNG    
Schedule of Equity Method Investments [Line Items]    
Investment Balance 1,220 1,148
SOUTHERN Co GAS | Other    
Schedule of Equity Method Investments [Line Items]    
Investment Balance $ 34 $ 34
v3.26.1
Consolidated Entities and Equity Method Investments - Schedule of Earnings (Loss) from Equity Method Investments (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Schedule of Equity Method Investments [Line Items]          
Earnings from equity method investments $ 86 $ 10 $ 136 $ 43  
Equity investments in unconsolidated subsidiaries 1,428   1,428   $ 1,318
SOUTHERN Co GAS          
Schedule of Equity Method Investments [Line Items]          
Earnings from equity method investments 32 23 78 62  
Equity investments in unconsolidated subsidiaries 1,254   1,254   1,182
SOUTHERN Co GAS | SNG          
Schedule of Equity Method Investments [Line Items]          
Earnings from equity method investments 32 23 77 62  
Equity investments in unconsolidated subsidiaries 1,220   1,220   1,148
SOUTHERN Co GAS | Other          
Schedule of Equity Method Investments [Line Items]          
Earnings from equity method investments 0 0 0 0  
Equity investments in unconsolidated subsidiaries 34   34   34
Southern Holdings Company          
Schedule of Equity Method Investments [Line Items]          
Earnings from equity method investments 45 $ (14) 48 $ (20)  
Equity investments in unconsolidated subsidiaries $ 156   $ 156   $ 124
v3.26.1
Financing and Leases - Schedule of Credit Arrangements (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Mar. 31, 2026
Feb. 20, 2026
Line of Credit Facility [Line Items]      
2026 $ 15    
2028 30    
2028 500    
2029 775    
2031 7,600    
Total 8,920    
Unused 8,909    
Expires within One Year 45    
Southern Company parent      
Line of Credit Facility [Line Items]      
2026 0    
2028 0    
2028 500    
2029 0    
2031 2,500    
Total 3,000    
Unused 2,999    
Expires within One Year 0    
ALABAMA POWER CO      
Line of Credit Facility [Line Items]      
2026 15    
2028 0    
2028 0    
2029 650    
2031 700    
Total 1,365    
Unused 1,365    
Expires within One Year 15    
ALABAMA POWER CO | FFB Credit Facility      
Line of Credit Facility [Line Items]      
Total     $ 4,100
GEORGIA POWER CO      
Line of Credit Facility [Line Items]      
2026 0    
2028 0    
2028 0    
2029 0    
2031 2,050    
Total 2,050    
Unused 2,042    
Expires within One Year 0    
GEORGIA POWER CO | Uncommited Letter Of Credit Facility      
Line of Credit Facility [Line Items]      
Letters of credit outstanding 26    
GEORGIA POWER CO | FFB Credit Facility      
Line of Credit Facility [Line Items]      
Total     $ 22,400
MISSISSIPPI POWER CO      
Line of Credit Facility [Line Items]      
2026 0    
2028 0    
2028 0    
2029 125    
2031 150    
Total 275    
Unused 275    
Expires within One Year 0    
SOUTHERN POWER CO      
Line of Credit Facility [Line Items]      
2026 0    
2028 0    
2028 0    
2029 0    
2031 600    
Total 600    
Unused 600    
Expires within One Year 0    
SOUTHERN POWER CO | Continuing Letter of Credit Facility A      
Line of Credit Facility [Line Items]      
Total 75    
Unused 17    
SOUTHERN POWER CO | Continuing Letter of Credit Facility B      
Line of Credit Facility [Line Items]      
Total 100    
Unused 4    
SOUTHERN POWER CO | Uncommited Letter Of Credit Facility      
Line of Credit Facility [Line Items]      
Letters of credit outstanding 23    
SOUTHERN Co GAS      
Line of Credit Facility [Line Items]      
2026 0    
2028 0    
2028 0    
2029 0    
2031 1,600    
Total 1,600    
Unused 1,598    
Expires within One Year 0    
SEGCO      
Line of Credit Facility [Line Items]      
2026 0    
2028 30    
2028 0    
2029 0    
2031 0    
Total 30    
Unused 30    
Expires within One Year 30    
Southern Company, Southern Power, And Mississippi Power      
Line of Credit Facility [Line Items]      
Total   $ 3,250  
Alabama Property Company      
Line of Credit Facility [Line Items]      
2026 15    
Unused 15    
Southern Company Gas Capital      
Line of Credit Facility [Line Items]      
2031 800    
Nicor Gas      
Line of Credit Facility [Line Items]      
2031 $ 800    
v3.26.1
Financing and Leases - Bank Credit Agreements Narrative (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Mar. 31, 2026
Debt Instrument [Line Items]    
Line of credit facility, maximum borrowing capacity $ 8,920  
Variable rate pollution control revenue bonds outstanding 1,500  
Southern Company, Southern Power, And Mississippi Power    
Debt Instrument [Line Items]    
Line of credit facility, maximum borrowing capacity   $ 3,250
ALABAMA POWER CO    
Debt Instrument [Line Items]    
Line of credit facility, maximum borrowing capacity 1,365  
Variable rate pollution control revenue bonds outstanding 796  
GEORGIA POWER CO    
Debt Instrument [Line Items]    
Line of credit facility, maximum borrowing capacity 2,050  
Variable rate pollution control revenue bonds outstanding 667  
Fixed rate pollution control revenue bonds outstanding 210  
MISSISSIPPI POWER CO    
Debt Instrument [Line Items]    
Line of credit facility, maximum borrowing capacity 275  
Variable rate pollution control revenue bonds outstanding $ 58  
v3.26.1
Financing and Leases - DOE Loan Guarantee Borrowings (Details) - USD ($)
$ in Millions
 1 Months Ended 6 Months Ended
Feb. 20, 2026
Mar. 31, 2026
Jun. 30, 2026
Line of Credit Facility [Line Items]      
Line of credit facility, maximum borrowing capacity     $ 8,920
GEORGIA POWER CO      
Line of Credit Facility [Line Items]      
Line of credit facility, maximum borrowing capacity     $ 2,050
GEORGIA POWER CO | FFB Credit Facility      
Line of Credit Facility [Line Items]      
Borrower reimbursement, maximum percentage of eligible project costs 80.00%    
Line of credit facility, maximum borrowing capacity $ 22,400    
Interest rate   5.041%  
Debt Instrument, Basis Spread on Variable Rate     0.375%
Prepayment requirement, percentage of total advances made to borrower, minimum threshold 95.00%    
Mandatory prepayment, percentage of principal to be prepaid 100.00%    
Proceeds from Lines of Credit   $ 1,000  
GEORGIA POWER CO | FFB Credit Facility | Minimum      
Line of Credit Facility [Line Items]      
Mandatory prepayment, payable period 1 year    
GEORGIA POWER CO | FFB Credit Facility | Maximum      
Line of Credit Facility [Line Items]      
Mandatory prepayment, payable period 5 years    
ALABAMA POWER CO      
Line of Credit Facility [Line Items]      
Line of credit facility, maximum borrowing capacity     $ 1,365
ALABAMA POWER CO | FFB Credit Facility      
Line of Credit Facility [Line Items]      
Borrower reimbursement, maximum percentage of eligible project costs 80.00%    
Line of credit facility, maximum borrowing capacity $ 4,100    
Debt Instrument, Basis Spread on Variable Rate     0.375%
Prepayment requirement, percentage of total advances made to borrower, minimum threshold 95.00%    
Mandatory prepayment, percentage of principal to be prepaid 100.00%    
ALABAMA POWER CO | FFB Credit Facility | Minimum      
Line of Credit Facility [Line Items]      
Mandatory prepayment, payable period 1 year    
ALABAMA POWER CO | FFB Credit Facility | Maximum      
Line of Credit Facility [Line Items]      
Mandatory prepayment, payable period 3 years    
v3.26.1
Financing and Leases - Equity Distribution Agreement (Details) - USD ($)
$ / shares in Units, $ in Millions
 1 Months Ended 3 Months Ended 6 Months Ended 7 Months Ended 12 Months Ended
Jun. 16, 2026
Jun. 12, 2026
Jun. 01, 2026
Mar. 31, 2026
Mar. 02, 2026
Jul. 29, 2026
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2026
Jun. 30, 2026
Jun. 30, 2025
Jul. 29, 2026
Dec. 31, 2025
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)       11,483,995                  
Proceeds from issuance of common stock                   $ 2,596 $ 62    
At The Market Program | Maximum                          
Line of Credit Facility [Line Items]                          
Common stock issued to settle purchase contracts (in shares)             50,000,000            
2024 At The Market Program                          
Line of Credit Facility [Line Items]                          
Common stock issued to settle purchase contracts (in shares)                 27,701,553        
Indexed shares (in shares)             49,885,779   49,885,779 49,885,779      
Proceeds from issuance of common stock                 $ 2,500        
2024 At The Market Program | Forward Sale Contract 1                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                   1,467,305     3,255,866
Forward price (in dollars per share)         $ 89.2443         $ 96.3883     $ 89.4692
Common stock issued to settle purchase contracts (in shares)         3,255,866                
2024 At The Market Program | Forward Sale Contract 2                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                   1,896,549     2,314,487
Forward price (in dollars per share)         $ 92.8723         $ 97.5815     $ 92.7805
Common stock issued to settle purchase contracts (in shares)         2,314,487                
2024 At The Market Program | Forward Sale Contract 3                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                   1,903,317     3,850,000
Forward price (in dollars per share)     $ 90.2362             $ 95.5086     $ 90.6617
Common stock issued to settle purchase contracts (in shares)     3,850,000                    
2024 At The Market Program | Forward Sale Contract 4                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                         2,470,306
Forward price (in dollars per share)     $ 93.8913                   $ 94.5394
Common stock issued to settle purchase contracts (in shares)     2,470,306                    
2024 At The Market Program | Forward Sale Contract 5                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                         1,590,200
Forward price (in dollars per share)     $ 93.4038                   $ 93.4524
Common stock issued to settle purchase contracts (in shares)     1,590,200                    
2024 At The Market Program | Forward Sale Contract 6                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                         4,000,000
Forward price (in dollars per share)   $ 90.6358                     $ 90.8141
Common stock issued to settle purchase contracts (in shares)   4,000,000                      
2024 At The Market Program | Forward Sale Contract 7                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                         2,876,034
Forward price (in dollars per share)   $ 91.9664                     $ 92.2437
Common stock issued to settle purchase contracts (in shares)   2,876,034                      
2024 At The Market Program | Forward Sale Contract 8                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                         3,015,668
Forward price (in dollars per share)   $ 93.1290                     $ 93.4521
Common stock issued to settle purchase contracts (in shares)   3,015,668                      
2024 At The Market Program | Forward Sale Contract 9                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                         3,130,641
Forward price (in dollars per share) $ 88.0620                       $ 88.2823
Common stock issued to settle purchase contracts (in shares) 1,070,641             2,060,000   1,070,641      
2024 At The Market Program | Forward Sale Contract 10                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                         2,346,903
Forward price (in dollars per share) $ 90.9425                       $ 91.1610
Common stock issued to settle purchase contracts (in shares) 2,346,903                        
2024 At The Market Program | Forward Sale Contract 11                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                         911,448
Forward price (in dollars per share) $ 93.9331                       $ 94.2411
Common stock issued to settle purchase contracts (in shares) 911,448                        
2026 At The Market Program                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                   6,216,824      
Indexed shares (in shares)             7,557,278   7,557,278 7,557,278      
2026 At The Market Program | Forward Sale Contract 1                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                   1,713,535      
Forward price (in dollars per share)                   $ 93.2987      
2026 At The Market Program | Forward Sale Contract 2                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                   1,909,112      
Forward price (in dollars per share)                   $ 92.4821      
2026 At The Market Program | Forward Sale Contract 3                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                   1,994,083      
Forward price (in dollars per share)                   $ 95.1457      
2026 At The Market Program | Forward Sale Contract 4                          
Line of Credit Facility [Line Items]                          
Number of shares authorized (in shares)                   600,094      
Forward price (in dollars per share)                   $ 95.9974      
2026 At The Market Program | Forward Sale Contract 4 | Subsequent Event                          
Line of Credit Facility [Line Items]                          
Common stock issued to settle purchase contracts (in shares)           1,340,454           1,940,548  
v3.26.1
Financing and Leases - Earnings Per Share (Details) - shares
shares in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Debt Disclosure [Abstract]        
As reported shares (in shares) 1,137 1,101 1,130 1,100
Effect of stock-based compensation (in shares) 3 6 3 6
Effect of convertible senior notes (in shares) 0 1 0 1
Effect of forward sale contracts (in shares) 1 0 1 0
Diluted (in shares) 1,141 1,108 1,134 1,107
v3.26.1
Financing and Leases - Georgia Power Lease Modifications (Details) - USD ($)
$ in Millions
Jun. 30, 2026
May 31, 2026
Dec. 31, 2025
Debt Instrument [Line Items]      
Operating lease ROU assets, net $ 1,369   $ 1,358
Operating lease obligations 207   197
GEORGIA POWER CO      
Debt Instrument [Line Items]      
Operating lease ROU assets, net 881   1,120
Operating lease obligations 132   $ 170
GEORGIA POWER CO | Revision of Prior Period, Adjustment      
Debt Instrument [Line Items]      
Operating lease ROU assets, net   $ 179  
Operating lease obligations   $ 197  
Finance lease ROU assets, net 1,300    
Finance lease obligations - current $ 1,300    
v3.26.1
Income Taxes (Details) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Income Tax Contingency [Line Items]    
Effective tax (benefit) rate 14.10% 21.10%
ALABAMA POWER CO    
Income Tax Contingency [Line Items]    
Sale of investment tax credit $ 39  
GEORGIA POWER CO    
Income Tax Contingency [Line Items]    
Sale of investment tax credit 91  
Payment for PTCs $ 83  
Effective tax (benefit) rate 14.30% 21.70%
SOUTHERN POWER CO    
Income Tax Contingency [Line Items]    
Sale of investment tax credit $ 49  
Effective tax (benefit) rate 85.10% (7.00%)
SOUTHERN Co GAS    
Income Tax Contingency [Line Items]    
Effective tax (benefit) rate 23.50% 23.70%
v3.26.1
Retirement Benefits (Details) - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2026
Pension Plans          
Pension Plans and Postretirement Plans          
Service cost $ 69,000,000 $ 66,000,000 $ 138,000,000 $ 132,000,000  
Interest cost 161,000,000 166,000,000 323,000,000 332,000,000  
Expected return on plan assets (322,000,000) (320,000,000) (644,000,000) (640,000,000)  
Amortization:          
Prior service costs 0 0 0 0  
Regulatory asset   0 0 0  
Net (gain) loss 19,000,000 10,000,000 37,000,000 19,000,000  
Net periodic pension income (73,000,000) (78,000,000) (146,000,000) (157,000,000)  
Pension Plans | Scenario, Forecast          
Defined Benefit Plan Disclosure [Line Items]          
Defined benefit plan, expected future employer contributions, remainder of fiscal year         $ 0
Pension Plans | ALABAMA POWER CO          
Pension Plans and Postretirement Plans          
Service cost 16,000,000 15,000,000 31,000,000 30,000,000  
Interest cost 37,000,000 38,000,000 75,000,000 77,000,000  
Expected return on plan assets (78,000,000) (78,000,000) (157,000,000) (156,000,000)  
Amortization:          
Prior service costs 0 0 0 0  
Regulatory asset   0 0 0  
Net (gain) loss 5,000,000 4,000,000 10,000,000 6,000,000  
Net periodic pension income (20,000,000) (21,000,000) (41,000,000) (43,000,000)  
Pension Plans | GEORGIA POWER CO          
Pension Plans and Postretirement Plans          
Service cost 16,000,000 15,000,000 33,000,000 31,000,000  
Interest cost 47,000,000 49,000,000 94,000,000 98,000,000  
Expected return on plan assets (100,000,000) (99,000,000) (199,000,000) (198,000,000)  
Amortization:          
Prior service costs 1,000,000 1,000,000 1,000,000 1,000,000  
Regulatory asset   0 0 0  
Net (gain) loss 7,000,000 3,000,000 13,000,000 7,000,000  
Net periodic pension income (29,000,000) (31,000,000) (58,000,000) (61,000,000)  
Pension Plans | MISSISSIPPI POWER CO          
Pension Plans and Postretirement Plans          
Service cost 3,000,000 2,000,000 6,000,000 5,000,000  
Interest cost 8,000,000 8,000,000 15,000,000 15,000,000  
Expected return on plan assets (14,000,000) (14,000,000) (29,000,000) (29,000,000)  
Amortization:          
Prior service costs 0 0 0 0  
Regulatory asset   0 0 0  
Net (gain) loss 0 0 1,000,000 1,000,000  
Net periodic pension income (3,000,000) (4,000,000) (7,000,000) (8,000,000)  
Pension Plans | SOUTHERN POWER CO          
Pension Plans and Postretirement Plans          
Service cost 1,000,000 2,000,000 3,000,000 3,000,000  
Interest cost 3,000,000 3,000,000 5,000,000 5,000,000  
Expected return on plan assets (4,000,000) (4,000,000) (8,000,000) (8,000,000)  
Amortization:          
Prior service costs 0 0 0 0  
Regulatory asset   0 0 0  
Net (gain) loss (1,000,000) (2,000,000) (1,000,000) (1,000,000)  
Net periodic pension income (1,000,000) (1,000,000) (1,000,000) (1,000,000)  
Pension Plans | SOUTHERN Co GAS          
Pension Plans and Postretirement Plans          
Service cost 7,000,000 7,000,000 14,000,000 13,000,000  
Interest cost 11,000,000 11,000,000 22,000,000 22,000,000  
Expected return on plan assets (22,000,000) (22,000,000) (43,000,000) (43,000,000)  
Amortization:          
Prior service costs (1,000,000) (1,000,000) (1,000,000) (1,000,000)  
Regulatory asset   4,000,000 3,000,000 8,000,000  
Net (gain) loss 1,000,000 0 1,000,000 0  
Net periodic pension income (4,000,000) (1,000,000) (4,000,000) (1,000,000)  
Postretirement Benefits          
Pension Plans and Postretirement Plans          
Service cost 3,000,000 3,000,000 6,000,000 6,000,000  
Interest cost 16,000,000 18,000,000 32,000,000 35,000,000  
Expected return on plan assets (22,000,000) (22,000,000) (45,000,000) (45,000,000)  
Amortization:          
Prior service costs     1,000,000 1,000,000  
Regulatory asset   0   0  
Net (gain) loss (2,000,000) (4,000,000) (4,000,000) (7,000,000)  
Net periodic pension income (5,000,000) (5,000,000) (10,000,000) (10,000,000)  
Postretirement Benefits | ALABAMA POWER CO          
Pension Plans and Postretirement Plans          
Service cost 1,000,000 1,000,000 2,000,000 2,000,000  
Interest cost 4,000,000 4,000,000 8,000,000 8,000,000  
Expected return on plan assets (8,000,000) (9,000,000) (17,000,000) (18,000,000)  
Amortization:          
Prior service costs     0 0  
Regulatory asset   0   0  
Net (gain) loss (1,000,000) 0 (1,000,000) 0  
Net periodic pension income (4,000,000) (4,000,000) (8,000,000) (8,000,000)  
Postretirement Benefits | GEORGIA POWER CO          
Pension Plans and Postretirement Plans          
Service cost 1,000,000 1,000,000 2,000,000 2,000,000  
Interest cost 6,000,000 7,000,000 12,000,000 13,000,000  
Expected return on plan assets (8,000,000) (8,000,000) (16,000,000) (16,000,000)  
Amortization:          
Prior service costs     0 0  
Regulatory asset   0   0  
Net (gain) loss 0 (2,000,000) 0 (2,000,000)  
Net periodic pension income (1,000,000) (2,000,000) (2,000,000) (3,000,000)  
Postretirement Benefits | MISSISSIPPI POWER CO          
Pension Plans and Postretirement Plans          
Service cost 0 0 0 0  
Interest cost 0 0 1,000,000 1,000,000  
Expected return on plan assets 1,000,000 0 0 0  
Amortization:          
Prior service costs     0 0  
Regulatory asset   0   0  
Net (gain) loss 0 1,000,000 0 0  
Net periodic pension income 1,000,000 1,000,000 1,000,000 1,000,000  
Postretirement Benefits | SOUTHERN POWER CO          
Pension Plans and Postretirement Plans          
Service cost 0 0 0 0  
Interest cost 0 0 0 0  
Expected return on plan assets 0 0 0 0  
Amortization:          
Prior service costs     0 0  
Regulatory asset   0   0  
Net (gain) loss 0 0 0 0  
Net periodic pension income 0 0 0 0  
Postretirement Benefits | SOUTHERN Co GAS          
Pension Plans and Postretirement Plans          
Service cost 0 0 0 0  
Interest cost 2,000,000 2,000,000 3,000,000 4,000,000  
Expected return on plan assets (2,000,000) (2,000,000) (4,000,000) (4,000,000)  
Amortization:          
Prior service costs     0 0  
Regulatory asset   2,000,000   3,000,000  
Net (gain) loss (2,000,000) (2,000,000) (4,000,000) (4,000,000)  
Net periodic pension income $ (2,000,000) $ 0 $ (5,000,000) $ (1,000,000)  
v3.26.1
Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Assets:    
Derivatives $ 35 $ 72
Cash equivalents 1,786  
Other investments 10  
Total 5,060  
Liabilities:    
Derivatives 434 321
Contingent consideration 12  
Other 24  
Total 470  
Collateral already posted, assets, aggregate fair value 18  
Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Cash equivalents 1,768  
Total 3,050  
Liabilities:    
Contingent consideration 0  
Other 0  
Total 11  
Significant Other Observable Inputs (Level 2)    
Assets:    
Cash equivalents 18  
Total 1,781  
Liabilities:    
Contingent consideration 0  
Other 13  
Total 436  
Significant Unobservable Inputs (Level 3)    
Assets:    
Cash equivalents 0  
Other investments 10  
Total 18  
Liabilities:    
Contingent consideration 12  
Other 11  
Total 23  
Net Asset Value as a Practical Expedient (NAV)    
Assets:    
Total 211  
Energy-related derivatives    
Assets:    
Derivatives 69  
Liabilities:    
Derivatives 166  
Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivatives 8  
Liabilities:    
Derivatives 11  
Energy-related derivatives | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivatives 61  
Liabilities:    
Derivatives 155  
Energy-related derivatives | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivatives 0  
Liabilities:    
Derivatives 0  
Interest rate derivatives    
Assets:    
Derivatives 5  
Liabilities:    
Derivatives 205  
Interest rate derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivatives 0  
Liabilities:    
Derivatives 0  
Interest rate derivatives | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivatives 5  
Liabilities:    
Derivatives 205  
Interest rate derivatives | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivatives 0  
Liabilities:    
Derivatives 0  
Domestic equity    
Assets:    
Investments in trusts 1,323  
Domestic equity | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 1,030  
Domestic equity | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 293  
Domestic equity | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
Foreign equity    
Assets:    
Investments in trusts 455  
Foreign equity | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 199  
Foreign equity | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 256  
Foreign equity | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
U.S. Treasury and government agency securities    
Assets:    
Investments in trusts 410  
Investments, available-for-sale: 13  
U.S. Treasury and government agency securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
Investments, available-for-sale: 1  
U.S. Treasury and government agency securities | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 410  
Investments, available-for-sale: 12  
U.S. Treasury and government agency securities | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
Investments, available-for-sale: 0  
Municipal bonds    
Assets:    
Investments in trusts 31  
Investments, available-for-sale: 2  
Municipal bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
Investments, available-for-sale: 0  
Municipal bonds | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 31  
Investments, available-for-sale: 2  
Municipal bonds | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
Investments, available-for-sale: 0  
Pooled funds – fixed income    
Assets:    
Investments in trusts 4  
Pooled funds – fixed income | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
Pooled funds – fixed income | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 4  
Pooled funds – fixed income | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
Corporate bonds    
Assets:    
Investments in trusts 533  
Investments, available-for-sale: 4  
Corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
Investments, available-for-sale: 0  
Corporate bonds | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 533  
Investments, available-for-sale: 4  
Corporate bonds | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
Investments, available-for-sale: 0  
Mortgage- and asset-backed securities    
Assets:    
Investments in trusts 110  
Investments, available-for-sale: 3  
Mortgage- and asset-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
Investments, available-for-sale: 0  
Mortgage- and asset-backed securities | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 110  
Investments, available-for-sale: 3  
Mortgage- and asset-backed securities | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
Investments, available-for-sale: 0  
Private equity    
Assets:    
Investments in trusts 202  
Private equity | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
Private equity | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 0  
Private equity | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
Private equity | Net Asset Value as a Practical Expedient (NAV)    
Assets:    
Investments in trusts 202  
Cash and cash equivalents    
Assets:    
Investments in trusts 1  
Cash and cash equivalents | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 1  
Cash and cash equivalents | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 0  
Cash and cash equivalents | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
Other    
Assets:    
Investments in trusts 46  
Other investments 53  
Other | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 33  
Other investments 10  
Other | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 4  
Other investments 35  
Other | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
Other investments 8  
Other | Net Asset Value as a Practical Expedient (NAV)    
Assets:    
Investments in trusts 9  
Foreign currency derivatives    
Liabilities:    
Derivatives 63  
Foreign currency derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Liabilities:    
Derivatives 0  
Foreign currency derivatives | Significant Other Observable Inputs (Level 2)    
Liabilities:    
Derivatives 63  
Foreign currency derivatives | Significant Unobservable Inputs (Level 3)    
Liabilities:    
Derivatives 0  
ALABAMA POWER CO    
Assets:    
Derivatives 11 6
Cash equivalents 58  
Other investments 35  
Total 1,761  
Liabilities:    
Derivatives 58 31
Collateral already posted, assets, aggregate fair value 0  
ALABAMA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Cash equivalents 40  
Other investments 0  
Total 822  
ALABAMA POWER CO | Significant Other Observable Inputs (Level 2)    
Assets:    
Cash equivalents 18  
Other investments 35  
Total 728  
ALABAMA POWER CO | Significant Unobservable Inputs (Level 3)    
Assets:    
Cash equivalents 0  
Other investments 0  
Total 0  
ALABAMA POWER CO | Net Asset Value as a Practical Expedient (NAV)    
Assets:    
Total 211  
ALABAMA POWER CO | Energy-related derivatives    
Assets:    
Derivatives 27  
Liabilities:    
Derivatives 58  
ALABAMA POWER CO | Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivatives 0  
Liabilities:    
Derivatives 0  
ALABAMA POWER CO | Energy-related derivatives | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivatives 27  
Liabilities:    
Derivatives 58  
ALABAMA POWER CO | Energy-related derivatives | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivatives 0  
Liabilities:    
Derivatives 0  
ALABAMA POWER CO | Domestic equity    
Assets:    
Investments in trusts 851  
ALABAMA POWER CO | Domestic equity | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 569  
ALABAMA POWER CO | Domestic equity | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 282  
ALABAMA POWER CO | Domestic equity | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | Foreign equity    
Assets:    
Investments in trusts 199  
ALABAMA POWER CO | Foreign equity | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 199  
ALABAMA POWER CO | Foreign equity | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | Foreign equity | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | U.S. Treasury and government agency securities    
Assets:    
Investments in trusts 16  
ALABAMA POWER CO | U.S. Treasury and government agency securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | U.S. Treasury and government agency securities | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 16  
ALABAMA POWER CO | U.S. Treasury and government agency securities | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | Municipal bonds    
Assets:    
Investments in trusts 1  
ALABAMA POWER CO | Municipal bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | Municipal bonds | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 1  
ALABAMA POWER CO | Municipal bonds | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | Corporate bonds    
Assets:    
Investments in trusts 319  
ALABAMA POWER CO | Corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | Corporate bonds | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 319  
ALABAMA POWER CO | Corporate bonds | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | Mortgage- and asset-backed securities    
Assets:    
Investments in trusts 28  
ALABAMA POWER CO | Mortgage- and asset-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | Mortgage- and asset-backed securities | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 28  
ALABAMA POWER CO | Mortgage- and asset-backed securities | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | Private equity    
Assets:    
Investments in trusts 202  
ALABAMA POWER CO | Private equity | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | Private equity | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | Private equity | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | Private equity | Net Asset Value as a Practical Expedient (NAV)    
Assets:    
Investments in trusts 202  
ALABAMA POWER CO | Other    
Assets:    
Investments in trusts 25  
ALABAMA POWER CO | Other | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 14  
ALABAMA POWER CO | Other | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 2  
ALABAMA POWER CO | Other | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
ALABAMA POWER CO | Other | Net Asset Value as a Practical Expedient (NAV)    
Assets:    
Investments in trusts 9  
GEORGIA POWER CO    
Assets:    
Derivatives 3 4
Cash equivalents 11  
Total 1,482  
Liabilities:    
Derivatives 48 33
GEORGIA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Cash equivalents 11  
Total 491  
GEORGIA POWER CO | Significant Other Observable Inputs (Level 2)    
Assets:    
Cash equivalents 0  
Total 991  
GEORGIA POWER CO | Significant Unobservable Inputs (Level 3)    
Assets:    
Cash equivalents 0  
Total 0  
GEORGIA POWER CO | Energy-related derivatives    
Assets:    
Derivatives 14  
Liabilities:    
Derivatives 48  
GEORGIA POWER CO | Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivatives 0  
Liabilities:    
Derivatives 0  
GEORGIA POWER CO | Energy-related derivatives | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivatives 14  
Liabilities:    
Derivatives 48  
GEORGIA POWER CO | Energy-related derivatives | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivatives 0  
Liabilities:    
Derivatives 0  
GEORGIA POWER CO | Domestic equity    
Assets:    
Investments in trusts 462  
GEORGIA POWER CO | Domestic equity | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 461  
GEORGIA POWER CO | Domestic equity | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 1  
GEORGIA POWER CO | Domestic equity | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
GEORGIA POWER CO | Foreign equity    
Assets:    
Investments in trusts 254  
GEORGIA POWER CO | Foreign equity | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
GEORGIA POWER CO | Foreign equity | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 254  
GEORGIA POWER CO | Foreign equity | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
GEORGIA POWER CO | U.S. Treasury and government agency securities    
Assets:    
Investments in trusts 394  
GEORGIA POWER CO | U.S. Treasury and government agency securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
GEORGIA POWER CO | U.S. Treasury and government agency securities | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 394  
GEORGIA POWER CO | U.S. Treasury and government agency securities | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
GEORGIA POWER CO | Municipal bonds    
Assets:    
Investments in trusts 30  
GEORGIA POWER CO | Municipal bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
GEORGIA POWER CO | Municipal bonds | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 30  
GEORGIA POWER CO | Municipal bonds | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
GEORGIA POWER CO | Corporate bonds    
Assets:    
Investments in trusts 214  
GEORGIA POWER CO | Corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
GEORGIA POWER CO | Corporate bonds | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 214  
GEORGIA POWER CO | Corporate bonds | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
GEORGIA POWER CO | Mortgage- and asset-backed securities    
Assets:    
Investments in trusts 82  
GEORGIA POWER CO | Mortgage- and asset-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 0  
GEORGIA POWER CO | Mortgage- and asset-backed securities | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 82  
GEORGIA POWER CO | Mortgage- and asset-backed securities | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
GEORGIA POWER CO | Other    
Assets:    
Investments in trusts 21  
GEORGIA POWER CO | Other | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Investments in trusts 19  
GEORGIA POWER CO | Other | Significant Other Observable Inputs (Level 2)    
Assets:    
Investments in trusts 2  
GEORGIA POWER CO | Other | Significant Unobservable Inputs (Level 3)    
Assets:    
Investments in trusts 0  
MISSISSIPPI POWER CO    
Assets:    
Derivatives 1 1
Cash equivalents 1  
Total 15  
MISSISSIPPI POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Cash equivalents 1  
Total 1  
MISSISSIPPI POWER CO | Significant Other Observable Inputs (Level 2)    
Assets:    
Cash equivalents 0  
Total 14  
MISSISSIPPI POWER CO | Significant Unobservable Inputs (Level 3)    
Assets:    
Cash equivalents 0  
Total 0  
MISSISSIPPI POWER CO | Energy-related derivatives    
Assets:    
Derivatives 14  
Liabilities:    
Derivatives 40  
MISSISSIPPI POWER CO | Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivatives 0  
Liabilities:    
Derivatives 0  
MISSISSIPPI POWER CO | Energy-related derivatives | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivatives 14  
Liabilities:    
Derivatives 40  
MISSISSIPPI POWER CO | Energy-related derivatives | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivatives 0  
Liabilities:    
Derivatives 0  
SOUTHERN POWER CO    
Assets:    
Derivatives 2 21
Cash equivalents 162  
Total 175  
Liabilities:    
Derivatives 4 1
Contingent consideration 12  
Other 24  
Total 40  
Collateral already posted, assets, aggregate fair value 0  
SOUTHERN POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Cash equivalents 162  
Total 162  
Liabilities:    
Contingent consideration 0  
Other 0  
Total 0  
SOUTHERN POWER CO | Significant Other Observable Inputs (Level 2)    
Assets:    
Cash equivalents 0  
Total 3  
Liabilities:    
Contingent consideration 0  
Other 13  
Total 17  
SOUTHERN POWER CO | Significant Unobservable Inputs (Level 3)    
Assets:    
Cash equivalents 0  
Total 10  
Liabilities:    
Contingent consideration 12  
Other 11  
Total 23  
SOUTHERN POWER CO | Energy-related derivatives    
Assets:    
Derivatives 3  
Liabilities:    
Derivatives 4  
SOUTHERN POWER CO | Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivatives 0  
Liabilities:    
Derivatives 0  
SOUTHERN POWER CO | Energy-related derivatives | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivatives 3  
Liabilities:    
Derivatives 4  
SOUTHERN POWER CO | Energy-related derivatives | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivatives 0  
Liabilities:    
Derivatives 0  
SOUTHERN POWER CO | Other    
Assets:    
Derivatives 10  
SOUTHERN POWER CO | Other | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivatives 0  
SOUTHERN POWER CO | Other | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivatives 0  
SOUTHERN POWER CO | Other | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivatives 10  
SOUTHERN Co GAS    
Assets:    
Derivatives 17 28
Cash equivalents 200  
Total 228  
Liabilities:    
Derivatives 78 79
Total 78  
Collateral already posted, assets, aggregate fair value 18 $ 33
SOUTHERN Co GAS | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Cash equivalents 200  
Total 209  
Liabilities:    
Total 11  
SOUTHERN Co GAS | Significant Other Observable Inputs (Level 2)    
Assets:    
Cash equivalents 0  
Total 19  
Liabilities:    
Total 67  
SOUTHERN Co GAS | Significant Unobservable Inputs (Level 3)    
Assets:    
Cash equivalents 0  
Total 0  
Liabilities:    
Total 0  
SOUTHERN Co GAS | Energy-related derivatives    
Assets:    
Derivatives 11  
Liabilities:    
Derivatives 16  
SOUTHERN Co GAS | Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Derivatives 8  
Liabilities:    
Derivatives 11  
SOUTHERN Co GAS | Energy-related derivatives | Significant Other Observable Inputs (Level 2)    
Assets:    
Derivatives 3  
Liabilities:    
Derivatives 5  
SOUTHERN Co GAS | Energy-related derivatives | Significant Unobservable Inputs (Level 3)    
Assets:    
Derivatives 0  
Liabilities:    
Derivatives 0  
SOUTHERN Co GAS | Interest rate derivatives    
Liabilities:    
Derivatives 62  
SOUTHERN Co GAS | Interest rate derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Liabilities:    
Derivatives 0  
SOUTHERN Co GAS | Interest rate derivatives | Significant Other Observable Inputs (Level 2)    
Liabilities:    
Derivatives 62  
SOUTHERN Co GAS | Interest rate derivatives | Significant Unobservable Inputs (Level 3)    
Liabilities:    
Derivatives 0  
SOUTHERN Co GAS | Domestic equity    
Assets:    
Non-qualified deferred compensation trusts 10  
SOUTHERN Co GAS | Domestic equity | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Non-qualified deferred compensation trusts 0  
SOUTHERN Co GAS | Domestic equity | Significant Other Observable Inputs (Level 2)    
Assets:    
Non-qualified deferred compensation trusts 10  
SOUTHERN Co GAS | Domestic equity | Significant Unobservable Inputs (Level 3)    
Assets:    
Non-qualified deferred compensation trusts 0  
SOUTHERN Co GAS | Foreign equity    
Assets:    
Non-qualified deferred compensation trusts 2  
SOUTHERN Co GAS | Foreign equity | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Non-qualified deferred compensation trusts 0  
SOUTHERN Co GAS | Foreign equity | Significant Other Observable Inputs (Level 2)    
Assets:    
Non-qualified deferred compensation trusts 2  
SOUTHERN Co GAS | Foreign equity | Significant Unobservable Inputs (Level 3)    
Assets:    
Non-qualified deferred compensation trusts 0  
SOUTHERN Co GAS | Pooled funds – fixed income    
Assets:    
Non-qualified deferred compensation trusts 4  
SOUTHERN Co GAS | Pooled funds – fixed income | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Non-qualified deferred compensation trusts 0  
SOUTHERN Co GAS | Pooled funds – fixed income | Significant Other Observable Inputs (Level 2)    
Assets:    
Non-qualified deferred compensation trusts 4  
SOUTHERN Co GAS | Pooled funds – fixed income | Significant Unobservable Inputs (Level 3)    
Assets:    
Non-qualified deferred compensation trusts 0  
SOUTHERN Co GAS | Cash and cash equivalents    
Assets:    
Non-qualified deferred compensation trusts 1  
SOUTHERN Co GAS | Cash and cash equivalents | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Non-qualified deferred compensation trusts 1  
SOUTHERN Co GAS | Cash and cash equivalents | Significant Other Observable Inputs (Level 2)    
Assets:    
Non-qualified deferred compensation trusts 0  
SOUTHERN Co GAS | Cash and cash equivalents | Significant Unobservable Inputs (Level 3)    
Assets:    
Non-qualified deferred compensation trusts $ 0  
v3.26.1
Fair Value Measurements - Schedule of Increase (Decrease) In Fair Value Of Funds (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Fair Value, Option, Quantitative Disclosures [Line Items]        
Increase (decrease) in fair value of funds $ 249 $ 165 $ 205 $ 159
ALABAMA POWER CO        
Fair Value, Option, Quantitative Disclosures [Line Items]        
Increase (decrease) in fair value of funds 156 99 126 86
GEORGIA POWER CO        
Fair Value, Option, Quantitative Disclosures [Line Items]        
Increase (decrease) in fair value of funds $ 93 $ 66 $ 79 $ 73
v3.26.1
Fair Value Measurements - Narrative (Details) - ALABAMA POWER CO - Private equity
$ in Millions
Jun. 30, 2026
USD ($)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]  
Fair value $ 211
Unfunded commitments $ 94
v3.26.1
Fair Value Measurements - Schedule of Financial Instruments for which Carrying Amount did not Equal Fair Value (Details)
$ in Billions
Jun. 30, 2026
USD ($)
Long-term debt, including securities due within one year:  
Carrying amount $ 72.7
Fair value 68.0
ALABAMA POWER CO  
Long-term debt, including securities due within one year:  
Carrying amount 12.0
Fair value 10.7
GEORGIA POWER CO  
Long-term debt, including securities due within one year:  
Carrying amount 22.3
Fair value 20.7
MISSISSIPPI POWER CO  
Long-term debt, including securities due within one year:  
Carrying amount 1.8
Fair value 1.7
SOUTHERN POWER CO  
Long-term debt, including securities due within one year:  
Carrying amount 3.0
Fair value 2.9
SOUTHERN Co GAS  
Long-term debt, including securities due within one year:  
Carrying amount 9.3
Fair value $ 8.4
v3.26.1
Derivatives - Schedule of Energy-Related Derivatives (Details) - Energy-related, Natural Gas
MMBTU in Millions
Jun. 30, 2026
MMBTU
Energy-related derivative contracts  
Net Purchased mmBtu 469
ALABAMA POWER CO  
Energy-related derivative contracts  
Net Purchased mmBtu 155
GEORGIA POWER CO  
Energy-related derivative contracts  
Net Purchased mmBtu 117
MISSISSIPPI POWER CO  
Energy-related derivative contracts  
Net Purchased mmBtu 114
SOUTHERN POWER CO  
Energy-related derivative contracts  
Net Purchased mmBtu 8
SOUTHERN Co GAS  
Energy-related derivative contracts  
Net Purchased mmBtu 75
SOUTHERN Co GAS | Energy-related derivatives not designated as hedging instruments | Long  
Energy-related derivative contracts  
Derivative nonmonetary notional amount net long short position volume 85
SOUTHERN Co GAS | Energy-related derivatives not designated as hedging instruments | Short  
Energy-related derivative contracts  
Derivative nonmonetary notional amount net long short position volume 10
v3.26.1
Derivatives - Narrative (Details)
MMBTU in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
MMBTU
Jun. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Derivative [Line Items]          
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU     15.0    
Energy-related derivative hedge gain (loss) to be reclassified within twelve months $ 0   $ 0    
Gain (Loss) From Derivatives Recognized in OCI (15,000,000) $ 46,000,000 (19,000,000) $ 65,000,000  
Collateral already posted, assets, aggregate fair value 18,000,000   18,000,000    
Derivatives 377,000,000   377,000,000   $ 267,000,000
Interest rate derivatives          
Derivative [Line Items]          
Derivatives 31,000,000   31,000,000    
Interest rate derivatives | Cash Flow Hedging          
Derivative [Line Items]          
Gain (Loss) From Derivatives Recognized in OCI 0 9,000,000 0 5,000,000  
Interest rate derivatives | Cash Flow Hedging | Income Statement Location [Axis]: us-gaap:InterestAndDebtExpense          
Derivative [Line Items]          
Gain (loss) on hedges (2,000,000) (3,000,000) (5,000,000) (6,000,000)  
Interest rate derivatives | Fair Value Hedging | Income Statement Location [Axis]: us-gaap:InterestAndDebtExpense          
Derivative [Line Items]          
Gain (loss) on hedges (41,000,000) 29,000,000 (21,000,000) 69,000,000  
Energy-related derivatives | Energy-related derivatives not designated as hedging instruments | Natural gas | Income Statement Location [Axis]: us-gaap:CostOfGoodsAndServicesSold          
Derivative [Line Items]          
Derivative instruments not designated as hedging instruments, gain (loss), net 7,000,000 (14,000,000) 2,000,000 (6,000,000)  
Energy-related derivatives | Cash Flow Hedging          
Derivative [Line Items]          
Gain (Loss) From Derivatives Recognized in OCI (8,000,000) (13,000,000) 1,000,000 6,000,000  
Energy-related derivatives | Cash Flow Hedging | Natural gas | Income Statement Location [Axis]: us-gaap:CostOfGoodsAndServicesSold          
Derivative [Line Items]          
Gain (loss) on hedges (3,000,000) 1,000,000 7,000,000 0  
Foreign currency derivatives | Cash Flow Hedging          
Derivative [Line Items]          
Gain (Loss) From Derivatives Recognized in OCI (7,000,000) 47,000,000 (19,000,000) 67,000,000  
Foreign currency derivatives | Cash Flow Hedging | Income Statement Location [Axis]: us-gaap:InterestAndDebtExpense          
Derivative [Line Items]          
Gain (loss) on hedges (2,000,000) (2,000,000) (5,000,000) (5,000,000)  
Foreign currency derivatives | Cash Flow Hedging | Income Statement Location [Axis]: us-gaap:OtherNonoperatingIncomeExpense          
Derivative [Line Items]          
Gain (loss) on hedges (2,000,000) 45,000,000 (14,000,000) 67,000,000  
Foreign currency derivatives | Fair Value Hedging | Income Statement Location [Axis]: us-gaap:OtherNonoperatingIncomeExpense          
Derivative [Line Items]          
Gain (loss) on hedges (13,000,000) 115,000,000 $ (45,000,000) 155,000,000  
ALABAMA POWER CO          
Derivative [Line Items]          
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU     4.0    
Energy-related derivative hedge gain (loss) to be reclassified within twelve months 0   $ 0    
Collateral already posted, assets, aggregate fair value 0   0    
Derivatives 42,000,000   42,000,000   18,000,000
ALABAMA POWER CO | Interest rate derivatives          
Derivative [Line Items]          
Cash flow hedge gain (loss) to be reclassified within twelve months 0   0    
ALABAMA POWER CO | Energy-related derivatives | Cash Flow Hedging          
Derivative [Line Items]          
Gain (Loss) From Derivatives Recognized in OCI (2,000,000) 0 $ (2,000,000) 0  
GEORGIA POWER CO          
Derivative [Line Items]          
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU     6.0    
Derivatives 37,000,000   $ 37,000,000   19,000,000
GEORGIA POWER CO | Interest rate derivatives          
Derivative [Line Items]          
Cash flow hedge gain (loss) to be reclassified within twelve months 0   0    
GEORGIA POWER CO | Interest rate derivatives | Cash Flow Hedging          
Derivative [Line Items]          
Gain (Loss) From Derivatives Recognized in OCI 0 5,000,000 $ 0 3,000,000  
MISSISSIPPI POWER CO          
Derivative [Line Items]          
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU     2.0    
Energy-related derivative hedge gain (loss) to be reclassified within twelve months 0   $ 0    
Derivatives 27,000,000   27,000,000   14,000,000
MISSISSIPPI POWER CO | Interest rate derivatives          
Derivative [Line Items]          
Cash flow hedge gain (loss) to be reclassified within twelve months 0   $ 0    
SOUTHERN POWER CO          
Derivative [Line Items]          
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU     3.0    
Energy-related derivative hedge gain (loss) to be reclassified within twelve months 0   $ 0    
Gain (Loss) From Derivatives Recognized in OCI (9,000,000) 46,000,000 (19,000,000) 69,000,000  
Collateral already posted, assets, aggregate fair value 0   0    
Derivatives 3,000,000   3,000,000   1,000,000
SOUTHERN POWER CO | Interest rate derivatives          
Derivative [Line Items]          
Cash flow hedge gain (loss) to be reclassified within twelve months 0   0    
SOUTHERN POWER CO | Energy-related derivatives          
Derivative [Line Items]          
Derivatives 0   0    
SOUTHERN POWER CO | Energy-related derivatives | Cash Flow Hedging          
Derivative [Line Items]          
Gain (Loss) From Derivatives Recognized in OCI (2,000,000) (1,000,000) 0 2,000,000  
SOUTHERN POWER CO | Foreign currency derivatives | Cash Flow Hedging          
Derivative [Line Items]          
Gain (Loss) From Derivatives Recognized in OCI (7,000,000) 47,000,000 (19,000,000) 67,000,000  
SOUTHERN POWER CO | Foreign currency derivatives | Cash Flow Hedging | Income Statement Location [Axis]: us-gaap:InterestAndDebtExpense          
Derivative [Line Items]          
Gain (loss) on hedges (2,000,000) (2,000,000) (5,000,000) (5,000,000)  
SOUTHERN POWER CO | Foreign currency derivatives | Cash Flow Hedging | Income Statement Location [Axis]: us-gaap:OtherNonoperatingIncomeExpense          
Derivative [Line Items]          
Gain (loss) on hedges (2,000,000) 45,000,000 (14,000,000) 67,000,000  
Registrants | Derivative Counterparties          
Derivative [Line Items]          
Collateral already posted, assets, aggregate fair value 0   0    
SOUTHERN Co GAS          
Derivative [Line Items]          
Energy-related derivative hedge gain (loss) to be reclassified within twelve months 0   0    
Gain (Loss) From Derivatives Recognized in OCI (4,000,000) (8,000,000) 3,000,000 8,000,000  
Collateral already posted, assets, aggregate fair value 18,000,000   18,000,000   33,000,000
Derivatives 66,000,000   66,000,000   $ 65,000,000
SOUTHERN Co GAS | Interest rate derivatives          
Derivative [Line Items]          
Cash flow hedge gain (loss) to be reclassified within twelve months 0   0    
SOUTHERN Co GAS | Interest rate derivatives | Cash Flow Hedging          
Derivative [Line Items]          
Gain (Loss) From Derivatives Recognized in OCI 0 4,000,000 0 4,000,000  
SOUTHERN Co GAS | Interest rate derivatives | Fair Value Hedging | Income Statement Location [Axis]: us-gaap:InterestAndDebtExpense          
Derivative [Line Items]          
Gain (loss) on hedges (32,000,000) 3,000,000 (3,000,000) 21,000,000  
SOUTHERN Co GAS | Energy-related derivatives | Cash Flow Hedging          
Derivative [Line Items]          
Gain (Loss) From Derivatives Recognized in OCI (4,000,000) (12,000,000) 3,000,000 4,000,000  
SOUTHERN Co GAS | Energy-related derivatives | Cash Flow Hedging | Natural gas | Income Statement Location [Axis]: us-gaap:CostOfGoodsAndServicesSold          
Derivative [Line Items]          
Gain (loss) on hedges (3,000,000) $ 1,000,000 7,000,000 $ 0  
Traditional Electric Operating Companies | Energy-related derivatives          
Derivative [Line Items]          
Derivatives $ 0   $ 0    
v3.26.1
Derivatives - Schedule of Interest Rate Derivatives (Details) - Interest rate derivatives
$ in Millions
 6 Months Ended
Jun. 30, 2026
USD ($)
Derivative [Line Items]  
Notional Amount $ 2,465
Fair Value Gain (Loss) (200)
Southern Company parent | 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) $ (23)
Southern Company parent | Fair Value Hedges of Existing Debt | Date Two  
Derivative [Line Items]  
Notional Amount $ 1,000
Weighted Average Interest Rate Paid 2.48%
Interest Rate Received 3.70%
Fair Value Gain (Loss) $ (103)
Southern Company parent | Fair Value Hedges of Existing Debt | Date Three  
Derivative [Line Items]  
Notional Amount $ 565
Weighted Average Interest Rate Paid 1.56%
Interest Rate Received 6.50%
Fair Value Gain (Loss) $ (12)
SOUTHERN Co GAS | Fair Value Hedges of Existing Debt | Date One  
Derivative [Line Items]  
Notional Amount $ 500
Weighted Average Interest Rate Paid 0.49%
Interest Rate Received 1.75%
Fair Value Gain (Loss) $ (62)
v3.26.1
Derivatives - Schedule of Foreign Currency Derivatives (Details) - 6 months ended Jun. 30, 2026 - Fair Value Hedges of Existing Debt - Foreign currency derivatives - Southern Company parent
€ in Millions, $ in Millions
USD ($)
EUR (€)
Derivative [Line Items]    
Pay Notional $ 1,476  
Pay Rate 3.39%  
Receive Notional | €   € 1,250
Receive Rate 1.88%  
Fair Value Gain (Loss) $ (63)  
v3.26.1
Derivatives - Schedule of Derivative Category and Balance Sheet Location (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized $ 74 $ 93
Gross amounts offset (39) (21)
Derivative asset, net amounts recognized in the balance sheets 35 72
Derivative liability, gross amount recognized 434 321
Gross amounts offset (57) (54)
Derivative liability, net amounts recognized in the balance sheets 377 267
Collateral already posted, assets, aggregate fair value 18  
Interest rate derivatives    
Derivatives, Fair Value [Line Items]    
Derivative liability, net amounts recognized in the balance sheets 31  
Energy-related derivatives not designated as hedging instruments | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:DerivativeAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 6 6
Energy-related derivatives not designated as hedging instruments | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:DerivativeLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 4 6
Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 58 55
Derivative liability, gross amount recognized 149 99
Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:DerivativeAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 28 24
Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:DerivativeLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 89 64
Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 30 31
Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 60 35
Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 10 32
Derivative liability, gross amount recognized 281 216
Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:DerivativeAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 3 1
Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:DerivativeLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 12 6
Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 2 2
Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 1 1
Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Balance Sheet Location [Axis]: us-gaap:DerivativeAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 5 8
Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Balance Sheet Location [Axis]: us-gaap:DerivativeLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 52 48
Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 0 0
Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 153 139
Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Balance Sheet Location [Axis]: us-gaap:DerivativeAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 0 17
Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Balance Sheet Location [Axis]: us-gaap:DerivativeLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 23 22
Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 0 4
Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 40 0
ALABAMA POWER CO    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 27 19
Gross amounts offset (16) (13)
Derivative asset, net amounts recognized in the balance sheets 11 6
Derivative liability, gross amount recognized 58 31
Gross amounts offset (16) (13)
Derivative liability, net amounts recognized in the balance sheets 42 18
Collateral already posted, assets, aggregate fair value 0  
ALABAMA POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 27 19
Derivative liability, gross amount recognized 56 31
ALABAMA POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 15 9
ALABAMA POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 12 10
ALABAMA POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 31 18
ALABAMA POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 25 13
ALABAMA POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:DerivativeAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 0 0
ALABAMA POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:DerivativeLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 2 0
GEORGIA POWER CO    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 14 18
Gross amounts offset (11) (14)
Derivative asset, net amounts recognized in the balance sheets 3 4
Derivative liability, gross amount recognized 48 33
Gross amounts offset (11) (14)
Derivative liability, net amounts recognized in the balance sheets 37 19
GEORGIA POWER CO | Energy-related derivatives not designated as hedging instruments | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 2 1
GEORGIA POWER CO | Energy-related derivatives not designated as hedging instruments | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 0 0
GEORGIA POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 12 17
Derivative liability, gross amount recognized 48 33
GEORGIA POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 5 7
GEORGIA POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 7 10
GEORGIA POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 32 23
GEORGIA POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 16 10
MISSISSIPPI POWER CO    
Derivatives, Fair Value [Line Items]    
Gross amounts offset (13) (13)
Derivative asset, net amounts recognized in the balance sheets 1 1
Gross amounts offset (13) (13)
Derivative liability, net amounts recognized in the balance sheets 27 14
MISSISSIPPI POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 14 14
Derivative liability, gross amount recognized 40 27
MISSISSIPPI POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 3 3
MISSISSIPPI POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 11 11
MISSISSIPPI POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 21 15
MISSISSIPPI POWER CO | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 19 12
SOUTHERN POWER CO    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 3 21
Gross amounts offset (1) 0
Derivative asset, net amounts recognized in the balance sheets 2 21
Derivative liability, gross amount recognized 4 1
Gross amounts offset (1) 0
Derivative liability, net amounts recognized in the balance sheets 3 1
Collateral already posted, assets, aggregate fair value 0  
SOUTHERN POWER CO | Energy-related derivatives    
Derivatives, Fair Value [Line Items]    
Derivative liability, net amounts recognized in the balance sheets 0  
SOUTHERN POWER CO | Energy-related derivatives not designated as hedging instruments | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 0 1
SOUTHERN POWER CO | Energy-related derivatives not designated as hedging instruments | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 1 0
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 3 20
Derivative liability, gross amount recognized 3 1
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 1 1
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 2 2
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 2 1
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 1 0
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 0 17
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 0 0
SOUTHERN Co GAS    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 11 9
Gross amounts offset 6 19
Derivative asset, net amounts recognized in the balance sheets 17 28
Derivative liability, gross amount recognized 78 79
Gross amounts offset (12) (14)
Derivative liability, net amounts recognized in the balance sheets 66 65
Collateral already posted, assets, aggregate fair value 18 33
SOUTHERN Co GAS | Energy-related derivatives not designated as hedging instruments | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 4 4
SOUTHERN Co GAS | Energy-related derivatives not designated as hedging instruments | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 3 6
SOUTHERN Co GAS | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 5 5
SOUTHERN Co GAS | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 5 8
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 2 0
Derivative liability, gross amount recognized 70 65
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 2 0
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 0 0
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 8 5
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 0 1
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 0 0
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative asset, gross amount recognized 0 0
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized 13 13
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Energy-related derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivatives, Fair Value [Line Items]    
Derivative liability, gross amount recognized $ 49 $ 46
v3.26.1
Derivatives - Schedule of Pre-tax Effects of Unrealized Derivative Gains (Losses) (Details) - Energy-related derivatives - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) $ (91) $ (45)
Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsCurrent    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) (75) (48)
Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsDeferred    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) (31) (8)
Balance Sheet Location [Axis]: so:OtherRegulatoryLiabilitiesCurrent    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) 15 7
Balance Sheet Location [Axis]: so:OtherRegulatoryLiabilitiesDeferred    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses)   4
ALABAMA POWER CO    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) (29) (12)
ALABAMA POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsCurrent    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) (26) (13)
ALABAMA POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsDeferred    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) (13) (5)
ALABAMA POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryLiabilitiesCurrent    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) 10 4
ALABAMA POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryLiabilitiesDeferred    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses)   2
GEORGIA POWER CO    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) (37) (16)
GEORGIA POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsCurrent    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) (27) (17)
GEORGIA POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsDeferred    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) (10) (1)
GEORGIA POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryLiabilitiesCurrent    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) 0 1
GEORGIA POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryLiabilitiesDeferred    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses)   1
MISSISSIPPI POWER CO    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) (26) (13)
MISSISSIPPI POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsCurrent    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) (18) (12)
MISSISSIPPI POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsDeferred    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) (8) (2)
MISSISSIPPI POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryLiabilitiesCurrent    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) 0 0
MISSISSIPPI POWER CO | Balance Sheet Location [Axis]: so:OtherRegulatoryLiabilitiesDeferred    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses)   1
SOUTHERN Co GAS    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) 1 (4)
SOUTHERN Co GAS | Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsCurrent    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) (4) (6)
SOUTHERN Co GAS | Balance Sheet Location [Axis]: so:OtherRegulatoryAssetsDeferred    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) 0 0
SOUTHERN Co GAS | Balance Sheet Location [Axis]: so:OtherRegulatoryLiabilitiesCurrent    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses) $ 5 2
SOUTHERN Co GAS | Balance Sheet Location [Axis]: so:OtherRegulatoryLiabilitiesDeferred    
Derivative Instruments, Gain (Loss) [Line Items]    
Total energy-related derivative gains (losses)   $ 0
v3.26.1
Derivatives - Schedule of Pre-Tax Effects of Hedging on AOCI (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) From Derivatives Recognized in OCI $ (15) $ 46 $ (19) $ 65
Cash Flow Hedging | Energy-related derivatives        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) From Derivatives Recognized in OCI (8) (13) 1 6
Cash Flow Hedging | Interest rate derivatives        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) From Derivatives Recognized in OCI 0 9 0 5
Cash Flow Hedging | Foreign currency derivatives        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) From Derivatives Recognized in OCI (7) 47 (19) 67
Fair Value Hedging | Foreign currency derivatives        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount excluded from effectiveness testing recognized in earnings 0 3 (1) (13)
GEORGIA POWER CO | Cash Flow Hedging | Interest rate derivatives        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) From Derivatives Recognized in OCI 0 5 0 3
SOUTHERN POWER CO        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) From Derivatives Recognized in OCI (9) 46 (19) 69
SOUTHERN POWER CO | Cash Flow Hedging | Energy-related derivatives        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) From Derivatives Recognized in OCI (2) (1) 0 2
SOUTHERN POWER CO | Cash Flow Hedging | Foreign currency derivatives        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) From Derivatives Recognized in OCI (7) 47 (19) 67
SOUTHERN Co GAS        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) From Derivatives Recognized in OCI (4) (8) 3 8
SOUTHERN Co GAS | Cash Flow Hedging | Energy-related derivatives        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) From Derivatives Recognized in OCI (4) (12) 3 4
SOUTHERN Co GAS | Cash Flow Hedging | Interest rate derivatives        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) From Derivatives Recognized in OCI 0 4 0 4
ALABAMA POWER CO | Cash Flow Hedging | Energy-related derivatives        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) From Derivatives Recognized in OCI $ (2) $ 0 $ (2) $ 0
v3.26.1
Derivatives - Schedule of Pre-Tax Effects of Cash Flow and Fair Value Hedging on Income (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Income Statement Location [Axis]: us-gaap:OtherNonoperatingIncomeExpense        
Derivative [Line Items]        
Amount excluded from effectiveness testing recognized in earnings $ 0 $ (3) $ 1 $ 13
Cash Flow Hedging | Energy-related derivatives | Income Statement Location [Axis]: us-gaap:CostOfGoodsAndServicesSold | Fuel        
Derivative [Line Items]        
Gain (loss) on hedges (1) 0 2 1
Cash Flow Hedging | Energy-related derivatives | Income Statement Location [Axis]: us-gaap:CostOfGoodsAndServicesSold | Natural gas        
Derivative [Line Items]        
Gain (loss) on hedges (3) 1 7 0
Cash Flow Hedging | Interest rate derivatives | Income Statement Location [Axis]: us-gaap:InterestAndDebtExpense        
Derivative [Line Items]        
Gain (loss) on hedges (2) (3) (5) (6)
Cash Flow Hedging | Foreign currency derivatives | Income Statement Location [Axis]: us-gaap:InterestAndDebtExpense        
Derivative [Line Items]        
Gain (loss) on hedges (2) (2) (5) (5)
Cash Flow Hedging | Foreign currency derivatives | Income Statement Location [Axis]: us-gaap:OtherNonoperatingIncomeExpense        
Derivative [Line Items]        
Gain (loss) on hedges (2) 45 (14) 67
Fair Value Hedging | Interest rate derivatives | Income Statement Location [Axis]: us-gaap:InterestAndDebtExpense        
Derivative [Line Items]        
Gain (loss) on hedges (41) 29 (21) 69
Fair Value Hedging | Foreign currency derivatives        
Derivative [Line Items]        
Amount excluded from effectiveness testing recognized in earnings 0 3 (1) (13)
Fair Value Hedging | Foreign currency derivatives | Income Statement Location [Axis]: us-gaap:OtherNonoperatingIncomeExpense        
Derivative [Line Items]        
Gain (loss) on hedges (13) 115 (45) 155
SOUTHERN POWER CO | Cash Flow Hedging | Energy-related derivatives | Income Statement Location [Axis]: us-gaap:CostOfGoodsAndServicesSold | Fuel        
Derivative [Line Items]        
Gain (loss) on hedges (1) 0 2 1
SOUTHERN POWER CO | Cash Flow Hedging | Foreign currency derivatives | Income Statement Location [Axis]: us-gaap:InterestAndDebtExpense        
Derivative [Line Items]        
Gain (loss) on hedges (2) (2) (5) (5)
SOUTHERN POWER CO | Cash Flow Hedging | Foreign currency derivatives | Income Statement Location [Axis]: us-gaap:OtherNonoperatingIncomeExpense        
Derivative [Line Items]        
Gain (loss) on hedges (2) 45 (14) 67
SOUTHERN Co GAS | Cash Flow Hedging | Energy-related derivatives | Income Statement Location [Axis]: us-gaap:CostOfGoodsAndServicesSold | Natural gas        
Derivative [Line Items]        
Gain (loss) on hedges (3) 1 7 0
SOUTHERN Co GAS | Fair Value Hedging | Interest rate derivatives | Income Statement Location [Axis]: us-gaap:InterestAndDebtExpense        
Derivative [Line Items]        
Gain (loss) on hedges $ (32) $ 3 $ (3) $ 21
v3.26.1
Derivatives - Schedule of Cumulative Basis Adjustments for Fair Value Hedges (Details) - Fair Value Hedging - Balance Sheet Location [Axis]: us-gaap:LongTermDebtAndCapitalLeaseObligations - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Derivative [Line Items]    
Carrying Amount of the Hedged Item $ (3,687) $ (3,742)
Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item 169 156
SOUTHERN Co GAS    
Derivative [Line Items]    
Carrying Amount of the Hedged Item (442) (446)
Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item $ 56 $ 51
v3.26.1
Acquisitions and Dispositions - Narrative (Details) - SOUTHERN POWER CO
$ in Millions
 6 Months Ended
Jun. 30, 2026
USD ($)
MW
Millers Branch Solar Development Phase 2  
Business Combination [Line Items]  
Approximate nameplate capacity | MW 180
Millers Branch Solar Development Phase 3  
Business Combination [Line Items]  
Approximate nameplate capacity | MW 132
Millers Branch Solar Development  
Business Combination [Line Items]  
Construction costs incurred to date $ 718
Construction work in progress 408
Wind Facilities  
Business Combination [Line Items]  
Construction costs incurred to date 598
Construction work in progress 409
Franklin And Wansley Natural Gas Facilities  
Business Combination [Line Items]  
Construction work in progress $ 82
Franklin And Wansley Natural Gas Facilities | Maximum  
Business Combination [Line Items]  
Additional capacity | MW 400
v3.26.1
Acquisitions and Dispositions - Schedule of Construction Projects (Details) - SOUTHERN POWER CO - MW
 6 Months Ended
Jun. 30, 2026
Feb. 28, 2026
Millers Branch Solar Development Phase 1    
Business Combination [Line Items]    
PPA Contract Period 20 years  
Nameplate capacity placed in service   200
Millers Branch Solar Development Phase 2    
Business Combination [Line Items]    
Approximate nameplate capacity 180  
PPA Contract Period 15 years  
Millers Branch Solar Development Phase 3    
Business Combination [Line Items]    
Approximate nameplate capacity 132  
PPA Contract Period 15 years  
v3.26.1
Acquisitions and Dispositions - Schedule of Wind Repowering Projects (Details) - SOUTHERN POWER CO - MW
Jul. 29, 2026
Jun. 30, 2026
Kay Wind    
Business Combination [Line Items]    
Approximate nameplate capacity   200
Kay Wind | Subsequent Event    
Business Combination [Line Items]    
Nameplate capacity placed in service 200  
Kay Wind | Maximum    
Business Combination [Line Items]    
Approximate nameplate capacity   299
Grant    
Business Combination [Line Items]    
Approximate nameplate capacity   152
Grant Plains    
Business Combination [Line Items]    
Approximate nameplate capacity   147
Wake    
Business Combination [Line Items]    
Approximate nameplate capacity   257
Bethel Wind Facility    
Business Combination [Line Items]    
Approximate nameplate capacity   276
v3.26.1
Segment and Related Information - Narrative (Details)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
USD ($)
state
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
segment
state
Jun. 30, 2025
USD ($)
Segment Reporting [Line Items]        
Number of states in which entity operates | state 3   3  
Operating revenues $ 6,722 $ 6,734 $ 14,765 $ 14,328
Earnings from equity method investments 86 10 136 43
Other segment items 3,472 3,617 $ 8,138 7,812
Traditional Electric Operating Companies        
Segment Reporting [Line Items]        
Number of operating segments | segment     3  
Number of reportable segments | segment     1  
SOUTHERN POWER CO        
Segment Reporting [Line Items]        
Number of reportable segments | segment     1  
Operating revenues 354 362 $ 878 795
Earnings from equity method investments     0 0
SOUTHERN POWER CO | Kay Wind Facility        
Segment Reporting [Line Items]        
Depreciation before tax 140 42 293 69
Depreciation after tax 109 31 228 51
SOUTHERN POWER CO | Reportable Segment        
Segment Reporting [Line Items]        
Other segment items $ 329 296 $ 772 599
SOUTHERN Co GAS        
Segment Reporting [Line Items]        
Number of states in which entity operates | state 4   4  
Number of reportable segments | segment     3  
Operating revenues $ 948 972 $ 3,122 2,811
Earnings from equity method investments 32 23 78 62
Other segment items $ 554 599 $ 1,911 1,670
SOUTHERN Co GAS | Southern Natural Gas Company, LLC        
Segment Reporting [Line Items]        
Ownership percentage, equity method investment 50.00%   50.00%  
SOUTHERN Co GAS | Dalton Pipeline        
Segment Reporting [Line Items]        
Ownership percentage, equity method investment 50.00%   50.00%  
MISSISSIPPI POWER CO        
Segment Reporting [Line Items]        
Operating revenues $ 404 381 $ 867 788
MISSISSIPPI POWER CO | Reportable Segment        
Segment Reporting [Line Items]        
Other segment items 173 183 424 400
Traditional Electric Operating Companies | Wholesale revenues, affiliates | SOUTHERN POWER CO        
Segment Reporting [Line Items]        
Operating revenues $ 92 $ 114 $ 192 $ 229
v3.26.1
Segment and Related Information - Schedule of Financial Data for Business Segments (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Jun. 30, 2025
Mar. 31, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Segment Reporting [Line Items]              
Operating revenues $ 6,977   $ 6,973   $ 15,374 $ 14,748  
Other segment items 3,472   3,617   8,138 7,812  
Depreciation and amortization(b) 1,434   1,323   2,854 2,608  
Earnings from equity method investments 86   10   136 43  
Interest expense(d) 796   874   1,573 1,588  
Income taxes (benefit) 187   289   414 569  
Consolidated Net Income Attributable to Southern Company 1,174   880   2,531 2,214  
Goodwill 5,161       5,161   $ 5,161
Total assets 162,027       162,027   155,720
Loss from extinguishment of debt     129   11 129  
Loss from extinguishment of debt, net of tax     97   8 97  
SOUTHERN POWER CO              
Segment Reporting [Line Items]              
Operating revenues 535   546   1,216 1,113  
Depreciation and amortization(b) 280   177   558 329  
Earnings from equity method investments         0 0  
Interest expense(d) 28   24   55 50  
Income taxes (benefit) (77)   (2)   (147) (3)  
Consolidated Net Income Attributable to Southern Company (25)   51   (22) 138  
Total assets 12,780       12,780   12,657
SOUTHERN POWER CO | Kay Wind Facility              
Segment Reporting [Line Items]              
Depreciation before tax 140   42   293 69  
Depreciation after tax 109   31   228 51  
SOUTHERN Co GAS              
Segment Reporting [Line Items]              
Operating revenues 966   979   3,157 2,818  
Other segment items 554   599   1,911 1,670  
Depreciation and amortization(b) 185   172   369 341  
Earnings from equity method investments 32   23   78 62  
Interest expense(d) 101   92   206 183  
Income taxes (benefit) 32   33   176 162  
Consolidated Net Income Attributable to Southern Company 126 $ 447 106 $ 418 573 524  
Goodwill 5,015       5,015   5,015
Total assets 27,604       27,604   27,387
GEORGIA POWER CO              
Segment Reporting [Line Items]              
Operating revenues 3,133   3,110   6,276 6,148  
Depreciation and amortization(b) 503   512   987 1,015  
Interest expense(d) 228   198   431 385  
Income taxes (benefit) 151   236   236 334  
Consolidated Net Income Attributable to Southern Company 779 628 607 596 1,408 1,204  
Total assets 73,371       73,371   68,077
ALABAMA POWER CO              
Segment Reporting [Line Items]              
Operating revenues 1,963   1,968   4,055 3,980  
Depreciation and amortization(b) 385   371   766 741  
Interest expense(d) 117   116   232 225  
Income taxes (benefit) 135   115   263 226  
Consolidated Net Income Attributable to Southern Company 437 $ 425 381 $ 375 862 755  
Total assets 38,679       38,679   38,124
Operating Segments              
Segment Reporting [Line Items]              
Operating revenues 6,792   6,783   15,005 14,378  
Other segment items 3,306   3,447   7,824 7,492  
Depreciation and amortization(b) 1,417   1,306   2,820 2,575  
Earnings from equity method investments 44   27   89 64  
Interest expense(d) 484   452   954 885  
Income taxes (benefit) 259   401   563 755  
Consolidated Net Income Attributable to Southern Company 1,370   1,204   2,933 2,735  
Goodwill 5,017       5,017   5,017
Total assets 158,477       158,477   153,416
Operating Segments | SOUTHERN Co GAS              
Segment Reporting [Line Items]              
Operating revenues 966   976   3,159 2,815  
Other segment items 551   595   1,911 1,668  
Depreciation and amortization(b) 185   171   367 340  
Earnings from equity method investments 32   23   78 62  
Interest expense(d) 100   92   201 183  
Income taxes (benefit) 34   27   189 165  
Consolidated Net Income Attributable to Southern Company 128   114   569 521  
Total assets 29,500       29,500   28,615
Operating Segments | Electric Utilities              
Segment Reporting [Line Items]              
Operating revenues 5,826   5,804   11,848 11,560  
Other segment items 2,752   2,848   5,913 5,822  
Depreciation and amortization(b) 1,232   1,134   2,451 2,234  
Earnings from equity method investments 12   4   11 2  
Interest expense(d) 383   360   748 702  
Income taxes (benefit) 227   368   387 593  
Consolidated Net Income Attributable to Southern Company 1,244   1,098   2,360 2,211  
Goodwill 2       2   2
Total assets 130,873       130,873   126,029
Operating Segments | Traditional Electric Operating Companies              
Segment Reporting [Line Items]              
Operating revenues 5,396   5,380   10,878 10,692  
Other segment items 2,501   2,674   5,360 5,468  
Depreciation and amortization(b) 967   957   1,908 1,905  
Earnings from equity method investments 12   4   11 2  
Interest expense(d) 367   336   705 652  
Income taxes (benefit) 304   370   534 596  
Consolidated Net Income Attributable to Southern Company 1,269   1,047   2,382 2,073  
Goodwill 0       0   0
Total assets 120,194       120,194   114,287
Operating Segments | SOUTHERN POWER CO              
Segment Reporting [Line Items]              
Operating revenues 535   546   1,216 1,113  
Other segment items 329   296   772 599  
Depreciation and amortization(b) 280   177   558 329  
Earnings from equity method investments 0   0   0 0  
Interest expense(d) 28   24   55 50  
Income taxes (benefit) (77)   (2)   (147) (3)  
Consolidated Net Income Attributable to Southern Company (25)   51   (22) 138  
Goodwill 2       2   2
Total assets 12,780       12,780   12,657
Operating Segments | SOUTHERN Co GAS              
Segment Reporting [Line Items]              
Operating revenues 966   979   3,157 2,818  
Other segment items 554   599   1,911 1,670  
Depreciation and amortization(b) 185   172   369 341  
Earnings from equity method investments 32   23   78 62  
Interest expense(d) 101   92   206 183  
Income taxes (benefit) 32   33   176 162  
Consolidated Net Income Attributable to Southern Company 126   106   573 524  
Goodwill 5,015       5,015   5,015
Total assets 27,604       27,604   27,387
Eliminations              
Segment Reporting [Line Items]              
Operating revenues (38)   (35)   (72) (84)  
Other segment items (27)   (23)   (68) (81)  
Depreciation and amortization(b) 0   0   0 0  
Earnings from equity method investments 0   0   0 0  
Interest expense(d) 0   0   0 0  
Income taxes (benefit) 0   0   0 0  
Consolidated Net Income Attributable to Southern Company (11)   (12)   (4) (3)  
Goodwill 0       0   0
Total assets (733)       (733)   (525)
Eliminations | SOUTHERN Co GAS              
Segment Reporting [Line Items]              
Operating revenues (2)   (2)   (6) (6)  
Other segment items (2)   (2)   (6) (6)  
Depreciation and amortization(b) 0   0   0 0  
Earnings from equity method investments 0   0   0 0  
Interest expense(d) 0   0   0 0  
Income taxes (benefit) 0   0   0 0  
Consolidated Net Income Attributable to Southern Company 0   0   0 0  
Total assets (13,161)       (13,161)   (11,871)
Eliminations | Electric Utilities              
Segment Reporting [Line Items]              
Operating revenues (105)   (122)   (246) (245)  
Other segment items (78)   (122)   (219) (245)  
Depreciation and amortization(b) (15)   0   (15) 0  
Earnings from equity method investments 0   0   0 0  
Interest expense(d) (12)   0   (12) 0  
Income taxes (benefit) 0   0   0 0  
Consolidated Net Income Attributable to Southern Company 0   0   0 0  
Goodwill 0       0   0
Total assets (2,101)       (2,101)   (915)
All Other              
Segment Reporting [Line Items]              
Operating revenues 223   225   441 454  
Other segment items 193   193   382 401  
Depreciation and amortization(b) 17   17   34 33  
Earnings from equity method investments 42   (17)   47 (21)  
Interest expense(d) 312   422   619 703  
Income taxes (benefit) (72)   (112)   (149) (186)  
Consolidated Net Income Attributable to Southern Company (185)   (312)   (398) (518)  
Goodwill 144       144   144
Total assets 4,283       4,283   2,829
All Other | SOUTHERN Co GAS              
Segment Reporting [Line Items]              
Operating revenues 2   5   4 9  
Other segment items 5   6   6 8  
Depreciation and amortization(b) 0   1   2 1  
Earnings from equity method investments 0   0   0 0  
Interest expense(d) 1   0   5 0  
Income taxes (benefit) (2)   6   (13) (3)  
Consolidated Net Income Attributable to Southern Company (2)   $ (8)   4 $ 3  
Total assets $ 11,265       $ 11,265   $ 10,643
v3.26.1
Segment and Related Information - Schedule of Traditional Electric Companies (Details)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
USD ($)
Mar. 31, 2026
USD ($)
Jun. 30, 2025
USD ($)
Mar. 31, 2025
USD ($)
Jun. 30, 2026
USD ($)
segment
Jun. 30, 2025
USD ($)
Segment Reporting [Line Items]            
Total operating revenues $ 6,977   $ 6,973   $ 15,374 $ 14,748
Utility operations and maintenance            
Total utility operations and maintenance 1,705   1,685   3,359 3,305
Other segment items 3,472   3,617   8,138 7,812
Depreciation and amortization(b) 1,434   1,323   2,854 2,608
Interest expense(d) 796   874   1,573 1,588
Income taxes (benefit) 187   289   414 569
Consolidated Net Income Attributable to Southern Company 1,174   880   $ 2,531 2,214
Traditional Electric Operating Companies            
Utility operations and maintenance            
Number of reportable segments | segment         1  
ALABAMA POWER CO            
Segment Reporting [Line Items]            
Total operating revenues 1,963   1,968   $ 4,055 3,980
Utility operations and maintenance            
Total utility operations and maintenance 415   472   808 935
Depreciation and amortization(b) 385   371   766 741
Interest expense(d) 117   116   232 225
Income taxes (benefit) 135   115   263 226
Consolidated Net Income Attributable to Southern Company 437 $ 425 381 $ 375 862 755
GEORGIA POWER CO            
Segment Reporting [Line Items]            
Total operating revenues 3,133   3,110   6,276 6,148
Utility operations and maintenance            
Total utility operations and maintenance 667   645   1,341 1,283
Depreciation and amortization(b) 503   512   987 1,015
Interest expense(d) 228   198   431 385
Income taxes (benefit) 151   236   236 334
Consolidated Net Income Attributable to Southern Company 779 628 607 596 1,408 1,204
MISSISSIPPI POWER CO            
Segment Reporting [Line Items]            
Total operating revenues 403   400   875 821
Utility operations and maintenance            
Total utility operations and maintenance 107   82   194 166
Depreciation and amortization(b) 58   52   113 105
Interest expense(d) 21   20   41 40
Income taxes (benefit) 16   17   34 34
Consolidated Net Income Attributable to Southern Company 52 $ 60 59 $ 55 112 114
SOUTHERN POWER CO            
Segment Reporting [Line Items]            
Total operating revenues 535   546   1,216 1,113
Utility operations and maintenance            
Total utility operations and maintenance 139   135   278 257
Depreciation and amortization(b) 280   177   558 329
Interest expense(d) 28   24   55 50
Income taxes (benefit) (77)   (2)   (147) (3)
Consolidated Net Income Attributable to Southern Company (25)   51   $ (22) 138
Number of reportable segments | segment         1  
Reportable Segment | ALABAMA POWER CO            
Segment Reporting [Line Items]            
Total operating revenues 1,963   1,968   $ 4,055 3,980
Utility operations and maintenance            
Rate RSE expenses 332   374   633 739
Rate CNP Compliance expenses 71   67   145 142
Total utility operations and maintenance 403   441   778 881
Other segment items 486   544   1,154 1,152
Depreciation and amortization(b) 385   371   766 741
Interest expense(d) 117   116   232 225
Income taxes (benefit) 135   115   263 226
Consolidated Net Income Attributable to Southern Company 437   381   862 755
Capital expenditures 501   599   1,019 1,159
Reportable Segment | GEORGIA POWER CO            
Segment Reporting [Line Items]            
Total operating revenues 3,133   3,110   6,276 6,148
Utility operations and maintenance            
Total utility operations and maintenance 586   568   1,164 1,104
Other segment items 886   989   2,050 2,106
Depreciation and amortization(b) 503   512   987 1,015
Interest expense(d) 228   198   431 385
Income taxes (benefit) 151   236   236 334
Consolidated Net Income Attributable to Southern Company 779   607   1,408 1,204
Capital expenditures 2,173   1,676   4,243 3,313
Reportable Segment | MISSISSIPPI POWER CO            
Segment Reporting [Line Items]            
Total operating revenues 403   400   875 821
Operational expenses 80   65   144 122
Environmental compliance expenses 3   4   7 6
Utility operations and maintenance            
Other segment items 173   183   424 400
Depreciation and amortization(b) 58   52   113 105
Interest expense(d) 21   20   41 40
Income taxes (benefit) 16   17   34 34
Consolidated Net Income Attributable to Southern Company 52   59   112 114
Capital expenditures 96   126   178 199
Reportable Segment | SOUTHERN POWER CO            
Segment Reporting [Line Items]            
Total operating revenues 535   546   1,216 1,113
Utility operations and maintenance            
Other segment items 329   296   772 599
Depreciation and amortization(b) 280   177   558 329
Interest expense(d) 28   24   55 50
Income taxes (benefit) (77)   (2)   (147) (3)
Consolidated Net Income Attributable to Southern Company $ (25)   $ 51   $ (22) $ 138
Traditional Electric Operating Companies            
Utility operations and maintenance            
Number of reportable segments | segment         1  
v3.26.1
Segment and Related Information - Schedule of Southern Power (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting [Line Items]        
Operating revenues $ 6,977 $ 6,973 $ 15,374 $ 14,748
Other segment items 3,472 3,617 8,138 7,812
Depreciation and amortization(b) 1,434 1,323 2,854 2,608
Earnings from equity method investments 86 10 136 43
Interest expense 796 874 1,573 1,588
Income taxes (benefit) 187 289 414 569
Net income 1,174 880 2,531 2,214
Loss from extinguishment of debt   129 11 129
Loss from extinguishment of debt, net of tax   97 8 97
Operating Segments        
Segment Reporting [Line Items]        
Operating revenues 6,792 6,783 15,005 14,378
Other segment items 3,306 3,447 7,824 7,492
Depreciation and amortization(b) 1,417 1,306 2,820 2,575
Earnings from equity method investments 44 27 89 64
Interest expense 484 452 954 885
Income taxes (benefit) 259 401 563 755
Net income 1,370 1,204 2,933 2,735
Eliminations        
Segment Reporting [Line Items]        
Operating revenues (38) (35) (72) (84)
Other segment items (27) (23) (68) (81)
Depreciation and amortization(b) 0 0 0 0
Earnings from equity method investments 0 0 0 0
Interest expense 0 0 0 0
Income taxes (benefit) 0 0 0 0
Net income (11) (12) (4) (3)
All Other        
Segment Reporting [Line Items]        
Operating revenues 223 225 441 454
Other segment items 193 193 382 401
Depreciation and amortization(b) 17 17 34 33
Earnings from equity method investments 42 (17) 47 (21)
Interest expense 312 422 619 703
Income taxes (benefit) (72) (112) (149) (186)
Net income (185) (312) (398) (518)
SOUTHERN POWER CO        
Segment Reporting [Line Items]        
Operating revenues 535 546 1,216 1,113
Depreciation and amortization(b) 280 177 558 329
Earnings from equity method investments     0 0
Interest expense 28 24 55 50
Income taxes (benefit) (77) (2) (147) (3)
Net income (25) 51 (22) 138
SOUTHERN POWER CO | Kay Wind Facility        
Segment Reporting [Line Items]        
Depreciation before tax 140 42 293 69
Depreciation after tax 109 31 228 51
Reportable Segment | SOUTHERN POWER CO        
Segment Reporting [Line Items]        
Operating revenues 535 546 1,216 1,113
Other segment items 329 296 772 599
Depreciation and amortization(b) 280 177 558 329
Interest expense 28 24 55 50
Income taxes (benefit) (77) (2) (147) (3)
Net income (25) 51 (22) 138
Traditional Electric Operating Companies | Operating Segments        
Segment Reporting [Line Items]        
Operating revenues 5,396 5,380 10,878 10,692
Other segment items 2,501 2,674 5,360 5,468
Depreciation and amortization(b) 967 957 1,908 1,905
Earnings from equity method investments 12 4 11 2
Interest expense 367 336 705 652
Income taxes (benefit) 304 370 534 596
Net income 1,269 1,047 2,382 2,073
SOUTHERN POWER CO | Operating Segments        
Segment Reporting [Line Items]        
Operating revenues 535 546 1,216 1,113
Other segment items 329 296 772 599
Depreciation and amortization(b) 280 177 558 329
Earnings from equity method investments 0 0 0 0
Interest expense 28 24 55 50
Income taxes (benefit) (77) (2) (147) (3)
Net income (25) 51 (22) 138
Electric Utilities | Operating Segments        
Segment Reporting [Line Items]        
Operating revenues 5,826 5,804 11,848 11,560
Other segment items 2,752 2,848 5,913 5,822
Depreciation and amortization(b) 1,232 1,134 2,451 2,234
Earnings from equity method investments 12 4 11 2
Interest expense 383 360 748 702
Income taxes (benefit) 227 368 387 593
Net income 1,244 1,098 2,360 2,211
Electric Utilities | Eliminations        
Segment Reporting [Line Items]        
Operating revenues (105) (122) (246) (245)
Other segment items (78) (122) (219) (245)
Depreciation and amortization(b) (15) 0 (15) 0
Earnings from equity method investments 0 0 0 0
Interest expense (12) 0 (12) 0
Income taxes (benefit) 0 0 0 0
Net income 0 0 0 0
SOUTHERN Co GAS | Operating Segments        
Segment Reporting [Line Items]        
Operating revenues 966 979 3,157 2,818
Other segment items 554 599 1,911 1,670
Depreciation and amortization(b) 185 172 369 341
Earnings from equity method investments 32 23 78 62
Interest expense 101 92 206 183
Income taxes (benefit) 32 33 176 162
Net income $ 126 $ 106 $ 573 $ 524
v3.26.1
Segment and Related Information - Schedule of Gas Revenues (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Jun. 30, 2025
Mar. 31, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Segment Reporting [Line Items]              
Total operating revenues $ 6,977   $ 6,973   $ 15,374 $ 14,748  
Other segment items 3,472   3,617   8,138 7,812  
Depreciation and amortization(b) 1,434   1,323   2,854 2,608  
Interest expense(d) 796   874   1,573 1,588  
Income taxes (benefit) 187   289   414 569  
Consolidated Net Income Attributable to Southern Company 1,174   880   2,531 2,214  
Total assets 162,027       162,027   $ 155,720
Earnings from equity method investments 86   10   136 43  
SOUTHERN Co GAS              
Segment Reporting [Line Items]              
Total operating revenues 966   979   3,157 2,818  
Other segment items 554   599   1,911 1,670  
Depreciation and amortization(b) 185   172   369 341  
Interest expense(d) 101   92   206 183  
Income taxes (benefit) 32   33   176 162  
Consolidated Net Income Attributable to Southern Company 126 $ 447 106 $ 418 573 524  
Total assets 27,604       27,604   27,387
Earnings from equity method investments 32   23   78 62  
Operating Segments              
Segment Reporting [Line Items]              
Total operating revenues 6,792   6,783   15,005 14,378  
Other segment items 3,306   3,447   7,824 7,492  
Depreciation and amortization(b) 1,417   1,306   2,820 2,575  
Interest expense(d) 484   452   954 885  
Income taxes (benefit) 259   401   563 755  
Consolidated Net Income Attributable to Southern Company 1,370   1,204   2,933 2,735  
Total assets 158,477       158,477   153,416
Earnings from equity method investments 44   27   89 64  
Operating Segments | SOUTHERN Co GAS              
Segment Reporting [Line Items]              
Total operating revenues 966   976   3,159 2,815  
Other segment items 551   595   1,911 1,668  
Depreciation and amortization(b) 185   171   367 340  
Interest expense(d) 100   92   201 183  
Income taxes (benefit) 34   27   189 165  
Consolidated Net Income Attributable to Southern Company 128   114   569 521  
Total assets 29,500       29,500   28,615
Earnings from equity method investments 32   23   78 62  
Operating Segments | Gas distribution operations | SOUTHERN Co GAS              
Segment Reporting [Line Items]              
Total operating revenues 885   885   2,785 2,454  
Other segment items 496   526   1,673 1,431  
Depreciation and amortization(b) 181   167   360 330  
Interest expense(d) 90   82   181 164  
Income taxes (benefit) 23   19   139 123  
Consolidated Net Income Attributable to Southern Company 95   91   432 406  
Total assets 26,244       26,244   25,391
Earnings from equity method investments 0   0   0 0  
Operating Segments | Gas Pipeline Investments | SOUTHERN Co GAS              
Segment Reporting [Line Items]              
Total operating revenues 8   8   16 16  
Other segment items 1   1   1 3  
Depreciation and amortization(b) 1   1   2 3  
Interest expense(d) 9   9   18 18  
Income taxes (benefit) 7   5   18 13  
Consolidated Net Income Attributable to Southern Company 22   15   55 41  
Total assets 1,546       1,546   1,475
Earnings from equity method investments 32   23   78 62  
Operating Segments | Gas marketing services | SOUTHERN Co GAS              
Segment Reporting [Line Items]              
Total operating revenues 73   83   358 345  
Other segment items 54   68   237 234  
Depreciation and amortization(b) 3   3   5 7  
Interest expense(d) 1   1   2 1  
Income taxes (benefit) 4   3   32 29  
Consolidated Net Income Attributable to Southern Company 11   8   82 74  
Total assets 1,710       1,710   1,749
Earnings from equity method investments 0   0   0 0  
All Other              
Segment Reporting [Line Items]              
Total operating revenues 223   225   441 454  
Other segment items 193   193   382 401  
Depreciation and amortization(b) 17   17   34 33  
Interest expense(d) 312   422   619 703  
Income taxes (benefit) (72)   (112)   (149) (186)  
Consolidated Net Income Attributable to Southern Company (185)   (312)   (398) (518)  
Total assets 4,283       4,283   2,829
Earnings from equity method investments 42   (17)   47 (21)  
All Other | SOUTHERN Co GAS              
Segment Reporting [Line Items]              
Total operating revenues 2   5   4 9  
Other segment items 5   6   6 8  
Depreciation and amortization(b) 0   1   2 1  
Interest expense(d) 1   0   5 0  
Income taxes (benefit) (2)   6   (13) (3)  
Consolidated Net Income Attributable to Southern Company (2)   (8)   4 3  
Total assets 11,265       11,265   10,643
Earnings from equity method investments 0   0   0 0  
Eliminations              
Segment Reporting [Line Items]              
Total operating revenues (38)   (35)   (72) (84)  
Other segment items (27)   (23)   (68) (81)  
Depreciation and amortization(b) 0   0   0 0  
Interest expense(d) 0   0   0 0  
Income taxes (benefit) 0   0   0 0  
Consolidated Net Income Attributable to Southern Company (11)   (12)   (4) (3)  
Total assets (733)       (733)   (525)
Earnings from equity method investments 0   0   0 0  
Eliminations | SOUTHERN Co GAS              
Segment Reporting [Line Items]              
Total operating revenues (2)   (2)   (6) (6)  
Other segment items (2)   (2)   (6) (6)  
Depreciation and amortization(b) 0   0   0 0  
Interest expense(d) 0   0   0 0  
Income taxes (benefit) 0   0   0 0  
Consolidated Net Income Attributable to Southern Company 0   0   0 0  
Total assets (13,161)       (13,161)   $ (11,871)
Earnings from equity method investments $ 0   $ 0   $ 0 $ 0