DOMINION ENERGY SOUTH CAROLINA, INC., 10-K filed on 2/25/2021
Annual Report
v3.20.4
Document and Entity Information - shares
 12 Months Ended
Dec. 31, 2020
Feb. 12, 2021
Cover [Abstract]    
Document Type 10-K  
Amendment Flag false  
Document Period End Date Dec. 31, 2020  
Document Fiscal Year Focus 2020  
Document Fiscal Period Focus FY  
Title of 12(g) Security Series A Nonvoting Preferred Shares  
Document Annual Report true  
Document Transition Report false  
Entity Interactive Data Current Yes  
Entity Incorporation, State or Country Code SC  
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  
Entity Small Business false  
Entity Emerging Growth Company 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 400 OTARRE PARKWAY  
Entity Address, City or Town CAYCE  
Entity Address, State or Province SC  
Entity Address, Postal Zip Code 29033  
City Area Code 803  
Local Phone Number 217-9000  
Entity Well-known Seasoned Issuer No  
Entity Voluntary Filers No  
ICFR Auditor Attestation Flag false  
v3.20.4
Consolidated Balance Sheets - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
ASSETS    
Utility plant in service $ 13,680 $ 13,208
Accumulated depreciation and amortization (5,027) (4,851)
Construction work in progress 460 339
Nuclear fuel, net of accumulated amortization 221 219
Utility plant, net 9,334 8,915
Nonutility Property and Investments:    
Nonutility property, net of accumulated depreciation 39 69
Assets held in trust, nuclear decommissioning 238 214
Nonutility property and investments, net 277 283
Current Assets:    
Cash and cash equivalents 5 4
Receivables, customer, net of allowance for uncollectible accounts 365 320
Receivables, affiliated and related party 16 14
Receivables, other 64 119
Inventories (at average cost):    
Fuel 82 104
Materials and supplies 176 168
Prepayments 75 91
Regulatory assets 229 271
Other current assets 27 27
Total current assets 1,039 1,118
Deferred Debits and Other Assets:    
Regulatory assets 3,726 3,892
Other 103 93
Total deferred debits and other assets 3,829 3,985
Total assets 14,479 14,301
CAPITALIZATION AND LIABILITIES    
Common Stock - no par value 4,017 3,695
Retained earnings 277 20
Accumulated other comprehensive income (loss) (2) (3)
Total common equity 4,292 3,712
Noncontrolling interest 192 180
Total Equity 4,484 3,892
Long-term debt, net 3,327 3,358
Affiliated long-term debt 230 230
Finance leases 15 20
Total long-term debt 3,572 3,608
Total capitalization 8,056 7,500
Current Liabilities:    
Securities due within one year 39 7
Accounts payable 178 245
Affiliated and related party payables 457 624
Customer deposits and customer prepayments 70 76
Taxes accrued 215 218
Interest accrued 95 88
Regulatory liabilities 283 256
Reserves for litigation and regulatory proceedings 208 492
Other 40 60
Total current liabilities 1,585 2,066
Deferred Credits and Other Liabilities:    
Deferred income taxes and investment tax credits 858 629
Asset retirement obligations 597 489
Pension and other postretirement benefits 172 203
Regulatory liabilities 3,005 3,210
Affiliated liabilities 13 15
Other 193 189
Total deferred credits and other liabilities 4,838 4,735
Commitments and Contingencies
Total capitalization and liabilities $ 14,479 $ 14,301
v3.20.4
Consolidated Balance Sheets (Parenthetical) - USD ($)
shares in Millions, $ in Millions
Dec. 31, 2020
Dec. 31, 2019
Utility plant, net $ 9,334 $ 8,915
Receivables, customer, allowance for uncollectible accounts 10 3
Total current assets 1,039 1,118
Total deferred debits and other assets $ 3,829 $ 3,985
Common stock, par value $ 0 $ 0
Common stock, shares outstanding 40.3 40.3
Variable Interest Entity, Primary Beneficiary [Member]    
Utility plant, net $ 730 $ 727
Total current assets 103 143
Total deferred debits and other assets $ 35 $ 32
v3.20.4
Consolidated Statements of Comprehensive Income (Loss) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Income Statement [Abstract]      
Operating Revenue [1] $ 2,739 $ 1,929 $ 2,762
Operating Expenses:      
Fuel used in electric generation [1] 447 573 671
Purchased power [1] 86 54 92
Gas purchased for resale [1] 181 216 239
Other operations and maintenance 357 388 449
Other operations and maintenance – affiliated suppliers 213 244 182
Impairment of assets and other charges 111 695 1,376
Depreciation and amortization 474 450 327
Other taxes [1] 239 250 257
Total operating expenses 2,108 2,870 3,593
Operating income (loss) 631 (941) (831)
Other income (expense), net (23) (33) 129
Interest charges, net of allowance for funds used during construction [1] 229 260 303
Income (loss) before income tax expense (benefit) 379 (1,234) (1,005)
Income tax expense (benefit) 71 (12) (416)
Net Income (Loss) 308 (1,222) (589)
Other Comprehensive Income:      
Deferred cost of employee benefit plans, net of tax 1 1 1
Total Comprehensive Income (Loss) 309 (1,221) (588)
Comprehensive Income Attributable to Noncontrolling Interest 12 18 25
Comprehensive Income (Loss) Available (Attributable) to Common Shareholder $ 297 $ (1,239) $ (613)
[1] See Note 16 for amounts attributable to affiliates.
v3.20.4
Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Income Statement [Abstract]      
Allowance for funds used during construction $ 5 $ 5 $ 9
Deferred cost of employee benefit plans, tax $ 0 $ 0 $ 0
v3.20.4
Consolidated Statements of Cash Flows - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Operating Activities      
Net income (loss) $ 308 $ (1,222) $ (589)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:      
Impairment of assets and other charges (14) 576 1,376
Provision for refunds to electric customers 0 800 0
Gain on sale of assets 0 (7) 0
Deferred income taxes, net 229 (379) (184)
Depreciation and amortization 474 464 342
Amortization of nuclear fuel 41 53 47
Other adjustments 14 (7) (17)
Changes in certain assets and liabilities:      
Receivables 3 (33) 50
Receivables – affiliated and related party 4 1 (2)
Income tax receivable 0 0 198
Inventories 14 (76) (54)
Prepayments 15 (9) 0
Regulatory assets 21 (20) (179)
Regulatory liabilities (193) 265 (360)
Accounts payable (19) (54) 61
Accounts payable – affiliated and related party 52 (15) 0
Revenue subject to refund 0 (73) 77
Unrecognized tax benefits 0 52 19
Taxes accrued (3) (10) 31
Pension and other postretirement benefits (31) (27) 15
Other assets and liabilities 97 169 96
Net cash provided by operating activities 1,012 448 927
Investing Activities      
Property additions and construction expenditures (742) (497) (633)
Proceeds from investments and sales of assets (12) 39 40
Purchase of investments 15 (54) (29)
Purchase of investments – affiliate (1) 0 (111)
Proceeds from interest rate derivative contract settlement 0 0 115
Investment in affiliate, net (7) 344 (214)
Net cash used in investing activities (747) (168) (832)
Financing Activities      
Proceeds from issuance of debt 0 0 795
Proceeds from issuance of affiliated debt 0 230 0
Repayment of long-term debt, including redemption premiums 0 (1,890) (825)
Dividend to parent (38) (30) (173)
Short-term borrowings, net 0 (73) (179)
Short-term borrowings – affiliated, net (219) 292 0
Money pool borrowings, net 0 0 245
Contribution from parent 0 838 24
Contribution returned to parent 0 (20) 0
Other (7) 0 0
Net cash used in financing activities (264) (653) (113)
Net increase (decrease) in cash, restricted cash and equivalents 1 (373) (18)
Cash, restricted cash and equivalents at beginning of period [1] 4 377 395
Cash, restricted cash and equivalents at end of period [1] 5 4 377
Supplemental Cash Flow Information      
Cash for interest paid (net of capitalized interest) 176 220 264
Cash for income taxes paid 0 13 3
Cash for income taxes received 220 0 216
Noncash investing and financing activities:      
Accrued construction expenditures [2] 48 120 69
Leases [2],[3] 3 12 8
Contributed capital [2] $ 322 $ 1 $ 6
[1] For the years ended December 31, 2020, 2019 and 2018 there were no restricted cash and equivalent balances.
[2] See Note 2 for noncash investing and financing activities related to the adoption of a new accounting standard for leasing arrangements. See Note 5 for noncash financing activities related to the capital contribution associated with the settlement of litigation. See Note 12 for noncash investing activities related to the property, plant and equipment conveyed to satisfy litigation.
[3] Includes $3 million and $4 million of financing leases for the years ended December 31, 2020 and 2019, respectively, $8 million of operating leases for the year ended December 31, 2019 and $8 million of capital leases for the year ended December 31, 2018.
v3.20.4
Consolidated Statements of Cash Flows (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Statement Of Cash Flows [Abstract]      
Cash paid for interest, capitalized interest $ 5 $ 5 $ 9
Restricted cash and equivalents 0 0 0
Financing leases $ 3 4  
Operating leases   $ 8  
Capital leases     $ 8
v3.20.4
Consolidated Statements of Changes in Common Equity - USD ($)
shares in Millions, $ in Millions
Total
Common Stock
Retained Earnings
Retained Earnings
Cumulative Effect, Period of Adoption, Adjustment
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss)
Cumulative Effect, Period of Adoption, Adjustment
Noncontrolling Interest
Beginning balance at Dec. 31, 2017 $ 4,980 $ 2,860 $ 1,982   $ (4)   $ 142
Beginning balance (in shares) at Dec. 31, 2017   40          
Total comprehensive income (loss) available (attributable) to common shareholder (588)   (614)   1   25
Capital contribution from parent 24           24
Dividend to parent (101)   (89)       (12)
Ending balance at Dec. 31, 2018 4,315 $ 2,860 1,279 $ 1 (3) $ (1) 179
Ending balance (in shares) at Dec. 31, 2018   40          
Total comprehensive income (loss) available (attributable) to common shareholder (1,221)   (1,240)   1   18
Capital contribution from parent 838 $ 835         3
Capital contribution returned to parent (20)           (20)
Dividend to parent (20)   (20)        
Ending balance at Dec. 31, 2019 3,892 $ 3,695 20   (3)   180
Ending balance (in shares) at Dec. 31, 2019   40          
Total comprehensive income (loss) available (attributable) to common shareholder 308   295   1   12
Capital contribution from parent 322 $ 322          
Dividend to parent (38)   (38)        
Ending balance at Dec. 31, 2020 $ 4,484 $ 4,017 $ 277   $ (2)   $ 192
Ending balance (in shares) at Dec. 31, 2020   40          
v3.20.4
Nature of Operations
 12 Months Ended
Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]  
Nature of Operations

1.  NATURE OF OPERATIONS

DESC is a wholly-owned subsidiary of SCANA which, effective January 2019, is a wholly-owned subsidiary of Dominion Energy.

DESC is engaged in the generation, transmission and distribution of electricity in the central, southern and southwestern portions of South Carolina. Additionally, DESC distributes natural gas to residential, commercial and industrial customers in South Carolina.

Beginning in December 2019, DESC manages its daily operations through one primary operating segment: Dominion Energy South Carolina. It also reports a Corporate and Other segment that primarily includes specific items attributable to its operating segment that are not included in profit measures evaluated by executive management in assessing the segment’s performance or in allocating resources.
v3.20.4
Summary of Significant Accounting Policies
 12 Months Ended
Dec. 31, 2020
Accounting Policies [Abstract]  
Summary of Significant Accounting Policies

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

General

DESC makes certain estimates and assumptions in preparing its Consolidated Financial Statements in accordance with GAAP. These estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the dates of the financial statements and the reported amounts of revenues, expenses and cash flows for the periods presented. Actual results may differ from those estimates.

DESC’s Consolidated Financial Statements include, after eliminating intercompany balances and transactions, the accounts of DESC, GENCO and Fuel Company. DESC has concluded that GENCO and Fuel Company are VIEs due to the members lacking the characteristics of a controlling financial interest. DESC is the primary beneficiary of GENCO and Fuel Company and therefore is required to consolidate the VIEs. The equity interests in GENCO and Fuel Company are held solely by SCANA, DESC’s parent. As a result, GENCO and Fuel Company’s equity and results of operations are reflected as noncontrolling interest in the Consolidated Financial Statements.

GENCO owns a coal-fired electric generating station with a 605 MW net generating capacity (summer rating). GENCO’s electricity is sold exclusively to DESC, pursuant to a FERC approved power purchase agreement and related operating agreement. The effects of these transactions are eliminated in consolidation. Fuel Company acquires, owns and provides financing for DESC's nuclear fuel, certain fossil fuels and emission and other environmental allowances. See also Note 6.

Additionally, effective January 2021, 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 had previously purchased such services from DESS, an affiliated VIE, that had provided such services to all SCANA subsidiaries. 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 16 for amounts attributable to affiliates.

DESC reports certain contracts and instruments at fair value. See Note 9 for further information on fair value measurements.

DESC maintains pension and other postretirement benefit plans. See Note 11 for further information on these plans.

Certain amounts in the 2019 and 2018 Consolidated Financial Statements and Notes have been reclassified to conform to the 2020 presentation for comparative purposes; however, such reclassifications did not affect DESC’s net income, total assets, liabilities, equity or cash flows.

Utility Plant

Utility plant is stated at original cost. The costs of additions, replacements and betterments to utility plant, including direct labor, material and indirect charges for engineering, supervision and AFUDC, are added to utility plant accounts. The original cost of utility property retired or otherwise disposed of is removed from utility plant accounts and generally charged to accumulated depreciation. The costs of repairs and replacements of items of property determined to be less than a unit of property or that do not increase the asset’s life or functionality are charged to expense.

AFUDC is a noncash item that reflects the period cost of capital devoted to plant under construction. This accounting practice results in the inclusion of, as a component of construction cost, the costs of debt and equity capital dedicated to construction investment. AFUDC is included in rate base investment and depreciated as a component of plant cost in establishing rates for utility services. DESC calculated AFUDC using average composite rates of 2.6%, 4.3% and 7.0% for 2020, 2019 and 2018, respectively. These rates do not exceed the maximum rates allowed in the various regulatory jurisdictions. DESC capitalizes interest on nuclear fuel in process at the actual interest cost incurred.

For property subject to cost-of-service rate regulation that will be abandoned significantly before the end of its useful life, the net carrying value is reclassified from utility plant-in-service when it becomes probable it will be abandoned and recorded as a regulatory asset for amounts expected to be collected through future rates.

Provisions for depreciation and amortization are recorded using the straight-line method based on the estimated service lives of the various classes of property, and in most cases, include provisions for future cost of removal. The composite weighted average depreciation rates for utility plant by function were as follows:

 

 

 

2020

 

 

2019

 

Generation

 

 

2.50

%

 

 

2.50

%

Transmission

 

 

2.56

%

 

 

2.57

%

Distribution

 

 

2.42

%

 

 

2.41

%

Storage

 

 

2.75

%

 

 

2.74

%

General and other

 

 

3.17

%

 

 

3.22

%

 

DESC records nuclear fuel amortization using the units-of-production method, which is included in fuel used in electric generation and recovered through the fuel cost component of retail electric rates.

Major Maintenance

Planned major maintenance costs related to certain fossil fuel turbine generator equipment and nuclear refueling outages are accrued in periods other than when incurred in accordance with approval by the South Carolina Commission for such accounting treatment and rate recovery of expenses accrued thereunder. The difference between such cumulative major maintenance costs and cumulative collections is classified as a regulatory asset or regulatory liability on the consolidated balance sheet. Other planned major maintenance is expensed when incurred.

DESC is authorized to collect $18 million annually through electric rates to offset certain turbine generator maintenance expenditures. For the years ended December 31, 2020 and 2019, DESC incurred $19 million and $10 million, respectively, for turbine generator maintenance.

Nuclear refueling outages are scheduled 18 months apart. As approved by the South Carolina Commission, DESC accrues $17 million annually for its portion of the nuclear refueling outages, of which DESC accrued $8 million for outages scheduled from the spring of 2014 through the spring of 2020 and $9 million for outages scheduled from the fall of 2021 through the fall of 2027. Refueling outage costs incurred for which DESC was responsible totaled $23 million in 2020 and $2 million in 2019.

Asset Retirement Obligations

DESC recognizes AROs at fair value as incurred or when sufficient information becomes available to determine a reasonable estimate of the fair value of future retirement activities to be performed, for which a legal obligation exists. These amounts are generally capitalized as costs of the related tangible long-lived assets. Since relevant market information is not available, fair value is estimated using discounted cash flow analyses. Periodically, DESC assesses its AROs to determine if circumstances indicate that estimates of the amounts or timing of future cash flows associated with retirement activities have changed. AROs are adjusted when significant changes in the amounts or timing of future cash flows are identified. DESC reports accretion of AROs and depreciation on asset retirement costs as an adjustment to regulatory assets.

Nuclear Decommissioning

Based on a decommissioning cost study completed in 2020, DESC’s two-thirds share of estimated site-specific nuclear decommissioning costs for Summer, including the cost of decommissioning plant components both subject to and not subject to radioactive contamination, totals $744 million, stated in 2020 dollars. Santee Cooper is responsible for decommissioning costs related to its one-third ownership interest in Summer. The cost estimate assumes that the site will be maintained over a period of approximately 60 years in such a manner as to allow for subsequent decontamination that would permit release for unrestricted use.

Under DESC’s method of funding decommissioning costs, DESC transfers to an external trust fund the amounts collected through rates ($3 million in each period presented), less expenses. The trust invests the amounts transferred into insurance policies on the lives of certain company personnel. Insurance proceeds are reinvested in insurance policies. The asset balance held in trust reflects the net cash surrender value of the insurance policies and cash held by the trust. Management intends for the fund, including earnings thereon, to provide for all eventual decommissioning expenditures for Summer on an after-tax basis.

Cash, Restricted Cash and Equivalents

Cash, restricted cash and equivalents include cash on hand, cash in banks and temporary investments purchased with an original maturity of three months or less. At both December 31, 2020 and 2019, there were no restricted cash and equivalent balances.

Receivables

Customer receivables reflect amounts due from customers arising from the delivery of energy or related services and include both billed and unbilled amounts earned pursuant to revenue recognition practices described in Note 4. Customer receivables are generally due within one month of receipt of invoices which are presented on a monthly cycle basis. Unbilled revenues totaled $156 million and $114 million at December 31, 2020 and 2019, respectively.

 

DESC sells electricity and natural gas and provides distribution and transmission services to customers in South Carolina. Management believes that this geographic concentration risk is mitigated by the diversity of DESC’s customer base, which includes a large number of residential, commercial and industrial customers. Credit risk associated with accounts receivable is limited due to the large number of customers. DESC’s exposure to potential concentrations of credit risk results primarily from amounts due from Santee Cooper related to the jointly owned nuclear generating facilities at Summer. Such receivables represented approximately 6% of DESC’s accounts receivable balance at December 31, 2020.

Inventories

Materials and supplies include the average cost of transmission, distribution, and generating plant materials. Materials are charged to inventory when purchased and then expensed or capitalized to plant, as appropriate, at weighted average cost when used. Fuel inventory includes the average cost of coal, natural gas, fuel oil and emission allowances. Fuel is charged to inventory when purchased and is expensed, at weighted average cost, as used and recovered through fuel cost recovery rates approved by the South Carolina Commission.

Income Taxes

A consolidated federal income tax return was filed for SCANA, including DESC for years through 2018. Beginning in 2019, SCANA and DESC are part of Dominion Energy’s consolidated federal income tax return. In addition, where applicable, combined income tax returns for Dominion Energy, including DESC, are filed in various states including South Carolina; otherwise, separate state income tax returns are filed.

DESC participated in intercompany tax sharing agreements with SCANA through the SCANA Combination, and currently participates in similar agreements with Dominion Energy. Under both SCANA and Dominion Energy’s tax sharing agreements, current income taxes are based on taxable income or loss and credits determined on a separate company basis.

Under the agreements, if a subsidiary incurs a tax loss or earns a credit, recognition of current income tax benefits is limited to refunds of prior year taxes obtained by the carryback of the net operating loss or credit or to the extent the tax loss or credit is absorbed by the taxable income of other SCANA or Dominion Energy consolidated group members. Otherwise, the net operating loss or credit is carried forward and is recognized as a deferred tax asset until realized.

Accounting for income taxes involves an asset and liability approach. Deferred income tax assets and liabilities are provided, representing future effects on income taxes for temporary differences between the bases of assets and liabilities for financial reporting and tax purposes. Accordingly, deferred taxes are recognized for the future consequences of different treatments used for the reporting of transactions in financial accounting and income tax returns. DESC establishes a valuation allowance when it is more-likely-than-not that all, or a portion, of a deferred tax asset will not be realized. DESC did not have any valuation allowances recorded for the periods presented. Where the treatment of temporary differences is different for rate-regulated operations, a regulatory asset is recognized if it is probable that future revenues will be provided for the payment of deferred tax liabilities.

DESC recognizes positions taken, or expected to be taken, in income tax returns that are more-likely-than-not to be realized, assuming that the position will be examined by tax authorities with full knowledge of all relevant information. At December 31, 2020, DESC had $138 million of unrecognized tax benefits.

If it is not more-likely-than-not that a tax position, or some portion thereof, will be sustained, the related tax benefits are not recognized in the financial statements. Unrecognized tax benefits may result in an increase in income taxes payable, a reduction of income tax refunds receivable or changes in deferred taxes. Also, when uncertainty about the deductibility of an amount is limited to the timing of such deductibility, the increase in income taxes payable (or reduction in tax refunds receivable) is accompanied by a decrease in deferred tax liabilities. Except when such amounts are presented net with amounts receivable from or amounts prepaid to tax authorities, noncurrent income taxes payable related to unrecognized tax benefits are classified in other deferred credits and other liabilities on the Consolidated Balance Sheets and current payables are included in taxes accrued on the Consolidated Balance Sheets.

 

DESC recognizes interest on underpayments and overpayments of income taxes in interest expense and interest income, respectively. Penalties are also recognized in other expenses.

Interest expense for DESC was $7 million, $18 million and $8 million in 2020, 2019, and 2018, respectively. Interest income for DESC was less than $1 million in 2020 and $2 million in both 2019 and 2018. DESC also recorded penalty expenses of $4 million in 2020 and $7 million in 2019.

At December 31, 2020, DESC had an income tax-related affiliated payable of $31 million to Dominion Energy. This balance is expected to be paid to Dominion Energy.

At December 31, 2019, DESC had an income tax-related affiliated receivable of $21 million from Dominion Energy. This balance was received from Dominion Energy in 2020.

At DESC investment tax credits are deferred and amortized over the service lives of the properties giving rise to the credits. Production tax credits are recognized as energy is generated and sold.

Regulatory Assets and Liabilities

The accounting for DESC’s regulated electric and gas operations differs from the accounting for nonregulated operations in that DESC is required to reflect the effect of rate regulation in its Consolidated Financial Statements. For regulated businesses subject to federal or state cost-of-service rate regulation, regulatory practices that assign costs to accounting periods may differ from accounting methods generally applied by nonregulated companies. When it is probable that regulators will permit the recovery of current costs through future rates charged to customers, these costs that otherwise would be expensed by nonregulated companies are deferred as regulatory assets. Likewise, regulatory liabilities are recognized when it is probable that regulators will require customer refunds through future rates or when revenue is collected from customers for expenditures that have yet to be incurred.

 

DESC evaluates whether or not recovery of its regulatory assets through future rates is probable as well as whether a regulatory liability due to customers is probable and makes various assumptions in its analyses. These analyses are generally based on:

 

 

•

Orders issued by regulatory commissions, legislation and judicial actions;

 

•

Past experience;

 

•

Discussions with applicable regulatory authorities and legal counsel;

 

•

Forecasted earnings; and

 

•

Considerations around the likelihood of impacts from events such as unusual weather conditions, extreme weather events and other natural disasters and unplanned outages of facilities.

 

Generally, regulatory assets and liabilities are amortized into income over the period authorized by the regulator. If recovery of a regulatory asset is determined to be less than probable, it will be written off in the period such assessment is made. A regulatory liability, if considered probable, will be recorded in the period such assessment is made or reversed into earnings if no longer probable. See Note 3 to the Consolidated Financial Statements for additional information.

Derivative Instruments

DESC uses derivative instruments such as swaps to manage interest rate risks of its business operations. Derivatives are required to be reported in the Consolidated Balance Sheets at fair value. Derivative contracts representing unrealized gain positions are reported as derivative assets. Derivative contracts representing unrealized losses are reported as derivative liabilities.

 

DESC does not offset amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral against amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement. DESC had margin assets of $17 million and $19 million associated with cash collateral at December 31, 2020 and 2019, respectively. DESC had no margin liabilities associated with cash collateral at December 31, 2020 and 2019. See Note 8 for further information about derivatives.

 

Changes in the fair value of derivative instruments result in the recognition of regulatory assets or regulatory liabilities. Realized gains or losses on the derivative instruments are generally recognized when the related transactions impact earnings. All income statement activity, including amounts realized upon settlement, is presented in interest charges based on the nature of the underlying risk.

 

DERIVATIVE INSTRUMENTS DESIGNATED AS HEDGING INSTRUMENTS

In accordance with accounting guidance pertaining to derivatives and hedge accounting, DESC designates a portion of their derivative instruments as cash flow hedges for accounting purposes. For derivative instruments that are accounted for as cash flow hedges, the cash flows from the derivatives and from the related hedged items are classified in operating cash flows.

 

Cash Flow Hedges- DESC uses interest rate swaps to hedge its exposure to variable interest rates on long-term debt. For transactions in which DESC is hedging the variability of cash flows, changes in the fair value of the derivatives are reported in regulatory assets or liabilities. Any derivative gains or losses reported in regulatory assets or liabilities are reclassified to earnings when the forecasted item is included in earnings. For cash flow hedge transactions, hedge accounting is discontinued if the occurrence of the forecasted transaction is no longer probable.

Pursuant to regulatory orders, interest rate derivatives entered into by DESC after October 2013 were not designated for accounting purposes as cash flow hedges, and fair value changes and settlement amounts related to them have been recorded as regulatory assets and liabilities. Settlement losses on swaps generally have been amortized over the lives of subsequent debt issuances, and gains have been amortized to interest charges or have been applied as otherwise directed by the South Carolina Commission. See Note 17 regarding the settlement gains realized in the first quarter of 2018.

Debt Issuance Costs

DESC defers and amortizes debt issuance costs and debt premiums or discounts over the expected lives of the respective debt issues, considering maturity dates and, if applicable, redemption rights held by others. Deferred debt issuance costs are recorded as a reduction in long-term debt in the Consolidated Balance Sheets. Amortization of the issuance costs is reported as interest charges. As permitted by regulatory authorities, gains or losses resulting from the refinancing or redemption of debt are deferred and amortized.

Environmental

An environmental assessment program is maintained to identify and evaluate current and former operations sites that could require environmental clean-up. As site assessments are initiated, estimates are made of the amount of expenditures, if any, deemed necessary to investigate and remediate each site. Environmental remediation liabilities are accrued when the criteria for loss contingencies are met. These estimates are refined as additional information becomes available; therefore, actual expenditures could differ significantly from the original estimates. Probable and estimable costs are accrued related to environmental sites on an undiscounted basis. Amounts estimated and accrued to date for site assessments and clean-up relate solely to regulated operations. Amounts expected to be recovered through rates are recorded in regulatory assets and, if applicable, amortized over approved amortization periods. Other environmental costs are expensed as incurred.

Statement of Operations Presentation

Revenues and expenses arising from regulated businesses are presented within Operating Income (Loss), and all other activities are presented within Other Income (Expense), net.

Operating Revenue

Operating revenue is recorded on the basis of services rendered, commodities delivered, or contracts settled and includes amounts yet to be billed to customers. DESC collects sales, consumption, consumer utility taxes and sales taxes; however, these amounts are excluded from revenue and are recorded as liabilities until they are remitted to the respective taxing authority.

The primary types of sales and service activities reported as operating revenue for DESC, subsequent to the adoption of revised guidance for revenue recognition from contracts with customers, are as follows:

Revenue from Contracts with Customers

 

•

Regulated electric sales consist primarily of state-regulated retail electric sales, and federally-regulated wholesale electric sales and electric transmission services;

 

•

Regulated gas sales consist primarily of state-regulated natural gas sales and related distribution services; and

 

•

Other regulated revenue consists primarily of miscellaneous service revenue from electric and gas distribution operations and sales of excess electric capacity and other commodities.

Other Revenue

 

•

Other revenue consists primarily of alternative revenue programs, gains and losses from derivative instruments not subject to hedge accounting and lease revenues.

 

DESC records refunds to customers as required by the South Carolina Commission as a reduction to regulated electric sales or regulated gas sales, as applicable. Revenues from electric and gas sales are recognized over time, as the customers of DESC consume gas and electricity as it is delivered. Sales of products and services typically transfer control and are recognized as revenue upon delivery of the product or service. The customer is able to direct the use of, and obtain substantially all of the benefits from, the product at the time the product is delivered. The contract with the customer states the final terms of the sale, including the description, quantity and price of each product or service purchased. Payment for most sales and services varies by contract type, but is typically due within a month of billing.

 

DESC customers subject to an electric fuel cost recovery component or a PGA are billed based on a fuel or cost of gas factor calculated in accordance with cost recovery procedures approved by the South Carolina Commission and subject to adjustment periodically. Any difference between actual costs and amounts contained in rates is adjusted through revenue and is deferred and included when making the next adjustment to the cost recovery factors.

 

Certain amounts deferred for the WNA arise under specific arrangements with regulators rather than customers and are accounted for as an alternative revenue program. This alternative revenue is included within Other operating revenues, separate from revenue arising from contracts with customers, in the month such adjustments are deferred within regulatory accounts. As permitted, DESC has elected to reduce the regulatory accounts in the period when such amounts are reflected on customer bills without affecting operating revenues.

Performance obligations which have not been satisfied by DESC relate primarily to demand or standby service for natural gas. Demand or standby charges for natural gas arise when an industrial customer reserves capacity on assets controlled by the service provider and may use that capacity to move natural gas it has acquired from other suppliers. For all periods presented, the amount of

revenue recognized by DESC for these charges is equal to the amount of consideration DESC has a right to invoice and corresponds directly to the value transferred to the customer.

Leases

DESC leases certain assets including vehicles, real estate, office equipment and other assets under both operating and finance leases. For operating leases, rent expense is recognized on a straight-line basis over the term of the lease agreement, subject to regulatory framework. Rent expense associated with operating leases, short-term leases and variable leases is primarily recorded in other operations and maintenance expense in the Consolidated Statements of Comprehensive Income (Loss). Rent expense associated with finance leases results in the separate presentation of interest expense on the lease liability and amortization expense of the related right-of-use asset in the Consolidated Statements of Comprehensive Income (Loss). Amortization expense and interest charges associated with finance leases are recorded in depreciation and amortization and interest charges, respectively, in the Consolidated Statements of Comprehensive Income (Loss) or deferred within regulatory assets in the Consolidated Balance Sheets.

Certain leases include one or more options to renew, with renewal terms that can extend the lease from one to 70 years. The exercise of renewal options is solely at DESC's discretion and is included in the lease term if the option is reasonably certain to be exercised. A right-of-use asset and corresponding lease liability for leases with original lease terms of one year or less are not included in the Consolidated Balance Sheets, unless such leases contain renewal options that DESC is reasonably certain will be exercised.

The determination of the discount rate utilized has a significant impact on the calculation of the present value of the lease liability included in the Consolidated Balance Sheets. For DESC’s leased assets, the discount rate implicit in the lease is generally unable to be determined from a lessee perspective. As such, DESC uses internally-developed incremental borrowing rates as a discount rate in the calculation of the present value of the lease liability. The incremental borrowing rates are determined based on an analysis of DESC's publicly available secured borrowing rates over various lengths of time that most closely corresponds to DESC's lease maturities.

New Accounting Standards

REVENUE RECOGNITION

In May 2014, the FASB issued revised accounting guidance for revenue recognition from contracts with customers. DESC adopted this revised accounting guidance for interim and annual reporting periods beginning January 1, 2018 using the modified retrospective method. No cumulative effect adjustment was recognized upon adoption. For additional required disclosures, see Note 4.

LEASES

In February 2016, the FASB issued revised accounting guidance for the recognition, measurement, presentation and disclosure of leasing arrangements. The update requires that a liability and corresponding right-of-use asset are recorded on the balance sheet for all leases, including those leases classified as operating leases, while also refining the definition of a lease. In addition, lessees will be required to disclose key information about the amount, timing, and uncertainty of cash flows arising from leasing arrangements. Lessor accounting remains largely unchanged.

The guidance became effective for DESC's interim and annual reporting periods beginning January 1, 2019. DESC adopted this revised accounting guidance using a modified retrospective approach, which requires lessees and lessors to recognize and measure leases at the date of adoption. Under this approach, DESC utilized the transition practical expedient to maintain historical presentation for periods before January 1, 2019. DESC also applied the other practical expedients, which required no reassessment of whether existing contracts are or contain leases, no reassessment of lease classification for existing leases and no evaluation of existing or expired land easements that were not previously accounted for as leases. In connection with the adoption of this revised accounting guidance, DESC recorded $19 million of offsetting right-of-use assets and liabilities for operating leases in effect at the adoption date. See Note 13 for additional information.

 

TAX REFORM

In February 2018, the FASB issued revised accounting guidance to provide clarification on the application of the 2017 Tax Reform Act for balances recorded within AOCI. The revised guidance provides for stranded amounts within AOCI from the impacts of the 2017 Tax Reform Act to be reclassified to retained earnings. DESC adopted this guidance for interim and annual reporting periods beginning January 1, 2019 on a prospective basis. In connection with the adoption of this guidance, DESC reclassified a benefit of $1 million from AOCI to retained earnings. The amounts reclassified reflect the reduction in the federal income tax rate, and the federal benefit of state income taxes, on the components of DESC’s AOCI.
v3.20.4
Rate and Other Regulatory Matters
 12 Months Ended
Dec. 31, 2020
Regulated Operations [Abstract]  
Rate and Other Regulatory Matters

3.  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.

FERC

In June 2019, DESC submitted the 2015 Task Order as a stand-alone rate schedule, which governs DESC’s provision of retail service to the DOE at the Savannah River Site. The 2015 Task Order also includes provisions that govern the operations and maintenance of certain transmission facilities, which DESC had determined to be services that are likely subject to FERC’s jurisdiction. DESC requested that FERC accept the 2015 Task Order for filing to become effective in August 2019 and accept the refund analysis included in the filing for amounts collected under the 2015 Task Order as well as under two prior task orders commencing in 1995 and each covering ten-year periods. During the second quarter of 2019, DESC recorded a $6 million ($4 million after-tax) charge primarily within interest charges in DESC’s Consolidated Statements of Comprehensive Income (Loss). In August 2019, DESC submitted a motion to withdraw the 2015 Task Order filing and related refund analysis as requested by FERC staff. As a result, DESC recorded a $10 million ($7 million after-tax) benefit, primarily within interest charges in DESC’s Consolidated Statements of Comprehensive Income (Loss) during the third quarter of 2019, to remove previously recorded reserves.

2017 Tax Reform Act

The 2017 Tax Reform Act lowered the federal corporate tax rate from 35% to 21% effective January 1, 2018. In response, the South Carolina Commission has required DESC to track and defer impacts related to the 2017 Tax Reform Act arising from customer rates in 2018 as subject to refund. In addition, as further discussed under Regulatory Assets and Regulatory Liabilities below, certain accumulated deferred income taxes contained within regulatory liabilities represent excess deferred income taxes arising from the remeasurement of deferred income taxes upon the enactment of the 2017 Tax Reform Act. Certain of these amounts are protected under normalization rules and will be amortized at the weighted average tax rate used to build the reserves over the remaining regulatory life of the property. Other, non-plant related regulatory liabilities will be amortized to the benefit of customers, as instructed by our regulators.

As part of the SCANA Combination, the South Carolina Commission approved credits of approximately $100 million by DESC for the impact of the lower federal tax rate resulting from the 2017 Tax Reform Act. The credits included amounts which had been collected through customer rates in 2018 and January 2019 and also included the effects of the amortization of certain excess deferred taxes during the same period. These credits were included in bills rendered on and after the first billing cycle of February 2019. In addition, the South Carolina Commission approved the implementation of a tax rider whereby amounts collected though customer rates effectively would be reduced and excess deferred income taxes arising from the remeasurement of deferred income taxes upon the enactment of the 2017 Tax Reform Act will be amortized to the benefit of customers. This tax rider reduced base rates to customers by $66 million in 2020 and $63 million in 2019. Unamortized excess deferred income taxes that remained at the end of 2020 will be considered in future rate proceedings.

DESC’s provision of electric transmission service is pursuant to a FERC approved formula rate. In December 2019, FERC issued an order requiring transmission providers with transmission formula rates to account for the impacts of the 2017 Tax Reform Act on rates charged to customers. The order requires companies to include a mechanism to decrease or increase their income tax allowances to account for the 2017 Tax Reform Act and any other future changes in tax law, and to submit annual information reflecting the amortization of these excess deferred income taxes. DESC submitted a proposed update to its formula rate to FERC in May 2020. This matter is pending.

In January 2020, GENCO filed to modify its formula rate to incorporate a mechanism to decrease or increase its income tax allowances by any excess deferred income taxes resulting from the 2017 Tax Reform Act, and future changes in tax laws. These modifications are expected to decrease charges to DESC for the power it purchases from GENCO. In April 2020, the FERC approved GENCO’s request.

 

Electric – BLRA

In July 2018, the South Carolina Commission issued orders implementing a legislatively-mandated temporary reduction in revenues that could be collected by DESC from customers under the BLRA. These orders reduced the portion of DESC’s retail electric rates associated with the NND Project from approximately 18% of the average residential electric customer's bill to approximately 3%, which equates to a reduction in revenues of approximately $31 million per month, retroactive to April 1, 2018. As a result, in 2018 DESC recorded a charge of $109 million ($82 million after-tax) to operating revenues in DESC’s Consolidated Statements of Comprehensive Income (Loss). The temporary rate reduction remained in effect until February 2019 when rates pursuant to the SCANA Merger Approval Order became effective.

 

Other Regulatory Matters

South Carolina Electric Base Rate Case

In August 2020, DESC filed its retail electric base rate case and schedules with the South Carolina Commission. DESC proposed a non-fuel, base rate increase of $178 million, or 7.75% based on an adjusted test year data, effective on or after the first billing cycle of March 2021. 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 5.90% based upon a fully-adjusted test period. The proposed rates would provide for an earned ROE equal to the current authorized earned ROE of 10.25% established in the previous rate case in 2012.  In January 2021, the South Carolina Commission approved a proposal made by the South Carolina Office of Regulatory Staff, and agreed to by DESC and other intervenors, to stay the base rate case due to the current economic conditions and to allow the parties more time to negotiate a settlement with a final order to be issued no later than August 2021.  In connection with this order, DESC, the South Carolina Office of Regulatory Staff and other parties of record are to provide monthly updates to the South Carolina Commission on the progress towards reaching a negotiated settlement. 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 2020, DESC filed with the South Carolina Commission a proposal to decrease the total fuel cost component of retail electric rates. DESC’s proposed decrease would reduce annual base fuel component recoveries by $44 million and is projected to return to customers the existing over-collected balance while recovering DESC’s current base fuel costs over the 12-month period beginning with the first billing cycle of May 2020. In addition, DESC proposed an increase to its variable environmental and DER components. In April 2020, the South Carolina Commission approved the filing.

In February 2021, DESC filed with the South Carolina Commission a proposal to increase the total fuel cost component of retail electric rates. DESC’s proposed adjustment would increase annual base fuel component recoveries by approximately $36 million and is designed to recover DESC’s current base fuel costs, net of the existing over-collected balance, over the 12-month period beginning with the first billing cycle of May 2021. In addition, DESC proposed a decrease to its variable environmental component and an increase to its distributed energy resource component. This matter is pending.

In April 2018, the South Carolina Commission approved DESC’s proposal to increase the total fuel cost component of retail electric rates. Petitions for rehearing and reconsideration were filed by various parties. In October 2018, the South Carolina Commission issued an order granting one such petition related to DESC supplying certain information as in previous years and denied the other petitions. Certain parties appealed the decision to deny their petitions to the South Carolina Supreme Court. In September 2020, the South Carolina Supreme Court dismissed the appeals.

Electric Transmission Projects

In 2020, DESC began several electric transmission projects in connection with two new nuclear plants under development by Southern. These transmission projects are required to be in place prior to these plants beginning operations to maintain reliability. DESC anticipates the projects to go into service in phases, costing approximately $75 million in aggregate. In February 2020, DESC filed an application with the South Carolina Commission requesting approval to construct and operate 28 miles of 230 kV transmission lines in Aiken County, South Carolina estimated to cost approximately $30 million. In June 2020, the South Carolina Commission approved the filing.

Electric – Other

DESC has approval for a DSM rider through which it recovers expenditures related to its DSM programs. In January 2020, DESC submitted its annual DSM programs filing to the South Carolina Commission seeking approval to recover $40 million of costs and net lost revenues associated with DSM programs, along with an incentive to invest in such programs. In April 2020, the South Carolina Commission approved the filing.

 

In January 2021, DESC filed an application with the South Carolina Commission seeking approval to recover $48 million of costs and net lost revenues associated with these programs, along with an incentive to invest in such programs. This matter is pending.

 

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 2020, DESC requested that the South Carolina Commission approve an adjustment to this rider to decrease annual revenue by $11 million. In April 2020, the South Carolina Commission approved the filing. In February 2021, DESC requested that the South Carolina Commission approve an adjustment to this rider to decrease annual revenue by less than $1 million. This matter is pending.

 

Natural Gas Rates

In June 2020, DESC filed with the South Carolina Commission its monitoring report for the 12-month period ended March 31, 2020 with a total revenue requirement of $409 million. This represents a $9 million overall annual increase to its natural gas rates under the terms of the RSA effective with the first billing cycle of November 2020. In October 2020, the South Carolina Commission approved a total revenue requirement of $406 million effective with the first billing cycle of November 2020. This represents a $6 million overall annual increase to DESC’s natural gas rates. Additionally, the South Carolina Commission authorized an allowed ROE of 9.90%, a reduction from the prior ROE of 10.25%. The South Carolina Commission also approved an agreement between the South Carolina Office of Regulatory Staff and DESC that DESC will file its next retail natural gas general rate proceeding no later than April 2023.

   

DESC's natural gas tariffs include a PGA that provides for the recovery of actual gas costs incurred, including transportation costs. DESC’s gas rates are calculated using a methodology which may adjust the cost of gas monthly based on a 12-month rolling average, and its gas purchasing policies and practices are reviewed annually by the South Carolina Commission.

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 plant costs, 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.

 

At December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Regulatory assets:

 

 

 

 

 

 

 

 

NND Project costs(1)

 

$

138

 

 

 

138

 

Deferred employee benefit plan costs(2)

 

 

9

 

 

 

13

 

Other unrecovered plant(3)

 

 

14

 

 

 

14

 

DSM programs(4)

 

 

29

 

 

 

17

 

AROs(5)

 

 

2

 

 

 

28

 

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

 

 

1

 

 

 

13

 

Other

 

 

36

 

 

 

48

 

Regulatory assets - current

 

 

229

 

 

 

271

 

NND Project costs(1)

 

 

2,364

 

 

 

2,503

 

AROs(5)

 

 

309

 

 

 

293

 

Cost of reacquired debt(7)(8)

 

 

243

 

 

 

259

 

Deferred employee benefit plan costs(2)

 

 

159

 

 

 

196

 

Deferred losses on interest rate derivatives(9)

 

 

308

 

 

 

305

 

Other unrecovered plant(3)

 

 

61

 

 

 

69

 

DSM programs(4)

 

 

46

 

 

 

54

 

Environmental remediation costs(10)

 

 

20

 

 

 

22

 

Deferred storm damage costs(11)

 

 

45

 

 

 

44

 

Deferred transmission operating costs(12)

 

 

63

 

 

 

37

 

Other(13)

 

 

108

 

 

 

110

 

Regulatory assets - noncurrent

 

 

3,726

 

 

 

3,892

 

Total regulatory assets

 

$

3,955

 

 

$

4,163

 

Regulatory liabilities:

 

 

 

 

 

 

 

 

Monetization of guaranty settlement(14)

 

$

67

 

 

 

67

 

Income taxes refundable through future rates(15)

 

 

21

 

 

 

16

 

Reserve for refunds to electric utility customers(16)

 

 

128

 

 

 

143

 

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

 

 

58

 

 

 

12

 

Other

 

 

9

 

 

 

18

 

Regulatory liabilities - current

 

 

283

 

 

 

256

 

Monetization of guaranty settlement(14)

 

 

903

 

 

 

970

 

Income taxes refundable through future rates(15)

 

 

919

 

 

 

948

 

Asset removal costs(17)

 

 

564

 

 

 

552

 

Deferred gains on interest rate derivatives(9)

 

 

69

 

 

 

71

 

Reserve for refunds to electric utility customers(16)

 

 

540

 

 

 

656

 

Other

 

 

10

 

 

 

13

 

Regulatory liabilities - noncurrent

 

 

3,005

 

 

 

3,210

 

Total regulatory liabilities

 

$

3,288

 

 

$

3,466

 

 

(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. See Note 12 for more information.

(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 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 to 2029. Unamortized amounts are included in rate base and are earning a current return.

(4)

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.

(5)

Represents 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.

(6)

Represents amounts under- or over-collected from customers pursuant to the cost of fuel components approved by the South Carolina Commission.

(7)

Costs of the reacquisition of debt are deferred and amortized as interest expense over the would-be remaining life of the reacquired debt or over the life of the replacement debt if refinanced. The reacquired debt had a weighted-average life of approximately 26 years as of December 31, 2020.

(8)

During 2019, DESC purchased certain of its first mortgage bonds. As a result of these transactions, DESC incurred net costs, including write-offs of unamortized swap losses and gains, discount, premium and debt issuance costs, of $270 million.

(9)

Represents (i) the changes in fair value and payments made or received upon settlement of certain interest rate derivatives designated as cash flow hedges and (ii) the changes in fair value and payments made or received upon settlement of certain other interest rate derivatives not so designated. The amounts recorded with respect to (i) are expected to be amortized to interest expense over the lives of the underlying debt through 2043.The amounts recorded with respect to (ii) are expected to be similarly amortized to interest expense through 2065.

(10)

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 16 years. See Note 12 for more information.

(11)

Represents storm restoration costs for which DESC expects to receive future recovery through customer rates.

(12)

Includes deferred depreciation and property taxes associated with certain transmission assets for which DESC expects recovery from customers through future rates. See Note 12 for more information.

(13)

Various other regulatory assets are expected to be recovered through rates over varying periods through 2047.

(14)

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. See Note 12 for more information.

(15)

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 for more information.

(16)

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. See Note 12 for more information.

(17)

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 the 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, including deferred transmission operating costs that are the subject of regulatory proceedings as discussed in Note 12. 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.
v3.20.4
Operating Revenue
 12 Months Ended
Dec. 31, 2020
Revenues [Abstract]  
Operating Revenue

4.  OPERATING REVENUE

DESC’s operating revenue consists of the following:

 

Year Ended December 31,

 

2020

 

 

2019

 

(millions)

 

Electric

 

 

Gas

 

 

Electric

 

 

Gas

 

Customer class:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Residential

 

$

1,127

 

 

$

201

 

 

$

669

 

 

$

194

 

Commercial

 

 

746

 

 

 

103

 

 

 

507

 

 

 

111

 

Industrial

 

 

341

 

 

 

65

 

 

 

224

 

 

 

81

 

Other

 

 

123

 

 

 

18

 

 

 

116

 

 

 

18

 

Revenues from contracts with customers

 

 

2,337

 

 

 

387

 

 

 

1,516

 

 

 

404

 

Other revenues

 

 

15

 

 

 

—

 

 

 

9

 

 

 

—

 

Total Operating Revenues

 

$

2,352

 

 

$

387

 

 

$

1,525

 

 

$

404

 

 

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 $5 million and $9 million at December 31, 2020 and 2019, respectively. For the years ended December 31, 2020 and 2019, DESC recognized revenue of $6 million and $3 million 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.

 

Contract Costs

Costs to obtain contracts are generally expensed when incurred. In limited instances, DESC provides economic development grants intended to support economic growth within DESC’s electric service territory and defers such grants as regulatory assets on the Consolidated Balance Sheets. Whenever these grants are contingent on a customer entering into a long-term electric supply contract with DESC, they are considered costs to obtain that underlying contract. Such costs that exceed certain thresholds are deferred and amortized on a straight-line basis over the term of the related service contract, which generally ranges from ten to 15 years.

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

 

 

Regulatory Assets

 

(millions)

 

2020

 

 

2019

 

Beginning balance, January 1

 

$

13

 

 

$

15

 

Amortization

 

 

(1

)

 

 

(2

)

Ending balance, December 31

 

$

12

 

 

$

13

 

 
v3.20.4
Equity
 12 Months Ended
Dec. 31, 2020
Stockholders Equity Note [Abstract]  
Equity

5.  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.

In 2020, Dominion Energy issued $322 million of shares of Dominion Energy common stock in accordance with the settlement agreement associated with the Santee Cooper Ratepayer Case, as discussed in Note 12. In connection with this transaction, DESC recorded an equity contribution from Dominion Energy.

In 2019, DESC received equity contributions of $835 million from SCANA which were funded by Dominion Energy. DESC primarily used these funds to redeem long-term debt and to repay intercompany credit agreement borrowings from Dominion Energy. See Note 6.

DESC’s bond indenture under which it issues first mortgage bonds contains provisions that could limit the payment of cash dividends on its common stock. DESC's bond indenture permits the payment of dividends on DESC's common stock only either (1) out of its Surplus (as defined in the bond indenture) or (2) in case there is no Surplus, out of its net profits for the fiscal year in which the dividend is declared and/or the preceding fiscal year. In addition, pursuant to the SCANA Merger Approval Order, the amount of any DESC dividends paid must be reasonable and consistent with the long-term payout ratio of the electric utility industry and gas distribution industry.

At December 31, 2020, DESC’s retained earnings exceed the balance established by the Federal Power Act as a reserve on earnings attributable to hydroelectric generation plants. As a result, DESC is permitted to pay dividends without additional regulatory approval provided that such amounts would not bring the retained earnings balance below the established threshold.
v3.20.4
Long-Term and Short-Term Debt
 12 Months Ended
Dec. 31, 2020
Debt Disclosure [Abstract]  
Long-Term and Short-Term Debt

6.  LONG-TERM AND SHORT-TERM DEBT

Long-term debt by type with related weighted-average coupon rates and maturities at December 31, 2020 and 2019 is as follows:

 

At December 31,

 

2020

Weighted-

average

Coupon(1)

 

 

2020

 

 

2019

 

(millions, except percentages)

 

 

 

 

 

 

 

 

 

 

 

 

DESC:

 

 

 

 

 

 

 

 

 

 

 

 

First Mortgage Bonds, 3.22% to 6.625%, due 2021 to 2065

 

 

5.42

%

 

$

3,267

 

 

$

3,267

 

Tax-Exempt Financings:(2)

 

 

 

 

 

 

 

 

 

 

 

 

Variable rate due 2038

 

 

0.13

%

 

 

35

 

 

 

35

 

3.625% and 4.00%, due 2028 and 2033

 

 

3.90

%

 

 

54

 

 

 

54

 

Other

 

 

3.67

%

 

 

1

 

 

 

1

 

GENCO:

 

 

 

 

 

 

 

 

 

 

 

 

Tax-Exempt Financing, variable rate due 2038

 

 

0.13

%

 

 

33

 

 

 

33

 

Affiliated note, 3.05% due 2024

 

 

3.05

%

 

 

230

 

 

 

230

 

Total principal

 

 

 

 

 

 

3,620

 

 

 

3,620

 

Securities due within one year

 

 

3.25

%

 

 

(33

)

 

 

—

 

Unamortized discount, premium and debt issuance costs, net

 

 

 

 

 

 

(30

)

 

 

(32

)

Finance leases

 

 

 

 

 

 

15

 

 

 

20

 

Total long-term debt

 

 

 

 

 

$

3,572

 

 

$

3,608

 

 

 

(1)

Represents weighted-average coupon rates for debt outstanding as of December 31, 2020.

 

(2)

Industrial revenue bonds totaling $68 million are secured by letters of credit that expire, subject to renewal, in the fourth quarter of 2021.

 

Based on stated maturity dates rather than early redemption dates that could be elected by instrument holders, the scheduled principal payments of long-term debt at December 31, 2020, were as follows:

 

(millions, except percentages)

 

2021

 

 

2022

 

 

2023

 

 

2024

 

 

2025

 

 

Thereafter

 

 

Total

 

First Mortgage Bonds

 

$

33

 

 

$

—

 

 

$

—

 

 

$

—

 

 

$

—

 

 

$

3,234

 

 

$

3,267

 

Tax-Exempt Financings

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

 

 

122

 

 

 

122

 

Other

 

 

—

 

 

 

—

 

 

 

—

 

 

 

230

 

 

 

—

 

 

 

1

 

 

 

231

 

Total

 

$

33

 

 

$

—

 

 

$

—

 

 

$

230

 

 

$

—

 

 

$

3,357

 

 

$

3,620

 

Weighted-average coupon

 

 

3.25

%

 

 

 

 

 

 

 

 

 

 

3.05

%

 

 

 

 

 

 

5.30

%

 

 

 

 

Substantially all of DESC’s electric utility plant is pledged as collateral in connection with long-term debt.

DESC is subject to a bond indenture dated April 1, 1993 (Mortgage) covering substantially all of its electric properties under which all of its first mortgage bonds (Bonds) have been issued. Bonds may be issued under the Mortgage in an aggregate principal amount not exceeding the sum of (1) 70% of Unfunded Net Property Additions (as therein defined), (2) the aggregate principal amount of retired Bonds and (3) cash deposited with the trustee. Bonds, other than certain Bonds issued on the basis of retired Bonds, may be issued

under the Mortgage only if Adjusted Net Earnings (as therein defined) for 12 consecutive months out of the 18 months immediately preceding the month of issuance are at least twice (2.0) the annual interest requirements on all outstanding Bonds and Bonds to be issued (Bond Ratio). For the year ended December 31, 2020, the Bond Ratio was 6.70.

Long-Term Debt – Affiliate

In May 2019, GENCO issued a $230 million 3.05% promissory note due to Dominion Energy that matures in May 2024. The issuance by GENCO was approved by the South Carolina Commission. Proceeds from the issuance were used to redeem GENCO’s 5.49% senior secured notes due in 2024 at the remaining principal outstanding of $33 million plus accrued interest, repay money pool borrowings and to return $20 million of contributed equity capital to SCANA.

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, Virginia Power and Questar Gas, and for other general corporate purposes.

DESC's share of commercial paper and letters of credit outstanding under its joint credit facility with Dominion Energy, were as follows:

(millions)

 

Facility Limit

 

 

Outstanding

Commercial

Paper

 

 

Outstanding

Letters of

Credit

 

At December 31, 2020

 

 

 

 

 

 

 

 

 

 

 

 

Joint revolving credit facility(1)(2)

 

$

1,000

 

 

$

—

 

 

$

—

 

At December 31, 2019

 

 

 

 

 

 

 

 

 

 

 

 

Joint revolving credit facility(1)

 

$

1,000

 

 

$

—

 

 

$

—

 

 

(1)

A maximum of $1.0 billion of the facility is available to DESC, less any amounts outstanding to co-borrowers. 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 December 31, 2020, 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 borrowings from DESC's parent or from Dominion Energy. This credit facility matures in March 2023 and 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 October 2020, the joint revolving credit facility was amended to remove Dominion Energy Gas as a co-borrower.

 

In January 2020, DESC and GENCO applied to FERC for a two-year short-term borrowing authorization. In March 2020, FERC granted DESC authority through March 2021 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. In addition, in March 2020, FERC granted GENCO authority through March 2021 to issue short-term indebtedness not to exceed $200 million outstanding with maturity dates of one year or less. In January 2021, DESC and GENCO applied to FERC for a two-year short-term borrowing authorization. The applications are pending.

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 2021.

DESC received FERC approval to enter into an inter-company credit agreement in April 2019 with Dominion Energy under which DESC may have short-term borrowings outstanding up to $900 million. At December 31, 2020 and 2019, DESC had borrowings outstanding under this credit agreement totaling $149 million and $355 million, respectively, which are recorded in affiliated and related party payables in DESC’s Consolidated Balance Sheets. For the twelve months ended December 31, 2020 and 2019, DESC recorded interest charges of $7 million and $3 million, respectively.

DESC participated in a utility money pool with SCANA and another regulated subsidiary of SCANA through April 2019. Fuel Company and GENCO remained in the SCANA utility money pool until January 2021, when that utility money pool was closed, and Fuel Company and GENCO joined the Dominion Energy utility money pool with other regulated subsidiaries of Dominion Energy. Money pool borrowings and investments bear interest at short-term market rates. For the years ended December 31, 2020 and 2019, DESC recorded interest income from money pool transactions of $2 million and $8 million, respectively, and for the same periods DESC recorded interest expense from money pool transactions of $2 million and $8 million, respectively. DESC had outstanding money pool borrowings due to an affiliate of $206 million and investments due from an affiliate of $15 million at December 31, 2020. At December 31, 2019, DESC had outstanding money pool borrowings due to an affiliate of $219 million and investments due from an affiliate of $9 million. On its Consolidated Balance Sheets, DESC includes money pool borrowings within affiliated and related party payables and money pool investments within affiliated and related party receivables.
v3.20.4
Income Taxes
 12 Months Ended
Dec. 31, 2020
Income Tax Disclosure [Abstract]  
Income Taxes

7.  INCOME TAXES

 

Judgment and the use of estimates are required in developing the provision for income taxes and reporting of tax-related assets and liabilities. The interpretation of tax laws involves uncertainty, since tax authorities may interpret the laws differently. DESC is routinely audited by federal and state tax authorities. Ultimate resolution of income tax matters may result in favorable or unfavorable impacts to net income and cash flows, and adjustments to tax-related assets and liabilities could be material.

In March 2020, the CARES Act was enacted which includes several significant business tax provisions that modify or temporarily suspend certain provisions of the 2017 Tax Reform Act. The CARES Act provisions are intended to improve cash flow and liquidity by, among other things, providing a temporary five-year carryback for certain net operating losses, accelerating the refund of previously generated corporate alternative minimum tax credits and temporarily increasing the business interest limitation to 50% of adjusted taxable income for certain businesses.  DESC utilized the income tax provisions of the CARES Act to accelerate the recognition of certain tax attributes, but they did not provide a material benefit.

As indicated in Note 2, DESC’s operations, including accounting for income taxes, are subject to regulatory accounting treatment. For regulated operations, many of the changes in deferred taxes represent amounts probable of collection from or refund to customers, and were recorded as either an increase to a regulatory asset or liability. See Note 3 for more information and current year developments.

 

Details of income tax expense for continuing operations including noncontrolling interests were as follows:

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

Current:

 

 

 

 

 

 

 

 

 

 

 

 

Federal

 

$

(139

)

 

$

—

 

 

$

(16

)

State

 

 

3

 

 

 

34

 

 

 

0

 

Total current expense (benefit)

 

 

(136

)

 

 

34

 

 

 

(16

)

Deferred:

 

 

 

 

 

 

 

 

 

 

 

 

Federal

 

 

 

 

 

 

 

 

 

 

 

 

Taxes before operating loss carryforwards, investment tax credits and tax reform

 

 

158

 

 

 

(90

)

 

 

(216

)

2017 Tax Reform Act impact

 

 

—

 

 

 

—

 

 

 

(176

)

Tax utilization expense of operating loss carryforwards

 

 

33

 

 

 

102

 

 

 

46

 

State

 

 

17

 

 

 

(57

)

 

 

(52

)

Total deferred expense (benefit)

 

 

208

 

 

 

(45

)

 

 

(398

)

Investment tax credit-amortization

 

 

(1

)

 

 

(1

)

 

 

(2

)

Total income tax expense (benefit)

 

$

71

 

 

$

(12

)

 

$

(416

)

 

Subsequent to the SCANA Combination, DESC’s annual utilization of its net operating losses are restricted by the tax law, however in certain circumstances the utilization may be increased if SCANA recognizes built-in gains on certain sales of assets. In December 2019, SCANA recognized a gain on the sale of SEMI’s assets to Dominion Energy, which increased the amount of DESC’s 2019 net operating loss utilization by approximately $79 million.

 

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

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

U.S. statutory rate

 

 

21.0

%

 

 

21.0

%

 

 

21.0

%

Increases (reductions) resulting from:

 

 

 

 

 

 

 

 

 

 

 

 

State taxes, net of federal benefit

 

 

4.2

 

 

 

3.9

 

 

 

3.8

 

State investment tax credits

 

 

—

 

 

 

—

 

 

 

0.3

 

AFUDC - equity

 

 

(0.1

)

 

 

—

 

 

 

0.2

 

Amortization of federal investment tax credits

 

 

(0.4

)

 

 

0.1

 

 

 

0.2

 

Production tax credits

 

 

—

 

 

 

0.4

 

 

 

0.9

 

Reversal of excess deferred income taxes

 

 

(6.0

)

 

 

(1.4

)

 

 

—

 

Federal legislative change

 

 

—

 

 

 

—

 

 

 

17.5

 

NND Project impairment

 

 

—

 

 

 

(2.4

)

 

 

(2.3

)

Write-off of regulatory asset

 

 

—

 

 

 

(15.8

)

 

 

—

 

Changes in unrecognized tax benefits

 

 

—

 

 

 

(5.1

)

 

 

—

 

Other

 

 

0.1

 

 

 

0.2

 

 

 

(0.2

)

Effective tax rate

 

 

18.8

%

 

 

0.9

%

 

 

41.4

%

 

At DESC, deferred taxes will reverse at the weighted average rate used to originate the deferred tax liability, which in some cases will be 35%. DESC has recorded an estimate of the portion of excess deferred income tax amortization in 2020, and changes in estimates of amounts probable of collection from or return to customers. The reversal of these excess deferred income taxes will impact the effective tax rate, and rates charged to customers. See Note 3 for current year developments.

 

In connection with the SCANA Combination, Dominion Energy committed to forgo, or limit, the recovery of certain income tax-related regulatory assets associated with the NND Project. DESC’s effective tax rate reflects deferred income tax expense of $194 million in satisfaction of this commitment. In addition, DESC recorded deferred income tax expense of $30 million with a corresponding increase to regulatory liabilities by $40 million and deferred tax assets by $10 million related to adjustments of amounts probable of return to customers on the nuclear project.

 

DESC’s deferred income taxes consist of the following:

 

At December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Deferred income taxes:

 

 

 

 

 

 

 

 

Total deferred income tax assets

 

$

1,101

 

 

$

1,258

 

Total deferred income tax liabilities

 

 

1,941

 

 

 

1,868

 

Total net deferred income tax liabilities

 

$

840

 

 

$

610

 

Total deferred income taxes:

 

 

 

 

 

 

 

 

Depreciation method and plant basis differences

 

$

1,098

 

 

$

1,007

 

Excess deferred income taxes

 

 

(233

)

 

 

(231

)

Unrecovered nuclear plant cost

 

 

529

 

 

 

553

 

DESC rate refund

 

 

(140

)

 

 

(169

)

Toshiba settlement

 

 

(204

)

 

 

(219

)

Nuclear decommissioning

 

 

(51

)

 

 

(43

)

Deferred state income taxes

 

 

208

 

 

 

200

 

Federal benefit of deferred state income taxes

 

 

(44

)

 

 

(42

)

Deferred fuel, purchased energy and gas costs

 

 

(12

)

 

 

7

 

Pension benefits

 

 

39

 

 

 

46

 

Other postretirement benefits

 

 

(37

)

 

 

(35

)

Loss and credit carryforwards

 

 

(382

)

 

 

(391

)

Other

 

 

69

 

 

 

(73

)

Total net deferred income tax liabilities

 

$

840

 

 

$

610

 

Deferred Investment Tax Credits-Regulated Operations

 

 

18

 

 

 

19

 

Total Deferred Taxes and Deferred Investment Tax Credits

 

$

858

 

 

$

629

 

 

 

At December 31, 2020, DESC had the following deductible loss and credit carryforwards:

 

(millions)

 

Deductible Amount

 

 

Deferred Tax Asset

 

 

Expiration Period

Federal losses

 

$

1,052

 

 

$

221

 

 

2037

Federal production and other credits

 

 

—

 

 

 

31

 

 

2035-2038

State losses

 

 

2,418

 

 

 

121

 

 

2037

State investment and other credits

 

 

—

 

 

 

36

 

 

2026-2031

Total

 

$

3,470

 

 

$

409

 

 

 

A reconciliation of changes in DESC’s unrecognized tax benefits follows:

 

(millions)

 

2020

 

 

2019

 

 

2018

 

Balance at January 1

 

$

132

 

 

$

106

 

 

$

98

 

Increases-prior period positions

 

 

5

 

 

 

76

 

 

 

8

 

Decreases-prior period positions

 

 

—

 

 

 

(53

)

 

 

—

 

Increases-current period positions

 

 

1

 

 

 

3

 

 

 

0

 

Balance at December 31

 

$

138

 

 

$

132

 

 

$

106

 

 

Throughout 2019, the evaluation of federal and state income tax positions taken in DESC’s tax returns prior to the SCANA Combination increased unrecognized tax benefits by $79 million and increased income tax expense by $67 million. In the fourth quarter of 2019, DESC also remeasured its beginning unrecognized tax benefits by $53 million. These changes were offset by a $45 million reduction in credit carryforward deferred tax assets and a $7 million increase to accrued taxes resulting in a $1 million benefit to income tax expense.

 

Certain unrecognized tax benefits, or portions thereof, if recognized, would affect the effective tax rate. Changes in these unrecognized tax benefits may result from remeasurement of amounts expected to be realized, settlements with tax authorities and expiration of statutes of limitations. If recognized, all the unrecognized tax benefits would impact the effective tax rate.

 

The statute is closed for IRS examination of years prior to 2013. The IRS is currently examining DESC’s federal returns from 2013 through 2017. DESC is no longer subject to state and local income tax examinations by tax authorities for years prior to 2013.

 

It is reasonably possible that these unrecognized tax benefits may decrease by $65 million within the next twelve months. If such changes were to occur, other than revisions of the accrual for interest on tax underpayments and overpayments, earnings could increase by $4 million. Otherwise, with regard to 2020 and prior years, DESC cannot estimate the range of reasonably possible changes to unrecognized tax benefits that may occur in 2021.

 

DESC is also obligated to report adjustments resulting from IRS settlements to state tax authorities. In addition, if DESC utilizes operating losses or tax credits generated in years for which the statute of limitations has expired, such amounts are generally subject to examination.
v3.20.4
Derivative Financial Instruments
 12 Months Ended
Dec. 31, 2020
Derivative Instruments And Hedging Activities Disclosure [Abstract]  
Derivative Financial Instruments

8.  DERIVATIVE FINANCIAL INSTRUMENTS

See Note 2 for DESC’s accounting policies, objectives, and strategies for using derivative instruments. See Note 9 for further information about fair value measurements and associated valuation methods for derivatives.

Derivative assets and liabilities are presented gross on DESC’s Consolidated Balance Sheets. DESC’s derivative contracts include over-the-counter transactions. Over-the-counter contracts are bilateral contracts that are transacted directly with a third party. Certain over-the-counter contracts contain contractual rights of setoff through master netting arrangements and contract default provisions. In addition, the contracts are subject to conditional rights of setoff through counterparty nonperformance, insolvency, or other conditions.

In general, most over-the-counter transactions are subject to collateral requirements. Types of collateral for over-the-counter contracts include cash, letters of credit, and, in some cases, other forms of security, none of which are subject to restrictions. Cash collateral is used in the table below to offset derivative assets and liabilities.

All 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 December 31, 2020, DESC would have been required to post $10 million of additional collateral to its counterparties. The collateral that would be required to be posted includes the impacts of any amounts already posted for derivatives per contractual terms. DESC had posted $1 million of collateral at December 31, 2020 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 was $11 million at December 31, 2020. DESC’s derivatives with credit related contingent provisions that were in a liability position were fully collateralized with cash at December 31, 2019.

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:

 

 

 

December 31, 2020

 

 

December 31, 2019

 

 

 

 

 

 

 

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

 

 

Financial

Instruments

 

 

Cash

Collateral

Paid

 

 

Net

Amounts

 

 

Gross

Liabilities

Presented in the

Consolidated

Balance Sheet

 

 

Financial

Instruments

 

 

Cash

Collateral

Paid

 

 

Net

Amounts

 

Interest rate contracts:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Over-the-counter

 

$

27

 

 

$

—

 

 

$

17

 

 

$

10

 

 

$

19

 

 

$

—

 

 

$

19

 

 

$

—

 

Total derivatives

 

$

27

 

 

$

—

 

 

$

17

 

 

$

10

 

 

$

19

 

 

$

—

 

 

$

19

 

 

$

—

 

 

Volumes

The following table presents the volume of derivative activity at December 31, 2020. These volumes are based on open derivative positions and represent the combined absolute value of their long and short positions.

 

 

 

Current

 

 

Noncurrent

 

Interest rate(1)

 

$

—

 

 

$

71,400,000

 

 

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

Fair Value and Gains and Losses on Derivative Instruments

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

 

(millions)

 

Fair Value -

Derivatives

under Hedge

Accounting

 

 

Fair Value -

Derivatives not

under Hedge

Accounting

 

 

Total Fair

Value

 

At December 31, 2020

 

 

 

 

 

 

 

 

 

 

 

 

Current Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

$

1

 

 

$

1

 

 

$

2

 

Total current derivative liabilities(1)

 

 

1

 

 

 

1

 

 

 

2

 

Noncurrent Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

 

15

 

 

 

10

 

 

 

25

 

Total noncurrent derivative liabilities(2)

 

 

15

 

 

 

10

 

 

 

25

 

Total derivative liabilities

 

$

16

 

 

$

11

 

 

$

27

 

At December 31, 2019

 

 

 

 

 

 

 

 

 

 

 

 

Current Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

$

1

 

 

$

1

 

 

$

2

 

Total current derivative liabilities(1)

 

 

1

 

 

 

1

 

 

 

2

 

Noncurrent Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

 

11

 

 

 

6

 

 

 

17

 

Total noncurrent derivative liabilities(2)

 

 

11

 

 

 

6

 

 

 

17

 

Total derivative liabilities

 

$

12

 

 

$

7

 

 

$

19

 

 

(1)   Current derivative liabilities are presented in other current liabilities in the Consolidated Balance Sheets.

(2)   Noncurrent derivative liabilities are presented in other deferred credits and other liabilities in the Consolidated Balance Sheets.

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

Derivatives in Cash Flow Hedging Relationships

(millions)

 

Gain (loss)

Reclassified

from Deferred

Accounts into

Income

 

 

Increase

(Decrease)

in Derivatives

Subject to

Regulatory

Treatment(1)

 

Year Ended December 31, 2020

 

 

 

 

 

 

 

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

 

 

Interest rate(2)

 

$

—

 

 

$

1

 

Total

 

$

—

 

 

$

1

 

Year Ended December 31, 2019

 

 

 

 

 

 

 

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

 

 

Interest rate(2)

 

$

—

 

 

$

1

 

Total

 

$

—

 

 

$

1

 

Year Ended December 31, 2018

 

 

 

 

 

 

 

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

 

 

Interest rate(2)

 

$

(1

)

 

$

1

 

Total

 

$

(1

)

 

$

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 (Loss).

(2)   Amounts recorded in DESC’s Consolidated Statements of Comprehensive Income (Loss) are classified in interest charges.

Derivatives Not designated as Hedging Instruments

 

(millions)

 

Amount of Gain (Loss)

Recognized in Income on

Derivatives(1)

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate contracts:

 

 

 

 

 

 

 

 

 

 

 

 

Interest income

 

$

(1

)

 

$

(1

)

 

$

(2

)

Other income

 

 

—

 

 

 

—

 

 

 

115

 

Total

 

$

(1

)

 

$

(1

)

 

$

113

 

 

(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 (Loss).
v3.20.4
Fair Value Measurements, Including Derivatives
 12 Months Ended
Dec. 31, 2020
Fair Value Disclosures [Abstract]  
Fair Value Measurements, Including Derivatives

9.  FAIR VALUE MEASUREMENTS, INCLUDING DERIVATIVES

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (exit price) in an orderly transaction between market participants at the measurement date. Fair values are based on assumptions that market participants would use when pricing an asset or liability, including assumptions about risk and the risks inherent in valuation techniques and the inputs to valuations. This includes not only the credit standing of counterparties involved and the impact of credit enhancements but also the impact of DESC’s own nonperformance risk on their liabilities. Fair value measurements assume that the transaction occurs in the principal market for the asset or liability (the market with the most volume and activity for the asset or liability from the perspective of the reporting entity), or in the absence of a principal market, the most advantageous market for the asset or liability (the market in which the reporting entity would be able to maximize the amount received or minimize the amount paid). DESC applies fair value measurements to interest rate assets and liabilities. DESC’s interest rate swap agreements are valued using discounted cash flow models with independently sourced data. DESC applies credit adjustments to its derivative fair values in accordance with the requirements described above.

Inputs and Assumptions

Fair value is based on actively-quoted market prices, if available. In the absence of actively-quoted market prices, price information is sought from external sources, including industry publications. The inputs and assumptions used in measuring fair value for interest rate derivative contracts include the following:

 

•

Interest rate curves

 

•

Credit quality of counterparties and DESC

 

•

Notional value

 

•

Credit enhancements

 

•

Time value

Levels

DESC utilizes the following fair value hierarchy, which prioritizes the inputs to valuation techniques used to measure fair value into three broad levels:

 

•

Level 1-Quoted prices (unadjusted) in active markets for identical assets and liabilities that they have the ability to access at the measurement date.

 

•

Level 2-Inputs other than quoted prices included within Level 1 that are either directly or indirectly observable for the asset or liability, including quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in inactive markets, inputs other than quoted prices that are observable for the asset or liability, and inputs that are derived from observable market data by correlation or other means. Instruments categorized in Level 2 include interest rate swaps.

 

•

Level 3-Unobservable inputs for the asset or liability, including situations where there is little, if any, market activity for the asset or liability.

The fair value hierarchy gives the highest priority to quoted prices in active markets (Level 1) and the lowest priority to unobservable data (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. In these cases, the lowest level input that is significant to a fair value measurement in its entirety determines the applicable level in the fair value hierarchy. Assessing the significance of a particular input to the fair value measurement in its entirety requires judgment, considering factors specific to the asset or liability.

Nonrecurring Fair Value Measurement

During the third quarter of 2020, DESC determined that certain of its nonutility property was impaired and recorded a $12 million charge ($9 million after-tax) within impairments and other charges in its Consolidated Statements of Comprehensive Income (Loss) to adjust the property down to its estimated fair value of $6 million. The fair value determinations are considered Level 2 fair value measurements due to the use of real estate appraised values.

Recurring Fair Value Measurements

Fair value disclosures for assets held in DESC’s pension and other postretirement benefit plans are presented in Note 11.

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

 

 

Level 1

 

 

Level 2

 

 

Level 3

 

 

Total

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

At December 31, 2020

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

$

—

 

 

$

27

 

 

$

—

 

 

$

27

 

Total liabilities

 

$

—

 

 

$

27

 

 

$

—

 

 

$

27

 

At December 31, 2019

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

$

—

 

 

$

19

 

 

$

—

 

 

$

19

 

Total liabilities

 

$

—

 

 

$

19

 

 

$

—

 

 

$

19

 

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:

 

At December 31,

 

2020

 

 

2019

 

(millions)

 

Carrying

Amount

 

 

Estimated

Fair Value(1)

 

 

Carrying

Amount

 

 

Estimated

Fair Value(1)

 

Long-term debt(2)

 

$

3,360

 

 

$

4,748

 

 

$

3,358

 

 

$

4,262

 

Affiliated long-term debt

 

 

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 included in securities due within one year and amounts which represent the unamortized debt issuance costs and discount or premium.
v3.20.4
Asset Retirement Obligations
 12 Months Ended
Dec. 31, 2020
Asset Retirement Obligation Disclosure [Abstract]  
Asset Retirement Obligations

10.  ASSET RETIREMENT OBLIGATIONS

A liability for the present value of an ARO is recognized when incurred if the liability can be reasonably estimated. Uncertainty about the timing or method of settlement of a conditional ARO is factored into the measurement of the liability when sufficient information exists, but such uncertainty is not a basis upon which to avoid liability recognition.

The legal obligations associated with the retirement of long-lived tangible assets that result from their acquisition, construction, development and normal operation relate primarily to DESC’s regulated utility operations. As of December 31, 2020, DESC has recorded AROs of $275 million for nuclear plant decommissioning. At December 31, 2020, DESC had $238 million in a trust for its two-thirds share of decommissioning activities. In addition, DESC has recorded AROs of $322 million for other conditional obligations primarily related to other generation, transmission and distribution properties, including gas pipelines. All of the amounts recorded are based upon estimates which are subject to varying degrees of precision, particularly since such payments will be made many years in the future.

A reconciliation of the beginning and ending aggregate carrying amount of AROs is as follows:

 

(millions)

 

2020

 

 

2019

 

Beginning balance

 

$

489

 

 

$

541

 

Liabilities settled

 

 

(4

)

 

 

(29

)

Accretion expense

 

 

23

 

 

 

23

 

Revisions in estimated cash flows(1)

 

 

89

 

 

 

(46

)

Ending balance

 

$

597

 

 

$

489

 

(1)   The increase in 2020 reflects revisions from the nuclear decommissioning cost study. The decrease in 2019 reflects a change in the estimated timing of cash flows for interim pipeline replacements and DOE recoveries.
v3.20.4
Employee Benefit Plans and Equity Compensation Plan
 12 Months Ended
Dec. 31, 2020
Compensation And Retirement Disclosure [Abstract]  
Employee Benefit Plans and Equity Compensation Plan

11.  EMPLOYEE BENEFIT PLANS AND EQUITY COMPENSATION PLAN

Pension and Other Postretirement Benefit Plans

SCANA sponsors a noncontributory defined benefit pension plan covering regular, full-time employees hired before January 1, 2014. DESC participates in SCANA's pension plan. SCANA’s policy has been to fund the plan as permitted by applicable federal income tax regulations, as determined by an independent actuary.

The pension plan provides benefits under a cash balance formula for employees hired before January 1, 2000 who elected that option and all eligible employees hired subsequently. Under the cash balance formula, benefits accumulate as a result of compensation credits and interest credits. Employees hired before January 1, 2000 who elected to remain under the final average pay formula earn benefits based on years of credited service and the employee’s average annual base earnings received during the last three years of employment. Benefits under the cash balance formula will continue to accrue through December 31, 2020, after which date no benefits will be accrued except that participants under the cash balance formula will continue to earn interest credits. Benefits under the final average pay formula will continue to accrue through December 31, 2023, after which date no benefits will be accrued. Once

the benefits under SCANA's pension plan no longer accrue, eligible participants will accrue benefits under a cash balance plan sponsored by Dominion Energy.

In addition to pension benefits, SCANA provides certain unfunded postretirement health care and life insurance benefits to certain active and retired employees. DESC participates in these programs. Retirees hired before January 1, 2011 share in a portion of their medical care cost, while employees hired subsequently are responsible for the full cost of retiree medical benefits elected by them. The costs of postretirement benefits other than pensions are accrued during the years the employees render the services necessary to be eligible for these benefits.

The same benefit formula applies to all SCANA subsidiaries participating in the parent sponsored plans and, with regard to the pension plan, there are no legally separate asset pools. The postretirement benefit plans are accounted for as multiple employer plans.

Voluntary Retirement Program

In March 2019, Dominion Energy announced a voluntary retirement program to employees, including employees of DESC, that meet certain age and service requirements. The voluntary retirement program will not compromise safety or DESC’s ability to comply with applicable laws and regulations. In 2019, upon the determinations made concerning the number of employees that elected to participate in the program, DESC recorded a charge of $63 million ($47 million after-tax), of which $51 million was included within other operations and maintenance expense, $3 million within other taxes and $9 million within other income (expense), net. In addition, as a result of the voluntary retirement program, DESC recorded pension plan settlement losses of $16 million within other income (expense), net in 2019.

In the second quarter of 2019, DESC remeasured its pension and other postretirement benefit plans as a result of the voluntary retirement program. The remeasurement resulted in an increase in the pension benefit obligation of $16 million and an increase in the accumulated postretirement benefit obligation of $10 million. In addition, the remeasurement resulted in an increase in the fair value of pension plan assets of $27 million. The impact of the remeasurement on net periodic benefit cost was recognized prospectively from the remeasurement date. The discount rate used for the remeasurement was 4.07% for the pension plan and 4.08% for the other postretirement benefit plan. All other assumptions used for the remeasurement were consistent with the measurement as of December 31, 2018.

In the third quarter of 2019, DESC remeasured a pension plan as a result of a settlement from the voluntary retirement program. The settlement and related remeasurement resulted in an increase in the pension benefit obligation of $25 million and an increase in the fair value of the pension plan assets of $35 million for DESC. The impact of the remeasurement on net periodic benefit cost (credit) was recognized prospectively from the remeasurement date. The discount rate used for the remeasurement was 3.57%. All other assumptions used for the remeasurement were consistent with the measurement as of December 31, 2018.

Changes in Benefit Obligations

The measurement date used to determine pension and other postretirement benefit obligations is December 31. Data related to the changes in the projected benefit obligation for pension benefits and the accumulated benefit obligation for other postretirement benefits are presented below.

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

(millions)

 

2020

 

 

2019

 

 

2020

 

 

2019

 

Benefit obligation, January 1

 

$

727

 

 

$

732

 

 

$

214

 

 

$

187

 

Service cost

 

 

12

 

 

 

15

 

 

 

3

 

 

 

3

 

Interest cost

 

 

24

 

 

 

28

 

 

 

8

 

 

 

9

 

Plan participants’ contributions

 

 

—

 

 

 

—

 

 

 

2

 

 

 

1

 

Actuarial (gain) loss

 

 

41

 

 

 

47

 

 

 

(31

)

 

 

22

 

Benefits paid

 

 

(22

)

 

 

(21

)

 

 

(13

)

 

 

(13

)

Settlements

 

 

(40

)

 

 

(80

)

 

 

—

 

 

 

—

 

Curtailment

 

 

—

 

 

 

6

 

 

 

—

 

 

 

3

 

Amounts funded to parent

 

 

—

 

 

 

—

 

 

 

1

 

 

 

2

 

Benefit obligation, December 31

 

$

742

 

 

$

727

 

 

$

184

 

 

$

214

 

 

The accumulated benefit obligation for pension benefits for DESC was $732 million at the end of 2020 and $711 million at the end of 2019. The accumulated pension benefit obligation differs from the projected pension benefit obligation above in that it reflects no assumptions about future compensation levels.

Significant assumptions used to determine the above benefit obligations are as follows:

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

 

 

2020

 

 

2019

 

 

2020

 

 

2019

 

Annual discount rate used to determine benefit obligation

 

 

2.73

%

 

 

3.47

%

 

 

2.80

%

 

 

3.52

%

Assumed annual rate of future salary increases for projected

   benefit obligation

 

 

4.52

%

 

 

3.00

%

 

N/A

 

 

N/A

 

Crediting interest rate for cash balance plans

 

 

1.93

%

 

 

2.67

%

 

N/A

 

 

N/A

 

 

 

Actuarial losses recognized during 2020 and 2019 in DESC’s pension benefit obligations include a $43 million and a $52 million loss, respectively, resulting from decreases in discount rates. Actuarial gains recognized during 2020 in DESC’s other postretirement benefit obligations include a $51 million gain as a result of a completed experience study and other healthcare-related assumption changes and were partially offset by a $19 million loss resulting from a decrease in the discount rate. Actuarial losses recognized during 2019 in Dominion Energy’s other postretirement benefit obligations include a $25 million loss resulting from a decrease in the discount rate.  

 

A 6.25% annual rate of increase in the per capita cost of covered health care benefits was assumed for 2020. The rate was assumed to decrease gradually to 5.0% in 2025-2026 and to remain at that level thereafter.

Funded Status

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

At December 31,

 

2020

 

 

2019

 

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fair value of plan assets

 

$

747

 

 

$

725

 

 

$

—

 

 

$

—

 

Benefit obligation

 

 

742

 

 

 

727

 

 

 

184

 

 

 

214

 

Funded status

 

$

5

 

 

$

(2

)

 

$

(184

)

 

$

(214

)

 

Amounts recognized on the consolidated balance sheets were as follows:

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

At December 31,

 

2020

 

 

2019

 

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Noncurrent assets

 

$

5

 

 

$

—

 

 

$

—

 

 

$

—

 

Current liability

 

 

—

 

 

 

—

 

 

 

(11

)

 

 

(13

)

Noncurrent liability

 

 

—

 

 

 

(2

)

 

 

(173

)

 

 

(201

)

 

 

Amounts recognized in accumulated other comprehensive loss were as follows:

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

At December 31,

 

2020

 

 

2019

 

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Net actuarial loss

 

$

4

 

 

$

2

 

 

$

—

 

 

$

2

 

 

 

Amounts recognized in regulatory assets were as follows:

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

At December 31,

 

2020

 

 

2019

 

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Net actuarial loss

 

$

114

 

 

$

125

 

 

$

1

 

 

$

29

 

 

In connection with the joint ownership of Summer, costs related to pensions attributable to Santee Cooper as of both December 31, 2020 and 2019 totaled $19 million and were recorded within deferred debits. Costs related to other postretirement benefits attributable to Santee Cooper as of December 31, 2020 and 2019 totaled $12 million and $15 million, respectively, and was recorded within deferred debits.

Changes in Fair Value of Plan Assets

 

Pension Benefits

 

 

 

 

 

 

 

 

(millions)

 

2020

 

 

2019

 

Fair value of plan assets, January 1

 

$

725

 

 

$

677

 

Actual return (loss) on plan assets

 

 

84

 

 

 

149

 

Benefits paid

 

 

(22

)

 

 

(21

)

Settlements

 

 

(40

)

 

 

(80

)

Fair value of plan assets, December 31

 

$

747

 

 

$

725

 

Investment Policies and Strategies

The assets of the pension plan are invested in accordance with the objectives of (1) fully funding the obligations of the pension plan, (2) overseeing the plan's investments in an asset-liability framework that considers the funding surplus (or deficit) between assets and liabilities, and overall risk associated with assets as compared to liabilities, and (3) maintaining sufficient liquidity to meet benefit payment obligations on a timely basis. DESC uses a dynamic investment strategy for the management of the pension plan assets. This strategy will lead to a reduction in equities and an increase in long duration fixed income allocations over time with the intention of reducing volatility of funded status and pension costs.

The pension plan operates with several risk and control procedures, including ongoing reviews of liabilities, investment objectives, levels of diversification, investment managers and performance expectations. The total portfolio is constructed and maintained to provide prudent diversification with regard to the concentration of holdings in individual issues, corporations, or industries.

Transactions involving certain types of investments are prohibited. These include, except where utilized by a hedge fund manager, any form of private equity; commodities or commodity contracts (except for unleveraged stock or bond index futures and currency futures and options); ownership of real estate in any form other than publicly traded securities; short sales, warrants or margin transactions, or any leveraged investments; and natural resource properties. Investments made for the purpose of engaging in speculative trading are also prohibited.

The pension plan asset allocation at December 31, 2020 and 2019 and the target allocation for 2021 are as follows:

 

 

 

Percentage of Plan Assets

 

 

 

Target

Allocation

 

December 31,

 

Asset Category

 

2021

 

2020

 

 

2019

 

U.S. equities

 

25 - 40%

 

 

34

%

 

 

40

%

Non-U.S. equities

 

10 - 20%

 

 

18

%

 

 

19

%

Fixed income

 

45- 65%

 

 

47

%

 

 

32

%

Cash and cash equivalents

 

2-10%

 

 

1

%

 

 

1

%

Company stock

 

0%

 

 

0

%

 

 

5

%

Real estate

 

0%

 

 

0

%

 

 

3

%

 

 

 

 

 

 

 

 

 

 

 

 

For 2021, the expected long-term rate of return on assets will be 7%. In developing the expected long-term rate of return assumptions, management evaluates the pension plan’s historical cumulative actual returns over several periods, considers the expected active and passive returns across various asset classes and assumes the target allocation is achieved. Management regularly reviews such allocations and periodically rebalances the portfolio when considered appropriate. Additional rebalancing may occur subject to funded status improvements as part of the dynamic investment strategy described previously.

Fair Value Measurements

Assets held by the pension plan are measured at fair value and are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. At December 31, 2020 and 2019, fair value measurements, and the level within the fair value hierarchy in which the measurements fall, were as follows:

 

At December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Investments with fair value measure at Level 1:

 

 

 

 

 

 

 

 

Cash and cash equivalents

 

$

10

 

 

$

3

 

Investments with fair value measure at Level 2:

 

 

 

 

 

 

 

 

Mutual funds

 

 

—

 

 

 

152

 

Corporate debt instruments

 

 

315

 

 

 

233

 

Government and other debt instruments

 

 

35

 

 

 

26

 

Total assets in the fair value hierarchy

 

 

360

 

 

 

414

 

Investments at net asset value:

 

 

 

 

 

 

 

 

Common collective trust

 

 

387

 

 

 

311

 

Total investments

 

$

747

 

 

$

725

 

 

For all periods presented there were no assets with fair value measurements classified as Level 3. There were no transfers of fair value amounts into or out of Levels 1, 2 or 3 during 2020 or 2019.

Mutual funds held by the plan were open-end mutual funds registered with the SEC. The price of the mutual funds' shares is based on its NAV, which is determined by dividing the total value of portfolio investments, less any liabilities, by the total number of shares outstanding. For purposes of calculating NAV, portfolio securities and other assets for which market quotes are readily available are valued at market value. Short-term investment vehicles are funds that invest in short-term fixed income instruments and are valued using observable prices of the underlying fund assets based on trade data for identical or similar securities. U.S. Treasury securities are valued using quoted market prices or based on models using observable inputs from market sources such as external prices or spreads or benchmarked thereto. Corporate debt instruments and government and other debt instruments are valued based on recently executed transactions, using quoted market prices, or based on models using observable inputs from market sources such as external prices or spreads or benchmarked thereto. In addition, corporate debt instruments include investments in open-end mutual funds registered with the SEC that invest in corporate debt instruments. The price of the mutual funds' shares is based on its NAV, which is determined by dividing the total value of portfolio investments, less any liabilities, by the total number of shares outstanding. Common collective trust assets and limited partnerships are valued at NAV, which has been determined based on the unit values of the trust funds. Unit values are determined by the organization sponsoring such trust funds by dividing the trust funds’ net assets at fair value by the units outstanding at each valuation date. Joint venture interests are invested in a hedge fund of funds partnership that invests directly in multiple hedge fund strategies that are not traded on exchanges and not traded on a daily basis. The valuation of such multi-strategy

hedge fund of funds is estimated based on the NAV of the underlying hedge fund strategies using consistent valuation guidelines that account for variations that may influence their fair value.

Expected Cash Flows

Total benefits expected to be paid from the pension plan or company assets for the other postretirement benefits plan (net of participant contributions), respectively, are as follows:

Expected Benefit Payments

 

(millions)

 

Pension

Benefits

 

 

Other

Postretirement

Benefits

 

2021

 

$

39

 

 

$

11

 

2022

 

 

45

 

 

 

11

 

2023

 

 

43

 

 

 

11

 

2024

 

 

45

 

 

 

11

 

2025

 

 

44

 

 

 

11

 

2026 - 2030

 

 

201

 

 

 

55

 

 

Pension Plan Contributions

Under its funding policies, DESC evaluates plan funding requirements annually, usually in the fourth quarter after receiving updated plan information from its actuary. Based on the funded status of each plan and other factors, DESC determines the amount of contributions for the current year, if any, at that time. DESC made no contributions to the pension trust in 2020. DESC expects to make $15 million of the minimum required contributions for its qualified pension plan in 2021.

Net Periodic Benefit Cost

Net periodic benefit cost is recorded utilizing beginning of the year assumptions. Disclosures required for these plans are set forth in the following tables.

Components of Net Periodic Benefit Cost

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

 

2020

 

 

2019

 

 

2018

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Service cost

 

$

12

 

 

$

15

 

 

$

17

 

 

$

3

 

 

$

3

 

 

$

4

 

Interest cost

 

 

24

 

 

 

28

 

 

 

29

 

 

 

8

 

 

 

9

 

 

 

8

 

Expected return on assets

 

 

(45

)

 

 

(40

)

 

 

(48

)

 

 

—

 

 

 

—

 

 

 

—

 

Prior service cost amortization

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

Amortization of actuarial losses

 

 

6

 

 

 

11

 

 

 

11

 

 

 

—

 

 

 

—

 

 

 

—

 

Settlement loss

 

 

7

 

 

 

16

 

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

Curtailment

 

 

—

 

 

 

6

 

 

 

—

 

 

 

—

 

 

 

3

 

 

 

—

 

Net periodic benefit cost

 

$

4

 

 

$

36

 

 

$

9

 

 

$

11

 

 

$

15

 

 

$

12

 

 

In connection with regulatory orders, DESC recovers current pension costs through a rate rider that may be adjusted annually for retail electric operations or through cost of service rates for gas operations. For retail electric operations, current pension expense is recognized based on amounts collected through a rate rider, and differences between actual pension expense and amounts recognized pursuant to the rider are deferred as a regulatory asset (for under-collections) or regulatory liability (for over-collections) as applicable. In addition, DESC amortizes certain previously deferred pension costs. See Note 3.

Other changes in plan assets and benefit obligations recognized in other comprehensive income (net of tax) were as follows:

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

 

2020

 

 

2019

 

 

2018

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Current year actuarial (gain) loss

 

$

2

 

 

$

(1

)

 

$

1

 

 

$

(2

)

 

$

1

 

 

$

(1

)

 

Other changes in plan assets and benefit obligations recognized in regulatory assets were as follows:

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

 

2020

 

 

2019

 

 

2018

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Current year actuarial (gain) loss

 

$

1

 

 

$

(51

)

 

$

41

 

 

$

(27

)

 

$

20

 

 

$

(26

)

Amortization of actuarial losses

 

 

(6

)

 

 

(11

)

 

 

(10

)

 

 

(1

)

 

 

—

 

 

 

(1

)

Settlement loss

 

 

(6

)

 

 

(16

)

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

Total recognized in regulatory assets

 

$

(11

)

 

$

(78

)

 

$

31

 

 

$

(28

)

 

$

20

 

 

$

(27

)

 

Significant assumptions used in determining net periodic benefit cost:

 

 

 

Pension Benefits

 

Other Postretirement Benefits

Year Ended December 31,

 

2020

 

2019

 

2018

 

2020

 

2019

 

2018

Discount rate

 

3.47%

 

3.57/4.38%

 

3.71%

 

2.80%

 

4.08/4.41%

 

3.74%

Expected return on plan assets

 

7.00%

 

7.00%

 

7.00%

 

n/a

 

n/a

 

n/a

Rate of compensation increase

 

3.00%

 

3.00%

 

3.00%

 

n/a

 

n/a

 

n/a

Crediting interest rate for cash balance plans

 

2.67%

 

2.77/3.58%

 

4.00%

 

n/a

 

n/a

 

n/a

Health care cost trend rate

 

 

 

 

 

 

 

6.25%

 

6.60%

 

7.00%

Ultimate health care cost trend rate

 

 

 

 

 

 

 

5.00%

 

5.00%

 

5.00%

Year achieved

 

 

 

 

 

 

 

2025-2026

 

2023

 

2023

 

 

401(k) Retirement Savings Plan

SCANA sponsors a defined contribution plan in which eligible employees may defer up to 75% of eligible earnings subject to certain limits and may diversify their investments. DESC participates in this plan. Contributions are matched 100% up to 6% of an employee’s eligible earnings. The matching contributions made by DESC totaled $14 million in both 2020 and 2019 and $20 million in 2018. Employee deferrals, matching contributions, and earnings on all contributions are fully vested and non-forfeitable at all times.
v3.20.4
Commitments And Contingencies
 12 Months Ended
Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]  
Commitments and Contingencies

12.  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. 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.

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 and GENCO continually monitor and evaluate their current and projected emission levels and strive to comply with all state and federal regulations regarding those emissions. DESC and GENCO participate in the SO2 and NOX emission allowance programs with respect to coal plant emissions and also have constructed additional pollution control equipment at their 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 address all 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.

 

MATS

In February 2019, the EPA published a proposed rule to reverse its previous finding that it is appropriate and necessary to regulate hazardous air pollutant emissions from coal- and oil-fired electric generating units. In May 2020, the EPA’s final rule became effective. The final rule is consistent with the EPA’s February 2019 proposal, and determines that it is not appropriate and necessary to regulate mercury and hazardous air pollutant emissions from coal- and oil-fired electric generating units. The final rule also states that the MATS rule remains in place and the emissions standards for affected coal- and oil-fired electric generating units will not change. DESC is complying with the applicable requirements of the rule and does not expect any material impacts to its operations.

 

Ozone Standards

The EPA published final non-attainment designations for the October 2015 ozone standard in June 2018. States have until August 2021 to develop plans to address the new standard. Until the states have developed implementation plans for the standard, DESC is unable to predict whether or to what extent the new rules will ultimately require additional controls. The expenditures required to implement additional controls could have a material impact on DESC’s results of operations and cash flows.

 

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. In January 2021, the U.S. Court of Appeals for the D.C. Circuit vacated the ACE Rule and remanded it to EPA. This decision will take effect upon issuance of the court’s mandate. The ACE Rule applies to existing coal-fired power plants and would require states to develop plans by July 2022 establishing unit-specific performance standards for existing coal-fired power plants. It is unknown at this time if or how the EPA will replace the ACE Rule and how that replacement will affect DESC’s operations, financial condition and/or cash flows.

 

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 the best operating practices. In January 2021, the EPA published a final rule affirming that the electric generating units are included for the purposes of regulating GHG emissions from new, modified and reconstructed stationary sources. The proposed revision to the performance standards remains pending. 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.

 

Oil and Gas NSPS

In August 2012, the EPA issued an NSPS impacting new and modified facilities in the natural gas production and gathering sectors and made revisions to the NSPS for natural gas processing and transmission facilities. These rules establish equipment performance specifications and emissions standards for control of VOC emissions for natural gas production wells, tanks, pneumatic controllers and compressors in the upstream sector. In June 2016, the EPA issued another NSPS regulation, for the oil and natural gas sector, to regulate methane and VOC emissions from new and modified facilities in transmission and storage, gathering and boosting, production and processing facilities. All projects which commenced construction after September 2015 are required to comply with this regulation. In October 2018, the EPA published a proposed rule reconsidering and amending portions of the 2016 rule, including but not limited to, the fugitive emissions requirements at well sites and compressor stations. The amended portions of the 2016 rule were effective immediately upon publication. In August 2020, the EPA issued two final amendments related to the reconsideration of the NSPS for the oil and natural gas sector applicable to VOC and methane emissions. Together, the two amendments have the effect of rescinding the methane portion of the NSPS for all segments of the oil and natural gas sector, rescinding all methane and VOC NSPS for the transmission and storage segment, and modifying some of the NSPS VOC requirements for facilities in the production and processing segments. The two amendments have been challenged in the U.S. Court of Appeals for the D.C. Circuit but remain in effect pending the outcome of the litigation. DESC has completed an evaluation of the potential impacts and expects that any impact would be insignificant to its results of operations, financial condition and/or cash flows.

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, technology, cost and 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 extends the latest dates for compliance.  Individual facilities’ compliance dates will vary based on circumstances and the determination by state regulators and may range from 2021 to 2028. While the impacts of this rule could be material to DESC’s results of operations, financial condition and/or cash flows, as DESC expects that wastewater treatment technology retrofits and modifications to the bottom ash handling systems will be required at Williams and Wateree generating stations, the existing regulatory framework in South Carolina provides rate recovery mechanisms that could substantially mitigate any such impacts for DESC.

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 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 MGP 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. DESC anticipates that activities at these sites will continue through 2025 at an estimated cost of $10 million. In addition, for one site, an updated work plan submitted to SCDHEC in September 2018, would increase costs by approximately $11 million if approved by federal and state agencies. In September 2020, this plan was submitted to the Army Corps of Engineers. DESC expects to recover costs arising from the remediation work at all four sites through rate recovery mechanisms and as of December 31, 2020, deferred amounts, net of amounts previously recovered through rates and insurance settlements, totaled $22 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 3 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. Until this matter is resolved and all phases of the CCR rule are promulgated, DESC is unable to precisely estimate potential incremental impacts or costs related to existing coal ash sites in connection with future implementation of the final CCR rule. While such amounts may 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.

Abandoned NND Project

DESC, on behalf of itself and as agent for Santee Cooper, entered into an engineering, construction and procurement contract with the Consortium in 2008 for the design and construction of the NND Project. DESC’s ownership share in the NND Project is 55%. Various difficulties were encountered in connection with the project. The ability of the Consortium to adhere to established budgets and construction schedules was affected by many variables, including unanticipated difficulties encountered in connection with project engineering and the construction of project components, constrained financial resources of the contractors, regulatory, legal, training and construction processes associated with securing approvals, permits and licenses and necessary amendments to them within projected time frames, the availability of labor and materials at estimated costs and the efficiency of project labor. There were also contractor and supplier performance issues, difficulties in timely meeting critical regulatory requirements, contract disputes, and changes in key contractors or subcontractors. These matters preceded the filing for bankruptcy protection by the Consortium on March 29, 2017 (see Contractor Bankruptcy Proceedings below) and were the subject of comprehensive analyses performed by SCANA, DESC and Santee Cooper.

Santee Cooper decided to suspend construction on the NND Project, on July 31, 2017, and in light of this decision and based on the results of SCANA and DESC’s analysis, SCANA and DESC determined to stop the construction of the units and to pursue recovery of costs incurred in connection with the construction under the abandonment provisions of the BLRA or through other means. This decision by SCANA became the focus of numerous legislative, regulatory and legal proceedings, and led to DESC recording pre-tax impairment charges in 2017 totaling approximately $1.1 billion (approximately $690 million after-tax). An additional pre-tax impairment loss was recorded in the first quarter of 2018 of approximately $4 million (approximately $3 million after-tax) in order to further reduce to estimated fair value the carrying value of nuclear fuel which had been acquired for use in the NND Project. These proceedings continued in 2018, and some of them remain unresolved and are described below under Claims and Litigation. On December 21, 2018, the South Carolina Commission issued the SCANA Merger Approval Order, which, among other things, limited recovery of capital costs related to the NND Project to $2.8 billion. As a result, DESC concluded that the NND Project capital costs exceeding the amounts established in the SCANA Merger Approval Order were probable of loss, regardless of whether the SCANA Combination was completed, and recorded an impairment charge of $1.4 billion ($870 million after-tax) in the fourth quarter of 2018.

On January 2, 2018, SCANA and Dominion Energy entered into the SCANA Merger Agreement and sought the consents and approvals from governmental entities and the shareholders of SCANA required to consummate the merger. After all consents and approvals were obtained, the SCANA Combination was effective January 1, 2019.

SCANA Merger Approval Order

In accordance with the terms of the South Carolina Commission's SCANA Merger Approval Order, DESC adopted the Plan-B Levelized Customer Benefits Plan, effective February 2019, whereby the average bill for a DESC residential electric customer approximates that which resulted from the legislatively-mandated temporary reduction that had been put into effect by the South Carolina Commission in August 2018. DESC also recorded a significant impairment charge in the fourth quarter of 2018, which charge resulted from its conclusion that NND Project capital costs exceeding the amount established in the SCANA Merger Approval Order were probable of loss, regardless of whether the SCANA Combination was completed. In addition, in the first quarter of 2019, DESC recorded the following charges and liabilities which arose from or are related to provisions in the SCANA Merger Approval Order.

 

•

A charge of $105 million ($79 million after-tax) included within the Corporate and Other segment related to certain assets that had been constructed in connection with the NND Project for which DESC committed to forgo recovery.

 

•

A regulatory liability for refunds and restitution of amounts previously collected from retail electric customers of $1.0 billion ($756 million after-tax), recorded as a reduction in operating revenue, which will be credited to customers over an estimated 11 years effective February 2019. In addition, a previously existing regulatory liability of $1.0 billion will be

 

credited to customers over 20 years ending 2039, which reflects amounts to be refunded to customers related to the monetization of guaranty settlement described in Note 3.

 

•

A regulatory liability for refunds to natural gas customers totaling $2 million ($2 million after-tax).

 

•

A tax charge of $194 million related to $258 million of regulatory assets for which DESC committed to forgo recovery.

Further, except for rate adjustments for fuel and environmental costs, DSM costs, and other rates routinely adjusted on an annual or biannual basis, DESC will freeze retail electric base rates at current levels until January 1, 2021. As discussed in Note 3, in April 2020, the South Carolina Commission issued an order vacating the portion of the SCANA Merger Approval Order requiring that new retail electric rates be implemented by January 1, 2021.

The South Carolina Commission order also approved the removal of DESC's investment in certain transmission assets that have not been abandoned from BLRA capital costs. As of December 31, 2020, such investment in these assets included $309 million within utility plant, net and $63 million within regulatory assets, which amount represents certain deferred operating costs. The South Carolina Commission approved deferral of these operating costs related to the investment until recovery of the transmission capital costs and associated deferred operating costs is addressed in a future rate proceeding. DESC believes these transmission capital and deferred operating costs are probable of recovery; however, if the South Carolina Commission were to disallow recovery of or a reasonable return on all or a portion of them, an impairment charge equal to the disallowed costs may be required. These amounts are included as part of DESC’s electric base rate case filing discussed in Note 3.

Various parties filed petitions for rehearing or reconsideration of the SCANA Merger Approval Order. In January 2019, the South Carolina Commission issued an order (1) granting the request of various parties and finding that DESC was imprudent in its actions by not disclosing material information to the ORS and the South Carolina Commission with regard to costs incurred subsequent to March 2015 and (2) denying the petitions for rehearing or consideration as to other issues raised in the various petitions. The deadline to appeal the SCANA Merger Approval Order and the order on rehearing expired in April 2019, and no party has sought appeal.

Claims and Litigation

The following describes certain legal proceedings involving DESC relating to events occurring before closing of the SCANA Combination. Dominion Energy intends to vigorously contest the lawsuits, claims and assessments which have been filed or initiated against DESC. No reference to, or disclosure of, any proceeding, item or matter described below shall be construed as an admission or indication that such proceeding, item or matter is material. For certain of these matters, and unless otherwise noted therein, DESC is unable to estimate a reasonable range of possible loss and the related financial statement impacts, but for any such matter there could be a material impact to its results of operations, financial condition and/or cash flows. For the matters for which DESC is able to reasonably estimate a probable loss, the Consolidated Balance Sheets at December 31, 2020 and 2019 include reserves of $208 million and $492 million, respectively, and insurance receivables of $8 million and $6 million, respectively, included within other receivables. During the twelve months ended December 31, 2020, the Consolidated Statements of Comprehensive Income (Loss) includes charges of $97 million ($73 million after-tax), included within impairment of assets and other charges. During the twelve months ended December 31, 2019, the Consolidated Statements of Comprehensive Income (Loss) includes charges of $590 million ($444 million after-tax), included within impairment of assets and other charges.

Ratepayer Class Actions

In May 2018, a consolidated complaint against DESC, SCANA and the State of South Carolina was filed in the State Court of Common Pleas in Hampton County, South Carolina (the DESC Ratepayer Case). In September 2018, the court certified this case as a class action. The plaintiffs allege, among other things, that DESC was negligent and unjustly enriched, breached alleged fiduciary and contractual duties and committed fraud and misrepresentation in failing to properly manage the NND Project, and that DESC committed unfair trade practices and violated state anti-trust laws. The plaintiffs sought a declaratory judgment that DESC may not charge its customers for any past or continuing costs of the NND Project, sought to have SCANA and DESC’s assets frozen and all monies recovered from Toshiba and other sources be placed in a constructive trust for the benefit of ratepayers and sought specific performance of the alleged implied contract to construct the NND Project.

In December 2018, the State Court of Common Pleas in Hampton County entered an order granting preliminary approval of a class action settlement and a stay of pre-trial proceedings in the DESC Ratepayer Case. The settlement agreement, contingent upon the closing of the SCANA Combination, provided that SCANA and DESC would establish an escrow account and proceeds from the escrow account would be distributed to the class members, after payment of certain taxes, attorneys' fees and other expenses and administrative costs. The escrow account would include (1) up to $2.0 billion, net of a credit of up to $2.0 billion in future electric bill relief, which would inure to the benefit of the escrow account in favor of class members over a period of time established by the South Carolina Commission in its order related to matters before the South Carolina Commission related to the NND Project, (2) a cash payment of $115 million and (3) the transfer of certain DESC-owned real estate or sales proceeds from the sale of such properties, which counsel for the DESC Ratepayer Class estimate to have an aggregate value between $60 million and $85 million. At the closing of the SCANA Combination, SCANA and DESC funded the cash payment portion of the escrow account. The court held a fairness hearing on the settlement in May 2019. In June 2019, the court entered an order granting final approval of the settlement, which order became effective July 2019. In July 2019, DESC transferred $117 million representing the cash payment, plus accrued interest, to the plaintiffs. Through August 2020, property, plant and equipment with a net recorded value of $22 million had been transferred to the plaintiffs in coordination with the court-appointed real estate trustee to satisfy the settlement agreement. In September 2020, the court entered an order approving a final resolution of the transfer of real estate or sales proceeds with a cash contribution of $38.5 million by DESC and the conveyance of property, plant and equipment with a net recorded value of $3 million. In October 2020, DESC completed the conveyance of property, plant and equipment and funded this cash contribution.

 

In September 2017, a purported class action was filed by Santee Cooper ratepayers against Santee Cooper, DESC, Palmetto Electric Cooperative, Inc. and Central Electric Power Cooperative, Inc. in the State Court of Common Pleas in Hampton County, South Carolina (the Santee Cooper Ratepayer Case). The allegations are substantially similar to those in the DESC Ratepayer Case. The plaintiffs seek a declaratory judgment that the defendants may not charge the purported class for reimbursement for past or future costs of the NND Project. In March 2018, the plaintiffs filed an amended complaint including as additional named defendants certain then current and former directors of Santee Cooper and SCANA. In June 2018, Santee Cooper filed a Notice of Petition for Original Jurisdiction with the Supreme Court of South Carolina which was denied. In December 2018, Santee Cooper filed its answer to the plaintiffs' fourth amended complaint and filed cross claims against DESC. In October 2019, Santee Cooper voluntarily consented to stay its cross claims against DESC pending the outcome of the trial of the underlying case. In November 2019, DESC removed the case to the U.S. District Court for the District of South Carolina. In December 2019, the plaintiffs and Santee Cooper filed a motion to remand the case to state court. In January 2020, the case was remanded to state court. In March 2020, the parties executed a settlement agreement relating to this matter as well as the Luquire Case and the Glibowski Case described below. The settlement agreement provides that Dominion Energy and Santee Cooper will establish a fund for the benefit of class members in the amount of $520 million, of which DESC’s portion is $320 million of shares of Dominion Energy common stock. Also in March 2020, the court granted preliminary approval for the settlement agreement. In July 2020, the court issued a final approval of the settlement agreement. In September 2020, Dominion Energy issued $322 million of shares of Dominion Energy common stock to satisfy its obligation under the settlement agreement, including interest charges.  

In July 2019, a similar purported class action was filed by certain Santee Cooper ratepayers against DESC, SCANA, Dominion Energy and former directors and officers of SCANA in the State Court of Common Pleas in Orangeburg, South Carolina (the Luquire Case). In August 2019, DESC, SCANA and Dominion Energy were voluntarily dismissed from the case. The claims are similar to the Santee Cooper Ratepayer Case. In March 2020, the parties executed a settlement agreement as described above relating to this matter as well as the Santee Cooper Ratepayer Case and the Glibowski Case. This case was dismissed as part of the Santee Cooper Ratepayer Case settlement described above.

RICO Class Action

In January 2018, a purported class action was filed, and subsequently amended, against SCANA, DESC and certain former executive officers in the U.S. District Court for the District of South Carolina (the Glibowski Case). The plaintiff alleges, among other things, that SCANA, DESC and the individual defendants participated in an unlawful racketeering enterprise in violation of RICO and conspired to violate RICO by fraudulently inflating utility bills to generate unlawful proceeds. The DESC Ratepayer Class Action settlement described previously contemplates dismissal of claims by DESC ratepayers in this case against DESC, SCANA and their officers. In August 2019, the individual defendants filed motions to dismiss. In March 2020, the parties executed a settlement agreement as described above relating to this matter as well as the Santee Cooper Ratepayer Case and the Luquire Case. This case was dismissed as part of the Santee Cooper Ratepayer Case settlement described above.

SCANA Shareholder Litigation

In February 2018, a purported class action was filed against Dominion Energy and certain former directors of SCANA and DESC in the State Court of Common Pleas in Richland County, South Carolina (the Metzler Lawsuit). The plaintiff alleges, among other things, that defendants violated their fiduciary duties to shareholders by executing a merger agreement that would unfairly deprive plaintiffs of the true value of their SCANA stock, and that Dominion Energy aided and abetted these actions. Among other remedies, the plaintiff seeks to enjoin and/or rescind the merger. In February 2018, Dominion Energy removed the case to the U.S. District Court for the District of South Carolina and filed a Motion to Dismiss in March 2018. In August 2018, the case was remanded back to the State Court of Common Pleas in Richland County. Dominion Energy appealed the decision to remand to the U.S. Court of Appeals for the Fourth Circuit, where the appeal was consolidated with another lawsuit regarding the SCANA Merger Agreement to which DESC is not a party. In June 2019, the U.S. Court of Appeals for the Fourth Circuit reversed the order remanding the case to state court. In September 2019, the U.S. District Court for the District of South Carolina granted the plaintiffs’ motion to consolidate the Metzler Lawsuit with another lawsuit regarding the SCANA Merger Agreement to which DESC is not a party. In October 2019, the plaintiffs filed an amended complaint against certain former directors and executive officers of SCANA and DESC, which stated substantially similar allegations to those in the initial lawsuits as well as an inseparable fraud claim. In November 2019, the defendants filed a motion to dismiss. In April 2020, the U.S. District Court for the District of South Carolina denied the motion to dismiss. In May 2020, SCANA filed a motion to intervene, which was denied in August 2020. In September 2020, SCANA filed a notice of appeal with the U.S. Court of Appeals for the Fourth Circuit. This case is pending.

 

Employment Class Actions and Indemnification

In August 2017, a case was filed in the U.S. District Court for the District of South Carolina on behalf of persons who were formerly employed at the NND Project. In July 2018, the court certified this case as a class action. In February 2019, certain of these plaintiffs filed an additional case, which case has been dismissed and the plaintiffs have joined the case filed in August 2017. The plaintiffs allege, among other things, that SCANA, DESC, Fluor Corporation and Fluor Enterprises, Inc. violated the Worker Adjustment and Retraining Notification Act in connection with the decision to stop construction at the NND Project. The plaintiffs allege that the defendants failed to provide adequate advance written notice of their terminations of employment and are seeking damages, which are estimated to be as much as $100 million for 100% of the NND Project. In January 2021, the U.S. District Court for the District of South Carolina granted summary judgment in favor of SCANA, DESC, Fluor Corporation and Fluor Enterprises, Inc. In February 2021, the plaintiffs filed a notice of appeal with the U.S. Court of Appeals for the Fourth Circuit. This case is pending.

In September 2018, a case was filed in the State Court of Common Pleas in Fairfield County, South Carolina by Fluor Enterprises, Inc. and Fluor Daniel Maintenance Services, Inc. against DESC and Santee Cooper. The plaintiffs make claims for indemnification, breach of contract and promissory estoppel arising from, among other things, the defendants' alleged failure and refusal to defend and indemnify the Fluor defendants in the aforementioned case. This case is pending.

FILOT Litigation and Related Matters

In November 2017, Fairfield County filed a complaint and a motion for temporary injunction against DESC in the State Court of Common Pleas in Fairfield County, South Carolina, making allegations of breach of contract, fraud, negligent misrepresentation, breach of fiduciary duty, breach of implied duty of good faith and fair dealing and unfair trade practices related to DESC’s termination of the FILOT agreement between DESC and Fairfield County related to the NND Project. The plaintiff sought a temporary and permanent injunction to prevent DESC from terminating the FILOT agreement. The plaintiff withdrew the motion for temporary injunction in December 2017. This case is pending.

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 September and October 2017, SCANA was served with subpoenas issued by the U.S. Attorney’s Office for the District of South Carolina and the Staff of the SEC’s Division of Enforcement seeking documents related to the NND Project. In February 2020, the SEC filed a complaint against SCANA, two of its former executive officers and DESC in the U.S. District Court for the District of South Carolina alleging that the defendants violated federal securities laws by making false and misleading statements about the NND Project. In April 2020, SCANA and DESC reached an agreement in principle with the Staff of the SEC’s Division of Enforcement to settle, without admitting or denying the allegations in the complaint. In December 2020, the U.S. District Court for the District of South Carolina issued an order approving the settlement which required SCANA to pay a civil monetary penalty totaling $25 million, and SCANA and DESC to pay disgorgement and prejudgment interest totaling $112.5 million, which disgorgement and prejudgment interest amount were deemed satisfied by the settlements in the SCANA Securities Class Action and the DESC Ratepayer Case. SCANA paid the civil penalty in December 2020. The SEC civil action against two former executive officers of SCANA remains pending and is currently subject to a stay granted by the court in June 2020 at the request of the U.S. Attorney’s Office for the District of South Carolina.

In addition, the South Carolina Law Enforcement Division is conducting a criminal investigation into the handling of the NND Project by SCANA and DESC. Dominion Energy is cooperating fully with the investigations by the U.S. Attorney’s Office and the South Carolina Law Enforcement Division, including responding to additional subpoenas and document requests. Dominion Energy has also entered into a cooperation agreement with the U.S. Attorney’s Office and the South Carolina Attorney General’s Office. The cooperation agreement provides that in consideration of its full cooperation with these investigations to the satisfaction of both agencies, neither such agency will criminally prosecute or bring any civil action against Dominion Energy or any of its current, previous, or future direct or indirect subsidiaries, including DESC, related to the NND Project. A former executive officer of SCANA entered a plea agreement with the U.S. Attorney’s Office and the South Carolina Attorney General’s Office in June 2020 and entered a guilty plea with the U.S. District Court for the District of South Carolina in July 2020. Another former executive officer of SCANA entered a plea agreement with the U.S. Attorney's Office and the South Carolina Attorney General's Office in November 2020. These matters are pending.

Other Litigation

In December 2018, arbitration proceedings commenced between DESC and Cameco Corporation related to a supply agreement signed in May 2008. This agreement provides the terms and conditions under which DESC agreed to purchase uranium hexafluoride from Cameco Corporation over a period from 2010 to 2020. Cameco Corporation alleges that DESC violated this agreement by failing to purchase the stated quantities of uranium hexafluoride for the 2017 and 2018 delivery years. DESC denies that it is in breach of the agreement and believes that it has reduced its purchase quantity within the terms of the agreement. In January 2021, the parties entered into a mutual release of claims and dismissed the arbitration.

In September 2019, a South Carolina state court jury awarded a judgment to the estate of Jose Larios in a wrongful death suit filed in June 2017 against DESC, of which DESC was apportioned $19 million. DESC holds general liability insurance coverage which is expected to provide payment for substantially all DESC’s liability in this matter. In October 2019, DESC filed a motion requesting a reduction in the judgment or, in the alternative, a new trial. In November 2019, DESC’s motion for a new trial was granted, setting aside the entire verdict amount. This matter is pending.

Contractor Bankruptcy Proceedings

Westinghouse’s Reorganization Plan became effective August 1, 2018. Initially, Westinghouse had projected that its Reorganization Plan would pay in full or nearly in full its pre-petition trade creditors, including several of the Westinghouse Subcontractors which have alleged non-payment by the Consortium for amounts owed for work performed on the NND Project and have filed liens on related property in Fairfield County, South Carolina. DESC is contesting approximately $285 million of such filed liens. Most of these

asserted liens are “pre-petition” claims that relate to work performed by Westinghouse Subcontractors before the Westinghouse bankruptcy, although some of them are “post-petition” claims arising from work performed after the Westinghouse bankruptcy. It is possible that the Reorganization Plan will not provide for payment in full or nearly in full to its pre-petition trade creditors. The shortfall could be significant. In addition, payments under the Toshiba Settlement are subject to reduction if Westinghouse pays Westinghouse Subcontractors holding pre-petition liens directly. Under these circumstances, DESC and Santee Cooper, each in its pro rata share, would be required to make Citibank, N.A., which purchased the scheduled payments under the Toshiba Settlement, whole for reductions related to valid subcontractor and vendor pre-petition liens up to $60 million ($33 million for DESC's 55% share).

DESC and Santee Cooper were responsible for amounts owed to Westinghouse for valid work performed by Westinghouse Subcontractors on the NND Project after the Westinghouse bankruptcy filing (i.e., post-petition) until termination of the IAA (the IAA Period). In the Westinghouse bankruptcy proceeding, deadlines were established for creditors of Westinghouse to assert the amounts owed to such creditors prior to the Westinghouse bankruptcy filing and during the IAA Period. Many of the Westinghouse Subcontractors have filed such claims. In December 2019, DESC and Santee Cooper entered into a confidential settlement agreement with W Wind Down Co LLC resolving claims relating to the IAA.

Further, some Westinghouse Subcontractors who have made claims against Westinghouse in the bankruptcy proceeding also filed against DESC and Santee Cooper in South Carolina state court for damages. The Westinghouse Subcontractor claims in South Carolina state court include common law claims for pre-petition work, IAA Period work, and work after the termination of the IAA. Many of these claimants have also asserted construction liens against the NND Project site. While DESC cannot be assured that it will not have any exposure on account of unpaid Westinghouse Subcontractor claims, which claims DESC is presently disputing, DESC believes it is unlikely that it will be required to make payments on account of such claims.

Nuclear Insurance

Under Price-Anderson, DESC (for itself and on behalf of Santee-Cooper) maintains agreements of indemnity with the U.S. Nuclear Regulatory Commission that, together with private insurance, cover third-party liability arising from any nuclear incident occurring at Summer. Price-Anderson provides funds up to $13.8 billion for public liability claims that could arise from a single nuclear incident. Each nuclear plant is insured against this liability to a maximum of $450 million by American Nuclear Insurers with the remaining coverage provided by a mandatory program of deferred premiums that could be assessed, after a nuclear incident, against all owners of commercial nuclear reactors. Each reactor licensee is liable for up to $138 million per reactor owned for each nuclear incident occurring at any reactor in the U.S., provided that not more than $21 million of the liability per reactor would be assessed per year. DESC’s maximum assessment, based on its two-thirds ownership of Summer, would be $92 million per incident, but not more than $14 million per year. Both the maximum assessment per reactor and the maximum yearly assessment are adjusted for inflation at least every five years.

DESC currently maintains insurance policies (for itself and on behalf of Santee Cooper) with NEIL. The policies provide coverage to Summer for property damage and outage costs up to $2.75 billion resulting from an event of nuclear origin and up to $2.33 billion resulting from an event of a non-nuclear origin. The NEIL policies in aggregate, are subject to a maximum loss of $2.75 billion for any single loss occurrence. The NEIL policies permit retrospective assessments under certain conditions to cover insurer’s losses. Based on the current annual premium, DESC’s portion of the retrospective premium assessment would not exceed $24 million. DESC currently maintains an excess property insurance policy (for itself and on behalf of Santee Cooper) with EMANI. The policy provides coverage to Summer for property damage and outage costs up to $415 million resulting from an event of a non-nuclear origin. The EMANI policy permits retrospective assessments under certain conditions to cover insurer's losses. Based on the current annual premium, DESC's portion of the retrospective premium assessment would not exceed $2 million.

To the extent that insurable claims for property damage, decontamination, repair and replacement and other costs and expenses arising from an incident at Summer exceed the policy limits of insurance, or to the extent such insurance becomes unavailable in the future, and to the extent that DESC's rates would not recover the cost of any purchased replacement power, DESC will retain the risk of loss as a self-insurer. DESC has no reason to anticipate a serious nuclear or other incident. However, if such an incident were to occur, it likely would have a material impact on DESC's results of operations, cash flows and financial position.

Spent Nuclear Fuel

The Nuclear Waste Policy Act of 1982 required that the United States government accept and permanently dispose of high-level radioactive waste and spent nuclear fuel by January 31, 1998, and it imposed on utilities the primary responsibility for storage of their spent nuclear fuel until the repository is available. DESC entered into a Standard Contract for Disposal of Spent Nuclear Fuel and/or High-Level Radioactive Waste with the DOE in 1983. By mutual agreement of the parties, damage award payments and settlement payments are made until the DOE has accepted the same amount of spent fuel from the facility as if it has fully performed its contractual obligations. In 2020, DESC received payment of $4 million for resolution of its share of claims incurred at Summer for the period of January 1, 2019 through December 31, 2019. In 2019, DESC received payment of $3 million for resolution of its share of claims incurred at Summer for the period of January 1, 2018 through December 31, 2018. As of December 31, 2020, the federal government has not accepted any spent fuel from Summer, and it remains unclear when the repository may become available. DESC has constructed an independent spent fuel storage installation to accommodate the spent nuclear fuel output for the life of Summer. DESC may evaluate other technology as it becomes available.

Long-Term Purchase Agreements

At December 31, 2020, DESC had the following long-term commitments that are noncancelable or cancelable only under certain conditions, and that a third party that will provide the contracted goods or services has used to secure financing.

 

(millions)

 

2021

 

 

2022

 

 

2023

 

 

2024

 

 

2025

 

 

Thereafter

 

 

Total

 

Purchased electric capacity(1)

 

$

83

 

 

$

82

 

 

$

82

 

 

$

81

 

 

$

82

 

 

$

915

 

 

$

1,325

 

(1)   Includes affiliated amounts with certain solar facilities of $246 million.

Commitments represent estimated amounts payable for energy under power purchase contracts with qualifying facilities which expire at various dates through 2046. Energy payments are generally based on fixed dollar amounts per month and totaled $64 million in 2020, $37 million in 2019 and $24 million in 2018.
v3.20.4
Leases
 12 Months Ended
Dec. 31, 2020
Leases [Abstract]  
Leases

13. LEASES

At December 31, 2020 and 2019, DESC had the following lease assets and liabilities recorded in the Consolidated Balance Sheets:

 

At December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Lease assets:

 

 

 

 

 

 

 

 

Operating lease assets(1)

 

$

21

 

 

$

23

 

Finance lease assets(2)

 

 

20

 

 

 

26

 

Total lease assets

 

$

41

 

 

$

49

 

Lease liabilities:

 

 

 

 

 

 

 

 

Operating lease - current(3)

 

$

3

 

 

$

3

 

Operating lease - noncurrent(4)

 

 

18

 

 

 

20

 

Finance lease - current(5)

 

 

6

 

 

 

7

 

Finance lease - noncurrent

 

 

15

 

 

 

20

 

Total lease liabilities

 

$

42

 

 

$

50

 

 

(1)   Included in other deferred debits and other assets in the Consolidated Balance Sheets.

(2)   Included in utility plant, net, in the Consolidated Balance Sheets, net of $24 million of accumulated amortization at both December 31, 2020 and 2019.

(3)   Included in other current liabilities in the Consolidated Balance Sheets.

(4)   Included in other deferred credits and other liabilities in the Consolidated Balance Sheets.

(5)   Included in current portion of long-term debt in the Consolidated Balance Sheets.

For the years ended December 31, 2020 and 2019, total lease cost consisted of the following:

 

Year Ended December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Finance lease cost:

 

 

 

 

 

 

 

 

Amortization

 

$

8

 

 

$

7

 

Interest

 

 

1

 

 

 

1

 

Operating lease cost

 

 

4

 

 

 

4

 

Short-term lease cost

 

 

2

 

 

 

1

 

Total lease cost

 

$

15

 

 

$

13

 

 

For the years ended December 31, 2020 and 2019, cash paid for amounts included in the measurement of lease liabilities consisted of the following amounts, included in the Consolidated Statements of Cash Flows:

 

Year Ended December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Operating cash flows from finance leases

 

$

1

 

 

$

1

 

Operating cash flows from operating leases

 

 

4

 

 

 

3

 

Financing cash flows from finance leases

 

 

8

 

 

 

7

 

 

At December 31, 2020 and 2019, the weighted average remaining lease term and weighted average discount rate for finance and operating leases were as follows:

 

At December 31,

 

2020

 

 

2019

 

Weighted average remaining lease term - finance leases

 

4 years

 

 

5 years

 

Weighted average remaining lease term - operating leases

 

19 years

 

 

18 years

 

Weighted average discount rate - finance leases

 

 

2.92

%

 

 

2.94

%

Weighted average discount rate - operating leases

 

 

3.95

%

 

 

3.94

%

 

Lease liabilities have the following scheduled maturities:

 

(millions)

 

Operating

 

 

Finance

 

2021

 

$

4

 

 

$

7

 

2022

 

 

3

 

 

 

6

 

2023

 

 

2

 

 

 

4

 

2024

 

 

2

 

 

 

3

 

2025

 

 

1

 

 

 

2

 

After 2025

 

 

21

 

 

 

2

 

Total undiscounted lease payments

 

 

33

 

 

 

24

 

Present value adjustment

 

 

(12

)

 

 

(3

)

Present value of lease liabilities

 

$

21

 

 

$

21

 

 
v3.20.4
Operating Segments
 12 Months Ended
Dec. 31, 2020
Segment Reporting [Abstract]  
Operating Segments

14.  OPERATING SEGMENTS

In December 2019, DESC realigned its segments which resulted in the formation of a single primary operating segment. The historical information presented herein has been recast to reflect the current segment presentation.

 

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

In 2020, DESC reported after-tax net expenses of $104 million for specific items in the Corporate and Other segment, all of which were attributable to its operating segment.

The net expense for specific items attributable to DESC’s operating segment in 2020 primarily related to $99 million ($74 million after-tax) of charges associated with litigation.

In 2019, DESC reported after-tax net expenses of $1.6 billion for specific items in the Corporate and Other segment, all of which were attributable to its operating segment.

The net expense for specific items attributable to DESC’s operating segment in 2019 primarily related to the impact of the following items:

 

•

A $1.0 billion ($756 million after-tax) charge for refunds of amounts previously collected from retail electric customers for the NND Project;

 

•

$590 million ($444 million after-tax) of charges associated with litigation;

 

•

A $194 million tax charge for $258 million of income tax-related regulatory assets for which DESC committed to forgo recovery;

 

•

A $114 million ($86 million after-tax) charge for utility plant primarily for which DESC committed to forgo recovery;

 

•

$100 million ($76 million after-tax) of merger-related costs associated with the SCANA Combination, including a $79 million ($59 million after-tax) charge related to a voluntary retirement program; and 

 

•

$66 million tax charges for changes in unrecognized tax benefits.

In 2018, DESC reported after-tax net expenses of $917 million for specific items in the Corporate and Other segment, all of which were attributable to its operating segment.

The net expense for specific items attributable to DESC’s operating segment in 2018 primarily related to a $1.4 billion ($870 million after-tax) impairment charge associated with the NND Project.  

The following table presents segment information pertaining to DESC’s operations:

 

Year Ended December 31,

 

Dominion Energy

South Carolina

 

 

Corporate

and Other

 

 

Consolidated

Total

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

2020

 

 

 

 

 

 

 

 

 

 

 

 

External revenue

 

$

2,739

 

 

$

—

 

 

$

2,739

 

Depreciation and amortization

 

 

474

 

 

 

—

 

 

 

474

 

Interest and related charges

 

 

223

 

 

 

6

 

 

 

229

 

Income tax expense (benefit)

 

 

107

 

 

 

(36

)

 

 

71

 

Comprehensive income (loss) available (attributable) to

   common shareholder

 

 

410

 

 

 

(113

)

 

 

297

 

Capital expenditures

 

 

742

 

 

 

—

 

 

 

742

 

Total assets (billions)

 

 

14.5

 

 

 

—

 

 

 

14.5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2019

 

 

 

 

 

 

 

 

 

 

 

 

External revenue

 

$

2,937

 

 

$

(1,008

)

 

$

1,929

 

Depreciation and amortization

 

 

452

 

 

 

(2

)

 

 

450

 

Interest and related charges

 

 

247

 

 

 

13

 

 

 

260

 

Income tax expense (benefit)

 

 

163

 

 

 

(175

)

 

 

(12

)

Comprehensive income (loss) available (attributable) to

   common shareholder

 

 

408

 

 

 

(1,647

)

 

 

(1,239

)

Capital expenditures

 

 

497

 

 

 

—

 

 

 

497

 

Total assets (billions)

 

 

14.3

 

 

 

—

 

 

 

14.3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2018

 

 

 

 

 

 

 

 

 

 

 

 

External revenue

 

$

2,763

 

 

$

(1

)

 

$

2,762

 

Depreciation and amortization

 

 

327

 

 

 

—

 

 

 

327

 

Interest and related charges

 

 

306

 

 

 

(3

)

 

 

303

 

Income tax expense (benefit)

 

 

98

 

 

 

(514

)

 

 

(416

)

Comprehensive income (loss) available (attributable) to

   common shareholder

 

 

304

 

 

 

(917

)

 

 

(613

)

Capital expenditures

 

 

633

 

 

 

—

 

 

 

633

 

 
v3.20.4
Utility Plant and Nonutility Property
 12 Months Ended
Dec. 31, 2020
Utility Plant And Non Utility Property [Abstract]  
Utility Plant and Nonutility Property

15.  UTILITY PLANT AND NONUTILITY PROPERTY

Major classes of utility plant and other property and their respective balances at December 31, 2020 and 2019 were as follows:

 

At December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Gross utility plant:

 

 

 

 

 

 

 

 

Generation

 

$

5,921

 

 

$

5,765

 

Transmission

 

 

1,963

 

 

 

1,905

 

Distribution

 

 

4,909

 

 

 

4,685

 

Storage

 

 

74

 

 

 

73

 

General and other

 

 

563

 

 

 

549

 

Intangible

 

 

250

 

 

 

231

 

Construction work in progress

 

 

460

 

 

 

339

 

Nuclear fuel

 

 

575

 

 

 

608

 

Total gross utility plant

 

$

14,715

 

 

$

14,155

 

Gross nonutility property

 

$

45

 

 

$

75

 

 

Jointly Owned Utility Plant

DESC jointly owns and is the operator of Summer. Each joint owner provides its own financing and shares the direct expenses and generation output in proportion to its ownership. DESC’s share of the direct expenses of Summer is included in the corresponding operating expenses on its income statement. The units associated with the NND Project have been reclassified from construction work in progress to a regulatory asset as a result of the decision to stop their construction. See additional discussion at Note 3. In May 2019, DESC and Santee Cooper entered into an agreement in which DESC agreed to purchase 11.7% of Santee Cooper’s ownership interest in the NND Project nuclear fuel, which will be used at Summer, for $8 million to true up the ownership percentage from the 55% ownership percentage that was applicable for the NND Project to the 66.7% ownership percentage applicable for Summer.

 

At December 31,

 

2020

 

2019

 

 

Summer Unit 1

 

Summer Unit 1

Percent owned

 

66.7%

 

66.7%

Plant in service

 

$

1.6

 

billion

 

$

1.4

 

billion

Accumulated depreciation

 

$

702

 

million

 

$

684

 

million

Construction work in progress

 

$

62

 

million

 

$

79

 

million

 

Included within other receivables on the balance sheet were amounts due to DESC from Santee Cooper for its share of direct expenses. These amounts totaled $28 million at December 31, 2020 and $50 million at December 31, 2019.

Sale of Warranty Service Contract Assets

In May 2019, DESC entered into an agreement to sell certain warranty service contract assets for total consideration of $7 million. The transaction closed in August 2019, resulting in a $7 million ($5 million after-tax) gain recorded in other income (expense), net in DESC’s Consolidated Statements of Comprehensive Income (Loss). Pursuant to the agreement, upon closing DESC entered into a service agreement with the buyer under which the buyer will compensate DESC in connection with the right to use DESC’s brand in marketing materials and other services over a ten-year term.
v3.20.4
Affiliated and Related Party Transactions
 12 Months Ended
Dec. 31, 2020
Related Party Transactions [Abstract]  
Affiliated and Related Party Transactions

16.  AFFILIATED AND RELATED PARTY TRANSACTIONS

DESC owns 40% of Canadys Refined Coal, LLC, which is involved in the manufacturing and sale of refined coal to reduce emissions at certain of DESC’s generating facilities. DESC accounts for this investment using the equity method. Purchases and sales of the related coal are recorded as other income (expense), net in the Consolidated Statements of Comprehensive Income (Loss).

DESC purchases natural gas and related pipeline capacity from SEMI to service its retail gas customers and to satisfy certain electric generation requirements. These purchases are included within gas purchased for resale or fuel used in electric generation, as applicable in the Consolidated Statements of Comprehensive Income (Loss).

DESS, on behalf of itself and its parent company, provided the following services to DESC through December 2020, which were 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. In addition, DESS processed and paid invoices for DESC and was reimbursed. Effective January 2021, DES provides to DESC the services previously provided by DESS. 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 (Loss).

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

Purchases of coal from affiliate

 

$

—

 

 

$

121

 

 

$

150

 

Sales of coal to affiliate

 

 

—

 

 

 

120

 

 

 

149

 

Purchases of fuel used in electric generation from affiliate

 

 

—

 

 

 

43

 

 

 

139

 

Direct and allocated costs from DESS(1)

 

 

294

 

 

 

297

 

 

 

283

 

Operating Revenues – Electric from sales to affiliate

 

 

4

 

 

 

4

 

 

 

5

 

Operating Revenues – Gas from sales to affiliate

 

 

1

 

 

 

1

 

 

 

1

 

Operating Expenses – Other taxes from affiliate

 

 

9

 

 

 

6

 

 

 

6

 

Purchases of electricity from solar affiliates

 

 

12

 

 

 

8

 

 

N/A

 

Demand and transportation charges from DECG - Fuel used in

   electric generation

 

 

16

 

 

 

19

 

 

N/A

 

Demand and transportation charges from DECG - Gas purchased

   for resale

 

 

36

 

 

 

44

 

 

N/A

 

(1)   Includes capitalized expenditures of $81 million, $53 million and $41 million for the years ended December 31, 2020, 2019 and 2018, respectively.

 

At December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Receivable from Canadys Refined Coal, LLC

 

$

—

 

 

$

2

 

Payable to Canadys Refined Coal, LLC

 

 

—

 

 

 

2

 

Payable to DESS

 

 

59

 

 

 

76

 

Payable to Public Service Company of North Carolina, Incorporated

 

 

5

 

 

 

8

 

Payable to solar affiliates

 

 

1

 

 

 

—

 

Receivable from DECG

 

 

—

 

 

 

1

 

Payable to DECG

 

 

—

 

 

 

5

 

 

Borrowings from an affiliate are described in Note 6. Certain disclosures regarding DESC’s participation in SCANA's noncontributory defined benefit pension plan and unfunded postretirement health care and life insurance programs are included in Note 11.
v3.20.4
Other Income (Expense), Net
 12 Months Ended
Dec. 31, 2020
Income Statement [Abstract]  
Other Income (Expense), Net

17.  OTHER INCOME (EXPENSE), NET

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

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

Revenues from contracts with customers

 

$

1

 

 

$

4

 

 

$

5

 

Other income

 

 

13

 

 

 

19

 

 

 

141

 

Other expense

 

 

(38

)

 

 

(57

)

 

 

(28

)

Allowance for equity funds used during construction

 

 

1

 

 

 

1

 

 

 

11

 

Other income (expense), net

 

$

(23

)

 

$

(33

)

 

$

129

 

 

Other income in 2018 includes gains from the settlement of interest rate derivatives of $115 million (see Note 8). Non-service cost components of pension and other postretirement benefits are included in other expense.
v3.20.4
Quarterly Financial Information
 12 Months Ended
Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]  
Quarterly Financial Information

18.  QUARTERLY FINANCIAL DATA (UNAUDITED)

A summary of DESC’s quarterly results of operations for the years ended December 31, 2020 and 2019 follows. Amounts reflect all adjustments necessary in the opinion of management for a fair statement of the results for the interim periods. Results for interim periods may fluctuate as a result of weather conditions, changes in rates and other factors.

 

(millions)

 

First

Quarter

 

 

Second

Quarter

 

 

Third

Quarter

 

 

Fourth

Quarter

 

2020

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Operating revenue

 

$

672

 

 

$

624

 

 

$

755

 

 

$

688

 

Operating income

 

 

171

 

 

 

144

 

 

 

180

 

 

 

136

 

Total comprehensive income

 

 

93

 

 

 

67

 

 

 

106

 

 

 

43

 

Comprehensive income available to

   common shareholder

 

 

88

 

 

 

69

 

 

 

101

 

 

 

39

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2019

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Operating revenue

 

$

(335

)

 

$

698

 

 

$

795

 

 

$

771

 

Operating income (loss)

 

 

(1,143

)

 

 

17

 

 

 

261

 

 

 

(76

)

Total comprehensive income (loss)

 

 

(1,103

)

 

 

(70

)

 

 

143

 

 

 

(191

)

Comprehensive income (loss) available (attributable) to

   common shareholder

 

 

(1,109

)

 

 

(78

)

 

 

143

 

 

 

(195

)

 

DESC’s 2020 results include the impact of the following significant item:

 

•

Fourth quarter results include a $35 million after-tax charge related to litigation.

 

•

Third quarter results include a $40 million after-tax charge related to litigation.

 

DESC’s 2019 results include the impact of the following significant items:

 

•

Fourth quarter results include a $240 million after-tax charge related to litigation.

 

•

Second quarter results include a $75 million after-tax charge related to litigation and a $47 million after-tax charge related to a voluntary retirement program.

 

•

First quarter results include a $756 million after-tax charge for refunds of amounts previously collected from retail electric customers for the NND Project, a $198 million tax charge for $264 million of income tax-related regulatory assets for which DESC committed to forgo recovery, a $118 million after-tax charge for a settlement agreement of a DESC ratepayer class

 

action lawsuit and an $86 million after-tax charge for property, plant and equipment for which DESC committed to forgo recovery.
v3.20.4
Summary of Significant Accounting Policies (Policies)
 12 Months Ended
Dec. 31, 2020
Accounting Policies [Abstract]  
General

General

DESC makes certain estimates and assumptions in preparing its Consolidated Financial Statements in accordance with GAAP. These estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the dates of the financial statements and the reported amounts of revenues, expenses and cash flows for the periods presented. Actual results may differ from those estimates.

DESC’s Consolidated Financial Statements include, after eliminating intercompany balances and transactions, the accounts of DESC, GENCO and Fuel Company. DESC has concluded that GENCO and Fuel Company are VIEs due to the members lacking the characteristics of a controlling financial interest. DESC is the primary beneficiary of GENCO and Fuel Company and therefore is required to consolidate the VIEs. The equity interests in GENCO and Fuel Company are held solely by SCANA, DESC’s parent. As a result, GENCO and Fuel Company’s equity and results of operations are reflected as noncontrolling interest in the Consolidated Financial Statements.

GENCO owns a coal-fired electric generating station with a 605 MW net generating capacity (summer rating). GENCO’s electricity is sold exclusively to DESC, pursuant to a FERC approved power purchase agreement and related operating agreement. The effects of these transactions are eliminated in consolidation. Fuel Company acquires, owns and provides financing for DESC's nuclear fuel, certain fossil fuels and emission and other environmental allowances. See also Note 6.

Additionally, effective January 2021, 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 had previously purchased such services from DESS, an affiliated VIE, that had provided such services to all SCANA subsidiaries. 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 16 for amounts attributable to affiliates.

DESC reports certain contracts and instruments at fair value. See Note 9 for further information on fair value measurements.

DESC maintains pension and other postretirement benefit plans. See Note 11 for further information on these plans.

Certain amounts in the 2019 and 2018 Consolidated Financial Statements and Notes have been reclassified to conform to the 2020 presentation for comparative purposes; however, such reclassifications did not affect DESC’s net income, total assets, liabilities, equity or cash flows.
Utility Plant

Utility Plant

Utility plant is stated at original cost. The costs of additions, replacements and betterments to utility plant, including direct labor, material and indirect charges for engineering, supervision and AFUDC, are added to utility plant accounts. The original cost of utility property retired or otherwise disposed of is removed from utility plant accounts and generally charged to accumulated depreciation. The costs of repairs and replacements of items of property determined to be less than a unit of property or that do not increase the asset’s life or functionality are charged to expense.

AFUDC is a noncash item that reflects the period cost of capital devoted to plant under construction. This accounting practice results in the inclusion of, as a component of construction cost, the costs of debt and equity capital dedicated to construction investment. AFUDC is included in rate base investment and depreciated as a component of plant cost in establishing rates for utility services. DESC calculated AFUDC using average composite rates of 2.6%, 4.3% and 7.0% for 2020, 2019 and 2018, respectively. These rates do not exceed the maximum rates allowed in the various regulatory jurisdictions. DESC capitalizes interest on nuclear fuel in process at the actual interest cost incurred.

For property subject to cost-of-service rate regulation that will be abandoned significantly before the end of its useful life, the net carrying value is reclassified from utility plant-in-service when it becomes probable it will be abandoned and recorded as a regulatory asset for amounts expected to be collected through future rates.

Provisions for depreciation and amortization are recorded using the straight-line method based on the estimated service lives of the various classes of property, and in most cases, include provisions for future cost of removal. The composite weighted average depreciation rates for utility plant by function were as follows:

 

 

 

2020

 

 

2019

 

Generation

 

 

2.50

%

 

 

2.50

%

Transmission

 

 

2.56

%

 

 

2.57

%

Distribution

 

 

2.42

%

 

 

2.41

%

Storage

 

 

2.75

%

 

 

2.74

%

General and other

 

 

3.17

%

 

 

3.22

%

 

DESC records nuclear fuel amortization using the units-of-production method, which is included in fuel used in electric generation and recovered through the fuel cost component of retail electric rates.
Major Maintenance

Major Maintenance

Planned major maintenance costs related to certain fossil fuel turbine generator equipment and nuclear refueling outages are accrued in periods other than when incurred in accordance with approval by the South Carolina Commission for such accounting treatment and rate recovery of expenses accrued thereunder. The difference between such cumulative major maintenance costs and cumulative collections is classified as a regulatory asset or regulatory liability on the consolidated balance sheet. Other planned major maintenance is expensed when incurred.

DESC is authorized to collect $18 million annually through electric rates to offset certain turbine generator maintenance expenditures. For the years ended December 31, 2020 and 2019, DESC incurred $19 million and $10 million, respectively, for turbine generator maintenance.

Nuclear refueling outages are scheduled 18 months apart. As approved by the South Carolina Commission, DESC accrues $17 million annually for its portion of the nuclear refueling outages, of which DESC accrued $8 million for outages scheduled from the spring of 2014 through the spring of 2020 and $9 million for outages scheduled from the fall of 2021 through the fall of 2027. Refueling outage costs incurred for which DESC was responsible totaled $23 million in 2020 and $2 million in 2019.
Asset Retirement Obligations

Asset Retirement Obligations

DESC recognizes AROs at fair value as incurred or when sufficient information becomes available to determine a reasonable estimate of the fair value of future retirement activities to be performed, for which a legal obligation exists. These amounts are generally capitalized as costs of the related tangible long-lived assets. Since relevant market information is not available, fair value is estimated using discounted cash flow analyses. Periodically, DESC assesses its AROs to determine if circumstances indicate that estimates of the amounts or timing of future cash flows associated with retirement activities have changed. AROs are adjusted when significant changes in the amounts or timing of future cash flows are identified. DESC reports accretion of AROs and depreciation on asset retirement costs as an adjustment to regulatory assets.
Nuclear Decommissioning

Nuclear Decommissioning

Based on a decommissioning cost study completed in 2020, DESC’s two-thirds share of estimated site-specific nuclear decommissioning costs for Summer, including the cost of decommissioning plant components both subject to and not subject to radioactive contamination, totals $744 million, stated in 2020 dollars. Santee Cooper is responsible for decommissioning costs related to its one-third ownership interest in Summer. The cost estimate assumes that the site will be maintained over a period of approximately 60 years in such a manner as to allow for subsequent decontamination that would permit release for unrestricted use.

Under DESC’s method of funding decommissioning costs, DESC transfers to an external trust fund the amounts collected through rates ($3 million in each period presented), less expenses. The trust invests the amounts transferred into insurance policies on the lives of certain company personnel. Insurance proceeds are reinvested in insurance policies. The asset balance held in trust reflects the net cash surrender value of the insurance policies and cash held by the trust. Management intends for the fund, including earnings thereon, to provide for all eventual decommissioning expenditures for Summer on an after-tax basis.
Cash, Restricted Cash and Equivalents

Cash, Restricted Cash and Equivalents

Cash, restricted cash and equivalents include cash on hand, cash in banks and temporary investments purchased with an original maturity of three months or less. At both December 31, 2020 and 2019, there were no restricted cash and equivalent balances.

Receivables

Receivables

Customer receivables reflect amounts due from customers arising from the delivery of energy or related services and include both billed and unbilled amounts earned pursuant to revenue recognition practices described in Note 4. Customer receivables are generally due within one month of receipt of invoices which are presented on a monthly cycle basis. Unbilled revenues totaled $156 million and $114 million at December 31, 2020 and 2019, respectively.

 

DESC sells electricity and natural gas and provides distribution and transmission services to customers in South Carolina. Management believes that this geographic concentration risk is mitigated by the diversity of DESC’s customer base, which includes a large number of residential, commercial and industrial customers. Credit risk associated with accounts receivable is limited due to the large number of customers. DESC’s exposure to potential concentrations of credit risk results primarily from amounts due from Santee Cooper related to the jointly owned nuclear generating facilities at Summer. Such receivables represented approximately 6% of DESC’s accounts receivable balance at December 31, 2020.
Inventories

Inventories

Materials and supplies include the average cost of transmission, distribution, and generating plant materials. Materials are charged to inventory when purchased and then expensed or capitalized to plant, as appropriate, at weighted average cost when used. Fuel inventory includes the average cost of coal, natural gas, fuel oil and emission allowances. Fuel is charged to inventory when purchased and is expensed, at weighted average cost, as used and recovered through fuel cost recovery rates approved by the South Carolina Commission.
Income Taxes

Income Taxes

A consolidated federal income tax return was filed for SCANA, including DESC for years through 2018. Beginning in 2019, SCANA and DESC are part of Dominion Energy’s consolidated federal income tax return. In addition, where applicable, combined income tax returns for Dominion Energy, including DESC, are filed in various states including South Carolina; otherwise, separate state income tax returns are filed.

DESC participated in intercompany tax sharing agreements with SCANA through the SCANA Combination, and currently participates in similar agreements with Dominion Energy. Under both SCANA and Dominion Energy’s tax sharing agreements, current income taxes are based on taxable income or loss and credits determined on a separate company basis.

Under the agreements, if a subsidiary incurs a tax loss or earns a credit, recognition of current income tax benefits is limited to refunds of prior year taxes obtained by the carryback of the net operating loss or credit or to the extent the tax loss or credit is absorbed by the taxable income of other SCANA or Dominion Energy consolidated group members. Otherwise, the net operating loss or credit is carried forward and is recognized as a deferred tax asset until realized.

Accounting for income taxes involves an asset and liability approach. Deferred income tax assets and liabilities are provided, representing future effects on income taxes for temporary differences between the bases of assets and liabilities for financial reporting and tax purposes. Accordingly, deferred taxes are recognized for the future consequences of different treatments used for the reporting of transactions in financial accounting and income tax returns. DESC establishes a valuation allowance when it is more-likely-than-not that all, or a portion, of a deferred tax asset will not be realized. DESC did not have any valuation allowances recorded for the periods presented. Where the treatment of temporary differences is different for rate-regulated operations, a regulatory asset is recognized if it is probable that future revenues will be provided for the payment of deferred tax liabilities.

DESC recognizes positions taken, or expected to be taken, in income tax returns that are more-likely-than-not to be realized, assuming that the position will be examined by tax authorities with full knowledge of all relevant information. At December 31, 2020, DESC had $138 million of unrecognized tax benefits.

If it is not more-likely-than-not that a tax position, or some portion thereof, will be sustained, the related tax benefits are not recognized in the financial statements. Unrecognized tax benefits may result in an increase in income taxes payable, a reduction of income tax refunds receivable or changes in deferred taxes. Also, when uncertainty about the deductibility of an amount is limited to the timing of such deductibility, the increase in income taxes payable (or reduction in tax refunds receivable) is accompanied by a decrease in deferred tax liabilities. Except when such amounts are presented net with amounts receivable from or amounts prepaid to tax authorities, noncurrent income taxes payable related to unrecognized tax benefits are classified in other deferred credits and other liabilities on the Consolidated Balance Sheets and current payables are included in taxes accrued on the Consolidated Balance Sheets.

 

DESC recognizes interest on underpayments and overpayments of income taxes in interest expense and interest income, respectively. Penalties are also recognized in other expenses.

Interest expense for DESC was $7 million, $18 million and $8 million in 2020, 2019, and 2018, respectively. Interest income for DESC was less than $1 million in 2020 and $2 million in both 2019 and 2018. DESC also recorded penalty expenses of $4 million in 2020 and $7 million in 2019.

At December 31, 2020, DESC had an income tax-related affiliated payable of $31 million to Dominion Energy. This balance is expected to be paid to Dominion Energy.

At December 31, 2019, DESC had an income tax-related affiliated receivable of $21 million from Dominion Energy. This balance was received from Dominion Energy in 2020.

At DESC investment tax credits are deferred and amortized over the service lives of the properties giving rise to the credits. Production tax credits are recognized as energy is generated and sold.
Regulatory Assets and Liabilities

Regulatory Assets and Liabilities

The accounting for DESC’s regulated electric and gas operations differs from the accounting for nonregulated operations in that DESC is required to reflect the effect of rate regulation in its Consolidated Financial Statements. For regulated businesses subject to federal or state cost-of-service rate regulation, regulatory practices that assign costs to accounting periods may differ from accounting methods generally applied by nonregulated companies. When it is probable that regulators will permit the recovery of current costs through future rates charged to customers, these costs that otherwise would be expensed by nonregulated companies are deferred as regulatory assets. Likewise, regulatory liabilities are recognized when it is probable that regulators will require customer refunds through future rates or when revenue is collected from customers for expenditures that have yet to be incurred.

 

DESC evaluates whether or not recovery of its regulatory assets through future rates is probable as well as whether a regulatory liability due to customers is probable and makes various assumptions in its analyses. These analyses are generally based on:

 

 

•

Orders issued by regulatory commissions, legislation and judicial actions;

 

•

Past experience;

 

•

Discussions with applicable regulatory authorities and legal counsel;

 

•

Forecasted earnings; and

 

•

Considerations around the likelihood of impacts from events such as unusual weather conditions, extreme weather events and other natural disasters and unplanned outages of facilities.

 

Generally, regulatory assets and liabilities are amortized into income over the period authorized by the regulator. If recovery of a regulatory asset is determined to be less than probable, it will be written off in the period such assessment is made. A regulatory liability, if considered probable, will be recorded in the period such assessment is made or reversed into earnings if no longer probable. See Note 3 to the Consolidated Financial Statements for additional information.
Derivative Instruments

Derivative Instruments

DESC uses derivative instruments such as swaps to manage interest rate risks of its business operations. Derivatives are required to be reported in the Consolidated Balance Sheets at fair value. Derivative contracts representing unrealized gain positions are reported as derivative assets. Derivative contracts representing unrealized losses are reported as derivative liabilities.

 

DESC does not offset amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral against amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement. DESC had margin assets of $17 million and $19 million associated with cash collateral at December 31, 2020 and 2019, respectively. DESC had no margin liabilities associated with cash collateral at December 31, 2020 and 2019. See Note 8 for further information about derivatives.

 

Changes in the fair value of derivative instruments result in the recognition of regulatory assets or regulatory liabilities. Realized gains or losses on the derivative instruments are generally recognized when the related transactions impact earnings. All income statement activity, including amounts realized upon settlement, is presented in interest charges based on the nature of the underlying risk.

 

DERIVATIVE INSTRUMENTS DESIGNATED AS HEDGING INSTRUMENTS

In accordance with accounting guidance pertaining to derivatives and hedge accounting, DESC designates a portion of their derivative instruments as cash flow hedges for accounting purposes. For derivative instruments that are accounted for as cash flow hedges, the cash flows from the derivatives and from the related hedged items are classified in operating cash flows.

 

Cash Flow Hedges- DESC uses interest rate swaps to hedge its exposure to variable interest rates on long-term debt. For transactions in which DESC is hedging the variability of cash flows, changes in the fair value of the derivatives are reported in regulatory assets or liabilities. Any derivative gains or losses reported in regulatory assets or liabilities are reclassified to earnings when the forecasted item is included in earnings. For cash flow hedge transactions, hedge accounting is discontinued if the occurrence of the forecasted transaction is no longer probable.

Pursuant to regulatory orders, interest rate derivatives entered into by DESC after October 2013 were not designated for accounting purposes as cash flow hedges, and fair value changes and settlement amounts related to them have been recorded as regulatory assets and liabilities. Settlement losses on swaps generally have been amortized over the lives of subsequent debt issuances, and gains have been amortized to interest charges or have been applied as otherwise directed by the South Carolina Commission. See Note 17 regarding the settlement gains realized in the first quarter of 2018.
Debt Issuance Costs

Debt Issuance Costs

DESC defers and amortizes debt issuance costs and debt premiums or discounts over the expected lives of the respective debt issues, considering maturity dates and, if applicable, redemption rights held by others. Deferred debt issuance costs are recorded as a reduction in long-term debt in the Consolidated Balance Sheets. Amortization of the issuance costs is reported as interest charges. As permitted by regulatory authorities, gains or losses resulting from the refinancing or redemption of debt are deferred and amortized.
Environmental

Environmental

An environmental assessment program is maintained to identify and evaluate current and former operations sites that could require environmental clean-up. As site assessments are initiated, estimates are made of the amount of expenditures, if any, deemed necessary to investigate and remediate each site. Environmental remediation liabilities are accrued when the criteria for loss contingencies are met. These estimates are refined as additional information becomes available; therefore, actual expenditures could differ significantly from the original estimates. Probable and estimable costs are accrued related to environmental sites on an undiscounted basis. Amounts estimated and accrued to date for site assessments and clean-up relate solely to regulated operations. Amounts expected to be recovered through rates are recorded in regulatory assets and, if applicable, amortized over approved amortization periods. Other environmental costs are expensed as incurred.
Statement of Operations Presentation

Statement of Operations Presentation

Revenues and expenses arising from regulated businesses are presented within Operating Income (Loss), and all other activities are presented within Other Income (Expense), net.
Operating Revenue

Operating Revenue

Operating revenue is recorded on the basis of services rendered, commodities delivered, or contracts settled and includes amounts yet to be billed to customers. DESC collects sales, consumption, consumer utility taxes and sales taxes; however, these amounts are excluded from revenue and are recorded as liabilities until they are remitted to the respective taxing authority.

The primary types of sales and service activities reported as operating revenue for DESC, subsequent to the adoption of revised guidance for revenue recognition from contracts with customers, are as follows:

Revenue from Contracts with Customers

 

•

Regulated electric sales consist primarily of state-regulated retail electric sales, and federally-regulated wholesale electric sales and electric transmission services;

 

•

Regulated gas sales consist primarily of state-regulated natural gas sales and related distribution services; and

 

•

Other regulated revenue consists primarily of miscellaneous service revenue from electric and gas distribution operations and sales of excess electric capacity and other commodities.

Other Revenue

 

•

Other revenue consists primarily of alternative revenue programs, gains and losses from derivative instruments not subject to hedge accounting and lease revenues.

 

DESC records refunds to customers as required by the South Carolina Commission as a reduction to regulated electric sales or regulated gas sales, as applicable. Revenues from electric and gas sales are recognized over time, as the customers of DESC consume gas and electricity as it is delivered. Sales of products and services typically transfer control and are recognized as revenue upon delivery of the product or service. The customer is able to direct the use of, and obtain substantially all of the benefits from, the product at the time the product is delivered. The contract with the customer states the final terms of the sale, including the description, quantity and price of each product or service purchased. Payment for most sales and services varies by contract type, but is typically due within a month of billing.

 

DESC customers subject to an electric fuel cost recovery component or a PGA are billed based on a fuel or cost of gas factor calculated in accordance with cost recovery procedures approved by the South Carolina Commission and subject to adjustment periodically. Any difference between actual costs and amounts contained in rates is adjusted through revenue and is deferred and included when making the next adjustment to the cost recovery factors.

 

Certain amounts deferred for the WNA arise under specific arrangements with regulators rather than customers and are accounted for as an alternative revenue program. This alternative revenue is included within Other operating revenues, separate from revenue arising from contracts with customers, in the month such adjustments are deferred within regulatory accounts. As permitted, DESC has elected to reduce the regulatory accounts in the period when such amounts are reflected on customer bills without affecting operating revenues.

Performance obligations which have not been satisfied by DESC relate primarily to demand or standby service for natural gas. Demand or standby charges for natural gas arise when an industrial customer reserves capacity on assets controlled by the service provider and may use that capacity to move natural gas it has acquired from other suppliers. For all periods presented, the amount of

revenue recognized by DESC for these charges is equal to the amount of consideration DESC has a right to invoice and corresponds directly to the value transferred to the customer.
Leases

Leases

DESC leases certain assets including vehicles, real estate, office equipment and other assets under both operating and finance leases. For operating leases, rent expense is recognized on a straight-line basis over the term of the lease agreement, subject to regulatory framework. Rent expense associated with operating leases, short-term leases and variable leases is primarily recorded in other operations and maintenance expense in the Consolidated Statements of Comprehensive Income (Loss). Rent expense associated with finance leases results in the separate presentation of interest expense on the lease liability and amortization expense of the related right-of-use asset in the Consolidated Statements of Comprehensive Income (Loss). Amortization expense and interest charges associated with finance leases are recorded in depreciation and amortization and interest charges, respectively, in the Consolidated Statements of Comprehensive Income (Loss) or deferred within regulatory assets in the Consolidated Balance Sheets.

Certain leases include one or more options to renew, with renewal terms that can extend the lease from one to 70 years. The exercise of renewal options is solely at DESC's discretion and is included in the lease term if the option is reasonably certain to be exercised. A right-of-use asset and corresponding lease liability for leases with original lease terms of one year or less are not included in the Consolidated Balance Sheets, unless such leases contain renewal options that DESC is reasonably certain will be exercised.

The determination of the discount rate utilized has a significant impact on the calculation of the present value of the lease liability included in the Consolidated Balance Sheets. For DESC’s leased assets, the discount rate implicit in the lease is generally unable to be determined from a lessee perspective. As such, DESC uses internally-developed incremental borrowing rates as a discount rate in the calculation of the present value of the lease liability. The incremental borrowing rates are determined based on an analysis of DESC's publicly available secured borrowing rates over various lengths of time that most closely corresponds to DESC's lease maturities.
New Accounting Standards

New Accounting Standards

REVENUE RECOGNITION

In May 2014, the FASB issued revised accounting guidance for revenue recognition from contracts with customers. DESC adopted this revised accounting guidance for interim and annual reporting periods beginning January 1, 2018 using the modified retrospective method. No cumulative effect adjustment was recognized upon adoption. For additional required disclosures, see Note 4.

LEASES

In February 2016, the FASB issued revised accounting guidance for the recognition, measurement, presentation and disclosure of leasing arrangements. The update requires that a liability and corresponding right-of-use asset are recorded on the balance sheet for all leases, including those leases classified as operating leases, while also refining the definition of a lease. In addition, lessees will be required to disclose key information about the amount, timing, and uncertainty of cash flows arising from leasing arrangements. Lessor accounting remains largely unchanged.

The guidance became effective for DESC's interim and annual reporting periods beginning January 1, 2019. DESC adopted this revised accounting guidance using a modified retrospective approach, which requires lessees and lessors to recognize and measure leases at the date of adoption. Under this approach, DESC utilized the transition practical expedient to maintain historical presentation for periods before January 1, 2019. DESC also applied the other practical expedients, which required no reassessment of whether existing contracts are or contain leases, no reassessment of lease classification for existing leases and no evaluation of existing or expired land easements that were not previously accounted for as leases. In connection with the adoption of this revised accounting guidance, DESC recorded $19 million of offsetting right-of-use assets and liabilities for operating leases in effect at the adoption date. See Note 13 for additional information.

 

TAX REFORM

In February 2018, the FASB issued revised accounting guidance to provide clarification on the application of the 2017 Tax Reform Act for balances recorded within AOCI. The revised guidance provides for stranded amounts within AOCI from the impacts of the 2017 Tax Reform Act to be reclassified to retained earnings. DESC adopted this guidance for interim and annual reporting periods beginning January 1, 2019 on a prospective basis. In connection with the adoption of this guidance, DESC reclassified a benefit of $1 million from AOCI to retained earnings. The amounts reclassified reflect the reduction in the federal income tax rate, and the federal benefit of state income taxes, on the components of DESC’s AOCI.
v3.20.4
Summary of Significant Accounting Policies (Tables)
 12 Months Ended
Dec. 31, 2020
Accounting Policies [Abstract]  
Schedule of Weighted Average Depreciation Rates The composite weighted average depreciation rates for utility plant by function were as follows:

 

 

 

2020

 

 

2019

 

Generation

 

 

2.50

%

 

 

2.50

%

Transmission

 

 

2.56

%

 

 

2.57

%

Distribution

 

 

2.42

%

 

 

2.41

%

Storage

 

 

2.75

%

 

 

2.74

%

General and other

 

 

3.17

%

 

 

3.22

%

 
v3.20.4
Rate and Other Regulatory Matters (Tables)
 12 Months Ended
Dec. 31, 2020
Regulated Operations [Abstract]  
Schedule of Regulatory Assets and Liabilities

 

At December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Regulatory assets:

 

 

 

 

 

 

 

 

NND Project costs(1)

 

$

138

 

 

 

138

 

Deferred employee benefit plan costs(2)

 

 

9

 

 

 

13

 

Other unrecovered plant(3)

 

 

14

 

 

 

14

 

DSM programs(4)

 

 

29

 

 

 

17

 

AROs(5)

 

 

2

 

 

 

28

 

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

 

 

1

 

 

 

13

 

Other

 

 

36

 

 

 

48

 

Regulatory assets - current

 

 

229

 

 

 

271

 

NND Project costs(1)

 

 

2,364

 

 

 

2,503

 

AROs(5)

 

 

309

 

 

 

293

 

Cost of reacquired debt(7)(8)

 

 

243

 

 

 

259

 

Deferred employee benefit plan costs(2)

 

 

159

 

 

 

196

 

Deferred losses on interest rate derivatives(9)

 

 

308

 

 

 

305

 

Other unrecovered plant(3)

 

 

61

 

 

 

69

 

DSM programs(4)

 

 

46

 

 

 

54

 

Environmental remediation costs(10)

 

 

20

 

 

 

22

 

Deferred storm damage costs(11)

 

 

45

 

 

 

44

 

Deferred transmission operating costs(12)

 

 

63

 

 

 

37

 

Other(13)

 

 

108

 

 

 

110

 

Regulatory assets - noncurrent

 

 

3,726

 

 

 

3,892

 

Total regulatory assets

 

$

3,955

 

 

$

4,163

 

Regulatory liabilities:

 

 

 

 

 

 

 

 

Monetization of guaranty settlement(14)

 

$

67

 

 

 

67

 

Income taxes refundable through future rates(15)

 

 

21

 

 

 

16

 

Reserve for refunds to electric utility customers(16)

 

 

128

 

 

 

143

 

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

 

 

58

 

 

 

12

 

Other

 

 

9

 

 

 

18

 

Regulatory liabilities - current

 

 

283

 

 

 

256

 

Monetization of guaranty settlement(14)

 

 

903

 

 

 

970

 

Income taxes refundable through future rates(15)

 

 

919

 

 

 

948

 

Asset removal costs(17)

 

 

564

 

 

 

552

 

Deferred gains on interest rate derivatives(9)

 

 

69

 

 

 

71

 

Reserve for refunds to electric utility customers(16)

 

 

540

 

 

 

656

 

Other

 

 

10

 

 

 

13

 

Regulatory liabilities - noncurrent

 

 

3,005

 

 

 

3,210

 

Total regulatory liabilities

 

$

3,288

 

 

$

3,466

 

 

(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. See Note 12 for more information.

(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 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 to 2029. Unamortized amounts are included in rate base and are earning a current return.

(4)

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.

(5)

Represents 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.

(6)

Represents amounts under- or over-collected from customers pursuant to the cost of fuel components approved by the South Carolina Commission.

(7)

Costs of the reacquisition of debt are deferred and amortized as interest expense over the would-be remaining life of the reacquired debt or over the life of the replacement debt if refinanced. The reacquired debt had a weighted-average life of approximately 26 years as of December 31, 2020.

(8)

During 2019, DESC purchased certain of its first mortgage bonds. As a result of these transactions, DESC incurred net costs, including write-offs of unamortized swap losses and gains, discount, premium and debt issuance costs, of $270 million.

(9)

Represents (i) the changes in fair value and payments made or received upon settlement of certain interest rate derivatives designated as cash flow hedges and (ii) the changes in fair value and payments made or received upon settlement of certain other interest rate derivatives not so designated. The amounts recorded with respect to (i) are expected to be amortized to interest expense over the lives of the underlying debt through 2043.The amounts recorded with respect to (ii) are expected to be similarly amortized to interest expense through 2065.

(10)

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 16 years. See Note 12 for more information.

(11)

Represents storm restoration costs for which DESC expects to receive future recovery through customer rates.

(12)

Includes deferred depreciation and property taxes associated with certain transmission assets for which DESC expects recovery from customers through future rates. See Note 12 for more information.

(13)

Various other regulatory assets are expected to be recovered through rates over varying periods through 2047.

(14)

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. See Note 12 for more information.

(15)

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 for more information.

(16)

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. See Note 12 for more information.

(17)

Represents estimated net collections through depreciation rates of amounts to be expended for the removal of assets in the future.
v3.20.4
Operating Revenue (Tables)
 12 Months Ended
Dec. 31, 2020
Revenue Recognition And Deferred Revenue [Abstract]  
Operating Revenue Subsequent to the Adoption of Guidance for Revenue Recognition from Contracts with Customers

DESC’s operating revenue consists of the following:

 

Year Ended December 31,

 

2020

 

 

2019

 

(millions)

 

Electric

 

 

Gas

 

 

Electric

 

 

Gas

 

Customer class:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Residential

 

$

1,127

 

 

$

201

 

 

$

669

 

 

$

194

 

Commercial

 

 

746

 

 

 

103

 

 

 

507

 

 

 

111

 

Industrial

 

 

341

 

 

 

65

 

 

 

224

 

 

 

81

 

Other

 

 

123

 

 

 

18

 

 

 

116

 

 

 

18

 

Revenues from contracts with customers

 

 

2,337

 

 

 

387

 

 

 

1,516

 

 

 

404

 

Other revenues

 

 

15

 

 

 

—

 

 

 

9

 

 

 

—

 

Total Operating Revenues

 

$

2,352

 

 

$

387

 

 

$

1,525

 

 

$

404

 
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)

 

2020

 

 

2019

 

Beginning balance, January 1

 

$

13

 

 

$

15

 

Amortization

 

 

(1

)

 

 

(2

)

Ending balance, December 31

 

$

12

 

 

$

13

 
v3.20.4
Long-Term and Short-Term Debt (Tables)
 12 Months Ended
Dec. 31, 2020
Debt Disclosure [Abstract]  
Schedule of Debt

Long-term debt by type with related weighted-average coupon rates and maturities at December 31, 2020 and 2019 is as follows:

 

At December 31,

 

2020

Weighted-

average

Coupon(1)

 

 

2020

 

 

2019

 

(millions, except percentages)

 

 

 

 

 

 

 

 

 

 

 

 

DESC:

 

 

 

 

 

 

 

 

 

 

 

 

First Mortgage Bonds, 3.22% to 6.625%, due 2021 to 2065

 

 

5.42

%

 

$

3,267

 

 

$

3,267

 

Tax-Exempt Financings:(2)

 

 

 

 

 

 

 

 

 

 

 

 

Variable rate due 2038

 

 

0.13

%

 

 

35

 

 

 

35

 

3.625% and 4.00%, due 2028 and 2033

 

 

3.90

%

 

 

54

 

 

 

54

 

Other

 

 

3.67

%

 

 

1

 

 

 

1

 

GENCO:

 

 

 

 

 

 

 

 

 

 

 

 

Tax-Exempt Financing, variable rate due 2038

 

 

0.13

%

 

 

33

 

 

 

33

 

Affiliated note, 3.05% due 2024

 

 

3.05

%

 

 

230

 

 

 

230

 

Total principal

 

 

 

 

 

 

3,620

 

 

 

3,620

 

Securities due within one year

 

 

3.25

%

 

 

(33

)

 

 

—

 

Unamortized discount, premium and debt issuance costs, net

 

 

 

 

 

 

(30

)

 

 

(32

)

Finance leases

 

 

 

 

 

 

15

 

 

 

20

 

Total long-term debt

 

 

 

 

 

$

3,572

 

 

$

3,608

 

 

 

(1)

Represents weighted-average coupon rates for debt outstanding as of December 31, 2020.

 

(2)

Industrial revenue bonds totaling $68 million are secured by letters of credit that expire, subject to renewal, in the fourth quarter of 2021.
Schedule of Principal Payments of Long-Term Debt

Based on stated maturity dates rather than early redemption dates that could be elected by instrument holders, the scheduled principal payments of long-term debt at December 31, 2020, were as follows:

 

(millions, except percentages)

 

2021

 

 

2022

 

 

2023

 

 

2024

 

 

2025

 

 

Thereafter

 

 

Total

 

First Mortgage Bonds

 

$

33

 

 

$

—

 

 

$

—

 

 

$

—

 

 

$

—

 

 

$

3,234

 

 

$

3,267

 

Tax-Exempt Financings

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

 

 

122

 

 

 

122

 

Other

 

 

—

 

 

 

—

 

 

 

—

 

 

 

230

 

 

 

—

 

 

 

1

 

 

 

231

 

Total

 

$

33

 

 

$

—

 

 

$

—

 

 

$

230

 

 

$

—

 

 

$

3,357

 

 

$

3,620

 

Weighted-average coupon

 

 

3.25

%

 

 

 

 

 

 

 

 

 

 

3.05

%

 

 

 

 

 

 

5.30

%

 

 

 

 
Schedule of Line of Credit Facilities

DESC's share of commercial paper and letters of credit outstanding under its joint credit facility with Dominion Energy, were as follows:

(millions)

 

Facility Limit

 

 

Outstanding

Commercial

Paper

 

 

Outstanding

Letters of

Credit

 

At December 31, 2020

 

 

 

 

 

 

 

 

 

 

 

 

Joint revolving credit facility(1)(2)

 

$

1,000

 

 

$

—

 

 

$

—

 

At December 31, 2019

 

 

 

 

 

 

 

 

 

 

 

 

Joint revolving credit facility(1)

 

$

1,000

 

 

$

—

 

 

$

—

 

 

(1)

A maximum of $1.0 billion of the facility is available to DESC, less any amounts outstanding to co-borrowers. 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 December 31, 2020, 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 borrowings from DESC's parent or from Dominion Energy. This credit facility matures in March 2023 and 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 October 2020, the joint revolving credit facility was amended to remove Dominion Energy Gas as a co-borrower.

v3.20.4
Income Taxes (Tables)
 12 Months Ended
Dec. 31, 2020
Income Tax Disclosure [Abstract]  
Details of Income Tax Expense for Continuing Operations Including Noncontrolling Interests

 

Details of income tax expense for continuing operations including noncontrolling interests were as follows:

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

Current:

 

 

 

 

 

 

 

 

 

 

 

 

Federal

 

$

(139

)

 

$

—

 

 

$

(16

)

State

 

 

3

 

 

 

34

 

 

 

0

 

Total current expense (benefit)

 

 

(136

)

 

 

34

 

 

 

(16

)

Deferred:

 

 

 

 

 

 

 

 

 

 

 

 

Federal

 

 

 

 

 

 

 

 

 

 

 

 

Taxes before operating loss carryforwards, investment tax credits and tax reform

 

 

158

 

 

 

(90

)

 

 

(216

)

2017 Tax Reform Act impact

 

 

—

 

 

 

—

 

 

 

(176

)

Tax utilization expense of operating loss carryforwards

 

 

33

 

 

 

102

 

 

 

46

 

State

 

 

17

 

 

 

(57

)

 

 

(52

)

Total deferred expense (benefit)

 

 

208

 

 

 

(45

)

 

 

(398

)

Investment tax credit-amortization

 

 

(1

)

 

 

(1

)

 

 

(2

)

Total income tax expense (benefit)

 

$

71

 

 

$

(12

)

 

$

(416

)
Schedule of Effective Income Tax Rate Reconciliation

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

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

U.S. statutory rate

 

 

21.0

%

 

 

21.0

%

 

 

21.0

%

Increases (reductions) resulting from:

 

 

 

 

 

 

 

 

 

 

 

 

State taxes, net of federal benefit

 

 

4.2

 

 

 

3.9

 

 

 

3.8

 

State investment tax credits

 

 

—

 

 

 

—

 

 

 

0.3

 

AFUDC - equity

 

 

(0.1

)

 

 

—

 

 

 

0.2

 

Amortization of federal investment tax credits

 

 

(0.4

)

 

 

0.1

 

 

 

0.2

 

Production tax credits

 

 

—

 

 

 

0.4

 

 

 

0.9

 

Reversal of excess deferred income taxes

 

 

(6.0

)

 

 

(1.4

)

 

 

—

 

Federal legislative change

 

 

—

 

 

 

—

 

 

 

17.5

 

NND Project impairment

 

 

—

 

 

 

(2.4

)

 

 

(2.3

)

Write-off of regulatory asset

 

 

—

 

 

 

(15.8

)

 

 

—

 

Changes in unrecognized tax benefits

 

 

—

 

 

 

(5.1

)

 

 

—

 

Other

 

 

0.1

 

 

 

0.2

 

 

 

(0.2

)

Effective tax rate

 

 

18.8

%

 

 

0.9

%

 

 

41.4

%
Schedule of Deferred Income Taxes

 

DESC’s deferred income taxes consist of the following:

 

At December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Deferred income taxes:

 

 

 

 

 

 

 

 

Total deferred income tax assets

 

$

1,101

 

 

$

1,258

 

Total deferred income tax liabilities

 

 

1,941

 

 

 

1,868

 

Total net deferred income tax liabilities

 

$

840

 

 

$

610

 

Total deferred income taxes:

 

 

 

 

 

 

 

 

Depreciation method and plant basis differences

 

$

1,098

 

 

$

1,007

 

Excess deferred income taxes

 

 

(233

)

 

 

(231

)

Unrecovered nuclear plant cost

 

 

529

 

 

 

553

 

DESC rate refund

 

 

(140

)

 

 

(169

)

Toshiba settlement

 

 

(204

)

 

 

(219

)

Nuclear decommissioning

 

 

(51

)

 

 

(43

)

Deferred state income taxes

 

 

208

 

 

 

200

 

Federal benefit of deferred state income taxes

 

 

(44

)

 

 

(42

)

Deferred fuel, purchased energy and gas costs

 

 

(12

)

 

 

7

 

Pension benefits

 

 

39

 

 

 

46

 

Other postretirement benefits

 

 

(37

)

 

 

(35

)

Loss and credit carryforwards

 

 

(382

)

 

 

(391

)

Other

 

 

69

 

 

 

(73

)

Total net deferred income tax liabilities

 

$

840

 

 

$

610

 

Deferred Investment Tax Credits-Regulated Operations

 

 

18

 

 

 

19

 

Total Deferred Taxes and Deferred Investment Tax Credits

 

$

858

 

 

$

629

 

 

 
Summary of Tax Credit Carryforwards

At December 31, 2020, DESC had the following deductible loss and credit carryforwards:

 

(millions)

 

Deductible Amount

 

 

Deferred Tax Asset

 

 

Expiration Period

Federal losses

 

$

1,052

 

 

$

221

 

 

2037

Federal production and other credits

 

 

—

 

 

 

31

 

 

2035-2038

State losses

 

 

2,418

 

 

 

121

 

 

2037

State investment and other credits

 

 

—

 

 

 

36

 

 

2026-2031

Total

 

$

3,470

 

 

$

409

 

 

 
Schedule of Unrecognized Tax Benefits Roll Forward

A reconciliation of changes in DESC’s unrecognized tax benefits follows:

 

(millions)

 

2020

 

 

2019

 

 

2018

 

Balance at January 1

 

$

132

 

 

$

106

 

 

$

98

 

Increases-prior period positions

 

 

5

 

 

 

76

 

 

 

8

 

Decreases-prior period positions

 

 

—

 

 

 

(53

)

 

 

—

 

Increases-current period positions

 

 

1

 

 

 

3

 

 

 

0

 

Balance at December 31

 

$

138

 

 

$

132

 

 

$

106

 
v3.20.4
Derivative Financial Instruments (Tables)
 12 Months Ended
Dec. 31, 2020
Derivative Instruments And Hedging Activities Disclosure [Abstract]  
Offsetting Liabilities

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:

 

 

 

December 31, 2020

 

 

December 31, 2019

 

 

 

 

 

 

 

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

 

 

Financial

Instruments

 

 

Cash

Collateral

Paid

 

 

Net

Amounts

 

 

Gross

Liabilities

Presented in the

Consolidated

Balance Sheet

 

 

Financial

Instruments

 

 

Cash

Collateral

Paid

 

 

Net

Amounts

 

Interest rate contracts:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Over-the-counter

 

$

27

 

 

$

—

 

 

$

17

 

 

$

10

 

 

$

19

 

 

$

—

 

 

$

19

 

 

$

—

 

Total derivatives

 

$

27

 

 

$

—

 

 

$

17

 

 

$

10

 

 

$

19

 

 

$

—

 

 

$

19

 

 

$

—

 
Schedule of Volume of Derivative Activity

The following table presents the volume of derivative activity at December 31, 2020. These volumes are based on open derivative positions and represent the combined absolute value of their long and short positions.

 

 

 

Current

 

 

Noncurrent

 

Interest rate(1)

 

$

—

 

 

$

71,400,000

 

 

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

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

 

(millions)

 

Fair Value -

Derivatives

under Hedge

Accounting

 

 

Fair Value -

Derivatives not

under Hedge

Accounting

 

 

Total Fair

Value

 

At December 31, 2020

 

 

 

 

 

 

 

 

 

 

 

 

Current Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

$

1

 

 

$

1

 

 

$

2

 

Total current derivative liabilities(1)

 

 

1

 

 

 

1

 

 

 

2

 

Noncurrent Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

 

15

 

 

 

10

 

 

 

25

 

Total noncurrent derivative liabilities(2)

 

 

15

 

 

 

10

 

 

 

25

 

Total derivative liabilities

 

$

16

 

 

$

11

 

 

$

27

 

At December 31, 2019

 

 

 

 

 

 

 

 

 

 

 

 

Current Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

$

1

 

 

$

1

 

 

$

2

 

Total current derivative liabilities(1)

 

 

1

 

 

 

1

 

 

 

2

 

Noncurrent Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

 

11

 

 

 

6

 

 

 

17

 

Total noncurrent derivative liabilities(2)

 

 

11

 

 

 

6

 

 

 

17

 

Total derivative liabilities

 

$

12

 

 

$

7

 

 

$

19

 

 

(1)   Current derivative liabilities are presented in other current liabilities in the Consolidated Balance Sheets.

(2)   Noncurrent derivative liabilities are presented in other deferred credits and other liabilities in the 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 its Consolidated Balance Sheets and Statements of Comprehensive Income (Loss):

Derivatives in Cash Flow Hedging Relationships

(millions)

 

Gain (loss)

Reclassified

from Deferred

Accounts into

Income

 

 

Increase

(Decrease)

in Derivatives

Subject to

Regulatory

Treatment(1)

 

Year Ended December 31, 2020

 

 

 

 

 

 

 

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

 

 

Interest rate(2)

 

$

—

 

 

$

1

 

Total

 

$

—

 

 

$

1

 

Year Ended December 31, 2019

 

 

 

 

 

 

 

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

 

 

Interest rate(2)

 

$

—

 

 

$

1

 

Total

 

$

—

 

 

$

1

 

Year Ended December 31, 2018

 

 

 

 

 

 

 

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

 

 

Interest rate(2)

 

$

(1

)

 

$

1

 

Total

 

$

(1

)

 

$

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 (Loss).

(2)   Amounts recorded in DESC’s Consolidated Statements of Comprehensive Income (Loss) are classified in interest charges.

Derivatives Not Designated as Hedging Instruments

Derivatives Not designated as Hedging Instruments

 

(millions)

 

Amount of Gain (Loss)

Recognized in Income on

Derivatives(1)

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

Derivative type and location of gains (losses):

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate contracts:

 

 

 

 

 

 

 

 

 

 

 

 

Interest income

 

$

(1

)

 

$

(1

)

 

$

(2

)

Other income

 

 

—

 

 

 

—

 

 

 

115

 

Total

 

$

(1

)

 

$

(1

)

 

$

113

 

 

(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 (Loss).
v3.20.4
Fair Value Measurements, Including Derivatives (Tables)
 12 Months Ended
Dec. 31, 2020
Fair Value Disclosures [Abstract]  
Schedule of Liabilities Measured at Fair Value on Recurring Basis

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

 

 

Level 1

 

 

Level 2

 

 

Level 3

 

 

Total

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

At December 31, 2020

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

$

—

 

 

$

27

 

 

$

—

 

 

$

27

 

Total liabilities

 

$

—

 

 

$

27

 

 

$

—

 

 

$

27

 

At December 31, 2019

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Liabilities

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Interest rate

 

$

—

 

 

$

19

 

 

$

—

 

 

$

19

 

Total liabilities

 

$

—

 

 

$

19

 

 

$

—

 

 

$

19

 
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:

At December 31,

 

2020

 

 

2019

 

(millions)

 

Carrying

Amount

 

 

Estimated

Fair Value(1)

 

 

Carrying

Amount

 

 

Estimated

Fair Value(1)

 

Long-term debt(2)

 

$

3,360

 

 

$

4,748

 

 

$

3,358

 

 

$

4,262

 

Affiliated long-term debt

 

 

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 included in securities due within one year and amounts which represent the unamortized debt issuance costs and discount or premium.
v3.20.4
Asset Retirement Obligations (Tables)
 12 Months Ended
Dec. 31, 2020
Asset Retirement Obligation Disclosure [Abstract]  
Schedule of Reconciliation of the Carrying Amount of AROs

A reconciliation of the beginning and ending aggregate carrying amount of AROs is as follows:

 

(millions)

 

2020

 

 

2019

 

Beginning balance

 

$

489

 

 

$

541

 

Liabilities settled

 

 

(4

)

 

 

(29

)

Accretion expense

 

 

23

 

 

 

23

 

Revisions in estimated cash flows(1)

 

 

89

 

 

 

(46

)

Ending balance

 

$

597

 

 

$

489

 

(1)   The increase in 2020 reflects revisions from the nuclear decommissioning cost study. The decrease in 2019 reflects a change in the estimated timing of cash flows for interim pipeline replacements and DOE recoveries.
v3.20.4
Employee Benefit Plans and Equity Compensation Plan (Tables)
 12 Months Ended
Dec. 31, 2020
Compensation And Retirement Disclosure [Abstract]  
Schedule of Changes in Projected Benefit Obligations

The measurement date used to determine pension and other postretirement benefit obligations is December 31. Data related to the changes in the projected benefit obligation for pension benefits and the accumulated benefit obligation for other postretirement benefits are presented below.

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

(millions)

 

2020

 

 

2019

 

 

2020

 

 

2019

 

Benefit obligation, January 1

 

$

727

 

 

$

732

 

 

$

214

 

 

$

187

 

Service cost

 

 

12

 

 

 

15

 

 

 

3

 

 

 

3

 

Interest cost

 

 

24

 

 

 

28

 

 

 

8

 

 

 

9

 

Plan participants’ contributions

 

 

—

 

 

 

—

 

 

 

2

 

 

 

1

 

Actuarial (gain) loss

 

 

41

 

 

 

47

 

 

 

(31

)

 

 

22

 

Benefits paid

 

 

(22

)

 

 

(21

)

 

 

(13

)

 

 

(13

)

Settlements

 

 

(40

)

 

 

(80

)

 

 

—

 

 

 

—

 

Curtailment

 

 

—

 

 

 

6

 

 

 

—

 

 

 

3

 

Amounts funded to parent

 

 

—

 

 

 

—

 

 

 

1

 

 

 

2

 

Benefit obligation, December 31

 

$

742

 

 

$

727

 

 

$

184

 

 

$

214

 
Schedule of Assumptions Used to Determine Benefit Obligations

Significant assumptions used to determine the above benefit obligations are as follows:

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

 

 

2020

 

 

2019

 

 

2020

 

 

2019

 

Annual discount rate used to determine benefit obligation

 

 

2.73

%

 

 

3.47

%

 

 

2.80

%

 

 

3.52

%

Assumed annual rate of future salary increases for projected

   benefit obligation

 

 

4.52

%

 

 

3.00

%

 

N/A

 

 

N/A

 

Crediting interest rate for cash balance plans

 

 

1.93

%

 

 

2.67

%

 

N/A

 

 

N/A

 
Schedule of Net Funded Status

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

At December 31,

 

2020

 

 

2019

 

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fair value of plan assets

 

$

747

 

 

$

725

 

 

$

—

 

 

$

—

 

Benefit obligation

 

 

742

 

 

 

727

 

 

 

184

 

 

 

214

 

Funded status

 

$

5

 

 

$

(2

)

 

$

(184

)

 

$

(214

)

 
Schedule of Amounts Recognized in Balance Sheet

Amounts recognized on the consolidated balance sheets were as follows:

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

At December 31,

 

2020

 

 

2019

 

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Noncurrent assets

 

$

5

 

 

$

—

 

 

$

—

 

 

$

—

 

Current liability

 

 

—

 

 

 

—

 

 

 

(11

)

 

 

(13

)

Noncurrent liability

 

 

—

 

 

 

(2

)

 

 

(173

)

 

 

(201

)
Schedule of Amounts Recognized in Accumulated Other Comprehensive Loss

Amounts recognized in accumulated other comprehensive loss were as follows:

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

At December 31,

 

2020

 

 

2019

 

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Net actuarial loss

 

$

4

 

 

$

2

 

 

$

—

 

 

$

2

 

 
Schedule of Amounts Recognized in Regulatory Assets

Amounts recognized in regulatory assets were as follows:

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

At December 31,

 

2020

 

 

2019

 

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Net actuarial loss

 

$

114

 

 

$

125

 

 

$

1

 

 

$

29

 

 
Schedule of Changes in Fair Value of Plan Assets

Changes in Fair Value of Plan Assets

 

Pension Benefits

 

 

 

 

 

 

 

 

(millions)

 

2020

 

 

2019

 

Fair value of plan assets, January 1

 

$

725

 

 

$

677

 

Actual return (loss) on plan assets

 

 

84

 

 

 

149

 

Benefits paid

 

 

(22

)

 

 

(21

)

Settlements

 

 

(40

)

 

 

(80

)

Fair value of plan assets, December 31

 

$

747

 

 

$

725

 
Schedule of Allocation of Plan Assets

The pension plan asset allocation at December 31, 2020 and 2019 and the target allocation for 2021 are as follows:

 

 

 

Percentage of Plan Assets

 

 

 

Target

Allocation

 

December 31,

 

Asset Category

 

2021

 

2020

 

 

2019

 

U.S. equities

 

25 - 40%

 

 

34

%

 

 

40

%

Non-U.S. equities

 

10 - 20%

 

 

18

%

 

 

19

%

Fixed income

 

45- 65%

 

 

47

%

 

 

32

%

Cash and cash equivalents

 

2-10%

 

 

1

%

 

 

1

%

Company stock

 

0%

 

 

0

%

 

 

5

%

Real estate

 

0%

 

 

0

%

 

 

3

%

 

 

 

 

 

 

 

 

 

 

 
Schedule of Fair Value Measurements By Category At December 31, 2020 and 2019, fair value measurements, and the level within the fair value hierarchy in which the measurements fall, were as follows:

 

At December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Investments with fair value measure at Level 1:

 

 

 

 

 

 

 

 

Cash and cash equivalents

 

$

10

 

 

$

3

 

Investments with fair value measure at Level 2:

 

 

 

 

 

 

 

 

Mutual funds

 

 

—

 

 

 

152

 

Corporate debt instruments

 

 

315

 

 

 

233

 

Government and other debt instruments

 

 

35

 

 

 

26

 

Total assets in the fair value hierarchy

 

 

360

 

 

 

414

 

Investments at net asset value:

 

 

 

 

 

 

 

 

Common collective trust

 

 

387

 

 

 

311

 

Total investments

 

$

747

 

 

$

725

 

 
Schedule of Expected Benefit Payments

Expected Benefit Payments

 

(millions)

 

Pension

Benefits

 

 

Other

Postretirement

Benefits

 

2021

 

$

39

 

 

$

11

 

2022

 

 

45

 

 

 

11

 

2023

 

 

43

 

 

 

11

 

2024

 

 

45

 

 

 

11

 

2025

 

 

44

 

 

 

11

 

2026 - 2030

 

 

201

 

 

 

55

 

 
Components of Net Periodic Benefit Cost

Components of Net Periodic Benefit Cost

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

 

2020

 

 

2019

 

 

2018

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Service cost

 

$

12

 

 

$

15

 

 

$

17

 

 

$

3

 

 

$

3

 

 

$

4

 

Interest cost

 

 

24

 

 

 

28

 

 

 

29

 

 

 

8

 

 

 

9

 

 

 

8

 

Expected return on assets

 

 

(45

)

 

 

(40

)

 

 

(48

)

 

 

—

 

 

 

—

 

 

 

—

 

Prior service cost amortization

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

Amortization of actuarial losses

 

 

6

 

 

 

11

 

 

 

11

 

 

 

—

 

 

 

—

 

 

 

—

 

Settlement loss

 

 

7

 

 

 

16

 

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

Curtailment

 

 

—

 

 

 

6

 

 

 

—

 

 

 

—

 

 

 

3

 

 

 

—

 

Net periodic benefit cost

 

$

4

 

 

$

36

 

 

$

9

 

 

$

11

 

 

$

15

 

 

$

12

 

 
Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss)

Other changes in plan assets and benefit obligations recognized in other comprehensive income (net of tax) were as follows:

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

 

2020

 

 

2019

 

 

2018

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Current year actuarial (gain) loss

 

$

2

 

 

$

(1

)

 

$

1

 

 

$

(2

)

 

$

1

 

 

$

(1

)
Schedule of Defined Benefit Plan Amounts Recognized in Regulatory Assets

Other changes in plan assets and benefit obligations recognized in regulatory assets were as follows:

 

 

 

Pension Benefits

 

 

Other Postretirement Benefits

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

 

2020

 

 

2019

 

 

2018

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Current year actuarial (gain) loss

 

$

1

 

 

$

(51

)

 

$

41

 

 

$

(27

)

 

$

20

 

 

$

(26

)

Amortization of actuarial losses

 

 

(6

)

 

 

(11

)

 

 

(10

)

 

 

(1

)

 

 

—

 

 

 

(1

)

Settlement loss

 

 

(6

)

 

 

(16

)

 

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

Total recognized in regulatory assets

 

$

(11

)

 

$

(78

)

 

$

31

 

 

$

(28

)

 

$

20

 

 

$

(27

)
Schedule of Assumptions Used in Determining Net Periodic Benefit Cost

Significant assumptions used in determining net periodic benefit cost:

 

 

 

Pension Benefits

 

Other Postretirement Benefits

Year Ended December 31,

 

2020

 

2019

 

2018

 

2020

 

2019

 

2018

Discount rate

 

3.47%

 

3.57/4.38%

 

3.71%

 

2.80%

 

4.08/4.41%

 

3.74%

Expected return on plan assets

 

7.00%

 

7.00%

 

7.00%

 

n/a

 

n/a

 

n/a

Rate of compensation increase

 

3.00%

 

3.00%

 

3.00%

 

n/a

 

n/a

 

n/a

Crediting interest rate for cash balance plans

 

2.67%

 

2.77/3.58%

 

4.00%

 

n/a

 

n/a

 

n/a

Health care cost trend rate

 

 

 

 

 

 

 

6.25%

 

6.60%

 

7.00%

Ultimate health care cost trend rate

 

 

 

 

 

 

 

5.00%

 

5.00%

 

5.00%

Year achieved

 

 

 

 

 

 

 

2025-2026

 

2023

 

2023

 
v3.20.4
Commitments and Contingencies (Tables)
 12 Months Ended
Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]  
Schedule of Long-Term Purchase Agreements

At December 31, 2020, DESC had the following long-term commitments that are noncancelable or cancelable only under certain conditions, and that a third party that will provide the contracted goods or services has used to secure financing.

 

(millions)

 

2021

 

 

2022

 

 

2023

 

 

2024

 

 

2025

 

 

Thereafter

 

 

Total

 

Purchased electric capacity(1)

 

$

83

 

 

$

82

 

 

$

82

 

 

$

81

 

 

$

82

 

 

$

915

 

 

$

1,325

 

(1)   Includes affiliated amounts with certain solar facilities of $246 million.
v3.20.4
Leases (Tables)
 12 Months Ended
Dec. 31, 2020
Leases [Abstract]  
Schedule Of Lease Assets and Liabilities Recorded in Consolidated Balance Sheets

At December 31, 2020 and 2019, DESC had the following lease assets and liabilities recorded in the Consolidated Balance Sheets:

 

At December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Lease assets:

 

 

 

 

 

 

 

 

Operating lease assets(1)

 

$

21

 

 

$

23

 

Finance lease assets(2)

 

 

20

 

 

 

26

 

Total lease assets

 

$

41

 

 

$

49

 

Lease liabilities:

 

 

 

 

 

 

 

 

Operating lease - current(3)

 

$

3

 

 

$

3

 

Operating lease - noncurrent(4)

 

 

18

 

 

 

20

 

Finance lease - current(5)

 

 

6

 

 

 

7

 

Finance lease - noncurrent

 

 

15

 

 

 

20

 

Total lease liabilities

 

$

42

 

 

$

50

 

 

(1)   Included in other deferred debits and other assets in the Consolidated Balance Sheets.

(2)   Included in utility plant, net, in the Consolidated Balance Sheets, net of $24 million of accumulated amortization at both December 31, 2020 and 2019.

(3)   Included in other current liabilities in the Consolidated Balance Sheets.

(4)   Included in other deferred credits and other liabilities in the Consolidated Balance Sheets.

(5)   Included in current portion of long-term debt in the Consolidated Balance Sheets.
Summary of Total Lease Cost

For the years ended December 31, 2020 and 2019, total lease cost consisted of the following:

 

Year Ended December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Finance lease cost:

 

 

 

 

 

 

 

 

Amortization

 

$

8

 

 

$

7

 

Interest

 

 

1

 

 

 

1

 

Operating lease cost

 

 

4

 

 

 

4

 

Short-term lease cost

 

 

2

 

 

 

1

 

Total lease cost

 

$

15

 

 

$

13

 
Cash Paid for Amounts Included in Measurement of Lease Liabilities

For the years ended December 31, 2020 and 2019, cash paid for amounts included in the measurement of lease liabilities consisted of the following amounts, included in the Consolidated Statements of Cash Flows:

 

Year Ended December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Operating cash flows from finance leases

 

$

1

 

 

$

1

 

Operating cash flows from operating leases

 

 

4

 

 

 

3

 

Financing cash flows from finance leases

 

 

8

 

 

 

7

 
Summary of Weighted Average Remaining Lease Term And Discount Rate for Operating and Finance Leases

At December 31, 2020 and 2019, the weighted average remaining lease term and weighted average discount rate for finance and operating leases were as follows:

 

At December 31,

 

2020

 

 

2019

 

Weighted average remaining lease term - finance leases

 

4 years

 

 

5 years

 

Weighted average remaining lease term - operating leases

 

19 years

 

 

18 years

 

Weighted average discount rate - finance leases

 

 

2.92

%

 

 

2.94

%

Weighted average discount rate - operating leases

 

 

3.95

%

 

 

3.94

%
Schedule of Maturity Analysis of Operating and Finance Lease Liabilities

Lease liabilities have the following scheduled maturities:

 

(millions)

 

Operating

 

 

Finance

 

2021

 

$

4

 

 

$

7

 

2022

 

 

3

 

 

 

6

 

2023

 

 

2

 

 

 

4

 

2024

 

 

2

 

 

 

3

 

2025

 

 

1

 

 

 

2

 

After 2025

 

 

21

 

 

 

2

 

Total undiscounted lease payments

 

 

33

 

 

 

24

 

Present value adjustment

 

 

(12

)

 

 

(3

)

Present value of lease liabilities

 

$

21

 

 

$

21

 
v3.20.4
Operating Segments (Tables)
 12 Months Ended
Dec. 31, 2020
Segment Reporting [Abstract]  
Schedule of Segment Reporting Information, by Segment

The following table presents segment information pertaining to DESC’s operations:

 

Year Ended December 31,

 

Dominion Energy

South Carolina

 

 

Corporate

and Other

 

 

Consolidated

Total

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

2020

 

 

 

 

 

 

 

 

 

 

 

 

External revenue

 

$

2,739

 

 

$

—

 

 

$

2,739

 

Depreciation and amortization

 

 

474

 

 

 

—

 

 

 

474

 

Interest and related charges

 

 

223

 

 

 

6

 

 

 

229

 

Income tax expense (benefit)

 

 

107

 

 

 

(36

)

 

 

71

 

Comprehensive income (loss) available (attributable) to

   common shareholder

 

 

410

 

 

 

(113

)

 

 

297

 

Capital expenditures

 

 

742

 

 

 

—

 

 

 

742

 

Total assets (billions)

 

 

14.5

 

 

 

—

 

 

 

14.5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2019

 

 

 

 

 

 

 

 

 

 

 

 

External revenue

 

$

2,937

 

 

$

(1,008

)

 

$

1,929

 

Depreciation and amortization

 

 

452

 

 

 

(2

)

 

 

450

 

Interest and related charges

 

 

247

 

 

 

13

 

 

 

260

 

Income tax expense (benefit)

 

 

163

 

 

 

(175

)

 

 

(12

)

Comprehensive income (loss) available (attributable) to

   common shareholder

 

 

408

 

 

 

(1,647

)

 

 

(1,239

)

Capital expenditures

 

 

497

 

 

 

—

 

 

 

497

 

Total assets (billions)

 

 

14.3

 

 

 

—

 

 

 

14.3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2018

 

 

 

 

 

 

 

 

 

 

 

 

External revenue

 

$

2,763

 

 

$

(1

)

 

$

2,762

 

Depreciation and amortization

 

 

327

 

 

 

—

 

 

 

327

 

Interest and related charges

 

 

306

 

 

 

(3

)

 

 

303

 

Income tax expense (benefit)

 

 

98

 

 

 

(514

)

 

 

(416

)

Comprehensive income (loss) available (attributable) to

   common shareholder

 

 

304

 

 

 

(917

)

 

 

(613

)

Capital expenditures

 

 

633

 

 

 

—

 

 

 

633

 

 
v3.20.4
Utility Plant and Nonutility Property (Tables)
 12 Months Ended
Dec. 31, 2020
Utility Plant And Non Utility Property [Abstract]  
Property, Plant and Equipment

Major classes of utility plant and other property and their respective balances at December 31, 2020 and 2019 were as follows:

 

At December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Gross utility plant:

 

 

 

 

 

 

 

 

Generation

 

$

5,921

 

 

$

5,765

 

Transmission

 

 

1,963

 

 

 

1,905

 

Distribution

 

 

4,909

 

 

 

4,685

 

Storage

 

 

74

 

 

 

73

 

General and other

 

 

563

 

 

 

549

 

Intangible

 

 

250

 

 

 

231

 

Construction work in progress

 

 

460

 

 

 

339

 

Nuclear fuel

 

 

575

 

 

 

608

 

Total gross utility plant

 

$

14,715

 

 

$

14,155

 

Gross nonutility property

 

$

45

 

 

$

75

 
Schedule of Jointly Owned Utility Plants

At December 31,

 

2020

 

2019

 

 

Summer Unit 1

 

Summer Unit 1

Percent owned

 

66.7%

 

66.7%

Plant in service

 

$

1.6

 

billion

 

$

1.4

 

billion

Accumulated depreciation

 

$

702

 

million

 

$

684

 

million

Construction work in progress

 

$

62

 

million

 

$

79

 

million

 
v3.20.4
Affiliated and Related Party Transactions (Tables)
 12 Months Ended
Dec. 31, 2020
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 (Loss).

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

Purchases of coal from affiliate

 

$

—

 

 

$

121

 

 

$

150

 

Sales of coal to affiliate

 

 

—

 

 

 

120

 

 

 

149

 

Purchases of fuel used in electric generation from affiliate

 

 

—

 

 

 

43

 

 

 

139

 

Direct and allocated costs from DESS(1)

 

 

294

 

 

 

297

 

 

 

283

 

Operating Revenues – Electric from sales to affiliate

 

 

4

 

 

 

4

 

 

 

5

 

Operating Revenues – Gas from sales to affiliate

 

 

1

 

 

 

1

 

 

 

1

 

Operating Expenses – Other taxes from affiliate

 

 

9

 

 

 

6

 

 

 

6

 

Purchases of electricity from solar affiliates

 

 

12

 

 

 

8

 

 

N/A

 

Demand and transportation charges from DECG - Fuel used in

   electric generation

 

 

16

 

 

 

19

 

 

N/A

 

Demand and transportation charges from DECG - Gas purchased

   for resale

 

 

36

 

 

 

44

 

 

N/A

 

(1)   Includes capitalized expenditures of $81 million, $53 million and $41 million for the years ended December 31, 2020, 2019 and 2018, respectively.
Schedule of Affiliated Transactions

At December 31,

 

2020

 

 

2019

 

(millions)

 

 

 

 

 

 

 

 

Receivable from Canadys Refined Coal, LLC

 

$

—

 

 

$

2

 

Payable to Canadys Refined Coal, LLC

 

 

—

 

 

 

2

 

Payable to DESS

 

 

59

 

 

 

76

 

Payable to Public Service Company of North Carolina, Incorporated

 

 

5

 

 

 

8

 

Payable to solar affiliates

 

 

1

 

 

 

—

 

Receivable from DECG

 

 

—

 

 

 

1

 

Payable to DECG

 

 

—

 

 

 

5

 

 
v3.20.4
Other Income (Expense), Net (Tables)
 12 Months Ended
Dec. 31, 2020
Income Statement [Abstract]  
Components of Other Income (Expense), Net

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

 

Year Ended December 31,

 

2020

 

 

2019

 

 

2018

 

(millions)

 

 

 

 

 

 

 

 

 

 

 

 

Revenues from contracts with customers

 

$

1

 

 

$

4

 

 

$

5

 

Other income

 

 

13

 

 

 

19

 

 

 

141

 

Other expense

 

 

(38

)

 

 

(57

)

 

 

(28

)

Allowance for equity funds used during construction

 

 

1

 

 

 

1

 

 

 

11

 

Other income (expense), net

 

$

(23

)

 

$

(33

)

 

$

129

 
v3.20.4
Quarterly Financial Information (Tables)
 12 Months Ended
Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]  
Schedule of Quarterly Financial Information

A summary of DESC’s quarterly results of operations for the years ended December 31, 2020 and 2019 follows. Amounts reflect all adjustments necessary in the opinion of management for a fair statement of the results for the interim periods. Results for interim periods may fluctuate as a result of weather conditions, changes in rates and other factors.

 

(millions)

 

First

Quarter

 

 

Second

Quarter

 

 

Third

Quarter

 

 

Fourth

Quarter

 

2020

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Operating revenue

 

$

672

 

 

$

624

 

 

$

755

 

 

$

688

 

Operating income

 

 

171

 

 

 

144

 

 

 

180

 

 

 

136

 

Total comprehensive income

 

 

93

 

 

 

67

 

 

 

106

 

 

 

43

 

Comprehensive income available to

   common shareholder

 

 

88

 

 

 

69

 

 

 

101

 

 

 

39

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2019

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Operating revenue

 

$

(335

)

 

$

698

 

 

$

795

 

 

$

771

 

Operating income (loss)

 

 

(1,143

)

 

 

17

 

 

 

261

 

 

 

(76

)

Total comprehensive income (loss)

 

 

(1,103

)

 

 

(70

)

 

 

143

 

 

 

(191

)

Comprehensive income (loss) available (attributable) to

   common shareholder

 

 

(1,109

)

 

 

(78

)

 

 

143

 

 

 

(195

)
v3.20.4
Nature of Operations (Narrative) (Detail) - Segment
 3 Months Ended 12 Months Ended
Dec. 31, 2019
Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]    
Number of primary operating segments 1 1
v3.20.4
Summary of Significant Accounting Policies (Narrative) (Detail)
$ in Millions
 12 Months Ended
Jan. 01, 2019
USD ($)
Dec. 31, 2020
USD ($)
MW
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Significant Accounting Policies          
Public utilities, allowance for funds used during construction, rate   2.60% 4.30% 7.00%  
Utilities operating expense, maintenance and operations   $ 357 $ 388 $ 449  
Turbine maintenance expense   19 10    
Amount accrued annually for nuclear fuel outages   17      
Nuclear refueling outage cost   23 2    
Decommissioning liability, noncurrent   744      
Payments to acquire investments to be held in decommissioning trust fund   3      
Restricted cash and equivalent balances   0 0 0  
Unbilled revenues   156 114    
Unrecognized tax benefits   138 132 106 $ 98
Interest expense   7 18 8  
Interest income     2 $ 2  
Penalty expenses   4 7    
Income taxes related to affiliated payable   31      
Income taxes related to affiliated receivable     21    
Margin liabilities with cash collateral   0 0    
Margin assets with cash collateral   $ 17 19    
Option to extend, existence, operating lease   true      
Operating lease, right of use asset $ 19 $ 21 [1] $ 23 [1]    
Operating lease liability $ 19 21      
Operating Lease, Liability, Statement of Financial Position [Extensible List] us-gaap:OtherLiabilitiesMember        
Reclassification From AOCI to retained earnings $ 1        
Maximum [Member]          
Significant Accounting Policies          
Interest income   $ 1      
Lease renewal term   70 years      
Original term of leases   1 year      
Minimum [Member]          
Significant Accounting Policies          
Lease renewal term   1 year      
Accounts Receivable [Member] | Credit Concentration Risk [Member]          
Significant Accounting Policies          
Concentration risk percentage   6.00%      
Outages Scheduled from the Spring of 2014 through the Spring of 2020 [Member]          
Significant Accounting Policies          
Amount accrued annually for nuclear fuel outages   $ 8      
Outages Scheduled from the Fall of 2021 through the Fall of 2027 [Member]          
Significant Accounting Policies          
Amount accrued annually for nuclear fuel outages   9      
Turbine [Member]          
Significant Accounting Policies          
Utilities operating expense, maintenance and operations   $ 18      
Genco          
Significant Accounting Policies          
Power Generation Capacity Megawatts | MW   605      
[1] Included in other deferred debits and other assets in the Consolidated Balance Sheets.
v3.20.4
Summary of Significant Accounting Policies (Schedule of Weighted Average Depreciation Rates) (Detail)
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Generation    
Composite weighted average depreciation rates for utility plant 2.50% 2.50%
Transmission    
Composite weighted average depreciation rates for utility plant 2.56% 2.57%
Distribution    
Composite weighted average depreciation rates for utility plant 2.42% 2.41%
Storage    
Composite weighted average depreciation rates for utility plant 2.75% 2.74%
General and other    
Composite weighted average depreciation rates for utility plant 3.17% 3.22%
v3.20.4
Rate and Other Regulatory Matters (Narrative) (Detail)
$ in Millions
 1 Months Ended 3 Months Ended 12 Months Ended
Jan. 01, 2021
USD ($)
Apr. 30, 2020
USD ($)
Feb. 28, 2021
USD ($)
Oct. 31, 2020
USD ($)
Aug. 31, 2020
USD ($)
Jun. 30, 2020
USD ($)
kV
mi
Apr. 30, 2020
USD ($)
Jul. 31, 2018
USD ($)
Sep. 30, 2019
USD ($)
Jun. 30, 2019
USD ($)
Dec. 31, 2020
USD ($)
NuclearPlant
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
Feb. 25, 2021
USD ($)
Rate And Other Regulatory Matters [Line Items]                              
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent                     21.00% 21.00% 21.00% 35.00%  
Credits to Customer Related to Tax Act                     $ 66 $ 63 $ 100    
Operating expense                     $ 2,108 2,870 3,593    
Percentage of current authorized earned ROE       9.90%                      
South Carolina Commission Order for Increase/Decrease of Total Fuel Cost Component of Retail Electric Rates to produce a projected under-recovery   $ (44)         $ (44)                
DESC's proposed adjustment to the South Carolina Commission for the Pension Costs Rider             $ 11                
South Carolina Commission order, revenue requirement under RSA       $ 406   $ 409                  
South Carolina Commission order, increase in natural gas rates under RSA       $ 6   9                  
Percentage Of Prior Authorized Earned From Return On Equity       10.25%                      
Regulatory asset recovery assessment end period                     2047        
Monetization Of Guaranty Settlement [Member]                              
Rate And Other Regulatory Matters [Line Items]                              
Electric service customers over period                     20 years        
End period for recovery                     2039        
Income Taxes Refundable Through Future Rates [Member]                              
Rate And Other Regulatory Matters [Line Items]                              
Remaining lives of related property period                     85 years        
Reserve For Refunds To Electric Utility Customers [Member]                              
Rate And Other Regulatory Matters [Line Items]                              
Electric service customers over 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                     2043        
Changes in fair value and payments of interest rate derivatives not designed, amortized to interest, year                     2065        
Transmission Project                              
Rate And Other Regulatory Matters [Line Items]                              
Number of nuclear plants under development by Southern | NuclearPlant                     2        
Cost of anticipated project           $ 30         $ 75        
Transmission lines length of miles to be approved | mi           28                  
Transmission lines capacity | kV           230                  
NND Project Costs [Member]                              
Rate And Other Regulatory Matters [Line Items]                              
Electric service customers over period                     20 years        
End period for recovery                     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]                              
Remaining useful lives of coal-fired generating units, year                     2025        
New expected remaining useful lives of coal-fired generating units, year                     2029        
Demand Side Management Programs [Member]                              
Rate And Other Regulatory Matters [Line Items]                              
Recovery period of regulatory asset                     3 years        
Asset Retirement Obligation Costs [Member]                              
Rate And Other Regulatory Matters [Line Items]                              
Recovery period of regulatory asset                     105 years        
Cost of Reacquired Debt [Member]                              
Rate And Other Regulatory Matters [Line Items]                              
Recovery period of regulatory asset                     26 years        
Net costs incurred                       $ 270      
Environmental Remediation Costs [Member]                              
Rate And Other Regulatory Matters [Line Items]                              
MPG environmental remediation                     16 years        
Subsequent Event [Member]                              
Rate And Other Regulatory Matters [Line Items]                              
South Carolina Commission Order for Increase/Decrease of Total Fuel Cost Component of Retail Electric Rates to produce a projected under-recovery                             $ 36
Subsequent Event [Member] | Maximum [Member]                              
Rate And Other Regulatory Matters [Line Items]                              
DESC's proposed adjustment to the South Carolina Commission for the Pension Costs Rider     $ 1                        
South Carolina Electric Base Rate Case                              
Rate And Other Regulatory Matters [Line Items]                              
Amount of Increase in proposed non fuel base rate         $ 178                    
Increase in proposed non fuel base rate         7.75%                    
Percentage of ROE based on fully adjusted test period         5.90%                    
Percentage of current authorized earned ROE         10.25%                    
DESC                              
Rate And Other Regulatory Matters [Line Items]                              
South Carolina Commission Order, Annual DSM Program Rate Rider Recovery Amount   $ 40                          
DESC | Subsequent Event [Member]                              
Rate And Other Regulatory Matters [Line Items]                              
South Carolina Commission Order, Annual DSM Program Rate Rider Recovery Amount $ 48                            
Electric Operations                              
Rate And Other Regulatory Matters [Line Items]                              
Public utilities percentage change in retail electric rates approved under BLRA               18.00%              
Public utilities, approved rate increase (decrease), percentage               3.00%              
Public utilities, requested rate increase (decrease), amount               $ 31              
Operating expense                         109    
Operating expense after tax                         $ 82    
Savannah River Site                              
Rate And Other Regulatory Matters [Line Items]                              
Interest charges (benefit)                 $ (10) $ 6          
Interest charges (benefit), after tax                 $ (7) $ 4          
v3.20.4
Rate and Other Regulatory Matters (Schedule of Regulatory Assets) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Regulatory Assets    
Regulatory assets, current $ 229 $ 271
Regulatory assets, noncurrent 3,726 3,892
Total regulatory assets 3,955 4,163
NND Project Costs [Member]    
Regulatory Assets    
Regulatory assets, current [1] 138 138
Regulatory assets, noncurrent [1] 2,364 2,503
Deferred Employee Benefit Plan Costs [Member]    
Regulatory Assets    
Regulatory assets, current [2] 9 13
Regulatory assets, noncurrent [2] 159 196
Other Unrecovered Plant [Member]    
Regulatory Assets    
Regulatory assets, current [3] 14 14
Regulatory assets, noncurrent [3] 61 69
Demand Side Management Programs [Member]    
Regulatory Assets    
Regulatory assets, current [4] 29 17
Regulatory assets, noncurrent [4] 46 54
Asset Retirement Obligation Costs [Member]    
Regulatory Assets    
Regulatory assets, current [5] 2 28
Regulatory assets, noncurrent [5] 309 293
Cost of Fuel and Purchased Gas Under-Collections [Member]    
Regulatory Assets    
Regulatory assets, current [6] 1 13
Other Regulatory Assets [Member]    
Regulatory Assets    
Regulatory assets, current 36 48
Regulatory assets, noncurrent [7] 108 110
Cost of Reacquired Debt [Member]    
Regulatory Assets    
Regulatory assets, noncurrent [8],[9] 243 259
Deferred Losses On Interest Rate Derivatives [Member]    
Regulatory Assets    
Regulatory assets, noncurrent [10] 308 305
Environmental Remediation Costs [Member]    
Regulatory Assets    
Regulatory assets, noncurrent [11] 20 22
Deferred Storm Damage Costs [Member]    
Regulatory Assets    
Regulatory assets, noncurrent [12] 45 44
Deferred Transmission Operating Costs [Member]    
Regulatory Assets    
Regulatory assets, noncurrent [13] $ 63 $ 37
[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. See Note 12 for more information
[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 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 to 2029. Unamortized amounts are included in rate base and are earning a current return.
[4] 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.
[5] Represents 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.
[6] Represents amounts under- or over-collected from customers pursuant to the cost of fuel components approved by the South Carolina Commission
[7] Various other regulatory assets are expected to be recovered through rates over varying periods through 2047.
[8] Costs of the reacquisition of debt are deferred and amortized as interest expense over the would-be remaining life of the reacquired debt or over the life of the replacement debt if refinanced. The reacquired debt had a weighted-average life of approximately 26 years as of December 31, 2020.
[9] During 2019, DESC purchased certain of its first mortgage bonds. As a result of these transactions, DESC incurred net costs, including write-offs of unamortized swap losses and gains, discount, premium and debt issuance costs, of $270 million.
[10] Represents (i) the changes in fair value and payments made or received upon settlement of certain interest rate derivatives designated as cash flow hedges and (ii) the changes in fair value and payments made or received upon settlement of certain other interest rate derivatives not so designated. The amounts recorded with respect to (i) are expected to be amortized to interest expense over the lives of the underlying debt through 2043.The amounts recorded with respect to (ii) are expected to be similarly amortized to interest expense through 2065.
[11] Reflects amounts associated with the assessment and clean-up of sites currently or formerly owned by DESC. Such remediation costs are expected to be recovered over periods of up to 16 years. See Note 12 for more information.
[12] Represents storm restoration costs for which DESC expects to receive future recovery through customer rates.
[13] Includes deferred depreciation and property taxes associated with certain transmission assets for which DESC expects recovery from customers through future rates. See Note 12 for more information.
v3.20.4
Rate and Other Regulatory Matters (Schedule of Regulatory Liabilities) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Regulatory Liabilities    
Regulatory liability, current $ 283 $ 256
Regulatory liability, noncurrent 3,005 3,210
Total regulatory liabilities 3,288 3,466
Monetization Of Guaranty Settlement [Member]    
Regulatory Liabilities    
Regulatory liability, current [1] 67 67
Regulatory liability, noncurrent [1] 903 970
Income Taxes Refundable Through Future Rates [Member]    
Regulatory Liabilities    
Regulatory liability, current [2] 21 16
Regulatory liability, noncurrent [2] 919 948
Reserve For Refunds To Electric Utility Customers [Member]    
Regulatory Liabilities    
Regulatory liability, current [3] 128 143
Regulatory liability, noncurrent [3] 540 656
Other Regulatory Liability [Member]    
Regulatory Liabilities    
Regulatory liability, current 9 18
Regulatory liability, noncurrent 10 13
Cost of Fuel and Purchased Gas Over-Collections [Member]    
Regulatory Liabilities    
Regulatory liability, current [4] 58 12
Asset Removal Costs [Member]    
Regulatory Liabilities    
Regulatory liability, noncurrent [5] 564 552
Deferred Gains On Interest Rate Derivatives [Member]    
Regulatory Liabilities    
Regulatory liability, noncurrent [6] $ 69 $ 71
[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. See Note 12 for more information.
[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 for more 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. See Note 12 for more information.
[4] Represents amounts under- or over-collected from customers pursuant to the cost of fuel 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 (i) the changes in fair value and payments made or received upon settlement of certain interest rate derivatives designated as cash flow hedges and (ii) the changes in fair value and payments made or received upon settlement of certain other interest rate derivatives not so designated. The amounts recorded with respect to (i) are expected to be amortized to interest expense over the lives of the underlying debt through 2043.The amounts recorded with respect to (ii) are expected to be similarly amortized to interest expense through 2065.
v3.20.4
Operating Revenue (Operating Revenue Subsequent to the Adoption of Guidance for Revenue Recognition from Contracts with Customers) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Operating revenue from contracts with customers $ 1 $ 4 $ 5
Total Operating Revenues [1] 2,739 1,929 $ 2,762
Electric Operations      
Operating revenue from contracts with customers 2,337 1,516  
Other revenues 15 9  
Total Operating Revenues 2,352 1,525  
Gas Distribution      
Operating revenue from contracts with customers 387 404  
Other revenues 0 0  
Total Operating Revenues 387 404  
Residential | Electric Operations      
Operating revenue from contracts with customers 1,127 669  
Residential | Gas Distribution      
Operating revenue from contracts with customers 201 194  
Commercial | Electric Operations      
Operating revenue from contracts with customers 746 507  
Commercial | Gas Distribution      
Operating revenue from contracts with customers 103 111  
Industrial | Electric Operations      
Operating revenue from contracts with customers 341 224  
Industrial | Gas Distribution      
Operating revenue from contracts with customers 65 81  
Other | Electric Operations      
Operating revenue from contracts with customers 123 116  
Other | Gas Distribution      
Operating revenue from contracts with customers $ 18 $ 18  
[1] See Note 16 for amounts attributable to affiliates.
v3.20.4
Operating Revenue (Narrative) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Disaggregation Of Revenue [Line Items]    
Contract liability balances $ 5 $ 9
Revenue recognized from contract liability balances $ 6 $ 3
Minimum [Member]    
Disaggregation Of Revenue [Line Items]    
Service Contract, Term 10 years  
Maximum [Member]    
Disaggregation Of Revenue [Line Items]    
Service Contract, Term 15 years  
v3.20.4
Operating Revenue (Balance and Activity Related to Contract Costs Deferred as Regulatory Assets) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Revenues [Abstract]    
Beginning balance $ 13 $ 15
Amortization (1) (2)
Ending balance $ 12 $ 13
v3.20.4
Equity (Narrative) (Detail) - USD ($)
$ / shares in Units, $ in Millions
 1 Months Ended 12 Months Ended
Sep. 30, 2020
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Class Of Stock [Line Items]        
Common stock, par value   $ 0    
Common stock, shares authorized   50,000,000    
Common stock, shares issued   40,300,000    
Common stock, shares outstanding   40,300,000 40,300,000  
Preferred stock, par value   $ 0    
Preferred stock, shares authorized   20,000,000    
Preferred stock, shares issued   1,000    
Preferred stock, shares outstanding   1,000    
Contributions from SCANA   $ 0 $ 838 $ 24
Dominion Energy        
Class Of Stock [Line Items]        
Contributions from SCANA     $ 835  
Dominion Energy | Common Stock        
Class Of Stock [Line Items]        
Common stock issued to satisfy the settlement $ 322      
Dominion Energy | Common Stock | DESC Ratepayer Case        
Class Of Stock [Line Items]        
Common stock issued to satisfy the settlement   $ 322    
v3.20.4
Long-Term and Short-Term Debt (Schedule of Debt) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Debt Instrument [Line Items]    
Weighted-average coupon rate [1] 3.25%  
Total principal $ 3,620 $ 3,620
Securities due within one year (33) 0
Unamortized discount, premium and debt issuance costs, net (30) (32)
Finance leases 21  
Total long-term debt 3,572 3,608
First Mortgage Bonds    
Debt Instrument [Line Items]    
Total principal $ 3,267  
First Mortgage Bonds | DESC    
Debt Instrument [Line Items]    
Weighted-average coupon rate [1] 5.42%  
Total principal $ 3,267 3,267
Tax Exempt Financings Variable Rate Due 2038 | DESC    
Debt Instrument [Line Items]    
Weighted-average coupon rate [1] 0.13%  
Total principal [2] $ 35 35
Tax Exempt Financings Variable Rate Due 2038 | Genco    
Debt Instrument [Line Items]    
Weighted-average coupon rate [1] 0.13%  
Total principal $ 33 33
Tax Exempt Financings 3.625% and 4.00% Due 2028 and 2033 | DESC    
Debt Instrument [Line Items]    
Weighted-average coupon rate [1] 3.90%  
Total principal [2] $ 54 54
Other Debt    
Debt Instrument [Line Items]    
Total principal $ 231  
Other Debt | DESC    
Debt Instrument [Line Items]    
Weighted-average coupon rate [1] 3.67%  
Total principal $ 1 1
3.05% Affiliated Note Due 2024 | Genco    
Debt Instrument [Line Items]    
Weighted-average coupon rate [1] 3.05%  
Total principal $ 230 230
Finance Lease    
Debt Instrument [Line Items]    
Finance leases $ 15 $ 20
[1] Represents weighted-average coupon rates for debt outstanding as of December 31, 2020.
[2]

Industrial revenue bonds totaling $68 million are secured by letters of credit that expire, subject to renewal, in the fourth quarter of 2021.
v3.20.4
Long-Term and Short-Term Debt (Schedule of Debt) (Parenthetical) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Debt Instrument [Line Items]      
Redemption of remaining principal outstanding plus accrued interest $ 0 $ 1,890 $ 825
Letter of Credit      
Debt Instrument [Line Items]      
Debt instrument, face amount $ 68    
First Mortgage Bonds | Minimum [Member] | DESC      
Debt Instrument [Line Items]      
Debt Instrument, Maturity Year 2021    
Debt instrument, interest rate 3.22%    
First Mortgage Bonds | Maximum [Member] | DESC      
Debt Instrument [Line Items]      
Debt Instrument, Maturity Year 2065    
Debt instrument, interest rate 6.625%    
Tax Exempt Financings Variable Rate Due 2038 | DESC      
Debt Instrument [Line Items]      
Debt Instrument, Maturity Year 2038    
Tax Exempt Financings Variable Rate Due 2038 | Genco      
Debt Instrument [Line Items]      
Debt Instrument, Maturity Year 2038    
Tax Exempt Financings 3.625% and 4.00% Due 2028 and 2033 | Minimum [Member] | DESC      
Debt Instrument [Line Items]      
Debt Instrument, Maturity Year 2028    
Debt instrument, interest rate 3.625%    
Tax Exempt Financings 3.625% and 4.00% Due 2028 and 2033 | Maximum [Member] | DESC      
Debt Instrument [Line Items]      
Debt Instrument, Maturity Year 2033    
Debt instrument, interest rate 4.00%    
3.05% Affiliated Note Due 2024 | Genco      
Debt Instrument [Line Items]      
Debt Instrument, Maturity Year 2024    
Debt instrument, interest rate 3.05%    
v3.20.4
Long-Term and Short-Term Debt (Schedule of Principal Payments of Long-Term Debt) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Debt Instrument [Line Items]    
2021 $ 33  
2022 0  
2023 0  
2024 230  
2025 0  
Thereafter 3,357  
Total $ 3,620 $ 3,620
Weighted-average coupon, 2021 3.25%  
Weighted-average coupon, 2024 3.05%  
Weighted-average coupon, Thereafter 5.30%  
Weighted-average coupon [1] 3.25%  
First Mortgage Bonds    
Debt Instrument [Line Items]    
2021 $ 33  
2022 0  
2023 0  
2024 0  
2025 0  
Thereafter 3,234  
Total 3,267  
Tax Exempt Financings    
Debt Instrument [Line Items]    
2021 0  
2022 0  
2023 0  
2024 0  
2025 0  
Thereafter 122  
Total 122  
Other Debt    
Debt Instrument [Line Items]    
2021 0  
2022 0  
2023 0  
2024 230  
2025 0  
Thereafter 1  
Total $ 231  
[1] Represents weighted-average coupon rates for debt outstanding as of December 31, 2020.
v3.20.4
Long-Term and Short-Term Debt (Narrative) (Detail) - USD ($)
 1 Months Ended 12 Months Ended
Mar. 31, 2020
May 31, 2019
Apr. 30, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Debt Instrument [Line Items]            
Unfunded property additions       70.00%    
Consecutive months for bond ratio       12 months    
Months preceding issuance of bonds       18 months    
Bond ratio       6.70%    
Redemption of remaining principal outstanding plus accrued interest       $ 0 $ 1,890,000,000 $ 825,000,000
Equity capital contribution returned to parent       0 20,000,000 0
Commercial paper borrowing limit $ 2,200,000,000          
Interest charges [1]       229,000,000 260,000,000 $ 303,000,000
Interest income from money pool transactions       2,000,000 8,000,000  
Interest expense from money pool transactions       2,000,000 8,000,000  
Money pool borrowings due to affiliates       206,000,000 219,000,000  
Investments due from affiliates       15,000,000 9,000,000  
Maximum [Member]            
Debt Instrument [Line Items]            
Short term commercial paper maturity period 1 year          
Dominion Energy            
Debt Instrument [Line Items]            
Short-term borrowings outstanding, maximum     $ 900,000,000      
Short-term borrowings outstanding       149,000,000 355,000,000  
Interest charges       7,000,000 $ 3,000,000  
Current Joint Revolving Credit Facility | Dominion Energy            
Debt Instrument [Line Items]            
Facility limit       6,000,000,000.0    
Letter of Credit            
Debt Instrument [Line Items]            
Debt instrument, face amount       68,000,000    
Facility limit       $ 1,000,000,000.0    
Genco            
Debt Instrument [Line Items]            
Commercial paper borrowing limit $ 200,000,000          
Genco | Maximum [Member]            
Debt Instrument [Line Items]            
Short term commercial paper maturity period 1 year          
Genco | 3.05% Promissory Note due in May 2024            
Debt Instrument [Line Items]            
Debt instrument, face amount   $ 230,000,000        
Debt instrument, interest rate   3.05%        
Debt instrument, maturity date   2024-05        
Genco | 5.49% Senior Secured Note Due 2024            
Debt Instrument [Line Items]            
Debt instrument, interest rate   5.49%        
Debt Instrument, Maturity Year   2024        
Redemption of remaining principal outstanding plus accrued interest   $ 33,000,000        
Equity capital contribution returned to parent   $ 20,000,000        
[1] See Note 16 for amounts attributable to affiliates.
v3.20.4
Long-Term and Short-Term Debt (Schedule of Line of Credit Facilities) (Detail) - Joint Revolving Credit Facility - USD ($)
Dec. 31, 2020
Dec. 31, 2019
 [1],[2]
Debt Instrument [Line Items]    
Facility limit $ 1,000,000,000 $ 1,000,000,000
Outstanding Commercial Paper 0 0
Outstanding Letters of Credit $ 0 $ 0
[1]

In October 2020, the joint revolving credit facility was amended to remove Dominion Energy Gas as a co-borrower.

[2]

A maximum of $1.0 billion of the facility is available to DESC, less any amounts outstanding to co-borrowers. 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 December 31, 2020, 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 borrowings from DESC's parent or from Dominion Energy. This credit facility matures in March 2023 and 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.

v3.20.4
Long-Term and Short-Term Debt (Schedule of Line of Credit Facilities) (Parenthetical) (Detail) - USD ($)
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
 [1],[2]
Joint Revolving Credit Facility    
Debt Instrument [Line Items]    
Facility limit $ 1,000,000,000 $ 1,000,000,000
Line of credit facility maturity date 2023-03  
Line of Credit Facility    
Debt Instrument [Line Items]    
Facility limit $ 500,000,000  
Letter of Credit    
Debt Instrument [Line Items]    
Facility limit $ 1,000,000,000.0  
[1]

In October 2020, the joint revolving credit facility was amended to remove Dominion Energy Gas as a co-borrower.

[2]

A maximum of $1.0 billion of the facility is available to DESC, less any amounts outstanding to co-borrowers. 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 December 31, 2020, 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 borrowings from DESC's parent or from Dominion Energy. This credit facility matures in March 2023 and 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.

v3.20.4
Income Taxes (Narrative) (Detail) - USD ($)
$ in Millions
 1 Months Ended 3 Months Ended 12 Months Ended
Mar. 31, 2020
Dec. 31, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Investments Owned Federal Income Tax Note [Line Items]          
Adjusted taxable income for certain businesses 50.00%        
Increase in net operating loss utilization       $ 79  
Weighted average rate used to originate deferred tax liability     35.00%    
Deferred income taxes, net     $ 229 (379) $ (184)
Regulatory liabilities     (193) 265 (360)
Increase in income tax expense   $ 1      
Increase in unrecognized tax benefits   53      
Reduction in credit carryforward deferred tax assets   (45)      
Increase in accrued taxes   $ 7 $ (3) (10) $ 31
Income tax examination, description     The statute is closed for IRS examination of years prior to 2013. The IRS is currently examining DESC’s federal returns from 2013 through 2017. DESC is no longer subject to state and local income tax examinations by tax authorities for years prior to 2013    
Decrease in Unrecognized Tax Benefits is Reasonably Possible     $ 65    
Potential increase in earnings in next twelve months if tax benefits recognized     $ 4    
Prior to SCANA Combination          
Investments Owned Federal Income Tax Note [Line Items]          
Increase in unrecognized tax benefits       79  
Increase in income tax expense       67  
Earliest Tax Year | Federal | IRS          
Investments Owned Federal Income Tax Note [Line Items]          
Income tax examination, year under examination     2013    
Latest Tax Year | Federal | IRS          
Investments Owned Federal Income Tax Note [Line Items]          
Income tax examination, year under examination     2017    
SCANA Combination          
Investments Owned Federal Income Tax Note [Line Items]          
Deferred income taxes, net       194  
Increase in deferred income tax expense       30  
Regulatory liabilities       40  
Increase in deferred tax assets       $ 10  
v3.20.4
Income Taxes (Details of Income Tax Expense for Continuing Operations Including Noncontrolling Interests) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Current:      
Federal $ (139) $ 0 $ (16)
State 3 34 0
Total current expense (benefit) (136) 34 (16)
Deferred:      
Taxes before operating loss carryforwards, investment tax credits and tax reform 158 (90) (216)
2017 Tax Reform Act impact 0 0 (176)
Tax utilization expense of operating loss carryforwards 33 102 46
State 17 (57) (52)
Total deferred expense (benefit) 208 (45) (398)
Investment tax credit-amortization (1) (1) (2)
Total income tax expense (benefit) $ 71 $ (12) $ (416)
v3.20.4
Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Detail)
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Income Tax Disclosure [Abstract]        
U.S. statutory rate 21.00% 21.00% 21.00% 35.00%
Increases (reductions) resulting from:        
State taxes, net of federal benefit 4.20% 3.90% 3.80%  
State investment tax credits 0.00% 0.00% 0.30%  
AFUDC - equity (0.10%) 0.00% 0.20%  
Amortization of federal investment tax credits (0.40%) 0.10% 0.20%  
Production tax credits 0.00% 0.40% 0.90%  
Reversal of excess deferred income taxes (6.00%) (1.40%) 0.00%  
Federal legislative change 0.00% 0.00% 17.50%  
NND Project impairment 0.00% (2.40%) (2.30%)  
Write-off of regulatory asset 0.00% (15.80%) 0.00%  
Changes in unrecognized tax benefits 0.00% (5.10%) 0.00%  
Other 0.10% 0.20% (0.20%)  
Effective tax rate 18.80% 0.90% 41.40%  
v3.20.4
Income Taxes (Schedule of Deferred Income Taxes) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Deferred income taxes:    
Total deferred income tax assets $ 1,101 $ 1,258
Total deferred income tax liabilities 1,941 1,868
Total net deferred income tax liabilities 840 610
Depreciation method and plant basis differences 1,098 1,007
Excess deferred income taxes (233) (231)
Unrecovered nuclear plant cost 529 553
DESC rate refund (140) (169)
Toshiba settlement (204) (219)
Nuclear decommissioning (51) (43)
Deferred state income taxes 208 200
Federal benefit of deferred state income taxes (44) (42)
Deferred fuel, purchased energy and gas costs (12) 7
Pension benefits 39 46
Other postretirement benefits (37) (35)
Loss and credit carryforwards (382) (391)
Other   (73)
Other 69  
Deferred Investment Tax Credits-Regulated Operations 18 19
Total Deferred Taxes and Deferred Investment Tax Credits $ 858 $ 629
v3.20.4
Income Taxes (Summary of Deductible Loss and Credit Carryforwards) (Detail)
$ in Millions
 12 Months Ended
Dec. 31, 2020
USD ($)
Investments Owned Federal Income Tax Note [Line Items]  
Loss and Credit Carryforwards, Deductible Amount $ 3,470
Loss and Credit Carryforwards, Deferred Tax Asset 409
Federal  
Investments Owned Federal Income Tax Note [Line Items]  
Loss Carryforwards, Deductible Amount 1,052
Loss Carryforwards, Deferred Tax Asset $ 221
Loss Carryforwards, Expiration Period 2037
Federal | Production and Other Credits  
Investments Owned Federal Income Tax Note [Line Items]  
Credit Carryforwards, Deductible Amount $ 0
Credit Carryforwards, Deferred Tax Asset $ 31
Federal | Production and Other Credits | Minimum [Member]  
Investments Owned Federal Income Tax Note [Line Items]  
Credit Carryforwards, Expiration Period 2035
Federal | Production and Other Credits | Maximum [Member]  
Investments Owned Federal Income Tax Note [Line Items]  
Credit Carryforwards, Expiration Period 2038
State  
Investments Owned Federal Income Tax Note [Line Items]  
Loss Carryforwards, Deductible Amount $ 2,418
Loss Carryforwards, Deferred Tax Asset $ 121
Loss Carryforwards, Expiration Period 2037
State | Investment and Other Credits  
Investments Owned Federal Income Tax Note [Line Items]  
Credit Carryforwards, Deductible Amount $ 0
Credit Carryforwards, Deferred Tax Asset $ 36
State | Investment and Other Credits | Minimum [Member]  
Investments Owned Federal Income Tax Note [Line Items]  
Credit Carryforwards, Expiration Period 2026
State | Investment and Other Credits | Maximum [Member]  
Investments Owned Federal Income Tax Note [Line Items]  
Credit Carryforwards, Expiration Period 2031
v3.20.4
Income Taxes (Reconciliation of Unrecognized Tax Benefits Roll Forward) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Income Tax Disclosure [Abstract]      
Balance at January 1 $ 132 $ 106 $ 98
Increases-prior period positions 5 76 8
Decreases-prior period positions 0 (53) 0
Increases-current period positions 1 3 0
Balance at December 31 $ 138 $ 132 $ 106
v3.20.4
Derivative Financial Instruments (Narrative) (Detail)
$ in Millions
Dec. 31, 2020
USD ($)
Derivative Instruments And Hedging Activities Disclosure [Abstract]  
Additional collateral to its counterparties $ 10
Collateral already posted 1
Fair value of derivative instruments with credit-related contingent provisions that are in liability position and not fully collateralized with cash $ 11
v3.20.4
Derivative Financial Instruments (Offsetting Liabilities) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Derivative [Line Items]    
Gross Liabilities Presented in the Consolidated Balance Sheet $ 27 $ 19
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 17 19
Gross amounts not offset in the consolidated balance sheet, net amounts 10 0
Interest Rate Contract [Member] | Over The Counter [Member]    
Derivative [Line Items]    
Gross Liabilities Presented in the Consolidated Balance Sheet 27 19
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 17 19
Gross amounts not offset in the consolidated balance sheet, net amounts $ 10 $ 0
v3.20.4
Derivative Financial Instruments (Schedule of Volume of Derivative Activity) (Detail)
Dec. 31, 2020
USD ($)
 [1]
Interest Rate Swap Current [Member]  
Derivative [Line Items]  
Interest rate $ 0
Interest Rate Swap Noncurrent [Member]  
Derivative [Line Items]  
Interest rate $ 71,400,000
[1] Maturity is determined based on final settlement period.
v3.20.4
Derivative Financial Instruments (Fair Value of Derivatives) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Derivative [Line Items]    
Derivative Liability $ 27 $ 19
Other Current Liabilities [Member]    
Derivative [Line Items]    
Derivative Liability [1] 2 2
Other Noncurrent Liabilities [Member]    
Derivative [Line Items]    
Derivative Liability [2] 25 17
Interest Rate Contract [Member] | Other Current Liabilities [Member]    
Derivative [Line Items]    
Derivative Liability 2 2
Interest Rate Contract [Member] | Other Noncurrent Liabilities [Member]    
Derivative [Line Items]    
Derivative Liability 25 17
Designated as Hedging Instrument [Member]    
Derivative [Line Items]    
Derivative Liability 16 12
Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]    
Derivative [Line Items]    
Derivative Liability [1] 1 1
Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member]    
Derivative [Line Items]    
Derivative Liability [2] 15 11
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Current Liabilities [Member]    
Derivative [Line Items]    
Derivative Liability 1 1
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Noncurrent Liabilities [Member]    
Derivative [Line Items]    
Derivative Liability 15 11
Not Designated as Hedging Instrument [Member]    
Derivative [Line Items]    
Derivative Liability 11 7
Not Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]    
Derivative [Line Items]    
Derivative Liability [1] 1 1
Not Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member]    
Derivative [Line Items]    
Derivative Liability [2] 10 6
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Current Liabilities [Member]    
Derivative [Line Items]    
Derivative Liability 1 1
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Noncurrent Liabilities [Member]    
Derivative [Line Items]    
Derivative Liability $ 10 $ 6
[1] Current derivative liabilities are presented in other current liabilities in the Consolidated Balance Sheets.
[2] Noncurrent derivative liabilities are presented in other deferred credits and other liabilities in the Consolidated Balance Sheets.
v3.20.4
Derivative Financial Instruments (Derivatives in Cash Flow Hedging Relationships) (Detail) - Cash Flow Hedging [Member] - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Derivative [Line Items]      
Gain (loss) Reclassified from Deferred Accounts into Income $ 0 $ 0 $ (1)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment [1] 1 1 1
Interest Rate Contract [Member]      
Derivative [Line Items]      
Gain (loss) Reclassified from Deferred Accounts into Income [2] 0 0 (1)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment [1],[2] $ 1 $ 1 $ 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 (Loss).
[2] Amounts recorded in DESC’s Consolidated Statements of Comprehensive Income (Loss) are classified in interest charges.
v3.20.4
Derivative Financial Instruments (Derivatives Not Designated as Hedging Instruments) (Detail) - Not Designated as Hedging Instrument [Member] - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Derivative [Line Items]      
Amount of Gain (Loss) Recognized in Income on Derivatives(1) [1] $ (1) $ (1) $ 113
Interest Income [Member] | Interest Rate Contract [Member]      
Derivative [Line Items]      
Amount of Gain (Loss) Recognized in Income on Derivatives(1) [1] (1) (1) (2)
Other Income [Member] | Interest Rate Contract [Member]      
Derivative [Line Items]      
Amount of Gain (Loss) Recognized in Income on Derivatives(1) [1] $ 0 $ 0 $ 115
[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 (Loss).
v3.20.4
Fair Value Measurements, Including Derivatives (Schedule of Liabilities Measured at Fair Value on Recurring Basis) (Narrative) (Detail) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Sep. 30, 2020
Mar. 31, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Impairment of assets and other charges   $ 105 $ (14) $ 576 $ 1,376
Impairment of assets and other charges, after-tax   $ 79      
Nonutility Property          
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Impairment of assets and other charges $ 12        
Impairment of assets and other charges, after-tax 9        
Estimated fair value of property $ 6        
v3.20.4
Fair Value Measurements, Including Derivatives (Schedule of Liabilities Measured at Fair Value on Recurring Basis) (Details) - Fair value, recurring - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Liabilities    
Total liabilities $ 27 $ 19
Interest Rate Contract [Member]    
Liabilities    
Total liabilities 27 19
Level 1    
Liabilities    
Total liabilities 0 0
Level 1 | Interest Rate Contract [Member]    
Liabilities    
Total liabilities 0 0
Level 2    
Liabilities    
Total liabilities 27 19
Level 2 | Interest Rate Contract [Member]    
Liabilities    
Total liabilities 27 19
Level 3    
Liabilities    
Total liabilities 0 0
Level 3 | Interest Rate Contract [Member]    
Liabilities    
Total liabilities $ 0 $ 0
v3.20.4
Fair Value Measurements, Including Derivatives (Schedule of Carrying Values and Estimated Fair Values of Debt Instruments) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Carrying Amount    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Long-term debt [1] $ 3,360 $ 3,358
Affiliated long-term debt 230 230
Estimated Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Long-term debt [1],[2] 4,748 4,262
Affiliated long-term debt [2] $ 230 $ 230
[1] Carrying amount includes current portions included in securities due within one year and amounts which represent the unamortized debt issuance costs and discount or premium.
[2] 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.
v3.20.4
Asset Retirement Obligations (Narrative) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Asset Retirement Obligation Disclosure [Abstract]    
Asset retirement obligation, other conditional obligations $ 322  
Assets held in trust, nuclear decommissioning 238 $ 214
Asset retirement obligation, nuclear decommissioning $ 275  
v3.20.4
Asset Retirement Obligations (Schedule of Reconciliation of the Carrying Amount of AROs) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Asset Retirement Obligation Disclosure [Abstract]    
Beginning balance $ 489 $ 541
Liabilities settled (4) (29)
Accretion expense 23 23
Revisions in estimated cash flows [1] 89 (46)
Ending balance $ 597 $ 489
[1] The increase in 2020 reflects revisions from the nuclear decommissioning cost study. The decrease in 2019 reflects a change in the estimated timing of cash flows for interim pipeline replacements and DOE recoveries.
v3.20.4
Employee Benefit Plans and Equity Compensation Plan (Narrative) (Detail) - USD ($)
 3 Months Ended 12 Months Ended
Sep. 30, 2019
Jun. 30, 2019
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]            
Voluntary retirement program related charges         $ 63,000,000  
Voluntary retirement program related charges net of taxes         47,000,000  
Increase in pension benefit obligation $ 25,000,000 $ 16,000,000        
Increase in accumulated postretirement benefit obligation   10,000,000        
Increase in fair value of pension plan assets $ 35,000,000 $ 27,000,000        
Defined benefit plan, accumulated benefit obligation       $ 732,000,000 711,000,000  
Gain (loss) from change in discount rate       $ (19,000,000)    
Defined benefit plan, annual rate of increase in the per capita cost of covered health care benefits       6.25%    
Defined benefit plan, ultimate health care cost trend rate       5.00%    
Fair value assets transfer from Level 1 to Level 2       $ 0 0  
Fair value assets transfer from Level 2 to Level 1       0 0  
Defined benefit plan, contributions by employer       $ 0    
Defined contribution plan maximum defer percentage of employer contribution of eligible employees earnings       75.00%    
Defined contribution plan, maximum percentage of employer contribution for up to six percent of participant contribution       100.00%    
Defined contribution plan, maximum percentage of participant contribution eligible for employer contribution match       6.00%    
Defined contribution plan, employer matching contributions       $ 14,000,000 14,000,000 $ 20,000,000
Scenario Forecast            
Defined Benefit Plan Disclosure [Line Items]            
Defined benefit plan, assumptions used calculating net periodic benefit cost, expected long-term rate of return on plan assets     7.00%      
Defined benefit plan, contributions by employer     $ 15,000,000      
Summer            
Defined Benefit Plan Disclosure [Line Items]            
Defined benefit plan, shared costs deferred with joint ownership       $ 19,000,000 $ 19,000,000  
Pension Benefits            
Defined Benefit Plan Disclosure [Line Items]            
Discount rate percentage 3.57% 4.07%   2.73% 3.47%  
Recognized actuarial gain (loss)       $ (43,000,000) $ (52,000,000)  
Defined benefit plan, assumptions used calculating net periodic benefit cost, expected long-term rate of return on plan assets       7.00% 7.00% 7.00%
Other Postretirement Benefits            
Defined Benefit Plan Disclosure [Line Items]            
Discount rate percentage   4.08%   2.80% 3.52%  
Recognized actuarial gain (loss)       $ 51,000,000 $ (25,000,000)  
Defined benefit plan, ultimate health care cost trend rate       5.00% 5.00% 5.00%
Other Postretirement Benefits | Summer            
Defined Benefit Plan Disclosure [Line Items]            
Defined benefit plan, shared costs deferred with joint ownership       $ 12,000,000 $ 15,000,000  
Other Operations and Maintenance Expense            
Defined Benefit Plan Disclosure [Line Items]            
Voluntary retirement program related charges         51,000,000  
Other Taxes            
Defined Benefit Plan Disclosure [Line Items]            
Voluntary retirement program related charges         3,000,000  
Other Income (Expense), Net            
Defined Benefit Plan Disclosure [Line Items]            
Voluntary retirement program related charges         9,000,000  
Settlement losses as a result of voluntary retirement program         $ 16,000,000  
v3.20.4
Employee Benefit Plans and Equity Compensation Plan (Changes in Benefit Obligations) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Benefit obligation, January 1 $ 727 $ 732  
Service cost 12 15 $ 17
Interest cost 24 28 29
Plan participants’ contributions 0 0  
Actuarial (gain) loss 41 47  
Benefits paid (22) (21)  
Settlements (40) (80)  
Curtailment 0 6  
Amounts funded to parent 0 0  
Benefit obligation, December 31 742 727 732
Other Postretirement Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Benefit obligation, January 1 214 187  
Service cost 3 3 4
Interest cost 8 9 8
Plan participants’ contributions 2 1  
Actuarial (gain) loss (31) 22  
Benefits paid (13) (13)  
Settlements 0 0  
Curtailment 0 3  
Amounts funded to parent 1 2  
Benefit obligation, December 31 $ 184 $ 214 $ 187
v3.20.4
Employee Benefit Plans and Equity Compensation Plan (Significant Assumptions Used to Determine Benefit Obligations) (Detail)
Dec. 31, 2020
Dec. 31, 2019
Sep. 30, 2019
Jun. 30, 2019
Pension Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Annual discount rate used to determine benefit obligation 2.73% 3.47% 3.57% 4.07%
Assumed annual rate of future salary increases for projected benefit obligation 4.52% 3.00%    
Crediting interest rate for cash balance plans 1.93% 2.67%    
Other Postretirement Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Annual discount rate used to determine benefit obligation 2.80% 3.52%   4.08%
v3.20.4
Employee Benefit Plans and Equity Compensation Plan (Funded Status) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets $ 747 $ 725 $ 677
Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 747 725  
Benefit obligation 742 727 732
Funded status 5 (2)  
Other Postretirement Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Benefit obligation 184 214 $ 187
Funded status $ (184) $ (214)  
v3.20.4
Employee Benefit Plans and Equity Compensation Plan (Amounts Recognized on Consolidated Balance Sheets) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Pension Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Noncurrent assets $ 5  
Noncurrent liability   $ (2)
Other Postretirement Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Current liability (11) (13)
Noncurrent liability $ (173) $ (201)
v3.20.4
Employee Benefit Plans and Equity Compensation Plan (Amounts Recognized in Accumulated Other Comprehensive Loss) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Pension Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Net actuarial loss $ 4 $ 2
Other Postretirement Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Net actuarial loss   $ 2
v3.20.4
Employee Benefit Plans and Equity Compensation Plan (Amounts Recognized in Regulatory Assets ) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Pension Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Net actuarial loss $ 114 $ 125
Other Postretirement Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Net actuarial loss $ 1 $ 29
v3.20.4
Employee Benefit Plans (Change in Fair Value of Plan Assets) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Compensation And Retirement Disclosure [Abstract]    
Fair value of plan assets, January 1 $ 725 $ 677
Actual return (loss) on plan assets 84 149
Benefits paid (22) (21)
Settlements (40) (80)
Fair value of plan assets, December 31 $ 747 $ 725
v3.20.4
Employee Benefit Plans (Pension Plan Asset Allocation and Target Allocation) (Detail)
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
U.S. Equities      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Plan asset   34.00% 40.00%
Non-U.S. Equities      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Plan asset   18.00% 19.00%
Fixed Income      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Plan asset   47.00% 32.00%
Cash and Cash Equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Plan asset   1.00% 1.00%
Company Stock      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Plan asset   0.00% 5.00%
Real Estate      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Plan asset   0.00% 3.00%
Scenario Forecast | U.S. Equities | Minimum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Target allocation plan asset 25.00%    
Scenario Forecast | U.S. Equities | Maximum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Target allocation plan asset 40.00%    
Scenario Forecast | Non-U.S. Equities | Minimum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Target allocation plan asset 10.00%    
Scenario Forecast | Non-U.S. Equities | Maximum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Target allocation plan asset 20.00%    
Scenario Forecast | Fixed Income | Minimum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Target allocation plan asset 45.00%    
Scenario Forecast | Fixed Income | Maximum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Target allocation plan asset 65.00%    
Scenario Forecast | Cash and Cash Equivalents | Minimum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Target allocation plan asset 2.00%    
Scenario Forecast | Cash and Cash Equivalents | Maximum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Target allocation plan asset 10.00%    
Scenario Forecast | Company Stock      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Target allocation plan asset 0.00%    
Scenario Forecast | Real Estate      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit Plan, Target allocation plan asset 0.00%    
v3.20.4
Employee Benefit Plans (Schedule of Fair Value Measurements By Category) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]    
Total assets in the fair value hierarchy $ 360 $ 414
Common collective trust 387 311
Total investments 747 725
Fair Value, Inputs, Level 1 | Cash and Cash Equivalents    
Defined Benefit Plan Disclosure [Line Items]    
Total assets in the fair value hierarchy 10 3
Fair Value, Inputs, Level 2 | Mutual Funds    
Defined Benefit Plan Disclosure [Line Items]    
Total assets in the fair value hierarchy   152
Fair Value, Inputs, Level 2 | Corporate Debt Securities    
Defined Benefit Plan Disclosure [Line Items]    
Total assets in the fair value hierarchy 315 233
Fair Value, Inputs, Level 2 | Government and Other Debt Instruments    
Defined Benefit Plan Disclosure [Line Items]    
Total assets in the fair value hierarchy $ 35 $ 26
v3.20.4
Employee Benefit Plans (Expected Benefit Payments) (Detail)
$ in Millions
Dec. 31, 2020
USD ($)
Pension Benefits  
Defined Benefit Plan Disclosure [Line Items]  
Defined benefit plan, expected benefit payments, 2021 $ 39
Defined benefit plan, expected benefit payments, 2022 45
Defined benefit plan, expected benefit payments, 2023 43
Defined benefit plan, expected benefit payments, 2024 45
Defined benefit plan, expected benefit payments, 2025 44
Defined benefit plan, expected benefit payments, 2026-2030 201
Other Postretirement Benefits  
Defined Benefit Plan Disclosure [Line Items]  
Defined benefit plan, expected benefit payments, 2021 11
Defined benefit plan, expected benefit payments, 2022 11
Defined benefit plan, expected benefit payments, 2023 11
Defined benefit plan, expected benefit payments, 2024 11
Defined benefit plan, expected benefit payments, 2025 11
Defined benefit plan, expected benefit payments, 2026-2030 $ 55
v3.20.4
Employee Benefit Plans (Components of Net Periodic Benefit Cost) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Service cost $ 12 $ 15 $ 17
Interest cost 24 28 29
Expected return on assets (45) (40) (48)
Prior service cost amortization 0 0 0
Amortization of actuarial losses 6 11 11
Settlement loss 7 16 0
Curtailment 0 6 0
Net periodic benefit cost 4 36 9
Other Postretirement Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 3 3 4
Interest cost 8 9 8
Amortization of actuarial losses   0 0
Settlement loss 0    
Curtailment 0 3 0
Net periodic benefit cost $ 11 $ 15 $ 12
v3.20.4
Employee Benefit Plans and Equity Compensation Plan (Schedule of Defined Benefit Plan, Amounts Recognized in Accumulated Other Comprehensive Income (Loss)) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Current year actuarial (gain) loss $ 2 $ (1) $ 1
Other Postretirement Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Current year actuarial (gain) loss $ (2) $ 1 $ (1)
v3.20.4
Employee Benefit Plans and Equity Compensation Plan (Schedule of Defined Benefit Plan Amounts Recognized in Regulatory Assets) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Regulatory assets, pension and other postretirement benefit plans, net unamortized gain (loss) arising during the period, net of tax $ 1 $ (51) $ 41
Regulatory assets, amortization of actuarial losses, pension and other postretirement benefit plans, net of tax (6) (11) (10)
Regulatory assets, settlement loss, pension and other postretirement benefit plans, net of tax (6) (16) 0
Regulatory assets, total recognized in regulatory assets, pension and other postretirement benefit plans, net of tax (11) (78) 31
Other Postretirement Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Regulatory assets, pension and other postretirement benefit plans, net unamortized gain (loss) arising during the period, net of tax (27) 20 (26)
Regulatory assets, amortization of actuarial losses, pension and other postretirement benefit plans, net of tax (1)   (1)
Regulatory assets, settlement loss, pension and other postretirement benefit plans, net of tax 0 0 0
Regulatory assets, total recognized in regulatory assets, pension and other postretirement benefit plans, net of tax $ (28) $ 20 $ (27)
v3.20.4
Employee Benefit Plans and Equity Compensation Plan (Schedule of Assumptions Used in Determining Net Periodic Benefit Cost) (Detail)
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]      
Ultimate health care cost trend rate 5.00%    
Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate 3.47%   3.71%
Expected return on plan assets 7.00% 7.00% 7.00%
Rate of compensation increase 3.00% 3.00% 3.00%
Crediting interest rate for cash balance plans 2.67%   4.00%
Pension Benefits | Minimum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate   3.57%  
Crediting interest rate for cash balance plans   2.77%  
Pension Benefits | Maximum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate   4.38%  
Crediting interest rate for cash balance plans   3.58%  
Other Postretirement Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate 2.80%   3.74%
Health care cost trend rate 6.25% 6.60% 7.00%
Ultimate health care cost trend rate 5.00% 5.00% 5.00%
Year achieved   2023 2023
Other Postretirement Benefits | Minimum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate   4.08%  
Year achieved 2025    
Other Postretirement Benefits | Maximum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate   4.41%  
Year achieved 2026    
v3.20.4
Commitments and Contingencies (Narrative) (Detail)
 1 Months Ended 3 Months Ended 12 Months Ended
Apr. 30, 2015
Facility
Oct. 31, 2014
MGD
Facility
Dec. 31, 2020
USD ($)
Oct. 31, 2020
USD ($)
Sep. 30, 2020
USD ($)
Aug. 31, 2020
USD ($)
Sep. 30, 2019
USD ($)
Jul. 31, 2019
USD ($)
Feb. 28, 2019
USD ($)
Dec. 31, 2018
USD ($)
Jun. 30, 2018
USD ($)
Aug. 31, 2016
T
Mar. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Mar. 31, 2018
USD ($)
Dec. 31, 2020
USD ($)
Product
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Mar. 31, 2020
USD ($)
Loss Contingencies [Line Items]                                        
Electric generating stations with water withdrawals under CWA | MGD   125                                    
Electric generating stations with water withdrawals with heightened entrainment analysis under CWA | MGD   2                                    
Number of DESC facilities subject to final regulations | Facility   5                                    
Number of MGP decommissioned sites that contain residues of byproduct chemicals | Product                               4        
Estimated environmental remediation activities at MGP sites                               $ 10,000,000        
Estimated increase in remediation costs for Congaree River site                               11,000,000        
Environmental remediation costs recognized in regulatory assets     $ 22,000,000                         22,000,000        
Number of CCR landfills facilities subject to final rule | Facility 3                                      
Impairment loss, NND Project                           $ 1,400,000,000 $ 4,000,000       $ 1,100,000,000  
Impairment loss, NND Project, after-tax                           870,000,000 $ 3,000,000       $ 690,000,000  
Maximum amount of capital cost recovery related to the NND Project                           2,800,000,000            
Impairment of assets and other charges                         $ 105,000,000     (14,000,000) $ 576,000,000 $ 1,376,000,000    
Impairment of assets and other charges, after-tax                         79,000,000              
Customer refundable fees, alternative plan     3,288,000,000                         3,288,000,000 3,466,000,000      
Regulatory liability for refunds to natural gas customers                         2,000,000              
Regulatory liability for refunds to natural gas customers, after tax                         2,000,000              
Regulatory asset impairment charges committed to forgo recovery                         264,000,000              
Tax charge related to regulatory assets committed to forgo recovery                         198,000,000              
Transmission assets related to BLRA capital costs     309,000,000                         309,000,000        
Transmission assets related to BLRA regulatory assets     63,000,000                         63,000,000        
Reserves for litigation and regulatory proceedings     208,000,000                         208,000,000 492,000,000      
Insurance receivables     8,000,000                         8,000,000 6,000,000      
Proposed settlement payable by all                                       $ 520,000,000
Proposed settlement payable by company                 $ 100,000,000                     $ 320,000,000
Proportionate ownership share in project                 100.00%   100.00%                  
Proposed assessment amount from SCDOR audit                     $ 410,000,000                  
Agreement in principle to resolve the SCDOR matter     165,000,000                                  
Contesting amount for filed liens in Fairfield country                               285,000,000        
Reduction of liens filed                               $ 60,000,000        
Percentage share of reduction of liens filed                               55.00%        
Energy payments under power purchase contracts     64,000,000             $ 24,000,000       24,000,000   $ 64,000,000 37,000,000 24,000,000    
Summer                                        
Loss Contingencies [Line Items]                                        
Proceeds from legal settlements of share of claims incurred in previous year                               4,000,000 3,000,000      
Nuclear Insurance                                        
Loss Contingencies [Line Items]                                        
Maximum liability each nuclear plant is insured against     450,000,000                         $ 450,000,000        
Inflation adjustment period for nuclear insurance                               5 years        
NEIL maximum insurance coverage to nuclear facility for property damage and outage costs     2,750,000,000                         $ 2,750,000,000        
NEIL maximum insurance coverage to nuclear facility for property damage and outage costs from non-nuclear event                               2,330,000,000        
NEIL aggregate maximum loss for any single loss occurrence     $ 2,750,000,000                         2,750,000,000        
NEIL maximum retrospective premium assessment                               24,000,000        
EMANI maximum insurance coverage for Summer station unit 1 for property damage and outage costs from non-nuclear event                               415,000,000        
EMANI maximum retrospective premium assessment                               2,000,000        
Common Stock | Dominion Energy                                        
Loss Contingencies [Line Items]                                        
Common stock issued to satisfy the settlement         $ 322,000,000                              
Dominion Energy South Carolina, Inc.                                        
Loss Contingencies [Line Items]                                        
Reduction of liens filed                               33,000,000        
SCANA                                        
Loss Contingencies [Line Items]                                        
Payment of civil monetary penalty                               25,000,000        
SCANA and DESC                                        
Loss Contingencies [Line Items]                                        
Payment of disgorgement and prejudgment interest                               112,500,000        
Impairment of Assets and Other Charges | Dominion Energy South Carolina, Inc.                                        
Loss Contingencies [Line Items]                                        
Impairment of assets and other charges                               97,000,000 590,000,000      
Impairment of assets and other charges, after-tax                               73,000,000 $ 444,000,000      
SCANA Combination                                        
Loss Contingencies [Line Items]                                        
Regulatory asset impairment charges committed to forgo recovery                         258,000,000              
Tax charge related to regulatory assets committed to forgo recovery                         194,000,000              
DESC Ratepayer Case                                        
Loss Contingencies [Line Items]                                        
Customer refundable fees, alternative plan                         1,000,000,000.0              
Customer refund fees alternative plan after tax                         $ 756,000,000              
Customer refunded estimated period                         11 years              
Previous existing regulatory liability                         $ 1,000,000,000.0              
Previous existing regulatory liability, years                         20 years              
Escrow amount                   2,000,000,000.0       $ 2,000,000,000.0       $ 2,000,000,000.0    
Credit in future electric rate relief for ratepayer case                   2,000,000,000.0                    
Cash payment related to Ratepayer Case               $ 117,000,000   115,000,000                    
Property with net value transferred           $ 22,000,000                            
Property with net value transferred, cash contribution       $ 38,500,000                                
Conveyance of property with net recorded value       $ 3,000,000                                
DESC Ratepayer Case | Common Stock | Dominion Energy                                        
Loss Contingencies [Line Items]                                        
Common stock issued to satisfy the settlement                               $ 322,000,000        
Wrongful Death Suit of Estate of Jose Larios | Dominion Energy South Carolina, Inc.                                        
Loss Contingencies [Line Items]                                        
Agreement in principle to resolve the SCDOR matter             $ 19,000,000                          
NND Project                                        
Loss Contingencies [Line Items]                                        
Jointly owned utility plant, proportionate ownership share     55.00%                         55.00%        
Maximum [Member] | Nuclear Insurance                                        
Loss Contingencies [Line Items]                                        
Maximum liability protection per nuclear incident amount                               $ 13,800,000,000        
Amount that could be assessed for each licensed reactor     $ 138,000,000                         138,000,000        
Amount that could be assessed for each licensed reactor per year                               21,000,000        
Maximum [Member] | DESC Summer | Nuclear Insurance                                        
Loss Contingencies [Line Items]                                        
Amount that could be assessed for each licensed reactor     $ 92,000,000                         92,000,000        
Amount that could be assessed for each licensed reactor per year                               $ 14,000,000        
Maximum [Member] | DESC Ratepayer Case                                        
Loss Contingencies [Line Items]                                        
Estimated aggregate fair value of certain real estate                   85,000,000                    
Minimum [Member] | DESC Ratepayer Case                                        
Loss Contingencies [Line Items]                                        
Estimated aggregate fair value of certain real estate                   $ 60,000,000                    
Carbon Regulations [Member] | Minimum [Member]                                        
Loss Contingencies [Line Items]                                        
Significant emission rate per year CO2 equivalent | T                       75,000                
v3.20.4
Commitments and Contingencies (Schedule of Long-Term Purchase Agreements) (Detail)
$ in Millions
Dec. 31, 2020
USD ($)
 [1]
Commitments And Contingencies Disclosure [Abstract]  
Purchased electric capacity, 2021 $ 83
Purchased electric capacity, 2022 82
Purchased electric capacity, 2023 82
Purchased electric capacity, 2024 81
Purchased electric capacity, 2025 82
Purchased electric capacity, Thereafter 915
Purchased electric capacity, Total $ 1,325
[1] (1)   Includes affiliated amounts with certain solar facilities of $246 million
v3.20.4
Commitments and Contingencies (Schedule of Long-Term Purchase Agreements) (Parenthetical) (Detail)
$ in Millions
 12 Months Ended
Dec. 31, 2020
USD ($)
Solar Affiliates [Member]  
Long Term Purchase Commitment [Line Items]  
Affiliated amount for long term commitments $ 246
v3.20.4
Leases (Schedule Of Lease Assets and Liabilities Recorded in Consolidated Balance Sheets) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Jan. 01, 2019
Leases [Abstract]      
Operating lease assets $ 21 [1] $ 23 [1] $ 19
Finance lease assets [2] 20 26  
Total lease assets 41 49  
Operating lease liabilities - current [3] 3 3  
Operating lease liabilities - noncurrent [4] 18 20  
Finance lease liabilities - current [5] 6 7  
Finance lease liabilities - noncurrent 15 20  
Total lease liabilities $ 42 $ 50  
[1] Included in other deferred debits and other assets in the Consolidated Balance Sheets.
[2] Included in utility plant, net, in the Consolidated Balance Sheets, net of $24 million of accumulated amortization at both December 31, 2020 and 2019.
[3] Included in other current liabilities in the Consolidated Balance Sheets.
[4] Included in other deferred credits and other liabilities in the Consolidated Balance Sheets.
[5] Included in current portion of long-term debt in the Consolidated Balance Sheets.
v3.20.4
Leases (Schedule Of Lease Assets and Liabilities Recorded in Consolidated Balance Sheets) (Parenthetical) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Utility Plant, Net    
Finance lease assets, accumulated amortization $ 24 $ 24
v3.20.4
Leases (Summary of Total Lease Cost) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Leases [Abstract]    
Finance lease cost, amortization $ 8 $ 7
Finance lease cost, interest 1 1
Operating lease cost 4 4
Short-term lease cost 2 1
Total lease cost $ 15 $ 13
v3.20.4
Leases (Cash Paid for Amounts Included in Measurement of Lease Liabilities) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Leases [Abstract]    
Operating cash flows from finance leases $ 1 $ 1
Operating cash flows from operating leases 4 3
Financing cash flows from finance leases $ 8 $ 7
v3.20.4
Leases (Summary of Weighted Average Remaining Lease Term And Discount Rate for Operating and Finance Leases) (Detail)
Dec. 31, 2020
Dec. 31, 2019
Leases [Abstract]    
Weighted average remaining lease term - finance leases 4 years 5 years
Weighted average remaining lease term - operating leases 19 years 18 years
Weighted average discount rate - finance leases 2.92% 2.94%
Weighted average discount rate - operating leases 3.95% 3.94%
v3.20.4
Leases (Schedule of Maturity Analysis of Operating and Finance Lease Liabilities) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Jan. 01, 2019
Operating Lease Liabilities, Payments Due [Abstract]    
Maturity of operating lease liabilities, 2021 $ 4  
Maturity of operating lease liabilities, 2022 3  
Maturity of operating lease liabilities, 2023 2  
Maturity of operating lease liabilities, 2024 2  
Maturity of operating lease liabilities, 2025 1  
Maturity of operating lease liabilities, after 2025 21  
Maturity of operating lease liabilities, total undiscounted lease payments 33  
Operating lease liabilities, present value adjustment (12)  
Present value of operating lease liabilities 21 $ 19
Finance Lease Liabilities, Payments, Due [Abstract]    
Maturity of finance lease liabilities, 2021 7  
Maturity of finance lease liabilities, 2022 6  
Maturity of finance lease liabilities, 2023 4  
Maturity of finance lease liabilities, 2024 3  
Maturity of finance lease liabilities, 2025 2  
Maturity of finance lease liabilities, after 2025 2  
Maturity of finance lease liabilities, total undiscounted lease payments 24  
Finance lease liabilities, present value adjustment (3)  
Present value of finance lease liabilities $ 21  
v3.20.4
Operating Segments (Narrative) (Detail)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2020
USD ($)
Sep. 30, 2020
USD ($)
Dec. 31, 2019
USD ($)
Segment
Jun. 30, 2019
USD ($)
Mar. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Mar. 31, 2018
USD ($)
Dec. 31, 2020
USD ($)
Segment
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Segment Reporting Information [Line Items]                      
Number of primary operating segments | Segment     1         1      
Litigation charges, after tax $ 35 $ 40 $ 240 $ 75 $ 118            
Charge for refund of amounts from customers $ 70   76         $ 70 $ 76    
Charge for refund of amounts from customers, after tax         756            
Charge for utility plant but committed to forgo recovery, after tax         86            
Charge related to a voluntary retirement program, after-tax       $ 47              
Asset impairment charge         $ 105     (14) 576 $ 1,376  
Asset impairment charge after-tax           $ 870 $ 3       $ 690
Operating Segment | Corporate and Other                      
Segment Reporting Information [Line Items]                      
After- tax net expenses               104 1,600 917  
Operating Segment | Dominion Energy South Carolina                      
Segment Reporting Information [Line Items]                      
Litigation charges               99 590    
Litigation charges, after tax               $ 74 444    
Charge for refund of amounts from customers     1,000           1,000    
Charge for refund of amounts from customers, after tax                 756    
Income tax related to regulatory assets acquired     194           194    
Income tax related to regulatory assets acquired, after tax     $ 258           258    
Charge for utility plant but committed to forgo recovery                 114    
Charge for utility plant but committed to forgo recovery, after tax                 86    
Merger-related costs                 100    
Merger-related costs, after tax                 76    
Charge related to a voluntary retirement program                 79    
Charge related to a voluntary retirement program, after-tax                 59    
Changes in unrecognized tax benefits                 $ 66    
Asset impairment charge                   1,400  
Asset impairment charge after-tax                   $ 870  
v3.20.4
Operating Segments - Schedule of Segment Information (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Segment Reporting Information [Line Items]      
Operating Revenue [1] $ 2,739 $ 1,929 $ 2,762
Depreciation and amortization 474 450 327
Interest charges [1] 229 260 303
Income tax expense (benefit) 71 (12) (416)
Comprehensive income (loss) available (attributable) to common shareholder 297 (1,239) (613)
Capital expenditures 742 497 633
Total assets 14,479 14,301  
Operating Segment | Dominion Energy South Carolina      
Segment Reporting Information [Line Items]      
Operating Revenue 2,739 2,937 2,763
Depreciation and amortization 474 452 327
Interest charges 223 247 306
Income tax expense (benefit) 107 163 98
Comprehensive income (loss) available (attributable) to common shareholder 410 408 304
Capital expenditures 742 497 633
Total assets 14,500 14,300  
Operating Segment | Corporate and Other      
Segment Reporting Information [Line Items]      
Operating Revenue 0 (1,008) (1)
Depreciation and amortization 0 (2) 0
Interest charges 6 13 (3)
Income tax expense (benefit) (36) (175) (514)
Comprehensive income (loss) available (attributable) to common shareholder (113) (1,647) (917)
Capital expenditures 0 0 $ 0
Total assets $ 0 $ 0  
[1] See Note 16 for amounts attributable to affiliates.
v3.20.4
Utility Plant and Nonutility Property - Property, Plant and Equipment (Details) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Property Plant And Equipment [Line Items]    
Gross nonutility property $ 45 $ 75
Generation    
Property Plant And Equipment [Line Items]    
Utility plant in service 5,921 5,765
Transmission    
Property Plant And Equipment [Line Items]    
Utility plant in service 1,963 1,905
Distribution    
Property Plant And Equipment [Line Items]    
Utility plant in service 4,909 4,685
Storage    
Property Plant And Equipment [Line Items]    
Utility plant in service 74 73
General and other    
Property Plant And Equipment [Line Items]    
Utility plant in service 563 549
Intangible    
Property Plant And Equipment [Line Items]    
Utility plant in service 250 231
Construction Work In Progress    
Property Plant And Equipment [Line Items]    
Utility plant in service 460 339
Nuclear Fuel    
Property Plant And Equipment [Line Items]    
Utility plant in service 575 608
Total Gross Utility Plant    
Property Plant And Equipment [Line Items]    
Utility plant in service $ 14,715 $ 14,155
v3.20.4
Utility Plant and Nonutility Property (Narrative) (Details) - USD ($)
$ in Millions
 1 Months Ended 12 Months Ended
Aug. 31, 2019
May 31, 2019
Dec. 31, 2020
Dec. 31, 2019
Utility Plant And Non Utility Property [Line Items]        
Amounts due from Santee Cooper for share of direct expenses     $ 64 $ 119
Warranty Service Contract Assets        
Utility Plant And Non Utility Property [Line Items]        
Total consideration from sale of assets   $ 7    
Contractual term of agreement to use brand     10 years  
Warranty Service Contract Assets | Other Income (Expense), Net        
Utility Plant And Non Utility Property [Line Items]        
Gain on sale of assets $ 7      
Gain on sale of assets, after tax $ 5      
Summer        
Utility Plant And Non Utility Property [Line Items]        
Percentage of ownership interest   66.70%    
Amounts due from Santee Cooper for share of direct expenses     $ 28 $ 50
NND Project | Summer        
Utility Plant And Non Utility Property [Line Items]        
Percentage of ownership interest   55.00%    
Santee Cooper | NND Project | Summer        
Utility Plant And Non Utility Property [Line Items]        
Percentage of ownership interest   11.70%    
Ownership interest purchased   $ 8    
v3.20.4
Utility Plant and Nonutility Property - Schedule of Jointly Owned Utility Plants (Details) - Summer Unit 1 - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Property Plant And Equipment [Line Items]    
Jointly owned utility plant, proportionate ownership share 66.70% 66.70%
Plant in service, jointly owned utility plant $ 1,600 $ 1,400
Accumulated depreciation, jointly owned utility plant 702 684
Construction work in progress, jointly owned utility plant $ 62 $ 79
v3.20.4
Affiliated and Related Party Transactions (Narrative) (Detail)
Dec. 31, 2020
Canadys Refined Coal [Member]  
Related Party Transaction [Line Items]  
Ownership percentage 40.00%
v3.20.4
Affiliated and Related Party Transactions (Schedule of Affiliated Transactions - Income Statement) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Related Party Transaction [Line Items]      
Purchases of fuel used in electric generation from affiliate $ 0 $ 43 $ 139
Operating Revenues – Electric from sales to affiliate 4 4 5
Operating Revenues – Gas from sales to affiliate 1 1 1
Operating Expenses – Other taxes from affiliate 9 6 6
DESS [Member]      
Related Party Transaction [Line Items]      
Direct and allocated costs [1] 294 297 283
Canadys Refined Coal [Member]      
Related Party Transaction [Line Items]      
Purchases from affiliate 0 121 150
Sales of coal to affiliate 0 120 $ 149
Solar Affiliates [Member]      
Related Party Transaction [Line Items]      
Purchases from affiliate 12 8  
DECG [Member]      
Related Party Transaction [Line Items]      
Purchases of fuel used in electric generation from affiliate 16 19  
Gas purchased for resale $ 36 $ 44  
[1] Includes capitalized expenditures of $81 million, $53 million and $41 million for the years ended December 31, 2020, 2019 and 2018, respectively.
v3.20.4
Affiliated and Related Party Transactions (Schedule of Affiliated Transactions - Income Statement) (Parenthetical) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
DESS [Member]      
Related Party Transaction [Line Items]      
Capitalized expenditures $ 81 $ 53 $ 41
v3.20.4
Affiliated and Related Party Transactions (Schedule of Affiliated Transactions - Balance Sheet) (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
DESS [Member]    
Related Party Transaction [Line Items]    
Payable to affiliates $ 59 $ 76
Public Service Company of North Carolina, Incorporated [Member]    
Related Party Transaction [Line Items]    
Payable to affiliates 5 8
Canadys Refined Coal [Member]    
Related Party Transaction [Line Items]    
Receivable from affiliates 0 2
Payable to affiliates 0 2
Solar Affiliates [Member]    
Related Party Transaction [Line Items]    
Payable to affiliates 1 0
DECG [Member]    
Related Party Transaction [Line Items]    
Receivable from affiliates 0 1
Payable to affiliates $ 0 $ 5
v3.20.4
Other Income (Expense), Net (Components of Other Income (Expense), Net) (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Condensed Statement Of Income Captions [Line Items]      
Operating revenue from contracts with customers $ 1 $ 4 $ 5
Other income 13 19 141
Other expense (38) (57) (28)
Allowance for equity funds used during construction 1 1 11
Other income (expense), net $ (23) $ (33) 129
Other Income [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]      
Condensed Statement Of Income Captions [Line Items]      
Gains from settlement of interest rate derivatives     $ 115
v3.20.4
Quarterly Financial Information (Schedule of Quarterly Financial Information) (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2020
Sep. 30, 2020
Jun. 30, 2020
Mar. 31, 2020
Dec. 31, 2019
Sep. 30, 2019
Jun. 30, 2019
Mar. 31, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]                      
Operating revenue $ 688 $ 755 $ 624 $ 672 $ 771 $ 795 $ 698 $ (335)      
Operating income (loss) 136 180 144 171 (76) 261 17 (1,143) $ 631 $ (941) $ (831)
Total comprehensive income (loss) 43 106 67 93 (191) 143 (70) (1,103) $ 308 $ (1,221)  
Comprehensive income (loss) available (attributable) to common shareholder $ 39 $ 101 $ 69 $ 88 $ (195) $ 143 $ (78) $ (1,109)      
v3.20.4
Quarterly Financial Information (Narrative) (Details) - USD ($)
$ in Millions
 3 Months Ended
Dec. 31, 2020
Sep. 30, 2020
Dec. 31, 2019
Jun. 30, 2019
Mar. 31, 2019
Quarterly Financial Information Disclosure [Abstract]          
Litigation charges, after tax $ 35 $ 40 $ 240 $ 75 $ 118
Charge related to voluntary retirement program, after-tax       $ 47  
Charge for refund of amounts from customers, after tax         756
Tax charge related to regulatory assets committed to forgo recovery         198
Regulatory asset impairment charges committed to forgo recovery         264
Charge for utility plant but committed to forgo recovery, after tax         $ 86