DOMINION ENERGY SOUTH CAROLINA, INC., 10-Q filed on 8/1/2024
Quarterly Report
v3.24.2.u1
Document and Entity Information - shares
 6 Months Ended
Jun. 30, 2024
Jul. 26, 2024
Cover [Abstract]    
Entity Registrant Name DOMINION ENERGY SOUTH CAROLINA, INC.  
Entity Central Index Key 0000091882  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Document Type 10-Q  
Document Fiscal Year Focus 2024  
Document Fiscal Period Focus Q2  
Amendment Flag false  
Entity Emerging Growth Company false  
Entity Small Business false  
Entity Common Stock, Shares Outstanding   40,296,147
Entity Current Reporting Status Yes  
Entity Shell Company false  
Entity File Number 001-3375  
Entity Tax Identification Number 57-0248695  
Entity Address, Address Line One 220 OPERATION WAY  
Entity Address, City or Town CAYCE  
Entity Address, State or Province SC  
Entity Address, Postal Zip Code 29033  
City Area Code 804  
Local Phone Number 819-2284  
Entity Incorporation, State or Country Code SC  
Document Quarterly Report true  
Document Transition Report false  
Entity Interactive Data Current Yes  
Document Period End Date Jun. 30, 2024  
v3.24.2.u1
Consolidated Balance Sheets (Unaudited) - USD ($)
$ in Millions
Jun. 30, 2024
Dec. 31, 2023
ASSETS    
Utility plant in service $ 16,041 $ 15,500
Accumulated depreciation and amortization (5,637) (5,557)
Construction work in progress 776 606
Nuclear fuel, net of accumulated amortization 217 229
Utility plant, net 11,397 10,778
Nonutility Property and Investments:    
Nonutility property, net of accumulated depreciation 16 24
Assets held in trust, nuclear decommissioning 255 247
Nonutility property and investments, net 271 271
Current Assets:    
Cash and cash equivalents 2 1
Customer, net of allowance for uncollectible accounts of $6 and $6 383 420
Receivables, other 65 97
Inventories (at average cost):    
Fuel 92 94
Gas stored 20 30
Materials and supplies 251 232
Prepayments 121 84
Regulatory assets 310 444
Other current assets [1] 38 23
Current assets held for sale 4  
Total current assets 1,287 1,429
Deferred Debits and Other Assets:    
Regulatory assets 3,362 3,107
Affiliated receivables 4 4
Other [1] 370 268
Total deferred debits and other assets 3,736 3,379
Total assets 16,691 15,857
CAPITALIZATION AND LIABILITIES    
Common Stock - no par value 4,088 4,088
Retained earnings 598 592
Accumulated other comprehensive loss (1) (1)
Total common equity 4,685 4,679
Noncontrolling interest 195 183
Total equity 4,880 4,862
Long-term debt, net 4,219 4,219
Affiliated long-term debt 230  
Finance leases 3 4
Total long-term debt 4,452 4,223
Total capitalization 9,332 9,085
Current Liabilities:    
Short-term borrowings 275 254
Securities due within one year 3 3
Accounts payable 189 180
Affiliated and related party payables 745 740
Customer deposits and customer prepayments 77 75
Taxes accrued 131 248
Interest accrued 79 79
Regulatory liabilities 230 205
Other 128 166
Total current liabilities 1,857 1,950
Deferred Credits and Other Liabilities:    
Deferred income taxes and investment tax credits 1,347 1,318
Asset retirement obligations 1,391 731
Pension and other postretirement benefits 114 115
Regulatory liabilities 2,575 2,579
Other 75 79
Total deferred credits and other liabilities 5,502 4,822
Commitments and Contingencies
Total capitalization and liabilities 16,691 15,857
Related Party    
Current Assets:    
Affiliated and related party $ 1 $ 4
[1] See Note 12 for amounts attributable to affiliates.
v3.24.2.u1
Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($)
shares in Millions, $ in Millions
Jun. 30, 2024
Dec. 31, 2023
Utility plant, net $ 11,397 $ 10,778
Receivables, customer, allowance for uncollectible accounts 6 6
Total current assets 1,287 1,429
Total deferred debits and other assets $ 3,736 $ 3,379
Common stock, par value $ 0 $ 0
Common stock, shares outstanding 40.3 40.3
Variable Interest Entity, Primary Beneficiary [Member]    
Utility plant, net $ 1,001 $ 773
Total current assets 87 89
Total deferred debits and other assets $ 27 $ 26
v3.24.2.u1
Consolidated Statements of Comprehensive Income (Unaudited) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Income Statement [Abstract]        
Operating Revenue [1] $ 731 $ 704 $ 1,506 $ 1,463
Operating Expenses:        
Fuel used in electric generation 135 135 280 285
Purchased power [1] 22 29 32 36
Gas purchased for resale 46 45 125 127
Other operations and maintenance 126 100 248 215
Other operations and maintenance - affiliated suppliers 42 42 83 83
Impairment of assets and other charges 4   4  
Depreciation and amortization 136 131 272 260
Other taxes [1] 76 74 154 152
Total operating expenses 587 556 1,198 1,158
Operating income 144 148 308 305
Other income (expense), net 1 18 2 28
Interest charges, net of AFUDC [1] 67 63 134 122
Income before income tax expense 78 103 176 211
Income tax expense 15 22 33 33
Net Income and Other Comprehensive Income 63 81 143 178
Comprehensive Income Attributable to Noncontrolling Interest 6 5 12 10
Comprehensive Income Available to Common Shareholder $ 57 $ 76 $ 131 $ 168
[1] See Note 12 for amounts attributable to affiliates.
v3.24.2.u1
Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Income Statement [Abstract]        
Allowance for funds used during construction $ 6 $ 5 $ 10 $ 9
v3.24.2.u1
Consolidated Statements of Cash Flows (Unaudited) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Operating Activities    
Net income $ 143 $ 178
Adjustments to reconcile net income to net cash provided by operating activities:    
Impairment of assets and other charges 4 0
Deferred income taxes, net 29 17
Depreciation and amortization 272 260
Amortization of nuclear fuel 19 14
Other adjustments (3) (27)
Changes in certain assets and liabilities:    
Receivables 60 73
Receivables - affiliated and related party 3 2
Inventories (7) (9)
Prepayments and deposits, net (35) (38)
Regulatory assets 112 109
Regulatory liabilities 17 (209)
Accounts payable 27 (73)
Accounts payable - affiliated and related party (13) (14)
Taxes accrued (117) (107)
Interest accrued 0 (1)
Pension and other postretirement benefits (1) 0
Other assets and liabilities (117) 89
Net cash provided by operating activities 393 264
Investing Activities    
Property additions and construction expenditures (490) (487)
Proceeds from investments and sales of assets (37) (14)
Purchase of investments (10) (4)
Other 2 3
Net cash used in investing activities (535) (502)
Financing Activities    
Dividend to parent (125) (100)
Short-term borrowings, net 21 54
Short-term borrowings - affiliated, net 248 275
Other (1) (1)
Net cash provided by financing activities 143 228
Net increase (decrease) in cash, restricted cash and equivalents 1 (10)
Cash, restricted cash and equivalents at beginning of period [1] 1 11
Cash, restricted cash and equivalents at end of period [1] 2 1
Significant noncash investing and financing activities:    
Accrued construction expenditures [2] $ 59 $ 29
[1] At June 30, 2024, December 31, 2023, June 30, 2023 and December 31, 2022 there were no restricted cash and equivalent balances.
[2] See Note 10 for noncash investing activities related to the transfer of property associated with the settlement of litigation and Note 5 for noncash financing activities related to an amendment of affiliated long-term debt.
v3.24.2.u1
Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($)
$ in Millions
Jun. 30, 2024
Dec. 31, 2023
Jun. 30, 2023
Dec. 31, 2022
Statement of Cash Flows [Abstract]        
Restricted cash and equivalents $ 0 $ 0 $ 0 $ 0
v3.24.2.u1
Consolidated Statements of Changes in Common Equity (Unaudited) - USD ($)
shares in Millions, $ in Millions
Total
Common Stock
Retained Earnings
AOCI
Noncontrolling Interest
Beginning balance at Dec. 31, 2022 $ 4,666 $ 4,088 $ 418 $ (2) $ 162
Beginning balance (in shares) at Dec. 31, 2022   40      
Total comprehensive income available to common shareholder 178   168   10
Dividend to parent (100)   (100)    
Ending balance at Jun. 30, 2023 4,744 $ 4,088 486 (2) 172
Ending balance (in shares) at Jun. 30, 2023   40      
Beginning balance at Mar. 31, 2023 4,713 $ 4,088 460 (2) 167
Beginning balance (in shares) at Mar. 31, 2023   40      
Total comprehensive income available to common shareholder 81   76   5
Dividend to parent (50)   (50)    
Ending balance at Jun. 30, 2023 4,744 $ 4,088 486 (2) 172
Ending balance (in shares) at Jun. 30, 2023   40      
Beginning balance at Dec. 31, 2023 4,862 $ 4,088 592 (1) 183
Beginning balance (in shares) at Dec. 31, 2023   40      
Total comprehensive income available to common shareholder 143   131   12
Dividend to parent (125)   (125)    
Ending balance at Jun. 30, 2024 4,880 $ 4,088 598 (1) 195
Ending balance (in shares) at Jun. 30, 2024   40      
Beginning balance at Mar. 31, 2024 4,880 $ 4,088 604 (1) 189
Beginning balance (in shares) at Mar. 31, 2024   40      
Total comprehensive income available to common shareholder 63   57   6
Dividend to parent (63)   (63)    
Ending balance at Jun. 30, 2024 $ 4,880 $ 4,088 $ 598 $ (1) $ 195
Ending balance (in shares) at Jun. 30, 2024   40      
v3.24.2.u1
Pay vs Performance Disclosure - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Pay vs Performance Disclosure        
Net Income (Loss) $ 57 $ 76 $ 131 $ 168
v3.24.2.u1
Insider Trading Arrangements
 3 Months Ended
Jun. 30, 2024
Trading Arrangements, by Individual  
Rule 10b5-1 Arrangement Adopted false
Non-Rule 10b5-1 Arrangement Adopted false
Rule 10b5-1 Arrangement Terminated false
Non-Rule 10b5-1 Arrangement Terminated false
v3.24.2.u1
Summary of Significant Accounting Policies
 6 Months Ended
Jun. 30, 2024
Accounting Policies [Abstract]  
Summary of Significant Accounting Policies

1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Consolidation and Variable Interest Entities

DESC has determined that it has a controlling financial interest in each of GENCO and Fuel Company (which are considered to be VIEs) and, accordingly, DESC’s Consolidated Financial Statements include, after eliminating intercompany balances and transactions, the accounts of DESC, GENCO and Fuel Company. See Note 2 to the Consolidated Financial Statements included in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023 for a description of GENCO and Fuel Company.

DESC purchases shared services from DES, an affiliated VIE that provides accounting, legal, finance and certain administrative and technical services to all Dominion Energy subsidiaries, including DESC. DESC has determined that it is not the primary beneficiary of DES as it does not have either the power to direct the activities that most significantly impact its economic performance or an obligation to absorb losses and benefits which could be significant to it. See Note 12 for amounts attributable to affiliates.

Significant Accounting Policies

There have been no significant changes from Note 2 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023, except as follows.

New Accounting Standards

Climate-Related Disclosures

In March 2024, the SEC issued guidance for climate-related disclosures. The guidance requires disclosure of the financial statement impacts of severe weather events and other natural conditions, including amounts capitalized or expensed as well as any associated recoveries. In addition, the guidance requires disclosure of amounts related to renewable energy credits or carbon offsets if utilized as a material component of plans to achieve climate-related targets or goals. This guidance, which is currently subject to a stay issued by the SEC, would be effective for the fiscal year beginning January 1, 2025. DESC expects this guidance to only impact its disclosures with no impacts to its results of operations, cash flows or financial condition.
v3.24.2.u1
Rate and Other Regulatory Matters
 6 Months Ended
Jun. 30, 2024
Regulated Operations [Abstract]  
Rate and Other Regulatory Matters

2. RATE AND OTHER REGULATORY MATTERS

 

Regulatory Matters Involving Potential Loss Contingencies

As a result of issues generated in the ordinary course of business, DESC is involved in various regulatory matters. Certain regulatory matters may ultimately result in a loss; however, as such matters are in an initial procedural phase, involve uncertainty as to the outcome of pending reviews or orders, and/or involve significant factual issues that need to be resolved, it is not possible for DESC to estimate a range of possible loss. For regulatory matters that DESC cannot estimate, a statement to this effect is made in the description of the matter. Other matters may have progressed sufficiently through the regulatory process such that DESC is able to estimate a range of possible loss. For regulatory matters that DESC is able to reasonably estimate a range of possible losses, an

estimated range of possible loss is provided, in excess of the accrued liability (if any) for such matters. Any estimated range is based on currently available information, involves elements of judgment and significant uncertainties and may not represent DESC’s maximum possible loss exposure. The circumstances of such regulatory matters will change from time to time and actual results may vary significantly from the current estimate. For current matters not specifically reported below, management does not anticipate that the outcome from such matters would have a material effect on DESC’s financial position, liquidity or results of operations.

Other Regulatory Matters

Other than the following matters, there have been no significant developments regarding the pending regulatory matters disclosed in Note 3 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023.

Electric Base Rate Case

In March 2024, DESC filed its retail electric base rate case and schedules with the South Carolina Commission. DESC proposed a non-fuel, base rate increase of $295 million, partially offset by a net decrease in storm damage and DSM components of $4 million. If approved, the overall proposed rate increase of $291 million, or 12.59%, would be effective on and after the first billing cycle of September 2024. The base rate increase was proposed to recover the significant investment in assets and operating resources required to serve an expanding customer base, maintain the safety, reliability and efficiency of DESC’s system and meet increasingly stringent reliability, security and environmental requirements for the benefit of South Carolina customers. DESC presented an earned ROE of 4.32% based upon a fully-adjusted test period. The proposed rates would provide for an earned ROE of 10.60% compared to the currently authorized ROE of 9.50%.

In July 2024, DESC, the South Carolina Office of Regulatory Staff and other parties of record filed a comprehensive settlement agreement with the South Carolina Commission for approval. The comprehensive settlement agreement provides for a non-fuel, base rate increase of $219 million prior to the effect of South Carolina Commission-ordered DSM reductions commencing with service rendered on September 1, 2024 and an authorized ROE of 9.94%. In addition, the comprehensive settlement agreement includes that DESC would provide a one-time bill credit in 2024 of approximately $7 million primarily to residential customers. If approved, DESC would expect to record an approximately $50 million charge primarily to write down certain materials and supplies inventory. This matter is pending.

Electric – Cost of Fuel

DESC’s retail electric rates include a cost of fuel component approved by the South Carolina Commission which may be adjusted periodically to reflect changes in the price of fuel purchased by DESC. In February 2024, DESC filed with the South Carolina Commission a proposal to decrease the total fuel cost component of retail electric rates. DESC’s proposed adjustment is designed to recover DESC’s current base fuel costs, including its existing under-collected balance, over the 12-month period beginning with the first billing cycle of May 2024. In addition, DESC proposed an increase to its variable environmental and avoided capacity cost component. The net effect is a proposed annual decrease of $315 million. In March 2024, DESC, the South Carolina Office of Regulatory Staff and another party of record filed a settlement agreement with the South Carolina Commission for approval to make certain adjustments to the February 2024 filing that would result in a net annual decrease of $316 million. In April 2024, the South Carolina Commission voted to approve the settlement agreement, with rates effective May 2024.

Electric - Transmission Project

In March 2024, DESC filed an application with the South Carolina Commission requesting approval of a CPCN to construct and operate the Church Creek - Charleston Transmission Line, comprised of a 7-mile 230 kV transmission line and associated facilities in Charleston County, South Carolina with an estimated total project cost of $40 million. In July 2024, the South Carolina Commission approved the application.

Electric – Other

 

DESC has approval for a DSM rider through which it recovers expenditures related to its DSM programs. In January 2024, DESC filed an application with the South Carolina Commission seeking approval to recover $47 million of costs and net lost revenues associated with these programs, along with an incentive to invest in such programs. DESC requested that rates be effective with the first billing cycle of May 2024. In April 2024, the South Carolina Commission approved the request, effective with the first billing cycle of May 2024.

DESC utilizes a pension costs rider approved by the South Carolina Commission which is designed to allow recovery of projected pension costs, including under-collected balances or net of over-collected balances, as applicable. The rider is typically reviewed for adjustment every 12 months with any resulting increase or decrease going into effect beginning with the first billing cycle in May. In February 2024, DESC requested that the South Carolina Commission approve an adjustment to this rider to increase annual revenue by $9 million. In April 2024, the South Carolina Commission approved the request.

Natural Gas Rates

In June 2024, DESC filed with the South Carolina Commission its monitoring report for the 12-month period ended March 31, 2024 with a total revenue requirement of $523 million. This represents a $13 million base rate increase under the terms of the Natural Gas Rate Stabilization Act effective with the first billing cycle of November 2024. This matter is pending.

Regulatory Assets and Regulatory Liabilities

Rate-regulated utilities recognize in their financial statements certain revenues and expenses in different periods than do other enterprises. As a result, DESC has recorded regulatory assets and regulatory liabilities which are summarized in the following table. Except for NND Project costs and certain other unrecovered costs referenced herein, substantially all regulatory assets are either explicitly excluded from rate base or are effectively excluded from rate base due to their being offset by related liabilities.

 

 

 

June 30,

 

 

December 31,

 

(millions)

 

2024

 

 

2023

 

Regulatory assets:

 

 

 

 

 

 

NND Project costs(1)

 

$

138

 

 

$

138

 

AROs(2)

 

 

31

 

 

 

44

 

Deferred employee benefit plan costs(3)

 

 

8

 

 

 

11

 

Other unrecovered plant(4)

 

 

19

 

 

 

19

 

DSM programs(5)

 

 

23

 

 

 

22

 

Cost of fuel and purchased gas under-collections(6)

 

 

37

 

 

 

154

 

Other

 

 

54

 

 

 

56

 

Regulatory assets - current

 

 

310

 

 

 

444

 

NND Project costs(1)

 

 

1,880

 

 

 

1,949

 

AROs(2)

 

 

688

 

 

 

379

 

Deferred employee benefit plan costs(3)

 

 

117

 

 

 

118

 

Interest rate hedges(7)

 

 

167

 

 

 

168

 

Other unrecovered plant(4)

 

 

69

 

 

 

66

 

DSM programs(5)

 

 

46

 

 

 

46

 

Environmental remediation costs(8)

 

 

42

 

 

 

34

 

Deferred storm damage costs(9)

 

 

38

 

 

 

40

 

Deferred transmission operating costs(10)

 

 

73

 

 

 

74

 

Derivatives(11)

 

 

99

 

 

 

103

 

Other(12)

 

 

143

 

 

 

130

 

Regulatory assets - noncurrent

 

 

3,362

 

 

 

3,107

 

Total regulatory assets

 

$

3,672

 

 

$

3,551

 

Regulatory liabilities:

 

 

 

 

 

 

Monetization of guaranty settlement(13)

 

$

67

 

 

$

67

 

Income taxes refundable through future rates(14)

 

 

37

 

 

 

37

 

Reserve for refunds to electric utility customers(15)

 

 

80

 

 

 

83

 

Derivatives(11)

 

 

23

 

 

 

12

 

Cost of fuel and purchased gas over-collections(6)

 

 

11

 

 

 

—

 

Other

 

 

12

 

 

 

6

 

Regulatory liabilities - current

 

 

230

 

 

 

205

 

Monetization of guaranty settlement(13)

 

 

602

 

 

 

635

 

Income taxes refundable through future rates(14)

 

 

821

 

 

 

839

 

Asset removal costs(16)

 

 

636

 

 

 

633

 

Reserve for refunds to electric utility customers(15)

 

 

193

 

 

 

237

 

Derivatives(11)

 

 

321

 

 

 

229

 

Other

 

 

2

 

 

 

6

 

Regulatory liabilities - noncurrent

 

 

2,575

 

 

 

2,579

 

Total regulatory liabilities

 

$

2,805

 

 

$

2,784

 

 

(1)
Reflects expenditures associated with the NND Project, which pursuant to the SCANA Merger Approval Order, will be recovered from electric service customers over a 20-year period ending in 2039.
(2)
Represents uncollected costs, including deferred depreciation and accretion expense, related to legal obligations associated with the future retirement of generation, transmission and distribution properties. The AROs primarily relate to DESC’s electric generating facilities, including Summer, and are expected to be recovered over the related property lives and periods of decommissioning which may range up to approximately 105 years. In addition, the balance at June 30, 2024 reflects amounts related to the EPA’s May 2024 final rule concerning CCR as discussed in Note 10.
(3)
Employee benefit plan costs have historically been recovered as they have been recorded under GAAP. Deferred employee benefit plan costs represent amounts of pension and other postretirement benefit costs which were accrued as liabilities and treated as regulatory assets pursuant to FERC guidance, and costs deferred pursuant to specific South Carolina Commission regulatory orders. DESC expects to recover deferred pension costs through utility rates over periods through 2044. DESC expects to recover other deferred benefit costs through utility rates, primarily over average service periods of participating employees up to 11 years.
(4)
Represents the carrying value of coal-fired generating units, including related materials and supplies inventory, retired from service prior to being fully depreciated. DESC is amortizing these amounts through cost of service rates following depreciation amounts that were designed to recover the retired units cost over their previous estimated remaining useful lives, which has been estimated to be through 2025. Based on current projections of remaining decommissioning costs, projected recovery is expected to extend through 2039. In addition, amounts include unrecovered costs of existing meters and equipment retired from service prior to being fully depreciated as part of the Advanced Metering Infrastructure project, which are being recovered through rates through 2028. This amount also includes certain inventory and preliminary survey and investigation charges being amortized over five years related to the transition or conversion from coal to gas fired generation at certain facilities.
(5)
Represents deferred costs associated with electric demand reduction programs, and such deferred costs are currently being recovered over three years through an approved rate rider.
(6)
Represents amounts under- or over-collected from customers pursuant to the cost of fuel and purchased gas components approved by the South Carolina Commission.
(7)
Represents settled interest rate derivatives designated as cash flow hedges expected to be amortized to interest expense over the lives of the underlying debt through 2065.
(8)
Reflects amounts associated with the assessment and clean-up of sites currently or formerly owned by DESC. Such remediation costs are expected to be recovered over periods of up to 24 years. See Note 10 for additional information.
(9)
Represents storm restoration costs for which DESC expects to receive future recovery through customer rates over approximately 10 years pursuant to the settlement agreement approved in DESC’s retail electric base rate case. Unamortized amounts are included in rate base and are earning a current return.
(10)
Includes deferred depreciation and property taxes associated with certain transmission assets for which DESC expects recovery from customers through future rates over approximately 42 years pursuant to the settlement agreement approved in DESC’s retail electric base rate case. Unamortized amounts are included in rate base and earning a current return. See Note 12 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023.
(11)
Represents changes in the fair value of derivatives, excluding separately presented interest rate hedges, that following settlement are expected to be recovered from or refunded to customers.
(12)
Various other regulatory assets are expected to be recovered through rates over varying periods through 2078.
(13)
Represents proceeds related to the monetization of the Toshiba Settlement. In accordance with the SCANA Merger Approval Order, this balance, net of amounts that may be required to satisfy liens, will be refunded to electric customers over a 20-year period ending in 2039.
(14)
Includes (i) excess deferred income taxes arising from the remeasurement of deferred income taxes in connection with the enactment of the 2017 Tax Reform Act (certain of which are protected under normalization rules and will be amortized over the remaining lives of related property, and certain of which will be amortized to the benefit of customers over prescribed periods as instructed by regulators) and (ii) deferred income taxes arising from investment tax credits, offset by (iii) deferred income taxes that arise from utility operations that have not been included in customer rates (a portion of which relate to depreciation and are expected to be recovered over the remaining lives of the related property which may range up to 85 years). See Note 7 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023 for additional information.
(15)
Reflects amounts previously collected from retail electric customers of DESC for the NND Project to be credited to customers over an estimated 11-year period effective February 2019 in connection with the SCANA Merger Approval Order.
(16)
Represents estimated net collections through depreciation rates of amounts to be expended for the removal of assets in the future.

 

Regulatory assets have been recorded based on the probability of their recovery. All regulatory assets represent incurred costs that may be deferred under GAAP for regulated operations. The South Carolina Commission or FERC has reviewed and approved through specific orders certain of the items shown as regulatory assets. In addition, regulatory assets include, but are not limited to, certain costs which have not been specifically approved for recovery by one of these regulatory agencies. While such costs are not currently being recovered, management believes that they would be allowable under existing rate-making concepts embodied in rate orders or applicable state law and expects to recover these costs through rates in future periods.
v3.24.2.u1
Revenue Recognition
 6 Months Ended
Jun. 30, 2024
Revenue from Contract with Customer [Abstract]  
Revenue Recognition

3. REVENUE RECOGNITION

DESC has disaggregated operating revenues by customer class as follows:

 

 

 

Three Months Ended
June 30, 2024

 

 

Three Months Ended
June 30, 2023

 

 

Six Months Ended
June 30, 2024

 

 

Six Months Ended
June 30, 2023

 

(millions)

 

Electric

 

 

Gas

 

 

Electric

 

 

Gas

 

 

Electric

 

 

Gas

 

 

Electric

 

 

Gas

 

Customer class:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Residential

 

$

294

 

 

$

48

 

 

$

266

 

 

$

43

 

 

$

577

 

 

$

165

 

 

$

528

 

 

$

152

 

Commercial

 

 

208

 

 

 

25

 

 

 

208

 

 

 

25

 

 

 

396

 

 

 

66

 

 

 

395

 

 

 

67

 

Industrial

 

 

94

 

 

 

17

 

 

 

97

 

 

 

15

 

 

 

181

 

 

 

35

 

 

 

188

 

 

 

37

 

Other

 

 

31

 

 

 

6

 

 

 

34

 

 

 

6

 

 

 

59

 

 

 

12

 

 

 

73

 

 

 

10

 

Revenues from contracts with
    customers

 

 

627

 

 

 

96

 

 

 

605

 

 

 

89

 

 

 

1,213

 

 

 

278

 

 

 

1,184

 

 

 

266

 

Other revenues

 

 

7

 

 

 

1

 

 

 

9

 

 

 

1

 

 

 

14

 

 

 

1

 

 

 

12

 

 

 

1

 

Total Operating Revenues

 

$

634

 

 

$

97

 

 

$

614

 

 

$

90

 

 

$

1,227

 

 

$

279

 

 

$

1,196

 

 

$

267

 

 

Contract liabilities represent the obligation to transfer goods or services to a customer for which consideration has already been received from the customer. DESC had contract liability balances of $8 million and $7 million at June 30, 2024 and December 31, 2023, respectively. During the six months ended June 30, 2024 and 2023, DESC recognized revenue of $4 million and $8 million, respectively, from the beginning contract liability balances as DESC fulfilled its obligations to provide service to its customers. Contract liabilities are recorded in customer deposits and customer prepayments in the Consolidated Balance Sheets.

 

Balances and activity related to contract costs deferred as regulatory assets were as follows:

 

 

 

Regulatory Assets

 

(millions)

 

June 30, 2024

 

 

December 31, 2023

 

Beginning balance

 

$

11

 

 

$

9

 

Additional costs

 

 

—

 

 

 

3

 

Amortization

 

 

—

 

 

 

(1

)

Ending balance

 

$

11

 

 

$

11

 
v3.24.2.u1
Equity
 6 Months Ended
Jun. 30, 2024
Equity [Abstract]  
Equity

4. EQUITY

For all periods presented, DESC’s authorized shares of common stock, no par value, were 50 million, of which 40.3 million were issued and outstanding, and DESC’s authorized shares of preferred stock, no par value, were 20 million, of which 1,000 shares were issued and outstanding. All outstanding shares of common and preferred stock are held by SCANA.

There have been no material changes to the dividend restrictions affecting DESC described in Note 5 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023.
v3.24.2.u1
Long-Term and Short-Term Debt
 6 Months Ended
Jun. 30, 2024
Debt Disclosure [Abstract]  
Long-Term and Short-Term Debt

5. LONG-TERM AND SHORT-TERM DEBT

DESC’s short-term financing is supported through its access as co-borrower to Dominion Energy’s $6.0 billion joint revolving credit facility, which can be used for working capital, as support for the combined commercial paper programs of DESC, Dominion Energy and Virginia Power and for other general corporate purposes. Other than the items discussed below, there have been no significant changes from Note 6 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023.

At June 30, 2024, DESC’s share of commercial paper and letters of credit outstanding under its joint credit facility with Dominion Energy was as follows:

 

(millions)

 

Maximum Facility Sub-Limit

 

 

Outstanding
Commercial Paper

 

 

Outstanding
Letters of Credit

 

Joint revolving credit facility(1)(2)

 

$

1,000

 

 

$

275

 

 

$

—

 

 

(1)
A maximum of $1.0 billion of the facility is available to DESC, assuming adequate capacity is available after giving effect to uses by co-borrowers Dominion Energy and Virginia Power. A sub-limit for DESC is set within the facility limit but can be changed at the option of the co-borrowers multiple times per year. At June 30, 2024, the sub-limit for DESC was $500 million. If DESC has liquidity needs in excess of its sub-limit, the sub-limit may be changed or such needs may be satisfied through short-term intercompany borrowings from Dominion Energy. This
credit facility matures in June 2026, with the potential to be extended by the borrowers to June 2028. The credit facility can be used to support bank borrowings and the issuance of commercial paper, as well as to support up to $1.0 billion (or the sub-limit, whichever is less) of letters of credit.
(2)
In May 2024, the joint revolving credit facility was amended to remove Questar Gas as a co-borrower.

In 2023, FERC granted DESC authority through March 2025 to issue short-term indebtedness (pursuant to Section 204 of the Federal Power Act) in amounts not to exceed $2.2 billion outstanding with maturity dates of one year or less. At June 30, 2024, DESC had issued $275 million in commercial paper supported by its joint credit facility with Dominion Energy as disclosed above and had drawn on $376 million of its intercompany credit facility with Dominion Energy, as permitted by this FERC authorization. In addition, in 2023, FERC granted GENCO authority through March 2025 to issue short-term indebtedness not to exceed $200 million outstanding with maturity dates of one year or less. At June 30, 2024, GENCO had drawn on $41 million of its intercompany credit facility with Dominion Energy, as permitted by this FERC authorization.

DESC is obligated with respect to an aggregate of $68 million of industrial revenue bonds which are secured by letters of credit. These letters of credit expire, subject to renewal, in the fourth quarter of 2024.

DESC, GENCO and Fuel Company each have intercompany credit facilities with Dominion Energy with a maximum capacity of $900 million, $200 million and $400 million, respectively. At June 30, 2024 and December 31, 2023, DESC, GENCO and Fuel Company collectively had borrowings outstanding under these agreements totaling $690 million and $442 million, respectively, which are recorded in affiliated and related party payables in DESC’s Consolidated Balance Sheets. Interest charges associated with these agreements were $12 million and $15 million for the three months ended June 30, 2024 and 2023, respectively, and $22 million and $28 million for the six months ended June 30, 2024 and 2023, respectively.

In May 2024, following approval from the South Carolina Commission, GENCO amended its $230 million promissory note due to Dominion Energy to change the maturity date from May 2024 to May 2027 and the interest rate from 3.05% to 5.31%.
v3.24.2.u1
Income Taxes
 6 Months Ended
Jun. 30, 2024
Income Tax Disclosure [Abstract]  
Income Taxes

6. INCOME TAXES

 

For continuing operations, including noncontrolling interests, the statutory U.S. federal income tax rate reconciles to DESC’s effective income tax rate as follows:

 

Six Months Ended June 30,

 

2024

 

 

2023

 

U.S. statutory rate

 

 

21.0

%

 

 

21.0

%

Increases (reductions) resulting from:

 

 

 

 

 

 

State taxes, net of federal benefit

 

 

4.0

 

 

 

4.1

 

Reversal of excess deferred income taxes

 

 

(5.7

)

 

 

(4.0

)

Allowance for equity funds used during construction

 

 

(0.7

)

 

 

—

 

Settlements of uncertain tax positions

 

 

—

 

 

 

(5.0

)

Other, net

 

 

0.1

 

 

 

(0.1

)

Effective tax rate

 

 

18.7

%

 

 

16.0

%

As of June 30, 2024, there have been no material changes in DESC’s unrecognized tax benefits or possible changes that could reasonably be expected to occur during the next twelve months. See Note 7 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023 for a discussion of these unrecognized tax benefits.

For the six months ended June 30, 2023, DESC’s effective tax rate reflects an income tax benefit of $11 million from the effective settlement of a position that management believed was reasonably possible to occur.
v3.24.2.u1
Derivative Financial Instruments
 6 Months Ended
Jun. 30, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Derivative Financial Instruments

7. DERIVATIVE FINANCIAL INSTRUMENTS

DESC’s accounting policies, objectives, and strategies for using derivative instruments are discussed in Note 2 in the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023. See Note 8 for further information about fair value measurements and associated valuation methods for derivatives.

Cash collateral, as presented in the table below, is used to offset derivative assets and liabilities. Certain of DESC’s derivative instruments contain credit-related contingent provisions. These provisions require DESC to provide collateral upon the occurrence of specific events, primarily a credit rating downgrade. If the credit-related contingent features underlying the instruments that are in a liability position and not fully collateralized with cash were fully triggered as of June 30, 2024 and December 31, 2023, DESC would have been required to post $2 million and $4 million, respectively, of additional collateral to its counterparties. The collateral that

would be required to be posted includes the impacts of any offsetting asset positions and any amounts already posted for derivatives and non-derivative contracts per contractual terms. DESC had not posted any collateral at June 30, 2024 and December 31, 2023 related to derivatives with credit-related contingent provisions that are in a liability position and not fully collateralized with cash. The aggregate fair value of all derivative instruments with credit-related contingent provisions that are in a liability position and not fully collateralized with cash as of June 30, 2024 and December 31, 2023 was $2 million and $4 million, respectively, which does not include the impact of any offsetting asset positions.

The table below presents derivative balances by type of financial instrument, if the gross amounts recognized in the Consolidated Balance Sheets were netted with derivative instruments and cash collateral received or paid:

 

 

June 30, 2024

 

 

December 31, 2023

 

 

 

Gross Amounts Not Offset in the Consolidated
Balance Sheet

 

 

Gross Amounts Not Offset in the Consolidated
Balance Sheet

 

(millions)

 

Gross
Assets
Presented in the
Consolidated
Balance Sheet(1)

 

 

Financial
Instruments

 

 

Cash
Collateral
Received

 

 

Net
Amounts

 

 

Gross
Assets
Presented in the
Consolidated
Balance Sheet(1)

 

 

Financial
Instruments

 

 

Cash
Collateral
Received

 

 

Net
Amounts

 

Interest rate contracts:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Over-the-counter

 

$

1

 

 

$

—

 

 

$

—

 

 

$

1

 

 

$

—

 

 

$

—

 

 

$

—

 

 

$

—

 

Commodity contracts:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Over-the-counter

 

 

7

 

 

 

—

 

 

 

—

 

 

 

7

 

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

Total derivatives

 

$

8

 

 

$

—

 

 

$

—

 

 

$

8

 

 

$

—

 

 

$

—

 

 

$

—

 

 

$

—

 
(1)
Excludes derivative assets of $278 million and $176 million at June 30, 2024 and December 31, 2023, respectively, which are not subject to master netting or similar arrangements.

 

 

 

June 30, 2024

 

 

December 31, 2023

 

 

 

Gross Amounts Not Offset in the Consolidated
Balance Sheet

 

 

Gross Amounts Not Offset in the Consolidated
Balance Sheet

 

(millions)

 

Gross
Liabilities
Presented in the
Consolidated
Balance Sheet(1)

 

 

Financial
Instruments

 

 

Cash
Collateral
Paid

 

 

Net
Amounts

 

 

Gross
Liabilities
Presented in the
Consolidated
Balance Sheet(1)

 

 

Financial
Instruments

 

 

Cash
Collateral
Paid

 

 

Net
Amounts

 

Interest rate contracts:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Over-the-counter

 

$

2

 

 

$

—

 

 

$

—

 

 

$

2

 

 

$

4

 

 

$

—

 

 

$

—

 

 

$

4

 

Total derivatives

 

$

2

 

 

$

—

 

 

$

—

 

 

$

2

 

 

$

4

 

 

$

—

 

 

$

—

 

 

$

4

 
(1)
DESC did not have any derivative liabilities at June 30, 2024 and December 31, 2023, respectively, which were not subject to master netting or similar arrangements.

Volumes

The following table presents the volume of derivative activity at June 30, 2024. These volumes are based on open derivative positions and represent the combined absolute value of their long and short positions.

 

Natural Gas (bcf):

 

Current

 

 

Noncurrent

 

Basis(1)

 

 

18

 

 

 

 

Fixed price

 

 

1

 

 

 

 

Electricity (MWh in millions):

 

 

 

 

 

 

Fixed price

 

 

2

 

 

 

22

 

Interest rate(2) (in millions)

 

$

—

 

 

$

71

 

 

(1)
Includes options.
(2)
Maturity is determined based on final settlement period.

Fair Value and Gains and Losses on Derivative Instruments

The following tables present the fair values of derivatives and where they are presented in the Consolidated Balance Sheets:

 

(millions)

 

Fair Value -
Derivatives not
under Hedge
Accounting

 

At June 30, 2024

 

 

 

ASSETS

 

 

 

Current Assets

 

 

 

Commodity

 

$

26

 

Total current derivative assets(1)

 

 

26

 

Noncurrent Assets

 

 

 

Commodity

 

 

259

 

Interest rate

 

 

1

 

Total noncurrent derivative assets(2)

 

 

260

 

Total derivative assets

 

$

286

 

LIABILITIES

 

 

 

Noncurrent Liabilities

 

 

 

Interest rate

 

 

2

 

Total noncurrent derivative liabilities(3)

 

 

2

 

Total derivative liabilities

 

$

2

 

At December 31, 2023

 

 

 

ASSETS

 

 

 

Current Assets

 

 

 

Commodity

 

$

9

 

Total current derivative assets(1)

 

 

9

 

Noncurrent Assets

 

 

 

Commodity

 

 

167

 

Total noncurrent derivative assets(2)

 

 

167

 

Total derivative assets

 

$

176

 

LIABILITIES

 

 

 

Noncurrent Liabilities

 

 

 

Interest rate

 

 

4

 

Total noncurrent derivative liabilities(3)

 

 

4

 

Total derivative liabilities

 

$

4

 

 

(1)
Current derivative assets are presented in other current assets in DESC’s Consolidated Balance Sheets.
(2)
Noncurrent derivative assets are presented in other deferred debits and other assets in DESC’s Consolidated Balance Sheets.
(3)
Noncurrent derivative liabilities are presented in other deferred credits and other liabilities in DESC’s Consolidated Balance Sheets.

 

The following tables present the gains and losses on derivatives, as well as where the associated activity is presented in the Consolidated Balance Sheets and Statements of Comprehensive Income:

Derivatives in Cash Flow Hedging Relationships

 

(millions)

 

Increase (Decrease) in Derivatives Subject to Regulatory Treatment(1)(2)

 

Three Months Ended June 30,

 

2024

 

 

2023

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

Interest rate

 

$

1

 

 

$

1

 

Total

 

$

1

 

 

$

1

 

Six Months Ended June 30,

 

 

 

 

 

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

Interest rate

 

$

1

 

 

$

—

 

Total

 

$

1

 

 

$

—

 

 

(1)
Represents net derivative activity deferred into and amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/ liabilities have no associated effect in the Consolidated Statements of Comprehensive Income.
(2)
All derivatives in cash flow hedging relationships have settled and are being amortized over the life of the debt.

Derivatives Not Designated as Hedging Instruments

 

(millions)

 

Amount of Gain (Loss) Recognized in Income on Derivatives(1)

 

Three Months Ended June 30,

 

2024

 

 

2023

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

Commodity:

 

 

 

 

 

 

Purchased power

 

$

(1

)

 

$

(1

)

Interest rate:

 

 

 

 

 

 

Interest charges

 

 

—

 

 

 

(1

)

Total

 

$

(1

)

 

$

(2

)

Six Months Ended June 30,

 

 

 

 

 

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

Commodity:

 

 

 

 

 

 

Purchased power

 

$

(3

)

 

$

—

 

Interest rate:

 

 

 

 

 

 

Interest charges

 

 

(1

)

 

 

(1

)

Total

 

$

(4

)

 

$

(1

)

 

(1)
Includes derivative activity amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/liabilities have no associated effect in the Consolidated Statements of Comprehensive Income.
v3.24.2.u1
Fair Value Measurements, Including Derivatives
 6 Months Ended
Jun. 30, 2024
Fair Value Disclosures [Abstract]  
Fair Value Measurements, Including Derivatives

8. FAIR VALUE MEASUREMENTS, INCLUDING DERIVATIVES

DESC’s fair value measurements are made in accordance with the policies discussed in Note 2 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023. See Note 7 in this report for further information about DESC’s derivatives and hedge accounting activities.

The following table presents DESC’s quantitative information about Level 3 fair value measurements at June 30, 2024. The range and weighted average are presented in dollars for market price inputs and percentages for price volatility.

 

 

Fair Value
(millions)

 

 

Valuation Techniques

 

Unobservable Input

 

 

Range

 

Weighted
Average(1)

Assets

 

 

 

 

 

 

 

 

 

 

 

 

Physical forwards:

 

 

 

 

 

 

 

 

 

 

 

 

Electricity

 

$

277

 

 

Discounted cash flow

 

Market price (per MWh)

(3)

 

28-99

 

54

Physical options:

 

 

 

 

 

 

 

 

 

 

 

 

Natural gas(2)

 

$

6

 

 

Option model

 

Market price (per Dth)

(3)

 

2-4

 

3

 

 

 

 

 

 

 

Price volatility

(4)

 

10%-49%

 

31%

Total assets

 

$

283

 

 

 

 

 

 

 

 

 

 

 

 

(1)
Averages weighted by volume.
(2)
Includes basis.
(3)
Represents market prices beyond defined terms for Levels 1 and 2.
(4)
Represents volatilities unrepresented in published markets.

Sensitivity of the fair value measurements to changes in the significant unobservable inputs is as follows:

 

Significant Unobservable Inputs

 

Position

 

Change to Input

 

Impact on Fair Value Measurement

Market price

 

Buy

 

Increase (decrease)

 

Gain (loss)

Market price

 

Sell

 

Increase (decrease)

 

Loss (gain)

Price volatility

 

Buy

 

Increase (decrease)

 

Gain (loss)

Price volatility

 

Sell

 

Increase (decrease)

 

Loss (gain)

Recurring Fair Value Measurements

The following table presents DESC’s assets and liabilities that are measured at fair value on a recurring basis for each hierarchy level, including both current and noncurrent portions:

 

(millions)

 

Level 1

 

 

Level 2

 

 

Level 3

 

 

Total

 

At June 30, 2024

 

 

 

 

 

 

 

 

 

 

 

 

Assets

 

 

 

 

 

 

 

 

 

 

 

 

Commodity

 

$

—

 

 

$

2

 

 

$

283

 

 

$

285

 

Interest rate

 

 

—

 

 

 

1

 

 

 

—

 

 

 

1

 

Total assets

 

$

—

 

 

$

3

 

 

$

283

 

 

$

286

 

Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

$

—

 

 

$

2

 

 

$

—

 

 

$

2

 

Total liabilities

 

$

—

 

 

$

2

 

 

$

—

 

 

$

2

 

At December 31, 2023

 

 

 

 

 

 

 

 

 

 

 

 

Assets

 

 

 

 

 

 

 

 

 

 

 

 

Commodity

 

$

—

 

 

$

—

 

 

$

176

 

 

$

176

 

Interest rate

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

Total assets

 

$

—

 

 

$

—

 

 

$

176

 

 

$

176

 

Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

$

—

 

 

$

4

 

 

$

—

 

 

$

4

 

Total liabilities

 

$

—

 

 

$

4

 

 

$

—

 

 

$

4

 

 

The following table presents the net change in DESC’s assets and liabilities measured at fair value on a recurring basis and included in the Level 3 fair value category.

 

 

 

Three Months Ended

 

 

Six Months Ended

 

 

 

June 30,

 

 

June 30,

 

 

 

2024

 

 

2023

 

 

2024

 

 

2023

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

Beginning balance

 

$

253

 

 

$

188

 

 

$

176

 

 

$

251

 

Total realized and unrealized gains (losses):

 

 

 

 

 

 

 

 

 

 

 

 

Included in earnings:

 

 

 

 

 

 

 

 

 

 

 

 

Purchased power

 

 

(1

)

 

 

(1

)

 

 

(3

)

 

 

—

 

Included in regulatory assets/liabilities

 

 

32

 

 

 

(21

)

 

 

102

 

 

 

(84

)

Settlements

 

 

(1

)

 

 

1

 

 

 

1

 

 

 

—

 

Purchases

 

 

—

 

 

 

—

 

 

 

7

 

 

 

—

 

Ending balance

 

$

283

 

 

$

167

 

 

$

283

 

 

$

167

 

There are no unrealized gains and losses included in earnings in the Level 3 fair value category related to assets/liabilities still held at the reporting date for the three and six months ended June 30, 2024 and 2023.

Fair Value of Financial Instruments

Substantially all of DESC’s financial instruments are recorded at fair value, with the exception of the instruments described below which are reported at historical cost. Estimated fair values have been determined using available market information and valuation methodologies considered appropriate by management. The carrying amount of financial instruments classified within current assets and current liabilities are representative of fair value because of the short-term nature of these instruments. For financial instruments that are not recorded at fair value, the carrying amounts and estimated fair values are as follows:

 

 

 

June 30, 2024

 

 

December 31, 2023

 

(millions)

 

Carrying Amount

 

 

Estimated Fair Value(1)

 

 

Carrying Amount

 

 

Estimated Fair Value(1)

 

Long-term debt(2)

 

$

4,219

 

 

$

4,121

 

 

$

4,219

 

 

$

4,301

 

Affiliated long-term debt(3)

 

 

230

 

 

 

230

 

 

 

230

 

 

 

230

 

 

(1)
Fair value is estimated using market prices, where available, and interest rates currently available for issuance of debt with similar terms and remaining maturities. All fair value measurements are classified as Level 2. The carrying amount of debt issuances with short-term maturities and variable rates refinanced at current market rates is a reasonable estimate of their fair value.
(2)
Carrying amount includes current portions, if any, presented in securities due within one year and amounts which represent the unamortized debt issuance costs and discount or premium.
(3)
Carrying amount includes current portions presented in affiliated and related party payables, as applicable.
v3.24.2.u1
Employee Benefit Plans
 6 Months Ended
Jun. 30, 2024
Retirement Benefits [Abstract]  
Employee Benefit Plans

9. EMPLOYEE BENEFIT PLANS

In DESC’s Consolidated Statements of Comprehensive Income, the service cost component of net periodic benefit (credit) cost is reflected in other operations and maintenance expense with the non-service cost components reflected in other income (expense). Components of net periodic benefit cost (credit) recorded by DESC were as follows:

 

(millions)

 

Pension Benefits

 

 

Other Postretirement Benefits

 

Three Months Ended June 30,

 

2024

 

 

2023

 

 

2024

 

 

2023

 

Service cost

 

$

2

 

 

$

2

 

 

$

1

 

 

$

1

 

Interest cost

 

 

8

 

 

 

8

 

 

 

2

 

 

 

2

 

Expected return on assets

 

 

(10

)

 

 

(9

)

 

 

—

 

 

 

—

 

Amortization of actuarial losses

 

 

2

 

 

 

3

 

 

 

(1

)

 

 

(1

)

Net periodic benefit cost

 

$

2

 

 

$

4

 

 

$

2

 

 

$

2

 

Six Months Ended June 30,

 

 

 

 

 

 

 

 

 

 

 

 

Service cost

 

$

4

 

 

$

4

 

 

$

1

 

 

$

1

 

Interest cost

 

 

16

 

 

 

16

 

 

 

4

 

 

 

4

 

Expected return on assets

 

 

(19

)

 

 

(17

)

 

 

—

 

 

 

—

 

Amortization of actuarial losses

 

 

4

 

 

 

6

 

 

 

(2

)

 

 

(2

)

Net periodic benefit cost

 

$

5

 

 

$

9

 

 

$

3

 

 

$

3

 

 

During the three and six months ended June 30, 2024, DESC made $1 million of contributions to its qualified pension plan. In July 2024, DESC made an additional $1 million of contributions to its qualified pension plan. DESC expects to make $8 million of minimum required contributions to its qualified pension plan in 2024 and expects to receive reimbursement for such contributions from Santee Cooper. DESC recovers current pension costs through either a rate rider that may be adjusted annually for retail electric operations or through cost of service rates for gas operations.
v3.24.2.u1
Commitments And Contingencies
 6 Months Ended
Jun. 30, 2024
Commitments and Contingencies Disclosure [Abstract]  
Commitments and Contingencies

10. COMMITMENTS AND CONTINGENCIES

As a result of issues generated in the ordinary course of business, DESC is involved in legal proceedings before various courts and is periodically subject to governmental examinations (including by regulatory authorities), inquiries and investigations. Certain legal proceedings and governmental examinations involve demands for unspecified amounts of damages, are in an initial procedural phase, involve uncertainty as to the outcome of pending appeals or motions or involve significant factual issues that need to be resolved, such that it is not possible for DESC to estimate a range of possible loss. For such matters that DESC cannot estimate, a statement to this effect is made in the description of the matter. Other matters may have progressed sufficiently through the litigation or investigative processes such that DESC is able to estimate a range of possible loss. For legal proceedings and governmental examinations that DESC is able to reasonably estimate a range of possible losses, an estimated range of possible loss is provided, in excess of the accrued liability (if any) for such matters. DESC maintains various insurance programs, including general liability insurance coverage which provides coverage for personal injury or wrongful death cases. Any accrued liability is recorded on a gross basis with a receivable also recorded for any probable insurance recoveries. Estimated ranges of loss are inclusive of legal fees and net of any anticipated insurance recoveries. Any estimated range is based on currently available information and involves elements of judgment and significant uncertainties. Any estimated range of possible loss may not represent DESC’s maximum possible loss exposure. The circumstances of such legal proceedings and governmental examinations will change from time to time and actual results may vary significantly from the current estimate. For current proceedings not specifically reported below, management does not anticipate that the liabilities, if any, arising from such proceedings would have a material effect on DESC’s financial position, liquidity or results of operations. During the three and six months ended June 30, 2024, DESC recorded $5 million and $11 million, respectively, of charges in aggregate for various personal injury or wrongful death cases.

Environmental Matters

DESC is subject to costs resulting from a number of federal, state and local laws and regulations designed to protect human health and the environment. These laws and regulations affect future planning and existing operations. They can result in increased capital, operating and other costs as a result of compliance, remediation, containment and monitoring obligations.

From a regulatory perspective, DESC continually monitors and evaluates its current and projected emission levels and strives to comply with all state and federal regulations regarding those emissions. DESC participates in the SO2 and NOx emission allowance programs with respect to coal plant emissions and also has constructed additional pollution control equipment at its coal-fired electric generating plants. These actions are expected to address many of the rules and regulations discussed herein.

Air

The CAA, as amended, is a comprehensive program utilizing a broad range of regulatory tools to protect and preserve the nation’s air quality. At a minimum, states are required to establish regulatory programs to meet applicable requirements of the CAA. However, states may choose to develop regulatory programs that are more restrictive. Many of DESC’s facilities are subject to the CAA’s permitting and other requirements.

ACE Rule

In July 2019, the EPA published the final rule informally referred to as the ACE Rule, as a replacement for the Clean Power Plan. The ACE Rule regulated GHG emissions from existing coal-fired power plants pursuant to Section 111(d) of the CAA and required states to develop plans by July 2022 establishing unit-specific performance standards for existing coal-fired power plants. In January 2021, the U.S. Court of Appeals for the D.C. Circuit vacated the ACE Rule and remanded it to the EPA. This decision would take effect upon issuance of the court’s mandate. In March 2021, the court issued a partial mandate vacating and remanding all parts of the ACE Rule except for the portion of the ACE Rule that repealed the Clean Power Plan. In October 2021, the U.S. Supreme Court agreed to hear a challenge of the U.S. Court of Appeals for the D.C. Circuit’s decision on the ACE Rule. In June 2022, the U.S. Supreme Court reversed the D.C. Circuit’s decision on the ACE Rule and remanded the case back to the D.C. Circuit. In May 2024, the EPA repealed the ACE Rule as part of a package of final rules addressing CO2 emissions from new and existing fossil fuel-fired electric generating units.

Carbon Regulations

In August 2016, the EPA issued a draft rule proposing to reaffirm that a source’s obligation to obtain a PSD or Title V permit for GHGs is triggered only if such permitting requirements are first triggered by non-GHG, or conventional, pollutants that are regulated by the New Source Review program, and exceed a significant emissions rate of 75,000 tons per year of CO2 equivalent emissions.

Until the EPA ultimately takes final action on this rulemaking, DESC cannot predict the impact to its results of operations, financial condition and/or cash flows.

In December 2018, the EPA proposed revised Standards of Performance for Greenhouse Gas Emissions from New, Modified, and Reconstructed Stationary Sources. The proposed rule would amend the previous determination that the best system of emission reduction for newly constructed coal-fired steam generating units is no longer partial carbon capture and storage. Instead, the proposed revised best system of emission reduction for this source category is the most efficient demonstrated steam cycle (e.g., supercritical steam conditions for large units and subcritical steam conditions for small units) in combination with best operating practices. In May 2024, the EPA withdrew the proposed revision to the performance standards for coal-fired steam generating units as part of a package of final rules addressing CO2 emissions from new and existing fossil fuel-fired electric generating units.

Water

The CWA, as amended, is a comprehensive program requiring a broad range of regulatory tools including a permit program to authorize and regulate discharges to surface waters with strong enforcement mechanisms. DESC must comply with applicable aspects of the CWA programs at its operating facilities.

Regulation 316(b)

 

In October 2014, the final regulations under Section 316(b) of the CWA that govern existing facilities and new units at existing facilities that employ a cooling water intake structure and that have flow levels exceeding a minimum threshold became effective. The rule establishes a national standard for impingement based on seven compliance options, but forgoes the creation of a single technology standard for entrainment. Instead, the EPA has delegated entrainment technology decisions to state regulators. State regulators are to make case-by-case entrainment technology determinations after an examination of five mandatory facility-specific factors, including a social cost-benefit test, and six optional facility-specific factors. The rule governs all electric generating stations with water withdrawals above two MGD, with a heightened entrainment analysis for those facilities over 125 MGD. DESC has five facilities that are subject to the final regulations. DESC is also working with the EPA and state regulatory agencies to assess the applicability of Section 316(b) to five hydroelectric facilities. DESC anticipates that it may have to install impingement control technologies at certain of these stations that have once-through cooling systems. DESC is currently evaluating the need or potential for entrainment controls under the final rule as these decisions will be made on a case-by-case basis after a thorough review of detailed biological, technological and cost benefit studies. DESC is conducting studies and implementing plans as required by the rule to determine appropriate intake structure modifications at certain facilities to ensure compliance with this rule. While the impacts of this rule could be material to DESC’s results of operations, financial condition and/or cash flows, the existing regulatory framework in South Carolina provides rate recovery mechanisms that could substantially mitigate any such impacts for DESC.

Effluent Limitations Guidelines

 

In September 2015, the EPA released a final rule to revise the ELG Rule. The final rule established updated standards for wastewater discharges that apply primarily at coal and oil steam generating stations. Affected facilities are required to convert from wet to dry or closed cycle coal ash management, improve existing wastewater treatment systems and/or install new wastewater treatment technologies in order to meet the new discharge limits. In April 2017, the EPA granted two separate petitions for reconsideration of the final ELG Rule and stayed future compliance dates in the rule. Also in April 2017, the U.S. Court of Appeals for the Fifth Circuit granted the EPA’s request for a stay of the pending consolidated litigation challenging the rule while the EPA addresses the petitions for reconsideration. In September 2017, the EPA signed a rule to postpone the earliest compliance dates for certain waste streams regulations in the final ELG Rule from November 2018 to November 2020; however, the latest date for compliance for these regulations was December 2023. In October 2020, the EPA released the final rule that extended the latest dates for compliance with individual facilities’ compliance dates that would vary based on circumstances and the determination by state regulators and may range from 2021 to 2028. In May 2024, the EPA released a final rule revising the 2015 and 2020 Effluent Limitations Guidelines, establishing more stringent standards for wastewater discharges for the Steam Electric Power Generating Category, which apply primarily to wastewater discharges at coal and oil steam generating stations. Individual facilities’ compliance dates will vary based on circumstances and the determination by state regulators and may range to 2029, except in certain circumstances when a facility will be retired by 2034. As discussed below, DESC recorded an increase to its AROs in the second quarter of 2024 in connection with the

expected compliance costs associated with the EPA’s May 2024 final rule concerning CCR. DESC expects that such costs would capture any necessary efforts for compliance with the EPA’s May 2024 Effluent Limitations Guidelines.

Capacity Use Area

In November 2019, a new CUA was established in the counties surrounding the Cope Generating Station (Western Capacity Use Area) under the South Carolina Groundwater Use and Reporting Regulation. Under the regulation any groundwater well in a CUA that withdraws above three million gallons per month must be permitted. The Cope Generating Station is located within this new Western Capacity Use Area. Cope has been using four deep groundwater wells for cooling water and other house loads since 1996. Prior to designation of the new Western Capacity Use Area, the wells at Cope Station were only required to be registered not permitted. As a result of this designation, Cope will need to restore the surface water equipment to operable status to reduce reliance on groundwater wells. This includes completion of 316(b) requirements, (including SCDHEC BACT determination and modification of the station national pollutant discharge elimination system permit) and extensive inspection, repair and/or replacement of the associated surface water withdrawal equipment which has been idle since 1996. While the impacts of this rule change are potentially material to DESC’s results of operations, financial condition and/or cash flows, the existing regulatory framework in South Carolina provides rate recovery mechanisms that could substantially mitigate any such impacts for DESC.

 

Waste Management and Remediation

 

The operations of DESC are subject to a variety of state and federal laws and regulations governing the management and disposal of solid and hazardous waste, and release of hazardous substances associated with current and/or historical operations. The CERCLA, as amended, and similar state laws, may impose joint, several and strict liability for cleanup on potentially responsible parties who owned, operated or arranged for disposal at facilities affected by a release of hazardous substances. In addition, many states have created programs to incentivize voluntary remediation of sites where historical releases of hazardous substances are identified and property owners or responsible parties decide to initiate cleanups.

 

From time to time, DESC may be identified as a potentially responsible party in connection with the alleged release of hazardous substances or wastes at a site. Under applicable federal and state laws, DESC could be responsible for costs associated with the investigation or remediation of impacted sites, or subject to contribution claims by other responsible parties for their costs incurred at such sites. DESC also may identify, evaluate and remediate other potentially impacted sites under voluntary state programs. Remediation costs may be subject to reimbursement under DESC’s insurance policies, rate recovery mechanisms, or both. Except as described below, DESC does not believe these matters will have a material effect on results of operations, financial condition and/or cash flows.

 

DESC has four decommissioned manufactured gas plant sites in South Carolina that are in various states of investigation, remediation and monitoring under work plans approved by, or under review by, the SCDHEC or the EPA. In the fourth quarter of 2023, DESC completed the majority of remediation activities at one site. DESC anticipates the remaining activities at that site will be completed by 2025 at an estimated cost of $1 million, after which the site will continue to incur ongoing maintenance and monitoring obligations. DESC expects to recover costs arising from the remediation work at all four sites through rate recovery mechanisms and as of June 30, 2024, deferred amounts, net of amounts previously recovered through rates and insurance settlements, totaled $34 million and are included in regulatory assets.

 

Ash Pond and Landfill Closure Costs

 

In April 2015, the EPA enacted a final rule regulating CCR landfills, existing ash ponds that still receive and manage CCRs and inactive ash ponds that do not receive, but still store, CCRs. DESC currently has inactive and existing CCR ponds and CCR landfills subject to the final rule at three different facilities. This rule created a legal obligation for DESC to retrofit or close all of its inactive and existing ash ponds over a certain period of time, as well as perform required monitoring, corrective action, and post-closure care activities as necessary.

 

In December 2016, legislation was enacted that creates a framework for EPA-approved state CCR permit programs. In August 2017, the EPA issued interim guidance outlining the framework for state CCR program approval. The EPA has enforcement authority until state programs are approved. The EPA and states with approved programs both will have authority to enforce CCR requirements under their respective rules and programs. In September 2017, the EPA agreed to reconsider portions of the CCR rule in response to two petitions for reconsideration. In March 2018, the EPA proposed certain changes to the CCR rule related to issues remanded as part of the pending litigation and other issues the EPA is reconsidering. Several of the proposed changes would allow states with approved CCR permit programs additional flexibility in implementing their programs. In July 2018, the EPA promulgated the first phase of changes to the CCR rule. In August 2018, the U.S. Court of Appeals for the D.C. Circuit issued its decision in the pending challenges of the CCR rule, vacating and remanding to the EPA three provisions of the rule. In May 2024, the EPA released a final rule to regulate inactive surface impoundments located at retired generating stations that contained CCR and liquids after October 2015, and certain other inactive or previously closed surface impoundments, landfills or other areas that contain accumulations of CCR. DESC believes that it may have inactive or closed units or areas that could be subject to the final rule at up to 7 different stations. In connection with this rule, in the second quarter of 2024, DESC recorded an increase to its AROs of $655 million, with a corresponding increase of $353 million to property, plant and equipment for amounts recoverable for electric generation stations that

are currently in service and $302 million to regulatory assets for amounts recoverable through retail electric rates for electric generation stations that have been retired. The actual AROs related to CCRs may vary substantially from the estimates used to record the obligation.

Claims and Litigation

The following describes certain legal proceedings involving DESC relating primarily to events occurring before closing of the SCANA Combination.

 

Matters Fully Resolved Prior to 2024 Impacting the Consolidated Financial Statements

Governmental Proceedings and Investigations

In June 2018, DESC received a notice of proposed assessment of approximately $410 million, excluding interest, from the SCDOR following its audit of DESC’s sales and use tax returns for the periods September 1, 2008 through December 31, 2017. The proposed assessment, which includes 100% of the NND Project, is based on the SCDOR’s position that DESC’s sales and use tax exemption for the NND Project does not apply because the facility will not become operational. In December 2020, the parties reached an agreement in principle in the amount of $165 million to resolve this matter. In June 2021, the parties executed a settlement agreement which allows DESC to fund the settlement amount through a combination of cash, shares of Dominion Energy common stock or real estate with an initial payment of at least $43 million in shares of Dominion Energy common stock. In August 2021, Dominion Energy issued 0.6 million shares of its common stock to satisfy DESC’s obligation for the initial payment under the settlement agreement. In May 2022, Dominion Energy issued an additional 0.9 million shares of its common stock to partially satisfy DESC’s remaining obligation under the settlement agreement. In June 2022, DESC requested approval from the South Carolina Commission to transfer certain real estate with a total settlement value of $51 million to satisfy its remaining obligation under the settlement agreement. In July 2022, the South Carolina Commission voted to approve the request and issued its final order in August 2022. In September 2022, DESC transferred certain non-utility property with a fair value of $28 million to the SCDOR under the settlement agreement. In December 2022, DESC transferred additional utility property with a fair value of $3 million to the SCDOR. In October 2022, DESC filed for approval to transfer the remaining real estate with FERC which was received in November 2022. In March 2023, DESC transferred utility property with a fair value of $10 million to the SCDOR resulting in a gain of $9 million ($7 million after-tax), recorded in other income (expense), net in DESC’s Consolidated Statements of Comprehensive Income for the six months ended June 30, 2023. In June 2023, DESC transferred the remaining utility property with a fair value of $11 million to the SCDOR resulting in a gain of $11 million ($8 million after-tax), recorded in other income (expense), net in DESC’s Consolidated Statements of Comprehensive Income for the three and six months ended June 30, 2023. In July 2023, DESC made a less than $1 million cash payment to the SCDOR to fully satisfy its remaining obligation, including applicable interest, under the settlement agreement.

 

Nuclear Operations

Other than the items discussed below, there have been no significant changes regarding DESC’s nuclear insurance and spent nuclear fuel as described in Note 12 to the Consolidated Financial Statements in the DESC’s Annual Report on Form 10-K for the year ended December 31, 2023.

During the first quarter of 2024, the total liability protection per nuclear incident available to all participants in the Secondary Financial Protection Program increased from $16.2 billion to $16.3 billion. This increase does not impact DESC’s responsibility per active unit under the Price-Anderson Amendments Act of 1988. Additionally, Dominion Energy increased the amount of coverage purchased from commercial insurance pools for Summer from $450 million to $500 million with the remainder provided through the mandatory industry retrospective rating plan.

Surety Bonds

At June 30, 2024, DESC had purchased $24 million of surety bonds. Under the terms of surety bonds, DESC is obligated to indemnify the respective surety bond company for any amounts paid.

v3.24.2.u1
Operating Segments
 6 Months Ended
Jun. 30, 2024
Segment Reporting [Abstract]  
Operating Segments

11. OPERATING SEGMENTS

The Corporate and Other segment primarily includes specific items attributable to DESC’s operating segment that are not included in profit measures evaluated by executive management in assessing the segment’s performance or in allocating resources.

 

In the six months ended June 30, 2024, DESC reported an insignificant amount of specific items in the Corporate and Other segment. In the six months ended June 30, 2023, DESC reported after-tax net income of $19 million in the Corporate and Other segment, including $21 million of after-tax net income for specific items all of which was attributable to its operating segment.

 

The net income for specific items attributable to DESC’s operating segment in 2023 primarily related to a $31 million ($23 million after-tax) benefit related to real estate transactions, including gains on the transfer of property to satisfy litigation associated with the NND Project.

 

(millions)

 

External
Revenue

 

 

Comprehensive
Income (Loss)
Available
(Attributable) to
Common
Shareholder

 

Three Months Ended June 30, 2024

 

 

 

 

 

 

Dominion Energy South Carolina

 

$

731

 

 

$

62

 

Corporate and Other

 

 

—

 

 

 

(5

)

Consolidated Total

 

$

731

 

 

$

57

 

 

 

 

 

 

 

Three Months Ended June 30, 2023

 

 

 

 

 

 

Dominion Energy South Carolina

 

$

704

 

 

$

63

 

Corporate and Other

 

 

—

 

 

 

13

 

Consolidated Total

 

$

704

 

 

$

76

 

 

 

 

 

 

 

Six Months Ended June 30, 2024

 

 

 

 

 

 

Dominion Energy South Carolina

 

$

1,506

 

 

$

137

 

Corporate and Other

 

 

—

 

 

 

(6

)

Consolidated total

 

$

1,506

 

 

$

131

 

 

 

 

 

 

 

 

Six Months Ended June 30, 2023

 

 

 

 

 

 

Dominion Energy South Carolina

 

$

1,463

 

 

$

149

 

Corporate and Other

 

 

—

 

 

 

19

 

Consolidated total

 

$

1,463

 

 

$

168

 
v3.24.2.u1
Affiliated and Related Party Transactions
 6 Months Ended
Jun. 30, 2024
Related Party Transactions [Abstract]  
Affiliated and Related Party Transactions

12. AFFILIATED AND RELATED PARTY TRANSACTIONS

DES, on behalf of itself and its parent company, provides the following services to DESC, which are rendered at direct or allocated cost: information systems, telecommunications, customer support, marketing and sales, human resources, corporate compliance, purchasing, financial, risk management, public affairs, legal, investor relations, gas supply and capacity management, strategic planning, general administrative and retirement benefits. Costs for these services include amounts capitalized. Amounts expensed are primarily recorded in other operations and maintenance - affiliated suppliers and other income (expense), net in the Consolidated Statements of Comprehensive Income.

DESC transacts with affiliates for certain quantities of electricity in the ordinary course of business. DESC also enters into certain commodity derivative contracts with affiliates. DESC uses these contracts, which are principally comprised of forward commodity purchases, to manage commodity price risks associated with purchases of electricity. See Note 7 for additional information.

 

 

 

Three Months Ended
June 30,

 

 

Six Months Ended
June 30,

 

(millions)

 

2024

 

 

2023

 

 

2024

 

 

2023

 

Direct and allocated costs from DES(1)

 

$

57

 

 

$

55

 

 

$

110

 

 

$

112

 

Operating Revenues - Electric from sales to affiliate

 

 

2

 

 

 

1

 

 

 

3

 

 

 

2

 

Operating Revenues - Gas from sales to affiliate

 

 

1

 

 

 

—

 

 

 

1

 

 

 

—

 

Operating Expenses - Other taxes from affiliate

 

 

2

 

 

 

2

 

 

 

5

 

 

 

5

 

Purchases of electricity from solar affiliates

 

 

3

 

 

 

4

 

 

 

4

 

 

 

6

 

 

(1)
Includes capitalized expenditures of $15 million and $13 million for the three months ended June 30, 2024 and 2023, respectively, and $27 million and $29 million for the six months ended June 30, 2024 and 2023, respectively.

 

(millions)

 

June 30, 2024

 

 

December 31, 2023

 

Payable to DES

 

$

20

 

 

$

18

 

Payable to SCANA Corporation

 

 

7

 

 

 

7

 

Payable to Public Service Company of North Carolina, Incorporated

 

 

9

 

 

 

13

 

Derivative assets with affiliates(1)

 

 

47

 

 

 

33

 

 

 

(1)
Includes amounts recorded in other current assets of $3 million and $2 million as of June 30, 2024 and December 31, 2023, respectively, and amounts recorded in other deferred debits and other assets of $44 million and $31 million as of June 30, 2024 and December 31, 2023, respectively.

 

Borrowings from an affiliate are described in Note 5.

v3.24.2.u1
Other Income (Expense), Net
 6 Months Ended
Jun. 30, 2024
Income Statement [Abstract]  
Other Income (Expense), Net

13. OTHER INCOME (EXPENSE), NET

Components of other income (expense), net are as follows:

 

 

 

Three Months Ended June 30,

 

 

Six Months Ended June 30,

 

(millions)

 

2024

 

 

2023

 

 

2024

 

 

2023

 

Other income

 

$

1

 

 

$

1

 

 

$

3

 

 

$

3

 

Gains on sales of assets(1)

 

 

1

 

 

 

22

 

 

 

2

 

 

 

32

 

Other expense

 

 

(4

)

 

 

(5

)

 

 

(9

)

 

 

(7

)

Allowance for equity funds used during construction

 

 

3

 

 

 

—

 

 

 

6

 

 

 

—

 

Other income (expense), net

 

$

1

 

 

$

18

 

 

$

2

 

 

$

28

 

 

(1) Includes amounts recognized in 2023 in connection with the transfer of property to satisfy litigation. See Note 10 for additional information.

In the second quarter of 2023, DESC completed the sale of certain utility property in South Carolina, as approved by the South Carolina Commission in February 2023, for total cash consideration of $11 million. In connection with the sale, DESC recognized a gain of $11 million ($8 million after-tax) for the three and six months ended June 30, 2023.
v3.24.2.u1
Summary of Significant Accounting Policies (Policies)
 6 Months Ended
Jun. 30, 2024
Accounting Policies [Abstract]  
Basis of Consolidation and Variable Interest Entities

Basis of Consolidation and Variable Interest Entities

DESC has determined that it has a controlling financial interest in each of GENCO and Fuel Company (which are considered to be VIEs) and, accordingly, DESC’s Consolidated Financial Statements include, after eliminating intercompany balances and transactions, the accounts of DESC, GENCO and Fuel Company. See Note 2 to the Consolidated Financial Statements included in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023 for a description of GENCO and Fuel Company.

DESC purchases shared services from DES, an affiliated VIE that provides accounting, legal, finance and certain administrative and technical services to all Dominion Energy subsidiaries, including DESC. DESC has determined that it is not the primary beneficiary of DES as it does not have either the power to direct the activities that most significantly impact its economic performance or an obligation to absorb losses and benefits which could be significant to it. See Note 12 for amounts attributable to affiliates.

Significant Accounting Policies

There have been no significant changes from Note 2 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023, except as follows.
New Accounting Standards

New Accounting Standards

Climate-Related Disclosures

In March 2024, the SEC issued guidance for climate-related disclosures. The guidance requires disclosure of the financial statement impacts of severe weather events and other natural conditions, including amounts capitalized or expensed as well as any associated recoveries. In addition, the guidance requires disclosure of amounts related to renewable energy credits or carbon offsets if utilized as a material component of plans to achieve climate-related targets or goals. This guidance, which is currently subject to a stay issued by the SEC, would be effective for the fiscal year beginning January 1, 2025. DESC expects this guidance to only impact its disclosures with no impacts to its results of operations, cash flows or financial condition.
v3.24.2.u1
Rate and Other Regulatory Matters (Tables)
 6 Months Ended
Jun. 30, 2024
Regulated Operations [Abstract]  
Schedule of Regulatory Assets and Liabilities

 

 

June 30,

 

 

December 31,

 

(millions)

 

2024

 

 

2023

 

Regulatory assets:

 

 

 

 

 

 

NND Project costs(1)

 

$

138

 

 

$

138

 

AROs(2)

 

 

31

 

 

 

44

 

Deferred employee benefit plan costs(3)

 

 

8

 

 

 

11

 

Other unrecovered plant(4)

 

 

19

 

 

 

19

 

DSM programs(5)

 

 

23

 

 

 

22

 

Cost of fuel and purchased gas under-collections(6)

 

 

37

 

 

 

154

 

Other

 

 

54

 

 

 

56

 

Regulatory assets - current

 

 

310

 

 

 

444

 

NND Project costs(1)

 

 

1,880

 

 

 

1,949

 

AROs(2)

 

 

688

 

 

 

379

 

Deferred employee benefit plan costs(3)

 

 

117

 

 

 

118

 

Interest rate hedges(7)

 

 

167

 

 

 

168

 

Other unrecovered plant(4)

 

 

69

 

 

 

66

 

DSM programs(5)

 

 

46

 

 

 

46

 

Environmental remediation costs(8)

 

 

42

 

 

 

34

 

Deferred storm damage costs(9)

 

 

38

 

 

 

40

 

Deferred transmission operating costs(10)

 

 

73

 

 

 

74

 

Derivatives(11)

 

 

99

 

 

 

103

 

Other(12)

 

 

143

 

 

 

130

 

Regulatory assets - noncurrent

 

 

3,362

 

 

 

3,107

 

Total regulatory assets

 

$

3,672

 

 

$

3,551

 

Regulatory liabilities:

 

 

 

 

 

 

Monetization of guaranty settlement(13)

 

$

67

 

 

$

67

 

Income taxes refundable through future rates(14)

 

 

37

 

 

 

37

 

Reserve for refunds to electric utility customers(15)

 

 

80

 

 

 

83

 

Derivatives(11)

 

 

23

 

 

 

12

 

Cost of fuel and purchased gas over-collections(6)

 

 

11

 

 

 

—

 

Other

 

 

12

 

 

 

6

 

Regulatory liabilities - current

 

 

230

 

 

 

205

 

Monetization of guaranty settlement(13)

 

 

602

 

 

 

635

 

Income taxes refundable through future rates(14)

 

 

821

 

 

 

839

 

Asset removal costs(16)

 

 

636

 

 

 

633

 

Reserve for refunds to electric utility customers(15)

 

 

193

 

 

 

237

 

Derivatives(11)

 

 

321

 

 

 

229

 

Other

 

 

2

 

 

 

6

 

Regulatory liabilities - noncurrent

 

 

2,575

 

 

 

2,579

 

Total regulatory liabilities

 

$

2,805

 

 

$

2,784

 

 

(1)
Reflects expenditures associated with the NND Project, which pursuant to the SCANA Merger Approval Order, will be recovered from electric service customers over a 20-year period ending in 2039.
(2)
Represents uncollected costs, including deferred depreciation and accretion expense, related to legal obligations associated with the future retirement of generation, transmission and distribution properties. The AROs primarily relate to DESC’s electric generating facilities, including Summer, and are expected to be recovered over the related property lives and periods of decommissioning which may range up to approximately 105 years. In addition, the balance at June 30, 2024 reflects amounts related to the EPA’s May 2024 final rule concerning CCR as discussed in Note 10.
(3)
Employee benefit plan costs have historically been recovered as they have been recorded under GAAP. Deferred employee benefit plan costs represent amounts of pension and other postretirement benefit costs which were accrued as liabilities and treated as regulatory assets pursuant to FERC guidance, and costs deferred pursuant to specific South Carolina Commission regulatory orders. DESC expects to recover deferred pension costs through utility rates over periods through 2044. DESC expects to recover other deferred benefit costs through utility rates, primarily over average service periods of participating employees up to 11 years.
(4)
Represents the carrying value of coal-fired generating units, including related materials and supplies inventory, retired from service prior to being fully depreciated. DESC is amortizing these amounts through cost of service rates following depreciation amounts that were designed to recover the retired units cost over their previous estimated remaining useful lives, which has been estimated to be through 2025. Based on current projections of remaining decommissioning costs, projected recovery is expected to extend through 2039. In addition, amounts include unrecovered costs of existing meters and equipment retired from service prior to being fully depreciated as part of the Advanced Metering Infrastructure project, which are being recovered through rates through 2028. This amount also includes certain inventory and preliminary survey and investigation charges being amortized over five years related to the transition or conversion from coal to gas fired generation at certain facilities.
(5)
Represents deferred costs associated with electric demand reduction programs, and such deferred costs are currently being recovered over three years through an approved rate rider.
(6)
Represents amounts under- or over-collected from customers pursuant to the cost of fuel and purchased gas components approved by the South Carolina Commission.
(7)
Represents settled interest rate derivatives designated as cash flow hedges expected to be amortized to interest expense over the lives of the underlying debt through 2065.
(8)
Reflects amounts associated with the assessment and clean-up of sites currently or formerly owned by DESC. Such remediation costs are expected to be recovered over periods of up to 24 years. See Note 10 for additional information.
(9)
Represents storm restoration costs for which DESC expects to receive future recovery through customer rates over approximately 10 years pursuant to the settlement agreement approved in DESC’s retail electric base rate case. Unamortized amounts are included in rate base and are earning a current return.
(10)
Includes deferred depreciation and property taxes associated with certain transmission assets for which DESC expects recovery from customers through future rates over approximately 42 years pursuant to the settlement agreement approved in DESC’s retail electric base rate case. Unamortized amounts are included in rate base and earning a current return. See Note 12 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023.
(11)
Represents changes in the fair value of derivatives, excluding separately presented interest rate hedges, that following settlement are expected to be recovered from or refunded to customers.
(12)
Various other regulatory assets are expected to be recovered through rates over varying periods through 2078.
(13)
Represents proceeds related to the monetization of the Toshiba Settlement. In accordance with the SCANA Merger Approval Order, this balance, net of amounts that may be required to satisfy liens, will be refunded to electric customers over a 20-year period ending in 2039.
(14)
Includes (i) excess deferred income taxes arising from the remeasurement of deferred income taxes in connection with the enactment of the 2017 Tax Reform Act (certain of which are protected under normalization rules and will be amortized over the remaining lives of related property, and certain of which will be amortized to the benefit of customers over prescribed periods as instructed by regulators) and (ii) deferred income taxes arising from investment tax credits, offset by (iii) deferred income taxes that arise from utility operations that have not been included in customer rates (a portion of which relate to depreciation and are expected to be recovered over the remaining lives of the related property which may range up to 85 years). See Note 7 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023 for additional information.
(15)
Reflects amounts previously collected from retail electric customers of DESC for the NND Project to be credited to customers over an estimated 11-year period effective February 2019 in connection with the SCANA Merger Approval Order.
(16)
Represents estimated net collections through depreciation rates of amounts to be expended for the removal of assets in the future.
v3.24.2.u1
Revenue Recognition (Tables)
 6 Months Ended
Jun. 30, 2024
Revenue from Contract with Customer [Abstract]  
Disaggregation of Revenue

DESC has disaggregated operating revenues by customer class as follows:

 

 

 

Three Months Ended
June 30, 2024

 

 

Three Months Ended
June 30, 2023

 

 

Six Months Ended
June 30, 2024

 

 

Six Months Ended
June 30, 2023

 

(millions)

 

Electric

 

 

Gas

 

 

Electric

 

 

Gas

 

 

Electric

 

 

Gas

 

 

Electric

 

 

Gas

 

Customer class:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Residential

 

$

294

 

 

$

48

 

 

$

266

 

 

$

43

 

 

$

577

 

 

$

165

 

 

$

528

 

 

$

152

 

Commercial

 

 

208

 

 

 

25

 

 

 

208

 

 

 

25

 

 

 

396

 

 

 

66

 

 

 

395

 

 

 

67

 

Industrial

 

 

94

 

 

 

17

 

 

 

97

 

 

 

15

 

 

 

181

 

 

 

35

 

 

 

188

 

 

 

37

 

Other

 

 

31

 

 

 

6

 

 

 

34

 

 

 

6

 

 

 

59

 

 

 

12

 

 

 

73

 

 

 

10

 

Revenues from contracts with
    customers

 

 

627

 

 

 

96

 

 

 

605

 

 

 

89

 

 

 

1,213

 

 

 

278

 

 

 

1,184

 

 

 

266

 

Other revenues

 

 

7

 

 

 

1

 

 

 

9

 

 

 

1

 

 

 

14

 

 

 

1

 

 

 

12

 

 

 

1

 

Total Operating Revenues

 

$

634

 

 

$

97

 

 

$

614

 

 

$

90

 

 

$

1,227

 

 

$

279

 

 

$

1,196

 

 

$

267

 

 
Balance and Activity Related to Contract Costs Deferred as Regulatory Assets

Balances and activity related to contract costs deferred as regulatory assets were as follows:

 

 

 

Regulatory Assets

 

(millions)

 

June 30, 2024

 

 

December 31, 2023

 

Beginning balance

 

$

11

 

 

$

9

 

Additional costs

 

 

—

 

 

 

3

 

Amortization

 

 

—

 

 

 

(1

)

Ending balance

 

$

11

 

 

$

11

 
v3.24.2.u1
Long-Term and Short-Term Debt (Tables)
 6 Months Ended
Jun. 30, 2024
Debt Disclosure [Abstract]  
Schedule of Line of Credit Facilities

At June 30, 2024, DESC’s share of commercial paper and letters of credit outstanding under its joint credit facility with Dominion Energy was as follows:

 

(millions)

 

Maximum Facility Sub-Limit

 

 

Outstanding
Commercial Paper

 

 

Outstanding
Letters of Credit

 

Joint revolving credit facility(1)(2)

 

$

1,000

 

 

$

275

 

 

$

—

 

 

(1)
A maximum of $1.0 billion of the facility is available to DESC, assuming adequate capacity is available after giving effect to uses by co-borrowers Dominion Energy and Virginia Power. A sub-limit for DESC is set within the facility limit but can be changed at the option of the co-borrowers multiple times per year. At June 30, 2024, the sub-limit for DESC was $500 million. If DESC has liquidity needs in excess of its sub-limit, the sub-limit may be changed or such needs may be satisfied through short-term intercompany borrowings from Dominion Energy. This
credit facility matures in June 2026, with the potential to be extended by the borrowers to June 2028. The credit facility can be used to support bank borrowings and the issuance of commercial paper, as well as to support up to $1.0 billion (or the sub-limit, whichever is less) of letters of credit.
(2)
In May 2024, the joint revolving credit facility was amended to remove Questar Gas as a co-borrower.
v3.24.2.u1
Income Taxes (Tables)
 6 Months Ended
Jun. 30, 2024
Income Tax Disclosure [Abstract]  
Schedule of Effective Income Tax Rate Reconciliation

Six Months Ended June 30,

 

2024

 

 

2023

 

U.S. statutory rate

 

 

21.0

%

 

 

21.0

%

Increases (reductions) resulting from:

 

 

 

 

 

 

State taxes, net of federal benefit

 

 

4.0

 

 

 

4.1

 

Reversal of excess deferred income taxes

 

 

(5.7

)

 

 

(4.0

)

Allowance for equity funds used during construction

 

 

(0.7

)

 

 

—

 

Settlements of uncertain tax positions

 

 

—

 

 

 

(5.0

)

Other, net

 

 

0.1

 

 

 

(0.1

)

Effective tax rate

 

 

18.7

%

 

 

16.0

%
v3.24.2.u1
Derivative Financial Instruments (Tables)
 6 Months Ended
Jun. 30, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Offsetting Assets

The table below presents derivative balances by type of financial instrument, if the gross amounts recognized in the Consolidated Balance Sheets were netted with derivative instruments and cash collateral received or paid:

 

 

June 30, 2024

 

 

December 31, 2023

 

 

 

Gross Amounts Not Offset in the Consolidated
Balance Sheet

 

 

Gross Amounts Not Offset in the Consolidated
Balance Sheet

 

(millions)

 

Gross
Assets
Presented in the
Consolidated
Balance Sheet(1)

 

 

Financial
Instruments

 

 

Cash
Collateral
Received

 

 

Net
Amounts

 

 

Gross
Assets
Presented in the
Consolidated
Balance Sheet(1)

 

 

Financial
Instruments

 

 

Cash
Collateral
Received

 

 

Net
Amounts

 

Interest rate contracts:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Over-the-counter

 

$

1

 

 

$

—

 

 

$

—

 

 

$

1

 

 

$

—

 

 

$

—

 

 

$

—

 

 

$

—

 

Commodity contracts:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Over-the-counter

 

 

7

 

 

 

—

 

 

 

—

 

 

 

7

 

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

Total derivatives

 

$

8

 

 

$

—

 

 

$

—

 

 

$

8

 

 

$

—

 

 

$

—

 

 

$

—

 

 

$

—

 
(1)
Excludes derivative assets of $278 million and $176 million at June 30, 2024 and December 31, 2023, respectively, which are not subject to master netting or similar arrangements.
Offsetting Liabilities

 

 

June 30, 2024

 

 

December 31, 2023

 

 

 

Gross Amounts Not Offset in the Consolidated
Balance Sheet

 

 

Gross Amounts Not Offset in the Consolidated
Balance Sheet

 

(millions)

 

Gross
Liabilities
Presented in the
Consolidated
Balance Sheet(1)

 

 

Financial
Instruments

 

 

Cash
Collateral
Paid

 

 

Net
Amounts

 

 

Gross
Liabilities
Presented in the
Consolidated
Balance Sheet(1)

 

 

Financial
Instruments

 

 

Cash
Collateral
Paid

 

 

Net
Amounts

 

Interest rate contracts:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Over-the-counter

 

$

2

 

 

$

—

 

 

$

—

 

 

$

2

 

 

$

4

 

 

$

—

 

 

$

—

 

 

$

4

 

Total derivatives

 

$

2

 

 

$

—

 

 

$

—

 

 

$

2

 

 

$

4

 

 

$

—

 

 

$

—

 

 

$

4

 
(1)
DESC did not have any derivative liabilities at June 30, 2024 and December 31, 2023, respectively, which were not subject to master netting or similar arrangements.
Schedule of Volume of Derivative Activity

The following table presents the volume of derivative activity at June 30, 2024. These volumes are based on open derivative positions and represent the combined absolute value of their long and short positions.

 

Natural Gas (bcf):

 

Current

 

 

Noncurrent

 

Basis(1)

 

 

18

 

 

 

 

Fixed price

 

 

1

 

 

 

 

Electricity (MWh in millions):

 

 

 

 

 

 

Fixed price

 

 

2

 

 

 

22

 

Interest rate(2) (in millions)

 

$

—

 

 

$

71

 

 

(1)
Includes options.
(2)
Maturity is determined based on final settlement period.
Fair Value of Derivatives

The following tables present the fair values of derivatives and where they are presented in the Consolidated Balance Sheets:

 

(millions)

 

Fair Value -
Derivatives not
under Hedge
Accounting

 

At June 30, 2024

 

 

 

ASSETS

 

 

 

Current Assets

 

 

 

Commodity

 

$

26

 

Total current derivative assets(1)

 

 

26

 

Noncurrent Assets

 

 

 

Commodity

 

 

259

 

Interest rate

 

 

1

 

Total noncurrent derivative assets(2)

 

 

260

 

Total derivative assets

 

$

286

 

LIABILITIES

 

 

 

Noncurrent Liabilities

 

 

 

Interest rate

 

 

2

 

Total noncurrent derivative liabilities(3)

 

 

2

 

Total derivative liabilities

 

$

2

 

At December 31, 2023

 

 

 

ASSETS

 

 

 

Current Assets

 

 

 

Commodity

 

$

9

 

Total current derivative assets(1)

 

 

9

 

Noncurrent Assets

 

 

 

Commodity

 

 

167

 

Total noncurrent derivative assets(2)

 

 

167

 

Total derivative assets

 

$

176

 

LIABILITIES

 

 

 

Noncurrent Liabilities

 

 

 

Interest rate

 

 

4

 

Total noncurrent derivative liabilities(3)

 

 

4

 

Total derivative liabilities

 

$

4

 

 

(1)
Current derivative assets are presented in other current assets in DESC’s Consolidated Balance Sheets.
(2)
Noncurrent derivative assets are presented in other deferred debits and other assets in DESC’s Consolidated Balance Sheets.
(3)
Noncurrent derivative liabilities are presented in other deferred credits and other liabilities in DESC’s Consolidated Balance Sheets.
Derivatives in Cash Flow Hedging Relationships

The following tables present the gains and losses on derivatives, as well as where the associated activity is presented in the Consolidated Balance Sheets and Statements of Comprehensive Income:

Derivatives in Cash Flow Hedging Relationships

 

(millions)

 

Increase (Decrease) in Derivatives Subject to Regulatory Treatment(1)(2)

 

Three Months Ended June 30,

 

2024

 

 

2023

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

Interest rate

 

$

1

 

 

$

1

 

Total

 

$

1

 

 

$

1

 

Six Months Ended June 30,

 

 

 

 

 

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

Interest rate

 

$

1

 

 

$

—

 

Total

 

$

1

 

 

$

—

 
(1)
Represents net derivative activity deferred into and amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/ liabilities have no associated effect in the Consolidated Statements of Comprehensive Income.
(2)
All derivatives in cash flow hedging relationships have settled and are being amortized over the life of the debt.
Derivatives Not Designated as Hedging Instruments

Derivatives Not Designated as Hedging Instruments

 

(millions)

 

Amount of Gain (Loss) Recognized in Income on Derivatives(1)

 

Three Months Ended June 30,

 

2024

 

 

2023

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

Commodity:

 

 

 

 

 

 

Purchased power

 

$

(1

)

 

$

(1

)

Interest rate:

 

 

 

 

 

 

Interest charges

 

 

—

 

 

 

(1

)

Total

 

$

(1

)

 

$

(2

)

Six Months Ended June 30,

 

 

 

 

 

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

Commodity:

 

 

 

 

 

 

Purchased power

 

$

(3

)

 

$

—

 

Interest rate:

 

 

 

 

 

 

Interest charges

 

 

(1

)

 

 

(1

)

Total

 

$

(4

)

 

$

(1

)

 

(1)
Includes derivative activity amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/liabilities have no associated effect in the Consolidated Statements of Comprehensive Income.
v3.24.2.u1
Fair Value Measurements, Including Derivatives (Tables)
 6 Months Ended
Jun. 30, 2024
Fair Value Disclosures [Abstract]  
Schedule of Quantitative Information About Level 3 Fair Value Measurements

The following table presents DESC’s quantitative information about Level 3 fair value measurements at June 30, 2024. The range and weighted average are presented in dollars for market price inputs and percentages for price volatility.

 

 

Fair Value
(millions)

 

 

Valuation Techniques

 

Unobservable Input

 

 

Range

 

Weighted
Average(1)

Assets

 

 

 

 

 

 

 

 

 

 

 

 

Physical forwards:

 

 

 

 

 

 

 

 

 

 

 

 

Electricity

 

$

277

 

 

Discounted cash flow

 

Market price (per MWh)

(3)

 

28-99

 

54

Physical options:

 

 

 

 

 

 

 

 

 

 

 

 

Natural gas(2)

 

$

6

 

 

Option model

 

Market price (per Dth)

(3)

 

2-4

 

3

 

 

 

 

 

 

 

Price volatility

(4)

 

10%-49%

 

31%

Total assets

 

$

283

 

 

 

 

 

 

 

 

 

 

 

 

(1)
Averages weighted by volume.
(2)
Includes basis.
(3)
Represents market prices beyond defined terms for Levels 1 and 2.
(4)
Represents volatilities unrepresented in published markets.
Schedule of Sensitivity of The Fair Value Measurements To Changes in The Significant Unobservable Inputs

Sensitivity of the fair value measurements to changes in the significant unobservable inputs is as follows:

 

Significant Unobservable Inputs

 

Position

 

Change to Input

 

Impact on Fair Value Measurement

Market price

 

Buy

 

Increase (decrease)

 

Gain (loss)

Market price

 

Sell

 

Increase (decrease)

 

Loss (gain)

Price volatility

 

Buy

 

Increase (decrease)

 

Gain (loss)

Price volatility

 

Sell

 

Increase (decrease)

 

Loss (gain)
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis

The following table presents DESC’s assets and liabilities that are measured at fair value on a recurring basis for each hierarchy level, including both current and noncurrent portions:

 

(millions)

 

Level 1

 

 

Level 2

 

 

Level 3

 

 

Total

 

At June 30, 2024

 

 

 

 

 

 

 

 

 

 

 

 

Assets

 

 

 

 

 

 

 

 

 

 

 

 

Commodity

 

$

—

 

 

$

2

 

 

$

283

 

 

$

285

 

Interest rate

 

 

—

 

 

 

1

 

 

 

—

 

 

 

1

 

Total assets

 

$

—

 

 

$

3

 

 

$

283

 

 

$

286

 

Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

$

—

 

 

$

2

 

 

$

—

 

 

$

2

 

Total liabilities

 

$

—

 

 

$

2

 

 

$

—

 

 

$

2

 

At December 31, 2023

 

 

 

 

 

 

 

 

 

 

 

 

Assets

 

 

 

 

 

 

 

 

 

 

 

 

Commodity

 

$

—

 

 

$

—

 

 

$

176

 

 

$

176

 

Interest rate

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

Total assets

 

$

—

 

 

$

—

 

 

$

176

 

 

$

176

 

Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

$

—

 

 

$

4

 

 

$

—

 

 

$

4

 

Total liabilities

 

$

—

 

 

$

4

 

 

$

—

 

 

$

4

 
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis and included in Level 3

The following table presents the net change in DESC’s assets and liabilities measured at fair value on a recurring basis and included in the Level 3 fair value category.

 

 

 

Three Months Ended

 

 

Six Months Ended

 

 

 

June 30,

 

 

June 30,

 

 

 

2024

 

 

2023

 

 

2024

 

 

2023

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

Beginning balance

 

$

253

 

 

$

188

 

 

$

176

 

 

$

251

 

Total realized and unrealized gains (losses):

 

 

 

 

 

 

 

 

 

 

 

 

Included in earnings:

 

 

 

 

 

 

 

 

 

 

 

 

Purchased power

 

 

(1

)

 

 

(1

)

 

 

(3

)

 

 

—

 

Included in regulatory assets/liabilities

 

 

32

 

 

 

(21

)

 

 

102

 

 

 

(84

)

Settlements

 

 

(1

)

 

 

1

 

 

 

1

 

 

 

—

 

Purchases

 

 

—

 

 

 

—

 

 

 

7

 

 

 

—

 

Ending balance

 

$

283

 

 

$

167

 

 

$

283

 

 

$

167

 
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments For financial instruments that are not recorded at fair value, the carrying amounts and estimated fair values are as follows:

 

 

 

June 30, 2024

 

 

December 31, 2023

 

(millions)

 

Carrying Amount

 

 

Estimated Fair Value(1)

 

 

Carrying Amount

 

 

Estimated Fair Value(1)

 

Long-term debt(2)

 

$

4,219

 

 

$

4,121

 

 

$

4,219

 

 

$

4,301

 

Affiliated long-term debt(3)

 

 

230

 

 

 

230

 

 

 

230

 

 

 

230

 

 

(1)
Fair value is estimated using market prices, where available, and interest rates currently available for issuance of debt with similar terms and remaining maturities. All fair value measurements are classified as Level 2. The carrying amount of debt issuances with short-term maturities and variable rates refinanced at current market rates is a reasonable estimate of their fair value.
(2)
Carrying amount includes current portions, if any, presented in securities due within one year and amounts which represent the unamortized debt issuance costs and discount or premium.
(3)
Carrying amount includes current portions presented in affiliated and related party payables, as applicable.
v3.24.2.u1
Employee Benefit Plans (Tables)
 6 Months Ended
Jun. 30, 2024
Retirement Benefits [Abstract]  
Components of Net Periodic Benefit Cost (Credit)

(millions)

 

Pension Benefits

 

 

Other Postretirement Benefits

 

Three Months Ended June 30,

 

2024

 

 

2023

 

 

2024

 

 

2023

 

Service cost

 

$

2

 

 

$

2

 

 

$

1

 

 

$

1

 

Interest cost

 

 

8

 

 

 

8

 

 

 

2

 

 

 

2

 

Expected return on assets

 

 

(10

)

 

 

(9

)

 

 

—

 

 

 

—

 

Amortization of actuarial losses

 

 

2

 

 

 

3

 

 

 

(1

)

 

 

(1

)

Net periodic benefit cost

 

$

2

 

 

$

4

 

 

$

2

 

 

$

2

 

Six Months Ended June 30,

 

 

 

 

 

 

 

 

 

 

 

 

Service cost

 

$

4

 

 

$

4

 

 

$

1

 

 

$

1

 

Interest cost

 

 

16

 

 

 

16

 

 

 

4

 

 

 

4

 

Expected return on assets

 

 

(19

)

 

 

(17

)

 

 

—

 

 

 

—

 

Amortization of actuarial losses

 

 

4

 

 

 

6

 

 

 

(2

)

 

 

(2

)

Net periodic benefit cost

 

$

5

 

 

$

9

 

 

$

3

 

 

$

3

 
v3.24.2.u1
Operating Segments (Tables)
 6 Months Ended
Jun. 30, 2024
Segment Reporting [Abstract]  
Schedule of Segment Reporting Information, by Segment

(millions)

 

External
Revenue

 

 

Comprehensive
Income (Loss)
Available
(Attributable) to
Common
Shareholder

 

Three Months Ended June 30, 2024

 

 

 

 

 

 

Dominion Energy South Carolina

 

$

731

 

 

$

62

 

Corporate and Other

 

 

—

 

 

 

(5

)

Consolidated Total

 

$

731

 

 

$

57

 

 

 

 

 

 

 

Three Months Ended June 30, 2023

 

 

 

 

 

 

Dominion Energy South Carolina

 

$

704

 

 

$

63

 

Corporate and Other

 

 

—

 

 

 

13

 

Consolidated Total

 

$

704

 

 

$

76

 

 

 

 

 

 

 

Six Months Ended June 30, 2024

 

 

 

 

 

 

Dominion Energy South Carolina

 

$

1,506

 

 

$

137

 

Corporate and Other

 

 

—

 

 

 

(6

)

Consolidated total

 

$

1,506

 

 

$

131

 

 

 

 

 

 

 

 

Six Months Ended June 30, 2023

 

 

 

 

 

 

Dominion Energy South Carolina

 

$

1,463

 

 

$

149

 

Corporate and Other

 

 

—

 

 

 

19

 

Consolidated total

 

$

1,463

 

 

$

168

 
v3.24.2.u1
Affiliated and Related Party Transactions (Tables)
 6 Months Ended
Jun. 30, 2024
Related Party Transactions [Abstract]  
Schedule of Affiliated Transactions Amounts expensed are primarily recorded in other operations and maintenance - affiliated suppliers and other income (expense), net in the Consolidated Statements of Comprehensive Income.

 

 

Three Months Ended
June 30,

 

 

Six Months Ended
June 30,

 

(millions)

 

2024

 

 

2023

 

 

2024

 

 

2023

 

Direct and allocated costs from DES(1)

 

$

57

 

 

$

55

 

 

$

110

 

 

$

112

 

Operating Revenues - Electric from sales to affiliate

 

 

2

 

 

 

1

 

 

 

3

 

 

 

2

 

Operating Revenues - Gas from sales to affiliate

 

 

1

 

 

 

—

 

 

 

1

 

 

 

—

 

Operating Expenses - Other taxes from affiliate

 

 

2

 

 

 

2

 

 

 

5

 

 

 

5

 

Purchases of electricity from solar affiliates

 

 

3

 

 

 

4

 

 

 

4

 

 

 

6

 

 

(1)
Includes capitalized expenditures of $15 million and $13 million for the three months ended June 30, 2024 and 2023, respectively, and $27 million and $29 million for the six months ended June 30, 2024 and 2023, respectively.
Schedule of Affiliated Transactions

(millions)

 

June 30, 2024

 

 

December 31, 2023

 

Payable to DES

 

$

20

 

 

$

18

 

Payable to SCANA Corporation

 

 

7

 

 

 

7

 

Payable to Public Service Company of North Carolina, Incorporated

 

 

9

 

 

 

13

 

Derivative assets with affiliates(1)

 

 

47

 

 

 

33

 

 

 

(1)
Includes amounts recorded in other current assets of $3 million and $2 million as of June 30, 2024 and December 31, 2023, respectively, and amounts recorded in other deferred debits and other assets of $44 million and $31 million as of June 30, 2024 and December 31, 2023, respectively.
v3.24.2.u1
Other Income (Expense), Net (Tables)
 6 Months Ended
Jun. 30, 2024
Income Statement [Abstract]  
Components of Other Income (Expense), Net

Components of other income (expense), net are as follows:

 

 

 

Three Months Ended June 30,

 

 

Six Months Ended June 30,

 

(millions)

 

2024

 

 

2023

 

 

2024

 

 

2023

 

Other income

 

$

1

 

 

$

1

 

 

$

3

 

 

$

3

 

Gains on sales of assets(1)

 

 

1

 

 

 

22

 

 

 

2

 

 

 

32

 

Other expense

 

 

(4

)

 

 

(5

)

 

 

(9

)

 

 

(7

)

Allowance for equity funds used during construction

 

 

3

 

 

 

—

 

 

 

6

 

 

 

—

 

Other income (expense), net

 

$

1

 

 

$

18

 

 

$

2

 

 

$

28

 

 

(1) Includes amounts recognized in 2023 in connection with the transfer of property to satisfy litigation. See Note 10 for additional information.
v3.24.2.u1
Rate and Other Regulatory Matters (Narrative) (Detail)
$ in Millions
 1 Months Ended 6 Months Ended
Jul. 31, 2024
USD ($)
Jun. 30, 2024
USD ($)
Mar. 31, 2024
USD ($)
mi
kV
Feb. 29, 2024
USD ($)
Jan. 31, 2024
USD ($)
Jun. 30, 2024
Rate And Other Regulatory Matters [Line Items]            
Miles of Lines | mi     7      
Type of Line | kV     230      
Estimated electric transmission project cost     $ 40      
Regulatory asset recovery assessment end period           2078
Dominion Energy South Carolina, Inc. [Member]            
Rate And Other Regulatory Matters [Line Items]            
Storm restoration recovery period           10 years
Electric Base Rate Case [Member]            
Rate And Other Regulatory Matters [Line Items]            
Amount of Increase in proposed non fuel base rate     295      
Decrease in storm damage and DSM components     4      
Increase in proposed base rate amount     $ 291      
Increase in proposed base rate percentage     12.59%      
Percentage of current authorized earned ROE     9.50%      
Percentage of earned return on equity     4.32%      
Percentage of earned return on equity proposed rate     10.60%      
Electric Base Rate Case [Member] | Subsequent Event [Member] | Comprehensive Settlement Agreement [Member]            
Rate And Other Regulatory Matters [Line Items]            
Increase in non-fuel base rate amount $ 219          
Percentage of authorized ROE 9.94%          
One-time bill credit to residential customers $ 7          
Potential charge related to materials and supplies inventory write-down $ 50          
Electric - Cost of Fuel [Member]            
Rate And Other Regulatory Matters [Line Items]            
Proposed South Carolina Commission Order for Decrease of Total Fuel Cost Component of Retail Electric Rates to produce a projected under-recovery       $ 315    
South Carolina Commission Order for Increase/Decrease of Total Fuel Cost Component of Retail Electric Rates to produce a projected under-recovery     $ 316      
Natural Gas Rates [Member]            
Rate And Other Regulatory Matters [Line Items]            
Public utilities, total revenue requirement amount   $ 523        
Amount of increase in base rate   $ 13        
Reserve For Refunds To Electric Utility Customers [Member]            
Rate And Other Regulatory Matters [Line Items]            
Electric service customers recovery period           11 years
Deferred Losses or Gains On Interest Rate Derivatives [Member]            
Rate And Other Regulatory Matters [Line Items]            
Changes in fair value and payments of interest rate derivatives designated as cash flow hedge, amortized to interest expense, year           2065
Monetization Of Guaranty Settlement [Member]            
Rate And Other Regulatory Matters [Line Items]            
Electric service customers recovery period           20 years
End period for recovery           Dec. 31, 2039
Income Taxes Refundable Through Future Rates [Member]            
Rate And Other Regulatory Matters [Line Items]            
Remaining lives of related property period           85 years
NND Project Costs [Member]            
Rate And Other Regulatory Matters [Line Items]            
Electric service customers recovery period           20 years
End period for recovery           Dec. 31, 2039
Deferred Employee Benefit Plan Costs [Member]            
Rate And Other Regulatory Matters [Line Items]            
Regulatory asset recovery assessment end period           2044
Average service period expected to recover other deferred benefit costs           11 years
Other Unrecovered Plant [Member]            
Rate And Other Regulatory Matters [Line Items]            
Amortization of carrying value of coal-fired generating unit           2025
New expected amortization of carrying value of coal-fired generating unit           2039
Advanced Metering Infrastructure Project [Member]            
Rate And Other Regulatory Matters [Line Items]            
New expected amortization of carrying value of coal-fired generating unit           2028
Demand Side Management Programs [Member]            
Rate And Other Regulatory Matters [Line Items]            
Recovery period of regulatory asset   3 years       3 years
Asset Retirement Obligation Costs [Member]            
Rate And Other Regulatory Matters [Line Items]            
Recovery period of regulatory asset   105 years       105 years
Environmental Remediation Costs [Member]            
Rate And Other Regulatory Matters [Line Items]            
Recovery period of regulatory asset   24 years       24 years
Deferred Transmission Operating Costs [Member]            
Rate And Other Regulatory Matters [Line Items]            
Recovery period of regulatory asset   42 years       42 years
Rider D S M [Member] | Electric - Other [Member]            
Rate And Other Regulatory Matters [Line Items]            
South Carolina Commission Order, Annual DSM Program Rate Rider Recovery Amount         $ 47  
South Carolina Commission [Member] | Electric - Other [Member]            
Rate And Other Regulatory Matters [Line Items]            
Annual increase (decrease) in pension cost rider       $ 9    
v3.24.2.u1
Rate and Other Regulatory Matters (Schedule of Regulatory Assets) (Detail) - USD ($)
$ in Millions
Jun. 30, 2024
Dec. 31, 2023
Regulatory Assets    
Regulatory assets, current $ 310 $ 444
Regulatory assets, noncurrent 3,362 3,107
Total regulatory assets 3,672 3,551
NND Project Costs [Member]    
Regulatory Assets    
Regulatory assets, current [1] 138 138
Regulatory assets, noncurrent [1] 1,880 1,949
Deferred Employee Benefit Plan Costs [Member]    
Regulatory Assets    
Regulatory assets, current [2] 8 11
Regulatory assets, noncurrent [2] 117 118
Interest Rate Hedges [Member]    
Regulatory Assets    
Regulatory assets, noncurrent [3] 167 168
Other Unrecovered Plant [Member]    
Regulatory Assets    
Regulatory assets, current [4] 19 19
Regulatory assets, noncurrent [4] 69 66
Demand Side Management Programs [Member]    
Regulatory Assets    
Regulatory assets, current [5] 23 22
Regulatory assets, noncurrent [5] 46 46
Other Regulatory Assets [Member]    
Regulatory Assets    
Regulatory assets, current 54 56
Regulatory assets, noncurrent [6] 143 130
Cost of Fuel and Purchased Gas Under-Collections [Member]    
Regulatory Assets    
Regulatory assets, current [7] 37 154
Asset Retirement Obligation Costs [Member]    
Regulatory Assets    
Regulatory assets, current [8] 31 44
Regulatory assets, noncurrent [8] 688 379
Environmental Remediation Costs [Member]    
Regulatory Assets    
Regulatory assets, noncurrent [9] 42 34
Deferred Storm Damage Costs [Member]    
Regulatory Assets    
Regulatory assets, noncurrent [10] 38 40
Deferred Transmission Operating Costs [Member]    
Regulatory Assets    
Regulatory assets, noncurrent [11] 73 74
Derivative [Member]    
Regulatory Assets    
Regulatory assets, noncurrent [12] $ 99 $ 103
[1] Reflects expenditures associated with the NND Project, which pursuant to the SCANA Merger Approval Order, will be recovered from electric service customers over a 20-year period ending in 2039.
[2] Employee benefit plan costs have historically been recovered as they have been recorded under GAAP. Deferred employee benefit plan costs represent amounts of pension and other postretirement benefit costs which were accrued as liabilities and treated as regulatory assets pursuant to FERC guidance, and costs deferred pursuant to specific South Carolina Commission regulatory orders. DESC expects to recover deferred pension costs through utility rates over periods through 2044. DESC expects to recover other deferred benefit costs through utility rates, primarily over average service periods of participating employees up to 11 years.
[3] Represents settled interest rate derivatives designated as cash flow hedges expected to be amortized to interest expense over the lives of the underlying debt through 2065.
[4] Represents the carrying value of coal-fired generating units, including related materials and supplies inventory, retired from service prior to being fully depreciated. DESC is amortizing these amounts through cost of service rates following depreciation amounts that were designed to recover the retired units cost over their previous estimated remaining useful lives, which has been estimated to be through 2025. Based on current projections of remaining decommissioning costs, projected recovery is expected to extend through 2039. In addition, amounts include unrecovered costs of existing meters and equipment retired from service prior to being fully depreciated as part of the Advanced Metering Infrastructure project, which are being recovered through rates through 2028. This amount also includes certain inventory and preliminary survey and investigation charges being amortized over five years related to the transition or conversion from coal to gas fired generation at certain facilities.
[5] Represents deferred costs associated with electric demand reduction programs, and such deferred costs are currently being recovered over three years through an approved rate rider.
[6] Various other regulatory assets are expected to be recovered through rates over varying periods through 2078.
[7] Represents amounts under- or over-collected from customers pursuant to the cost of fuel and purchased gas components approved by the South Carolina Commission.
[8] Represents uncollected costs, including deferred depreciation and accretion expense, related to legal obligations associated with the future retirement of generation, transmission and distribution properties. The AROs primarily relate to DESC’s electric generating facilities, including Summer, and are expected to be recovered over the related property lives and periods of decommissioning which may range up to approximately 105 years. In addition, the balance at June 30, 2024 reflects amounts related to the EPA’s May 2024 final rule concerning CCR as discussed in Note 10.
[9] Reflects amounts associated with the assessment and clean-up of sites currently or formerly owned by DESC. Such remediation costs are expected to be recovered over periods of up to 24 years. See Note 10 for additional information.
[10] Represents storm restoration costs for which DESC expects to receive future recovery through customer rates over approximately 10 years pursuant to the settlement agreement approved in DESC’s retail electric base rate case. Unamortized amounts are included in rate base and are earning a current return.
[11] Includes deferred depreciation and property taxes associated with certain transmission assets for which DESC expects recovery from customers through future rates over approximately 42 years pursuant to the settlement agreement approved in DESC’s retail electric base rate case. Unamortized amounts are included in rate base and earning a current return. See Note 12 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023.
[12] Represents changes in the fair value of derivatives, excluding separately presented interest rate hedges, that following settlement are expected to be recovered from or refunded to customers.
v3.24.2.u1
Rate and Other Regulatory Matters (Schedule of Regulatory Liabilities) (Detail) - USD ($)
$ in Millions
Jun. 30, 2024
Dec. 31, 2023
Regulatory Liabilities    
Regulatory liability, current $ 230 $ 205
Regulatory liability, noncurrent 2,575 2,579
Total regulatory liabilities 2,805 2,784
Monetization Of Guaranty Settlement [Member]    
Regulatory Liabilities    
Regulatory liability, current [1] 67 67
Regulatory liability, noncurrent [1] 602 635
Income Taxes Refundable Through Future Rates [Member]    
Regulatory Liabilities    
Regulatory liability, current [2] 37 37
Regulatory liability, noncurrent [2] 821 839
Reserve For Refunds To Electric Utility Customers [Member]    
Regulatory Liabilities    
Regulatory liability, current [3] 80 83
Regulatory liability, noncurrent [3] 193 237
Cost of Fuel and Purchased Gas Under-Collections [Member]    
Regulatory Liabilities    
Regulatory liability, current [4] 11  
Other Regulatory Liability [Member]    
Regulatory Liabilities    
Regulatory liability, current 12 6
Regulatory liability, noncurrent 2 6
Asset Removal Costs [Member]    
Regulatory Liabilities    
Regulatory liability, noncurrent [5] 636 633
Derivative [Member]    
Regulatory Liabilities    
Regulatory liability, current [6] 23 12
Regulatory liability, noncurrent [6] $ 321 $ 229
[1] Represents proceeds related to the monetization of the Toshiba Settlement. In accordance with the SCANA Merger Approval Order, this balance, net of amounts that may be required to satisfy liens, will be refunded to electric customers over a 20-year period ending in 2039.
[2] Includes (i) excess deferred income taxes arising from the remeasurement of deferred income taxes in connection with the enactment of the 2017 Tax Reform Act (certain of which are protected under normalization rules and will be amortized over the remaining lives of related property, and certain of which will be amortized to the benefit of customers over prescribed periods as instructed by regulators) and (ii) deferred income taxes arising from investment tax credits, offset by (iii) deferred income taxes that arise from utility operations that have not been included in customer rates (a portion of which relate to depreciation and are expected to be recovered over the remaining lives of the related property which may range up to 85 years). See Note 7 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2023 for additional information.
[3] Reflects amounts previously collected from retail electric customers of DESC for the NND Project to be credited to customers over an estimated 11-year period effective February 2019 in connection with the SCANA Merger Approval Order.
[4] Represents amounts under- or over-collected from customers pursuant to the cost of fuel and purchased gas components approved by the South Carolina Commission.
[5] Represents estimated net collections through depreciation rates of amounts to be expended for the removal of assets in the future.
[6] Represents changes in the fair value of derivatives, excluding separately presented interest rate hedges, that following settlement are expected to be recovered from or refunded to customers.
v3.24.2.u1
Revenue Recognition (Disaggregation of Revenue) (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Total Operating Revenues [1] $ 731 $ 704 $ 1,506 $ 1,463
Electric Operations        
Operating revenue from contracts with customers 627 605 1,213 1,184
Other revenues 7 9 14 12
Total Operating Revenues 634 614 1,227 1,196
Gas Distribution        
Operating revenue from contracts with customers 96 89 278 266
Other revenues 1 1 1 1
Total Operating Revenues 97 90 279 267
Residential | Electric Operations        
Operating revenue from contracts with customers 294 266 577 528
Residential | Gas Distribution        
Operating revenue from contracts with customers 48 43 165 152
Commercial | Electric Operations        
Operating revenue from contracts with customers 208 208 396 395
Commercial | Gas Distribution        
Operating revenue from contracts with customers 25 25 66 67
Industrial | Electric Operations        
Operating revenue from contracts with customers 94 97 181 188
Industrial | Gas Distribution        
Operating revenue from contracts with customers 17 15 35 37
Other | Electric Operations        
Operating revenue from contracts with customers 31 34 59 73
Other | Gas Distribution        
Operating revenue from contracts with customers $ 6 $ 6 $ 12 $ 10
[1] See Note 12 for amounts attributable to affiliates.
v3.24.2.u1
Revenue Recognition (Narrative) (Detail) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Dec. 31, 2023
Revenue from Contract with Customer [Abstract]      
Contract liability balances $ 8   $ 7
Revenue recognized from contract liability balances $ 4 $ 8  
v3.24.2.u1
Revenue Recognition (Balance and Activity Related to Contract Costs Deferred as Regulatory Assets) (Detail) - USD ($)
$ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2024
Dec. 31, 2023
Revenues [Abstract]    
Beginning balance $ 11 $ 9
Additional costs 0 3
Amortization 0 (1)
Ending balance $ 11 $ 11
v3.24.2.u1
Equity (Narrative) (Detail) - $ / shares
Jun. 30, 2024
Dec. 31, 2023
Class Of Stock [Line Items]    
Common stock, par value
Common stock, shares authorized 50,000,000 50,000,000
Common stock, shares issued 40,300,000 40,300,000
Common stock, shares outstanding 40,300,000 40,300,000
Preferred stock, par value
Preferred stock, shares authorized 20,000,000 20,000,000
Preferred stock, shares issued 1,000 1,000
Preferred stock, shares outstanding 1,000 1,000
v3.24.2.u1
Long-Term and Short-Term Debt (Narrative) (Detail) - USD ($)
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
May 31, 2024
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Dec. 31, 2023
Apr. 30, 2024
Debt Instrument [Line Items]              
Commercial paper borrowing limit           $ 2,200,000,000  
Affiliated and related party payables and other   $ 128,000,000   $ 128,000,000   $ 166,000,000  
Interest charges [1]   67,000,000 $ 63,000,000 134,000,000 $ 122,000,000    
Maximum [Member]              
Debt Instrument [Line Items]              
Short term commercial paper maturity period           1 year  
Genco              
Debt Instrument [Line Items]              
Commercial paper borrowing limit           $ 200,000,000  
Genco | 5.31% Promissory Note due in May 2027              
Debt Instrument [Line Items]              
Debt instrument, face amount   230,000,000   230,000,000      
Interest rate percentage 5.31%           3.05%
Debt instrument, maturity date 2024-05            
Debt instrument extended maturity date 2027-05            
Genco | Maximum [Member]              
Debt Instrument [Line Items]              
Short term commercial paper maturity period           1 year  
Dominion Energy              
Debt Instrument [Line Items]              
Affiliated and related party payables and other   690,000,000   690,000,000   $ 442,000,000  
Interest charges   12,000,000 $ 15,000,000 22,000,000 $ 28,000,000    
Inter company credit facility maximum capacity   900,000,000   900,000,000      
Dominion Energy | Genco              
Debt Instrument [Line Items]              
Inter company credit facility maximum capacity   200,000,000   200,000,000      
Dominion Energy | Fuel company              
Debt Instrument [Line Items]              
Inter company credit facility maximum capacity   400,000,000   400,000,000      
Joint Revolving Credit Facility              
Debt Instrument [Line Items]              
Maximum Facility Sub-Limit [2],[3]   1,000,000,000   1,000,000,000      
Joint Revolving Credit Facility | Commercial Paper              
Debt Instrument [Line Items]              
Debt instrument, face amount   275,000,000   275,000,000      
Joint Revolving Credit Facility | Dominion Energy              
Debt Instrument [Line Items]              
Maximum Facility Sub-Limit   6,000,000,000   6,000,000,000      
Industrial Revenue Bonds              
Debt Instrument [Line Items]              
Debt instrument, face amount   68,000,000   68,000,000   $ 68,000,000  
Intercompany Credit Facility              
Debt Instrument [Line Items]              
Line of credit, outstanding   376,000,000   376,000,000      
Intercompany Credit Facility | Genco              
Debt Instrument [Line Items]              
Line of credit, outstanding   $ 41,000,000   $ 41,000,000      
[1] See Note 12 for amounts attributable to affiliates.
[2] A maximum of $1.0 billion of the facility is available to DESC, assuming adequate capacity is available after giving effect to uses by co-borrowers Dominion Energy and Virginia Power. A sub-limit for DESC is set within the facility limit but can be changed at the option of the co-borrowers multiple times per year. At June 30, 2024, the sub-limit for DESC was $500 million. If DESC has liquidity needs in excess of its sub-limit, the sub-limit may be changed or such needs may be satisfied through short-term intercompany borrowings from Dominion Energy. This
credit facility matures in June 2026, with the potential to be extended by the borrowers to June 2028. The credit facility can be used to support bank borrowings and the issuance of commercial paper, as well as to support up to $1.0 billion (or the sub-limit, whichever is less) of letters of credit.
[3] In May 2024, the joint revolving credit facility was amended to remove Questar Gas as a co-borrower.
v3.24.2.u1
Long-Term and Short-Term Debt (Schedule of Line of Credit Facilities) (Detail) - Joint Revolving Credit Facility
Jun. 30, 2024
USD ($)
 [1],[2]
Debt Instrument [Line Items]  
Maximum Facility Sub-Limit $ 1,000,000,000
Outstanding Commercial Paper 275,000,000
Outstanding Letters of Credit $ 0
[1] A maximum of $1.0 billion of the facility is available to DESC, assuming adequate capacity is available after giving effect to uses by co-borrowers Dominion Energy and Virginia Power. A sub-limit for DESC is set within the facility limit but can be changed at the option of the co-borrowers multiple times per year. At June 30, 2024, the sub-limit for DESC was $500 million. If DESC has liquidity needs in excess of its sub-limit, the sub-limit may be changed or such needs may be satisfied through short-term intercompany borrowings from Dominion Energy. This
credit facility matures in June 2026, with the potential to be extended by the borrowers to June 2028. The credit facility can be used to support bank borrowings and the issuance of commercial paper, as well as to support up to $1.0 billion (or the sub-limit, whichever is less) of letters of credit.
[2] In May 2024, the joint revolving credit facility was amended to remove Questar Gas as a co-borrower.
v3.24.2.u1
Long-Term and Short-Term Debt (Schedule of Line of Credit Facilities) (Parenthetical) (Detail)
 6 Months Ended
Jun. 30, 2024
USD ($)
Minimum [Member]  
Debt Instrument [Line Items]  
Line of credit facility maturity date 2026-06
Maximum [Member]  
Debt Instrument [Line Items]  
Line of credit facility maturity date 2028-06
Joint Revolving Credit Facility  
Debt Instrument [Line Items]  
Maximum Facility Sub-Limit $ 1,000,000,000 [1],[2]
Line of Credit Facility  
Debt Instrument [Line Items]  
Maximum Facility Sub-Limit 500,000,000
Letter of Credit  
Debt Instrument [Line Items]  
Maximum Facility Sub-Limit $ 1,000,000,000
[1] A maximum of $1.0 billion of the facility is available to DESC, assuming adequate capacity is available after giving effect to uses by co-borrowers Dominion Energy and Virginia Power. A sub-limit for DESC is set within the facility limit but can be changed at the option of the co-borrowers multiple times per year. At June 30, 2024, the sub-limit for DESC was $500 million. If DESC has liquidity needs in excess of its sub-limit, the sub-limit may be changed or such needs may be satisfied through short-term intercompany borrowings from Dominion Energy. This
credit facility matures in June 2026, with the potential to be extended by the borrowers to June 2028. The credit facility can be used to support bank borrowings and the issuance of commercial paper, as well as to support up to $1.0 billion (or the sub-limit, whichever is less) of letters of credit.
[2] In May 2024, the joint revolving credit facility was amended to remove Questar Gas as a co-borrower.
v3.24.2.u1
Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Detail)
 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Income Tax Disclosure [Abstract]    
U.S. statutory rate 21.00% 21.00%
Increases (reductions) resulting from:    
State taxes, net of federal benefit 4.00% 4.10%
Reversal of excess deferred income taxes (5.70%) (4.00%)
Allowance for equity funds used during construction (0.70%) 0.00%
Settlements of uncertain tax positions 0.00% (5.00%)
Other, net 0.10% (0.10%)
Effective tax rate 18.70% 16.00%
v3.24.2.u1
Income Taxes (Narrative) (Detail)
$ in Millions
Jun. 30, 2024
USD ($)
Income Taxes [Line Items]  
Income tax benefit reasonably possible to occur $ 11
v3.24.2.u1
Derivative Financial Instruments (Narrative) (Detail) - USD ($)
$ in Millions
Jun. 30, 2024
Dec. 31, 2023
Derivative [Line Items]    
Additional collateral to its counterparties $ 2 $ 4
Collateral already posted 0 0
Fair value of derivative instruments with credit-related contingent provisions that are in liability position and not fully collateralized with cash $ 2 $ 4
v3.24.2.u1
Derivative Financial Instruments (Offsetting Assets and Liabilities) (Detail) - USD ($)
$ in Millions
Jun. 30, 2024
Dec. 31, 2023
Assets    
Derivative [Line Items]    
Assets not offset in the consolidated balance sheet [1] $ 8 $ 0
Gross amounts not offset in the consolidated balance sheet, financial instruments 0 0
Gross amounts not offset in the consolidated balance sheet, cash collateral received 0 0
Gross amounts not offset in the consolidated balance sheet, net amounts 8 0
Over The Counter [Member] | Assets | Interest Rate Contract [Member]    
Derivative [Line Items]    
Assets not offset in the consolidated balance sheet [1] 1 0
Gross amounts not offset in the consolidated balance sheet, financial instruments 0 0
Gross amounts not offset in the consolidated balance sheet, cash collateral received 0 0
Gross amounts not offset in the consolidated balance sheet, net amounts 1 0
Over The Counter [Member] | Assets | Commodity Contract [Member]    
Derivative [Line Items]    
Assets not offset in the consolidated balance sheet [1] 7 0
Gross amounts not offset in the consolidated balance sheet, financial instruments 0 0
Gross amounts not offset in the consolidated balance sheet, cash collateral received 0 0
Gross amounts not offset in the consolidated balance sheet, net amounts 7 0
Liability    
Derivative [Line Items]    
Gross liabilities presented in the consolidated balance sheet [2] 2 4
Gross amounts not offset in the consolidated balance sheet, financial instruments 0 0
Gross amounts not offset in the consolidated balance sheet, cash collateral paid 0 0
Gross amounts not offset in the consolidated balance sheet, net amounts 2 4
Liability | Over The Counter [Member] | Interest Rate Contract [Member]    
Derivative [Line Items]    
Gross liabilities presented in the consolidated balance sheet [2] 2 4
Gross amounts not offset in the consolidated balance sheet, financial instruments 0 0
Gross amounts not offset in the consolidated balance sheet, cash collateral paid 0 0
Gross amounts not offset in the consolidated balance sheet, net amounts $ 2 $ 4
[1] Excludes derivative assets of $278 million and $176 million at June 30, 2024 and December 31, 2023, respectively, which are not subject to master netting or similar arrangements.
[2] DESC did not have any derivative liabilities at June 30, 2024 and December 31, 2023, respectively, which were not subject to master netting or similar arrangements.
v3.24.2.u1
Derivative Financial Instruments (Offsetting Assets and Liabilities) (Parenthetical) (Details) - USD ($)
Jun. 30, 2024
Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]    
Derivative assets not subject to master netting or similar arrangements $ 278,000,000 $ 176,000,000
Derivative liability not subject to master netting or similar arrangements $ 0 $ 0
v3.24.2.u1
Derivative Financial Instruments (Schedule of Volume of Derivative Activity) (Detail)
MWh in Millions, Bcf in Millions
 6 Months Ended
Jun. 30, 2024
USD ($)
Bcf
MWh
Interest Rate Swap Current [Member]  
Derivative [Line Items]  
Interest rate | $ $ 0 [1]
Interest Rate Swap Current [Member] | Natural Gas (bcf)  
Derivative [Line Items]  
Basis | Bcf 18 [2]
Fixed price 1
Interest Rate Swap Current [Member] | Electricity [Member]  
Derivative [Line Items]  
Fixed price 2
Interest Rate Swap Noncurrent [Member]  
Derivative [Line Items]  
Interest rate | $ $ 71,000,000 [1]
Interest Rate Swap Noncurrent [Member] | Electricity [Member]  
Derivative [Line Items]  
Fixed price 22
[1] Maturity is determined based on final settlement period.
[2] Includes options.
v3.24.2.u1
Derivative Financial Instruments (Fair Value of Derivatives) (Detail) - Not Designated as Hedging Instrument [Member] - USD ($)
$ in Millions
Jun. 30, 2024
Dec. 31, 2023
Derivative [Line Items]    
Derivative Asset, Current [1] $ 26 $ 9
Derivative Asset, Current, Statement of Financial Position [Extensible Enumeration] Other Assets, Current Other Assets, Current
Derivative Asset, Noncurrent [2] $ 260 $ 167
Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration] Regulated Entity, Other Assets, Noncurrent Regulated Entity, Other Assets, Noncurrent
Derivative Assets $ 286 $ 176
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Assets Assets
Derivative Liability, Noncurrent [3] $ 2 $ 4
Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Liabilities, Noncurrent Liabilities, Noncurrent
Derivative Liability $ 2 $ 4
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Liabilities and Equity Liabilities and Equity
Commodity Contract [Member]    
Derivative [Line Items]    
Derivative Asset, Current $ 26 $ 9
Derivative Asset, Current, Statement of Financial Position [Extensible Enumeration] Other Assets, Current Other Assets, Current
Derivative Asset, Noncurrent $ 259 $ 167
Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration] Regulated Entity, Other Assets, Noncurrent Regulated Entity, Other Assets, Noncurrent
Interest Rate Contract [Member]    
Derivative [Line Items]    
Derivative Asset, Noncurrent $ 1  
Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration] Regulated Entity, Other Assets, Noncurrent  
Derivative Liability, Noncurrent $ 2 $ 4
Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Liabilities, Noncurrent Liabilities, Noncurrent
[1] Current derivative assets are presented in other current assets in DESC’s Consolidated Balance Sheets.
[2] Noncurrent derivative assets are presented in other deferred debits and other assets in DESC’s Consolidated Balance Sheets.
[3] Noncurrent derivative liabilities are presented in other deferred credits and other liabilities in DESC’s Consolidated Balance Sheets.
v3.24.2.u1
Derivative Financial Instruments (Derivatives in Cash Flow Hedging Relationships) (Detail) - Cash Flow Hedging [Member] - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Derivative [Line Items]        
Increase (Decrease) in Derivatives Subject to Regulatory Treatment [1],[2] $ 1 $ 1 $ 1 $ 0
Interest Rate Contract [Member]        
Derivative [Line Items]        
Increase (Decrease) in Derivatives Subject to Regulatory Treatment [1],[2] $ 1 $ 1 $ 1 $ 0
[1] All derivatives in cash flow hedging relationships have settled and are being amortized over the life of the debt.
[2] Represents net derivative activity deferred into and amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/ liabilities have no associated effect in the Consolidated Statements of Comprehensive Income.
v3.24.2.u1
Derivative Financial Instruments (Derivatives Not Designated as Hedging Instruments) (Detail) - Not Designated as Hedging Instruments [Member] - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Derivative [Line Items]        
Amount of Gain (Loss) Recognized in Income on Derivatives [1] $ (1) $ (2) $ (4) $ (1)
Commodity Contract [Member]        
Derivative [Line Items]        
Amount of Gain (Loss) Recognized in Income on Derivatives [1] $ (1) $ (1) $ (3) $ 0
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Utilities Operating Expense, Purchased Power Utilities Operating Expense, Purchased Power Utilities Operating Expense, Purchased Power Utilities Operating Expense, Purchased Power
Interest Rate Contract [Member]        
Derivative [Line Items]        
Amount of Gain (Loss) Recognized in Income on Derivatives [1] $ 0 $ (1) $ (1) $ (1)
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Interest Expense Interest Expense Interest Expense Interest Expense
[1] Includes derivative activity amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/liabilities have no associated effect in the Consolidated Statements of Comprehensive Income.
v3.24.2.u1
Fair Value Measurements, Including Derivatives (Schedule of Quantitative Information About Level 3 Fair Value Measurements) (Details)
Jun. 30, 2024
USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]  
Total assets, fair value $ 283,000,000
Electricity [Member]  
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]  
Total assets, fair value 277,000,000
Natural gas [Member]  
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]  
Total assets, fair value $ 6,000,000 [1]
Fair value inputs price volatility 31.00% [2]
Minimum [Member] | Electricity [Member]  
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]  
Total assets, fair value $ 28,000,000
Minimum [Member] | Natural gas [Member]  
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]  
Total assets, fair value $ 2,000,000
Fair value inputs price volatility 10.00%
Maximum [Member] | Electricity [Member]  
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]  
Total assets, fair value $ 99,000,000
Maximum [Member] | Natural gas [Member]  
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]  
Total assets, fair value $ 4,000,000
Fair value inputs price volatility 49.00%
Weighted Average [Member] | Electricity [Member]  
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]  
Total assets, fair value $ 54,000,000 [2]
Weighted Average [Member] | Natural gas [Member]  
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]  
Total assets, fair value $ 3,000,000 [2]
[1] Includes basis.
[2] Averages weighted by volume.
v3.24.2.u1
Fair Value Measurements, Including Derivatives (Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - Fair value, recurring - USD ($)
$ in Millions
Jun. 30, 2024
Dec. 31, 2023
Assets    
Total assets $ 286 $ 176
Liabilities    
Total liabilities 2 4
Commodity Contract [Member]    
Assets    
Total assets 285 176
Interest Rate Contract [Member]    
Assets    
Total assets 1 0
Liabilities    
Total liabilities 2 4
Level 1    
Assets    
Total assets 0 0
Liabilities    
Total liabilities 0 0
Level 1 | Commodity Contract [Member]    
Assets    
Total assets 0 0
Level 1 | Interest Rate Contract [Member]    
Assets    
Total assets 0 0
Liabilities    
Total liabilities 0 0
Level 2    
Assets    
Total assets 3 0
Liabilities    
Total liabilities 2 4
Level 2 | Commodity Contract [Member]    
Assets    
Total assets 2 0
Level 2 | Interest Rate Contract [Member]    
Assets    
Total assets 1 0
Liabilities    
Total liabilities 2 4
Level 3    
Assets    
Total assets 283 176
Liabilities    
Total liabilities 0 0
Level 3 | Commodity Contract [Member]    
Assets    
Total assets 283 176
Level 3 | Interest Rate Contract [Member]    
Assets    
Total assets 0 0
Liabilities    
Total liabilities $ 0 $ 0
v3.24.2.u1
Fair Value Measurements, Including Derivatives (Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis and Included in Level 3) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Regulatory Assets        
Beginning balance $ 253 $ 188 $ 176 $ 251
Included in earnings:        
Purchased power (1) (1) (3)  
Settlements (1) 1 1  
Purchases     7  
Ending balance 283 167 283 167
Other Regulatory Assets Liabilities        
Included in earnings:        
Included in regulatory assets/liabilities $ 32 $ (21) $ 102 $ (84)
v3.24.2.u1
Fair Value Measurements, Including Derivatives (Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis) (Narrative) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]        
Unrealized gains and losses $ 0 $ 0 $ 0 $ 0
v3.24.2.u1
Fair Value Measurements, Including Derivatives (Schedule of Carrying Values and Estimated Fair Values of Debt Instruments) (Detail) - USD ($)
$ in Millions
Jun. 30, 2024
Dec. 31, 2023
Carrying Amount    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Long-term debt [1] $ 4,219 $ 4,219
Affiliated long-term debt [2] 230 230
Estimated Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Long-term debt [1],[3] 4,121 4,301
Affiliated long-term debt [2],[3] $ 230 $ 230
[1] Carrying amount includes current portions, if any, presented in securities due within one year and amounts which represent the unamortized debt issuance costs and discount or premium.
[2] Carrying amount includes current portions presented in affiliated and related party payables, as applicable.
[3] Fair value is estimated using market prices, where available, and interest rates currently available for issuance of debt with similar terms and remaining maturities. All fair value measurements are classified as Level 2. The carrying amount of debt issuances with short-term maturities and variable rates refinanced at current market rates is a reasonable estimate of their fair value.
v3.24.2.u1
Employee Benefit Plans (Components of Net Periodic Benefit Cost (Credit) (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Pension Plan        
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 2 $ 2 $ 4 $ 4
Interest cost 8 8 16 16
Expected return on assets (10) (9) (19) (17)
Amortization of actuarial losses 2 3 4 6
Net periodic benefit cost (credit) 2 4 5 9
Other Postretirement Benefits Plan        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 1 1 1 1
Interest cost 2 2 4 4
Expected return on assets 0 0 0 0
Amortization of actuarial losses (1) (1) (2) (2)
Net periodic benefit cost (credit) $ 2 $ 2 $ 3 $ 3
v3.24.2.u1
Employee Benefit Plans (Narrative) (Detail) - Pension Plan - USD ($)
$ in Millions
 1 Months Ended 3 Months Ended 6 Months Ended
Jul. 31, 2024
Jun. 30, 2024
Jun. 30, 2024
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan, contributions by employer   $ 1 $ 1
Defined benefit plan, expected contributions in 2024   $ 8 $ 8
Subsequent Event      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan, contributions by employer $ 1    
v3.24.2.u1
Commitments and Contingencies (Narrative) (Detail)
shares in Millions
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Oct. 31, 2014
Facility
MGD
May 31, 2024
Station
Jul. 31, 2023
USD ($)
Jun. 30, 2023
USD ($)
Sep. 30, 2022
USD ($)
Jun. 30, 2022
USD ($)
May 31, 2022
shares
Aug. 31, 2021
shares
Jun. 30, 2021
USD ($)
Dec. 31, 2020
USD ($)
Oct. 31, 2020
Nov. 30, 2019
gal
Jun. 30, 2018
USD ($)
Sep. 30, 2017
Petition
Apr. 30, 2017
Petition
Aug. 31, 2016
T
Jun. 30, 2024
USD ($)
Mar. 31, 2024
USD ($)
Jun. 30, 2023
USD ($)
Mar. 31, 2023
USD ($)
Jun. 30, 2024
USD ($)
Product
Indicator
Facility
Jun. 30, 2023
USD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Loss Contingencies [Line Items]                                                
Personal injury or wrongful death charges                                 $ 5,000,000       $ 11,000,000      
Number of DESC facilities subject to final regulations | Facility 5                                              
Measurement of groundwater withdrawals | gal                       3,000,000                        
Number of manufacturing gas plant decommissioned sites that contain residues of byproduct chemicals | Product                                         4      
Estimated environmental remediation activities at manufacturing gas plant sites                                         $ 1,000,000      
Environmental remediation costs recognized in regulatory assets                                 34,000,000       $ 34,000,000      
Number of facilities inactive subject to final rule | Facility                                         3      
Increase in regulatory assets                                         $ (112,000,000) $ (109,000,000)    
Proportionate ownership share in project                         100.00%                      
Proposed assessment amount from SCDOR audit                         $ 410,000,000                      
Litigation settlement expense awarded                   $ 165,000,000                            
Real estate transfer to satisfy obligation under settlement           $ 51,000,000                                    
Nuclear Insurance                                                
Loss Contingencies [Line Items]                                                
Maximum liability protection per nuclear incident amount                                   $ 16,300,000,000         $ 16,200,000,000  
Maximum liability each nuclear plant is insured against                                   $ 500,000,000         $ 450,000,000  
Surety Bonds                                                
Loss Contingencies [Line Items]                                                
Guarantee obligation                                 24,000,000       $ 24,000,000      
SCDOR                                                
Loss Contingencies [Line Items]                                                
Fair value of certain additional utility property transferred                                               $ 3,000,000
Fair value of certain remaining utility property transferred       $ 11,000,000                                        
Fair value of certain non-utility property transferred         $ 28,000,000                                      
Fair value of certain utility property transferred                                       $ 10,000,000        
Gain from transferred utility property                                           9,000,000    
Gain from transferred utility property, after tax                                           7,000,000    
Gain from transferred remaining utility property                                     $ 11,000,000     11,000,000    
Gain from transferred remaining utility property, after tax                                     $ 8,000,000     $ 8,000,000    
Common Stock | Dominion Energy                                                
Loss Contingencies [Line Items]                                                
Litigation settlement through cash                 $ 43,000,000                              
Shares issued on settlement | shares             0.9 0.6                                
Unfavorable Regulatory Action | CWA                                                
Loss Contingencies [Line Items]                                                
Electric generating stations with water withdrawals with heightened entrainment analysis under CWA | MGD 2                                              
Number of mandatory facility specific factors. | Indicator                                         5      
Number of optional facility specific factors | Indicator                                         6      
Maximum [Member] | SCDOR                                                
Loss Contingencies [Line Items]                                                
Cash payment     $ 1,000,000                                          
Carbon Regulations [Member]                                                
Loss Contingencies [Line Items]                                                
Significant emission rate per year CO2 equivalent | T                               75,000                
EPA                                                
Loss Contingencies [Line Items]                                                
Number of petition agreed for reconsideration | Petition                           2                    
Increase in asset retirement obligations                                 655,000,000              
Increase in property, plant and equipment                                 353,000,000              
Increase in regulatory assets                                 $ 302,000,000              
EPA | Unfavorable Regulatory Action                                                
Loss Contingencies [Line Items]                                                
Electric generating stations with water withdrawals under CWA | MGD 125                                              
EPA | Unfavorable Regulatory Action | CWA | Final Rule to Revise Effluent Limitations Guidelines for Steam Electric Power Generating Category                                                
Loss Contingencies [Line Items]                                                
Number of separate petitions for reconsideration granted | Petition                             2                  
Loss contingencies facility retirement period   2034                                            
EPA | Minimum [Member] | Unfavorable Regulatory Action | CWA | Final Rule to Revise Effluent Limitations Guidelines for Steam Electric Power Generating Category                                                
Loss Contingencies [Line Items]                                                
Loss contingencies individual facilities circumstances period                     2021                          
EPA | Maximum [Member]                                                
Loss Contingencies [Line Items]                                                
Number of stations inactive subject to final rule | Station   7                                            
EPA | Maximum [Member] | Unfavorable Regulatory Action | CWA | Final Rule to Revise Effluent Limitations Guidelines for Steam Electric Power Generating Category                                                
Loss Contingencies [Line Items]                                                
Loss contingencies individual facilities circumstances period   2029                 2028                          
Environmental Protection Agency And State Regulatory Agencies                                                
Loss Contingencies [Line Items]                                                
Number of DESC hydroelectric facilities subject to regulations | Facility 5                                              
v3.24.2.u1
Operating Segments (Narrative) (Detail) - Operating Segments
$ in Millions
 6 Months Ended
Jun. 30, 2023
USD ($)
Corporate and Other  
Segment Reporting Information [Line Items]  
After- tax net income $ 19
Dominion Energy South Carolina, Inc. [Member]  
Segment Reporting Information [Line Items]  
After- tax net income 21
Benefit related to real estate transactions 31
Benefit related to real estate transactions, after tax $ 23
v3.24.2.u1
Operating Segments - Schedule of Segment Information (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Segment Reporting Information [Line Items]        
External revenue [1] $ 731 $ 704 $ 1,506 $ 1,463
Comprehensive income (loss) available (attributable) to common shareholder 57 76 131 168
Dominion Energy South Carolina, Inc. [Member]        
Segment Reporting Information [Line Items]        
External revenue 731 704 1,506 1,463
Comprehensive income (loss) available (attributable) to common shareholder 62 63 137 149
Corporate and Other        
Segment Reporting Information [Line Items]        
External revenue 0 0 0 0
Comprehensive income (loss) available (attributable) to common shareholder $ (5) $ 13 $ (6) $ 19
[1] See Note 12 for amounts attributable to affiliates.
v3.24.2.u1
Affiliated and Related Party Transactions (Schedule of Affiliated Transactions - Income Statement) (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Related Party Transaction [Line Items]        
Operating Revenues - Electric from sales to affiliate $ 2 $ 1 $ 3 $ 2
Operating Revenues – Gas from sales to affiliate 1 0 1 0
Operating Expenses - Other taxes from affiliate 2 2 5 5
Solar Affiliates [Member]        
Related Party Transaction [Line Items]        
Purchases from affiliate 3 4 4 6
Related Party | DES        
Related Party Transaction [Line Items]        
Direct and allocated costs [1] $ 57 $ 55 $ 110 $ 112
[1] Includes capitalized expenditures of $15 million and $13 million for the three months ended June 30, 2024 and 2023, respectively, and $27 million and $29 million for the six months ended June 30, 2024 and 2023, respectively.
v3.24.2.u1
Affiliated and Related Party Transactions (Schedule of Affiliated Transactions - Income Statement) (Parenthetical) (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
DES        
Related Party Transaction [Line Items]        
Capitalized expenditures $ 15 $ 13 $ 27 $ 29
v3.24.2.u1
Affiliated and Related Party Transactions (Schedule of Affiliated Transactions - Balance Sheet) (Detail) - USD ($)
$ in Millions
Jun. 30, 2024
Dec. 31, 2023
Related Party Transaction [Line Items]    
Affiliated and related party payables and other $ 128 $ 166
Derivative assets with affiliates [1] 47 33
DES | Related Party    
Related Party Transaction [Line Items]    
Affiliated and related party payables and other 20 18
SCANA Corporation | Related Party    
Related Party Transaction [Line Items]    
Affiliated and related party payables and other 7 7
Public Service Company Of North Carolina Incorporated | Related Party    
Related Party Transaction [Line Items]    
Affiliated and related party payables and other $ 9 $ 13
[1] Includes amounts recorded in other current assets of $3 million and $2 million as of June 30, 2024 and December 31, 2023, respectively, and amounts recorded in other deferred debits and other assets of $44 million and $31 million as of June 30, 2024 and December 31, 2023, respectively.
v3.24.2.u1
Affiliated and Related Party Transactions (Schedule of Affiliated Transactions - Balance Sheet) (Parenthetical) (Detail) - USD ($)
$ in Millions
Jun. 30, 2024
Dec. 31, 2023
Related Party Transaction [Line Items]    
Derivative assets with affiliates [1] $ 47 $ 33
Other Current Assets [Member]    
Related Party Transaction [Line Items]    
Derivative assets with affiliates 3 2
Other Deferred Debits and Other Assets [Member]    
Related Party Transaction [Line Items]    
Derivative assets with affiliates $ 44 $ 31
[1] Includes amounts recorded in other current assets of $3 million and $2 million as of June 30, 2024 and December 31, 2023, respectively, and amounts recorded in other deferred debits and other assets of $44 million and $31 million as of June 30, 2024 and December 31, 2023, respectively.
v3.24.2.u1
Other Income (Expense), Net (Components of Other Income (Expense), Net) (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Income Statement [Abstract]        
Other income $ 1 $ 1 $ 3 $ 3
Gains on sales of assets [1] 1 22 2 32
Other expense (4) (5) (9) (7)
Allowance for equity funds used during construction 3 0 6 0
Other income (expense), net $ 1 $ 18 $ 2 $ 28
[1] Includes amounts recognized in 2023 in connection with the transfer of property to satisfy litigation. See Note 10 for additional information.

In the second quarter of 2023, DESC completed the sale of certain utility property in South Carolina, as approved by the South Carolina Commission in February 2023, for total cash consideration of $11 million. In connection with the sale, DESC recognized a gain of $11 million ($8 million after-tax) for the three and six months ended June 30, 2023.
v3.24.2.u1
Other Income (Expense), Net (Additional Information) (Details)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2023
USD ($)
Jun. 30, 2023
USD ($)
Total cash consideration $ 11 $ 11
Corporate and Other    
Gain on sale of assets 11 11
Gain on sale of assets, after tax $ 8 $ 8