Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Utility plant, net | $ 8,915 | $ 8,783 |
| Receivables, customer, allowance for uncollectible accounts | 3 | 4 |
| Total current assets | 1,118 | 1,689 |
| Total deferred debits and other assets | $ 3,985 | $ 4,228 |
| Common stock, par value | $ 0 | $ 0 |
| Common stock, shares outstanding | 40.3 | 40.3 |
| Variable Interest Entity, Primary Beneficiary [Member] | ||
| Utility plant, net | $ 727 | $ 711 |
| Total current assets | 143 | 96 |
| Total deferred debits and other assets | $ 32 | $ 34 |
Consolidated Statements of Comprehensive Loss (Parenthetical) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Income Statement [Abstract] | |||
| Allowance for funds used during construction | $ 5 | $ 9 | $ 15 |
| Deferred cost of employee benefit plans, tax | $ 0 | $ 0 | $ 0 |
Consolidated Statements of Cash Flows - USD ($) $ in Millions |
12 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
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| Operating Activities | |||||||||
| Net loss | $ (1,222) | $ (589) | $ (172) | ||||||
| Adjustments to reconcile net loss to net cash provided by operating activities: | |||||||||
| Impairment of assets and other charges | 576 | 1,376 | 1,118 | ||||||
| Provision for refunds to electric customers | 800 | 0 | 0 | ||||||
| Gain on sale of assets | (7) | 0 | 0 | ||||||
| Deferred income taxes, net | (379) | (184) | (780) | ||||||
| Depreciation and amortization | 464 | 342 | 323 | ||||||
| Amortization of nuclear fuel | 53 | 47 | 44 | ||||||
| Other adjustments | (7) | (17) | (49) | ||||||
| Changes in certain assets and liabilities: | |||||||||
| Receivables | (33) | 50 | (32) | ||||||
| Receivables – affiliated and related party | 1 | (2) | 12 | ||||||
| Income tax receivable | 0 | 198 | (145) | ||||||
| Inventories | (76) | (54) | (60) | ||||||
| Prepayments | (9) | 0 | 6 | ||||||
| Regulatory assets | (20) | (179) | 185 | ||||||
| Regulatory liabilities | 265 | (360) | 899 | ||||||
| Accounts payable | (54) | 61 | 20 | ||||||
| Accounts payable – affiliated and related party | (15) | 0 | (28) | ||||||
| Revenue subject to refund | (73) | 77 | 0 | ||||||
| Unrecognized tax benefits | 52 | 19 | (241) | ||||||
| Taxes accrued | (10) | 31 | 13 | ||||||
| Pension and other postretirement benefits | (27) | 15 | (21) | ||||||
| Other assets and liabilities | 169 | 96 | (86) | ||||||
| Net cash provided by operating activities | 448 | 927 | 1,006 | ||||||
| Investing Activities | |||||||||
| Property additions and construction expenditures | (497) | (633) | (928) | ||||||
| Proceeds from monetization of guaranty settlement | 0 | 0 | 1,096 | ||||||
| Proceeds from investments and sales of assets | 39 | 40 | 118 | ||||||
| Purchase of investments | (54) | (29) | (122) | ||||||
| Purchase of investments – affiliate | 0 | (111) | 0 | ||||||
| Payments upon interest rate derivative contract settlement | 0 | 0 | (39) | ||||||
| Proceeds from interest rate derivative contract settlement | 0 | 115 | 0 | ||||||
| Investment in affiliate, net | 344 | (214) | (28) | ||||||
| Net cash provided by (used in) investing activities | (168) | (832) | 97 | ||||||
| Financing Activities | |||||||||
| Proceeds from issuance of debt | 0 | 795 | 0 | ||||||
| Proceeds from issuance of affiliated debt | 230 | 0 | 0 | ||||||
| Repayment of long-term debt, including redemption premiums | (1,890) | (825) | (12) | ||||||
| Dividend to parent | (30) | (173) | (319) | ||||||
| Short-term borrowings, net | (73) | (179) | (552) | ||||||
| Short-term borrowings – affiliated, net | 292 | 0 | 0 | ||||||
| Money pool borrowings, net | 0 | 245 | 8 | ||||||
| Contribution from parent | 838 | 24 | 3 | ||||||
| Contribution returned to parent | (20) | 0 | 0 | ||||||
| Net cash used in financing activities | (653) | (113) | (872) | ||||||
| Net increase (decrease) in cash, restricted cash and equivalents | (373) | (18) | 231 | ||||||
| Cash, restricted cash and equivalents at beginning of period | [1] | 377 | 395 | 164 | |||||
| Cash, restricted cash and equivalents at end of period | [1] | 4 | 377 | 395 | |||||
| Supplemental Cash Flow Information | |||||||||
| Cash for interest paid (net of capitalized interest) | 220 | 264 | 269 | ||||||
| Cash for income taxes paid | 13 | 3 | 47 | ||||||
| Cash for income taxes received | 0 | 216 | 145 | ||||||
| Noncash investing and financing activities: | |||||||||
| Accrued construction expenditures | [2] | 120 | 69 | 99 | |||||
| Leases | [2],[3] | 12 | 8 | 8 | |||||
| Contributed capital | [2] | $ 1 | $ 6 | $ 0 | |||||
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Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Statement Of Cash Flows [Abstract] | |||
| Cash paid for interest, capitalized interest | $ 5 | $ 9 | $ 15 |
| Restricted cash and equivalents | 0 | 0 | 0 |
| Financing leases | 4 | ||
| Operating leases | $ 8 | ||
| Capital leases | $ 8 | $ 8 | |
Consolidated Statements of Changes in Common Equity - USD ($) shares in Millions, $ in Millions |
Total |
Common Stock |
Retained Earnings |
Accumulated Other Comprehensive Income (Loss) |
Noncontrolling Interest |
|---|---|---|---|---|---|
| Beginning balance at Dec. 31, 2016 | $ 5,472 | $ 2,860 | $ 2,481 | $ (3) | $ 134 |
| Beginning balance (in shares) at Dec. 31, 2016 | 40 | ||||
| Total comprehensive income (loss) available (attributable) to common shareholder | (172) | ||||
| Total comprehensive income (loss) available (attributable) to common shareholder | (173) | (185) | (1) | 13 | |
| Capital contribution from parent | 3 | 3 | |||
| Dividend to parent | (322) | (314) | (8) | ||
| Ending balance at Dec. 31, 2017 | 4,980 | $ 2,860 | 1,982 | (4) | 142 |
| Ending 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 | (3) | 179 |
| Ending balance (in shares) at Dec. 31, 2018 | 40 | ||||
| Cumulative-effect of change in accounting principle | 1 | (1) | |||
| 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 |
Nature of Operations |
12 Months Ended |
|---|---|
Dec. 31, 2019 | |
| 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 sells 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. |
Summary of Significant Accounting Policies |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2019 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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 VIE’s 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 VIE’s. 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. GENCO’s property (carrying value of $508 million) previously served as collateral for its long-term borrowings. 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, DESC purchases shared services from DESS, an affiliated VIE that provides accounting, legal, finance and certain administrative and technical services to all SCANA subsidiaries, including DESC. DESC has determined that it is not the primary beneficiary of DESS 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 2018 and 2017 Consolidated Financial Statements and Notes have been reclassified to conform to the 2019 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 4.3%, 7.0% and 3.9% for 2019, 2018 and 2017, 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:
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 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 maintenance expenditures. For the years ended December 31, 2019 and 2018, DESC incurred $10 million and $16 million, respectively, for turbine 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 scheduled from the spring of 2014 through the spring of 2020. Refueling outage costs incurred for which DESC was responsible totaled $2 million in 2019 and $29 million in 2018. 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 2016, 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 $646 million, stated in 2019 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 December 31, 2019, there were no restricted cash and equivalent balances. At December 31, 2018, cash and cash equivalents at DESC included $115 million held in escrow pending a settlement which was contingent on the consummation of the merger with Dominion Energy. As such, DESC did not consider this amount to be restricted at December 31, 2018. 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 $114 million and $129 million at December 31, 2019 and 2018, 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 10% of DESC’s accounts receivable balance at December 31, 2019. 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. The 2017 Tax Reform Act included a broad range of tax reform provisions affecting DESC, including changes in corporate tax rates and business deductions. The 2017 Tax Reform Act reduces the corporate income tax rate from 35% to 21% for tax years beginning after December 31, 2017. Deferred tax assets and liabilities are classified as noncurrent in the Consolidated Balance Sheets and measured at the enacted tax rate expected to apply when temporary differences are realized or settled. Thus, at the date of enactment, federal deferred taxes were remeasured based upon the new 21% tax rate. The total effect of tax rate changes on deferred tax balances was recorded as a component of the income tax provision related to continuing operations for the period in which the law is enacted, even if the assets and liabilities relate to other components of the financial statements, such as items of accumulated other comprehensive income. DESC, as a rate-regulated utility, was required to adjust deferred income tax assets and liabilities for the change in income tax rates. However, if it is probable that the effect of the change in income tax rates will be recovered or shared with customers in future rates, DESC recorded a regulatory asset or liability instead of an increase or decrease to deferred income tax expense. 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, 2019, DESC had $132 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 $18 million, $8 million and less than $1 million in 2019, 2018, and 2017, respectively. Interest income for DESC was $2 million in 2019 and 2018, and less than $1 million in 2017. DESC also recorded penalty expenses of $7 million in 2019. At December 31, 2019, DESC had an income tax-related affiliated receivable of $21 million from Dominion Energy. This balance is expected to be received from Dominion Energy. 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 gas and regulated electric 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:
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 $19 million and $11 million associated with cash collateral at December 31, 2019 and 2018, respectively. DESC had no margin liabilities associated with cash collateral at December 31, 2019 and 2018. 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 the Company 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 3 and 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
Other Revenue
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 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 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 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. NET PERIODIC PENSION AND OTHER POSTRETIREMENT BENEFIT COSTS In March 2017, the FASB issued revised accounting guidance for the presentation of net periodic pension and other postretirement benefit costs. This guidance became effective for DESC beginning January 1, 2018 and requires that the service cost component of net periodic pension and other postretirement benefit costs be classified in the same line item as other compensation costs arising from services rendered by employees, while all other components of net periodic pension and other postretirement costs are classified outside of income from operations. In addition, only the service cost component remains eligible for capitalization during construction. The standard also recognizes that in the event that a regulator continues to require capitalization of all net periodic benefit costs prospectively, the difference would result in recognition of a regulatory asset or liability. For costs not capitalized for which regulators are expected to provide recovery, a regulatory asset will be established.
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. |
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| 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 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 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 approximately $63 million in 2019 and is expected to reduce these rates by $67 million in 2020. Unamortized excess deferred income taxes that remain 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 will make such changes to its formula rate as part of its annual update in May 2020. 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.
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 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 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 approximately $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. This matter is pending. In April 2019, the South Carolina Commission approved DESC’s proposal to decrease the total fuel cost component of retail electric rates. DESC's proposal included maintaining its base fuel component at the current level to produce a projected under-recovered balance of $35 million at the end of the 12-month period beginning with the first billing cycle of May 2019 and requested carrying costs for any base fuel under-collected balances, should they occur. DESC also proposed reducing its variable environmental component and maintaining or reducing its DER components. Changes in rates became effective beginning with the first billing cycle of May 2019. 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, and on October 30, 2018, the South Carolina Commission issued an order granting one such petition related to DESC supplying certain information as in previous years. The other petitions were denied, and certain parties have appealed the decision to deny their petitions to the South Carolina Supreme Court. These appeals primarily relate to avoided cost rates that DESC is required to pay to solar energy developers, and these appeals are pending. DESC cannot predict the outcome of these matters. Electric Transmission Projects In 2020, DESC expects to begin 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. This matter is pending. Electric – Other DESC has approval for a DSM rider through which it recovers expenditures related to its DSM programs. In January 2019, DESC filed an application with the South Carolina Commission seeking approval to recover $30 million of costs incurred and net lost future revenues associated with these programs, along with an incentive to invest in such programs. In April 2019, the South Carolina Commission approved the request for the rate year beginning with the first billing cycle of May 2019.
In January 2020, DESC submitted its annual DSM programs filing to the South Carolina Commission. If approved the filing would allow recovery of approximately $40 million of costs and net lost revenues associated with DSM 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. No adjustment was made in 2019. In 2020, DESC requested that the South Carolina Commission approve an adjustment to this rider to decrease annual revenue by approximately $11 million. This matter is pending. Gas In June 2019, DESC filed with the South Carolina Commission its monitoring report for the 12-month period ended March 31, 2019 with a total revenue requirement of $437 million. This represents a $7 million overall increase to its natural gas rates under the terms of the RSA effective for the rate year beginning November 2019. In October 2019, the South Carolina Commission approved a total revenue requirement of $436 million effective with the first billing cycle of November 2019.
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.
(6) Represents amounts under-collected from customers pursuant to the cost of fuel components approved by the South Carolina Commission.
(8) During 2019, DESC purchased certain of its first mortgage bonds as discussed in Note 6. As a result of these transactions, DESC incurred net costs, including write-offs of unamortized discount, premium and debt issuance costs, of $270 million.
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. |
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| Operating Revenue |
4. OPERATING REVENUE The Company’s operating revenue, subsequent to the adoption of revised guidance for revenue recognition from contracts with customers, consists of the following:
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 $9 million and $4 million at December 31, 2019 and 2018, respectively. For the years ended December 31, 2019 and 2018, DESC recognized revenue of $3 million and $4 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:
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Equity |
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| 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 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, the Federal Power Act requires the appropriation of a portion of certain earnings from hydroelectric projects. At both December 31, 2019 and 2018, retained earnings of $115 million were restricted by this requirement as to payment of cash dividends on DESC’s common stock. 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, 2019, DESC’s retained earnings are below the balance established by the Federal Power Act as a reserve on earnings attributable to hydroelectric generation plants. As a result, DESC is prohibited from the payment of dividends without regulatory approval until the balance of its retained earnings increases. |
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| 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, 2019 and 2018 is as follows:
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, 2019, were as follows:
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, 2019, the Bond Ratio was 6.88. Adjusted Net Earnings, as therein defined, excludes the impairment loss. 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 In March 2019, DESC became a co-borrower under Dominion Energy's $6.0 billion joint revolving credit facility. DESC's short-term financing is supported through its access to this joint revolving credit facility, which can be used for working capital, as support for the combined commercial paper programs of DESC, Dominion Energy and certain other of its subsidiaries (co-borrowers), 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:
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, 2019, 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. Also in March 2019, DESC canceled its previous committed long-term facility which was a revolving line of credit under a credit agreement with a syndicate of banks. This previous credit agreement was used for general corporate purposes, including liquidity support for DESC's commercial paper program and working capital needs, and was set to expire in December 2020.
The weighted-average interest rate of the outstanding commercial paper supported by this credit facility was 3.82% at December 31, 2018. In April 2019, DESC renewed its FERC authority through April 2020 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 April 2019, GENCO renewed its FERC authority through April 2020 to issue short-term indebtedness not to exceed $200 million outstanding with maturity dates of one year or less. In January 2020, DESC and GENCO applied to FERC for a 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 2020. 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, 2019, DESC had borrowings outstanding under this credit agreement totaling $355 million, which are recorded in affiliated and related party payables in DESC’s Consolidated Balance Sheets. For the twelve months ended December 31, 2019, DESC recorded interest charges of $3 million. DESC participated in a utility money pool with SCANA and another regulated subsidiary of SCANA through April 2019. Fuel Company and GENCO remain in the utility money pool. Money pool borrowings and investments bear interest at short-term market rates. For the years ended December 31, 2019 and 2018, DESC recorded interest income from money pool transactions of $8 million and $4 million, respectively, and for the same periods DESC recorded interest expense from money pool transactions of $8 million and $4 million, respectively. DESC had outstanding money pool borrowings due to an affiliate of $219 million and investments due from an affiliate of $9 million at December 31, 2019. At December 31, 2018, DESC had outstanding money pool borrowings due to an affiliate of $282 million and investments due from an affiliate of $353 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. |
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Income Taxes |
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| 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. The 2017 Tax Reform Act included a broad range of tax reform provisions. The 2017 Tax Reform Act reduced the corporate income tax rate from 35% to 21% for tax years beginning after December 31, 2017. At the date of enactment, deferred tax assets and liabilities were remeasured based upon the new 21% enacted tax rate expected to apply when temporary differences are realized or settled. The specific provisions related to regulated public utilities in the 2017 Tax Reform Act generally allow for the continued deductibility of interest expense, changed the tax depreciation of certain property acquired after September 27, 2017, and continued certain rate normalization requirements for accelerated depreciation benefits. 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. The 2017 Tax Reform Act included provisions that stipulate how these excess deferred taxes may be passed back to customers for certain accelerated tax depreciation benefits. Potential sharing of other deferred taxes will be determined by our regulators. See Note 3 for more information. DESC has completed the accounting for the effects of the 2017 Tax Reform Act, although changes could occur as additional guidance is issued and finalized, particularly as it relates to the deductibility of interest expense in consolidated groups such as Dominion Energy. In addition, the major states in which DESC operates have addressed conformity with some or all of the provisions of the 2017 Tax Reform Act, although they may have modified certain provisions.
Details of income tax expense for continuing operations including noncontrolling interests were as follows:
The 2017 Tax Reform Act reduced the statutory federal income tax rate to 21% beginning in January 2018. Accordingly, current and deferred income taxes are recorded at the new 21% rate.
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 SCANA Energy Marketing, Inc.’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:
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 2019, 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 may ultimately impact 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.
In connection with the remeasurement of federal deferred income tax assets and liabilities resulting from the lower federal income tax rate, DESC recorded a deferred income tax benefit of approximately $1 million in the statements of operations for the year ended December 31, 2017. As a result of the filing of the 2017 tax return in the fourth quarter of 2018 and the additional impairment charges recorded in 2018, adjustments to such excess deferred income taxes of approximately $176 million were recorded. Also in connection with the additional impairment charges, DESC recorded additional adjustments to deferred income taxes in the aggregate amount of approximately $23 million. In addition, certain states in which DESC operates may or may not conform to some or all of the provisions of the 2017 Tax Reform Act. Ultimate resolution or clarification of these matters may result in favorable or unfavorable impacts to results of operations and cash flows, and adjustments to tax-related assets and liabilities, and such impacts or adjustments could be material.
DESC’s deferred income taxes consist of the following:
At December 31, 2019, DESC had the following deductible loss and credit carryforwards:
A reconciliation of changes in DESC’s unrecognized tax benefits follows:
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 2010, except for certain outstanding refund claims. The IRS has completed examinations of DESC’s federal returns through 2012. The IRS is currently examining DESC’s federal returns from 2013 through 2017. With few exceptions, DESC is no longer subject to state and local income tax examinations by tax authorities for years prior to 2012.
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 up to $4 million. Otherwise, with regard to 2019 and prior years, DESC cannot estimate the range of reasonably possible changes to unrecognized tax benefits that may occur in 2020.
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. |
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Derivative Financial Instruments |
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| Derivative Instruments And Hedging Activities Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Derivative Financial Instruments |
8. DERIVATIVE FINANCIAL INSTRUMENTS See Note 2 for the Company’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 the Company’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. Certain DESC 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. DESC’s derivatives with credit-related contingent provisions that were in a liability position were fully collateralized with cash at December 31, 2019 and 2018. 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:
Volumes The following table presents the volume of derivative activity at December 31, 2019. These volumes are based on open derivative positions and represent the combined absolute value of their long and short positions.
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:
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
Derivatives Not designated as Hedging Instruments
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Fair Value Measurements, Including Derivatives |
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| 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:
Levels DESC utilizes the following fair value hierarchy, which prioritizes the inputs to valuation techniques used to measure fair value into three broad levels:
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. 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:
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:
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Asset Retirement Obligations |
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Dec. 31, 2019 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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, 2019, DESC has recorded AROs of $177 million for nuclear plant decommissioning. At December 31, 2019, DESC had $214 million in a trust for its two-thirds share of decommissioning activities. In addition, DESC has recorded AROs of $312 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:
(1) The decrease in 2019 reflects a change in the estimated timing of cash flows for interim pipeline replacements and DOE recoveries. |
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Employee Benefit Plans and Equity Compensation Plan |
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| 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.
The accumulated benefit obligation for pension benefits for DESC was $711 million at the end of 2019 and $714 million at the end of 2018. 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:
A 6.6% annual rate of increase in the per capita cost of covered health care benefits was assumed for 2019. The rate was assumed to decrease gradually to 5.0% for 2023 and to remain at that level thereafter. A one percent increase in the assumed health care cost trend rate for DESC would increase the postretirement benefit obligation by less than $1 million at December 31, 2019 and by $1 million at December 31, 2018. A one percent decrease in the assumed health care cost trend rate for DESC would decrease the postretirement benefit obligation by less than $1 million at December 31, 2019 and by $1 million at December 31, 2018. Funded Status
Amounts recognized on the consolidated balance sheets were as follows:
Amounts recognized in accumulated other comprehensive loss were as follows:
Amounts recognized in regulatory assets were as follows:
In connection with the joint ownership of Summer, costs related to pensions attributable to Santee Cooper as of December 31, 2019 and 2018 totaled $19 million and $25 million, respectively, and were recorded within deferred debits. Costs related to other postretirement benefits attributable to Santee Cooper as of December 31, 2019 and 2018 totaled $15 million and $12 million, respectively, and was recorded within deferred debits. Changes in Fair Value of Plan Assets
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, 2019 and 2018 and the target allocation for 2020 are as follows:
For 2020, 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, 2019 and 2018, fair value measurements, and the level within the fair value hierarchy in which the measurements fall, were as follows:
For all periods presented, assets with fair value measurements classified as Level 1 were insignificant, and 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 2019 or 2018. Mutual funds held by the plan are 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. US 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. 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
Pension Plan Contributions The pension trust is adequately funded under current regulations. No contributions have been required since 1997, and as a result of closing the plan to new entrants and freezing benefit accruals at the end of 2023, no significant contributions to the pension trust are expected for the foreseeable future based on current market conditions and assumptions, nor is a limitation on benefit payments expected to apply. 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
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:
Other changes in plan assets and benefit obligations recognized in regulatory assets were as follows:
Significant assumptions used in determining net periodic benefit cost:
The estimated amounts to be amortized from regulatory assets into net periodic benefit cost in 2020 are as follows:
Other postretirement benefit costs are subject to annual per capita limits pursuant to the plan's design. As a result, the effect of a one-percent increase or decrease in the assumed health care cost trend rate on total service and interest cost is not significant. 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 2019, $20 million in 2018 and $23 million in 2017. Employee deferrals, matching contributions, and earnings on all contributions are fully vested and non-forfeitable at all times. |
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Commitments And Contingencies |
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| 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 CAA 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 toxic emissions from power plants. However, the emissions standards and other requirements of the MATS rule would remain in place as the EPA is not proposing to remove coal and oil-fired power plants from the list of sources that are regulated under MATS. Although litigation of the MATS rule and the outcome of the EPA’s rulemaking are still pending, the regulation remains in effect and DESC is complying with the applicable requirements of the rule and does not expect any adverse impacts to its operations at this time.
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. The ACE Rule applies to existing coal-fired power plants. The final rule includes unit-specific performance standards based on the degree of emission reduction levels achievable from unit efficiency improvements to be determined by the permitting agency. The ACE Rule requires states to develop plans by July 2022 to implement these performance standards. These state plans must be approved by the EPA by January 2024. While the impacts of this rule could be material to DESC’s results of operations, financial condition and/or cash flows, the existing regulatory frameworks in South Carolina provide rate recovery mechanisms that could substantially mitigate any such impacts for DESC.
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 to set a significant emissions rate at 75,000 tons per year of CO2 equivalent emissions under which a source would not be required to apply BACT for its GHG emissions. Until the EPA ultimately takes final action on this rulemaking, DESC cannot predict the impact to their 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.
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. Until the proposed rule regarding reconsideration is final, DESC is implementing the 2016 regulation. DESC is still evaluating whether potential impacts on results of operations, financial condition and/or cash flows related to this matter will be material. 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 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 establishes 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 remains December 2023. 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 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. In December 2019, the EPA released proposed revisions to the ELG Rule that, if adopted, could extend the deadlines for compliance with certain standards at several facilities. While the impacts of this rule could be material to DESC’s results of operations, financial condition and/or cash flows, the existing regulatory frameworks in South Carolina provide rate recovery mechanisms that could substantially mitigate any such impacts for the regulated electric utilities.
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 2024 at an estimated cost of $10 million. In September 2018, DESC submitted an updated remediation work plan for one site to SCDHEC, which if approved, would increase costs by approximately $8 million. DESC expects to recover costs arising from the remediation work at all four sites through rate recovery mechanisms and as of December 31, 2019, deferred amounts, net of amounts previously recovered through rates and insurance settlements, totaled $23 million and are included in regulatory assets. Due to the uncertainty surrounding the other sites, DESC is unable to make an estimate of the potential financial statement impacts. 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 flexibilities in implementing their programs. In July 2018, the EPA promulgated the first phase of changes to the CCR rule. Until all phases of the CCR rule are promulgated, DESC cannot forecast potential incremental impacts or costs related to existing coal ash sites in connection with future implementation of the 2016 CCR legislation and reconsideration of 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 regulatory action is taken to incorporate the U.S. Court of Appeals for the D.C. Circuit’s decision, DESC is unable to make an estimate of the potential financial statement impacts associated with any future changes to the CCR rule in connection with the court’s remand. 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.
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. 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, 2019, such investment in these assets included $345 million within utility plant, net and $37 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 up to the disallowed costs may be required. 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 include reserves of $492 million and insurance receivables of $6 million included within other receivables at December 31, 2019. During the twelve months ended December 31, 2019, the Consolidated Statements of Comprehensive Loss includes charges of $590 million ($444 million after-tax), included within the Corporate and Other segment. 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. In addition, property with a net recorded cost of $42 million is in the process of being transferred to the plaintiffs in coordination with the court-appointed real estate trustee to satisfy the settlement agreement.
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 February 2020, the parties executed a preliminary settlement term sheet relating to this matter as well as the Luquire Case and the Glibowski Case described below. The proposed settlement is expected to be $520 million, of which DESC’s portion is $320 million. The parties are currently negotiating a settlement agreement based on the preliminary settlement term sheet that will be presented to the court for preliminary approval. This case is pending. 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 February 2020, the parties executed a preliminary settlement term sheet as described above relating to this matter as well as the Santee Cooper Ratepayer Case and the Glibowski Case. This case is pending. 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 February 2020, the parties executed a preliminary settlement term sheet as described above relating to this matter as well as the Santee Cooper Ratepayer Case and the Luquire Case. This case is pending. 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. The case is pending in the U.S. District Court for the District of South Carolina. 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 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. These cases are 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. DESC has protested the proposed assessment, which remains pending. 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 addition, the South Carolina Law Enforcement Division is conducting a criminal investigation into the handling of the NND Project by SCANA and DESC. These matters are pending. SCANA and DESC are cooperating fully with the investigations, including responding to additional subpoenas and document requests; however, Dominion Energy cannot currently predict whether or to what extent SCANA or DESC may incur a material liability. 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. This matter is pending. 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 $14.0 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. As of December 31, 2019, 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, 2019, 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.
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 $37 million in 2019 and $24 million in 2018.
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Leases |
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| Leases [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Leases |
13. LEASES At December 31, 2019, DESC had the following lease assets and liabilities recorded in the Consolidated Balance Sheets:
For the year ended December 31, 2019, total lease cost consisted of the following:
For the year ended December 31, 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:
At December 31, 2019, the weighted average remaining lease term and weighted average discount rate for finance and operating leases were as follows:
Lease liabilities have the following scheduled maturities:
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Operating Segments |
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| Segment Reporting [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Operating Segments |
14. OPERATING SEGMENTS In December 2019, DESC realigned its segments which resulted in the formation of a 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 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:
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. In 2017, DESC reported after-tax net expenses of $690 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 2017 related to a $1.1 billion ($690 million after-tax) impairment charge associated with the NND Project. The following table presents segment information pertaining to DESC’s operations:
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Utility Plant and Nonutility Property |
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| 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, 2019 and 2018 were as follows:
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.
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 $50 million at December 31, 2019 and $46 million at December 31, 2018. 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 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 term. |
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Affiliated and Related Party Transactions |
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| 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 Loss. DESC purchases natural gas and related pipeline capacity from SCANA Energy Marketing, Inc. 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 Loss. DESS, on behalf of itself and its parent company, provides the following services to DESC, which are rendered at direct or allocated cost: information systems, telecommunications, customer support, marketing and sales, human resources, corporate compliance, purchasing, financial, risk management, public affairs, legal, investor relations, gas supply and capacity management, strategic planning, general administrative, and retirement benefits. In addition, DESS processes and pays invoices for DESC and is reimbursed. 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 Loss.
In connection with the SCANA Combination, purchases from certain entities owned by Dominion Energy became affiliated transactions. During the year ended December 31, 2019, DESC purchased electricity generated by certain solar facilities, totaling $8 million, which is recorded as purchased power in the Consolidated Statements of Comprehensive Loss. At December 31, 2019, DESC had accounts payable balances to these affiliates totaling less than $1 million. In addition, during the year ended December 31, 2019, DESC incurred demand and transportation charges from DECG totaling $63 million, of which $19 million is recorded as fuel used in electric generation and $44 million is recorded as gas purchased for resale in the Consolidated Statements of Comprehensive Loss. At December 31, 2019, DESC had an accounts payable balance due to this affiliate totaling $5 million and an accounts receivable to this affiliate totaling $1 million. 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. |
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Other Income (Expense), Net |
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| Income Statement [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Other Income (Expense), Net |
17. OTHER INCOME (EXPENSE), NET Components of other income (expense), net are as follows:
The recording of revenue from contracts with customers within other income (expense) arose upon the adoption of related accounting guidance described in Note 1 and Note 4, and as permitted, periods prior to adoption have not been restated. 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. |
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Quarterly Financial Information |
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| 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, 2019 and 2018 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.
DESC’s 2019 results include the impact of the following significant items:
DESC’s 2018 results include the impact of the following significant item:
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Summary of Significant Accounting Policies (Policies) |
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| 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 VIE’s 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 VIE’s. 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. GENCO’s property (carrying value of $508 million) previously served as collateral for its long-term borrowings. 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, DESC purchases shared services from DESS, an affiliated VIE that provides accounting, legal, finance and certain administrative and technical services to all SCANA subsidiaries, including DESC. DESC has determined that it is not the primary beneficiary of DESS 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 2018 and 2017 Consolidated Financial Statements and Notes have been reclassified to conform to the 2019 presentation for comparative purposes; however, such reclassifications did not affect DESC’s net income, total assets, liabilities, equity or cash flows. |
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| 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 4.3%, 7.0% and 3.9% for 2019, 2018 and 2017, 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:
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. |
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| Major Maintenance |
Major Maintenance Planned major maintenance costs related to certain fossil fuel turbine 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 maintenance expenditures. For the years ended December 31, 2019 and 2018, DESC incurred $10 million and $16 million, respectively, for turbine 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 scheduled from the spring of 2014 through the spring of 2020. Refueling outage costs incurred for which DESC was responsible totaled $2 million in 2019 and $29 million in 2018. |
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| 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. |
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| Nuclear Decommissioning |
Nuclear Decommissioning Based on a decommissioning cost study completed in 2016, 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 $646 million, stated in 2019 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. |
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| 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 December 31, 2019, there were no restricted cash and equivalent balances. At December 31, 2018, cash and cash equivalents at DESC included $115 million held in escrow pending a settlement which was contingent on the consummation of the merger with Dominion Energy. As such, DESC did not consider this amount to be restricted at December 31, 2018. |
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| 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 $114 million and $129 million at December 31, 2019 and 2018, 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 10% of DESC’s accounts receivable balance at December 31, 2019. |
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| 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. |
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| 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. The 2017 Tax Reform Act included a broad range of tax reform provisions affecting DESC, including changes in corporate tax rates and business deductions. The 2017 Tax Reform Act reduces the corporate income tax rate from 35% to 21% for tax years beginning after December 31, 2017. Deferred tax assets and liabilities are classified as noncurrent in the Consolidated Balance Sheets and measured at the enacted tax rate expected to apply when temporary differences are realized or settled. Thus, at the date of enactment, federal deferred taxes were remeasured based upon the new 21% tax rate. The total effect of tax rate changes on deferred tax balances was recorded as a component of the income tax provision related to continuing operations for the period in which the law is enacted, even if the assets and liabilities relate to other components of the financial statements, such as items of accumulated other comprehensive income. DESC, as a rate-regulated utility, was required to adjust deferred income tax assets and liabilities for the change in income tax rates. However, if it is probable that the effect of the change in income tax rates will be recovered or shared with customers in future rates, DESC recorded a regulatory asset or liability instead of an increase or decrease to deferred income tax expense. 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, 2019, DESC had $132 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 $18 million, $8 million and less than $1 million in 2019, 2018, and 2017, respectively. Interest income for DESC was $2 million in 2019 and 2018, and less than $1 million in 2017. DESC also recorded penalty expenses of $7 million in 2019. At December 31, 2019, DESC had an income tax-related affiliated receivable of $21 million from Dominion Energy. This balance is expected to be received from Dominion Energy. 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. |
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| Regulatory Assets and Liabilities |
Regulatory Assets and Liabilities The accounting for DESC’s regulated gas and regulated electric 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:
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. |
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| 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 $19 million and $11 million associated with cash collateral at December 31, 2019 and 2018, respectively. DESC had no margin liabilities associated with cash collateral at December 31, 2019 and 2018. 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 the Company 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 3 and Note 17 regarding the settlement gains realized in the first quarter of 2018. |
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| 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. |
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| 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. |
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| 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. |
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| 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
Other Revenue
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. |
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| 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 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 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 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. |
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| 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. NET PERIODIC PENSION AND OTHER POSTRETIREMENT BENEFIT COSTS In March 2017, the FASB issued revised accounting guidance for the presentation of net periodic pension and other postretirement benefit costs. This guidance became effective for DESC beginning January 1, 2018 and requires that the service cost component of net periodic pension and other postretirement benefit costs be classified in the same line item as other compensation costs arising from services rendered by employees, while all other components of net periodic pension and other postretirement costs are classified outside of income from operations. In addition, only the service cost component remains eligible for capitalization during construction. The standard also recognizes that in the event that a regulator continues to require capitalization of all net periodic benefit costs prospectively, the difference would result in recognition of a regulatory asset or liability. For costs not capitalized for which regulators are expected to provide recovery, a regulatory asset will be established.
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. |
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Summary of Significant Accounting Policies (Tables) |
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| Accounting Policies [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Weighted Average Depreciation Rates | The composite weighted average depreciation rates for utility plant by function were as follows:
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Rate and Other Regulatory Matters (Tables) |
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| Regulated Operations [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Regulatory Assets and Liabilities |
(6) Represents amounts under-collected from customers pursuant to the cost of fuel components approved by the South Carolina Commission.
(8) During 2019, DESC purchased certain of its first mortgage bonds as discussed in Note 6. As a result of these transactions, DESC incurred net costs, including write-offs of unamortized discount, premium and debt issuance costs, of $270 million.
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Operating Revenue (Tables) |
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| Revenue Recognition And Deferred Revenue [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Operating Revenue Subsequent to the Adoption of Guidance for Revenue Recognition from Contracts with Customers |
The Company’s operating revenue, subsequent to the adoption of revised guidance for revenue recognition from contracts with customers, consists of the following:
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| 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:
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Long-Term and Short-Term Debt (Tables) |
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| Debt Disclosure [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Debt |
Long-term debt by type with related weighted-average coupon rates and maturities at December 31, 2019 and 2018 is as follows:
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| 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, 2019, were as follows:
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| 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:
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Income Taxes (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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:
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| 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:
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| Schedule of Deferred Income Taxes |
DESC’s deferred income taxes consist of the following:
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| Summary of Tax Credit Carryforwards |
At December 31, 2019, DESC had the following deductible loss and credit carryforwards:
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| Schedule of Unrecognized Tax Benefits Roll Forward |
A reconciliation of changes in DESC’s unrecognized tax benefits follows:
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Derivative Financial Instruments (Tables) |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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:
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| Schedule of Volume of Derivative Activity |
The following table presents the volume of derivative activity at December 31, 2019. These volumes are based on open derivative positions and represent the combined absolute value of their long and short positions.
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| Fair Value of Derivatives |
The following table presents the fair values of derivatives and where they are presented in the Consolidated Balance Sheets:
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| 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
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| Derivatives Not Designated as Hedging Instruments |
Derivatives Not designated as Hedging Instruments
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Fair Value Measurements, Including Derivatives (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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:
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| 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:
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Asset Retirement Obligations (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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:
(1) The decrease in 2019 reflects a change in the estimated timing of cash flows for interim pipeline replacements and DOE recoveries. |
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Employee Benefit Plans and Equity Compensation Plan (Tables) |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2019 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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.
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| Schedule of Assumptions Used to Determine Benefit Obligations |
Significant assumptions used to determine the above benefit obligations are as follows:
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| Schedule of Net Funded Status |
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| Schedule of Amounts Recognized in Balance Sheet |
Amounts recognized on the consolidated balance sheets were as follows:
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| Schedule of Amounts Recognized in Accumulated Other Comprehensive Loss |
Amounts recognized in accumulated other comprehensive loss were as follows:
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| Schedule of Amounts Recognized in Regulatory Assets |
Amounts recognized in regulatory assets were as follows:
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| Schedule of Changes in Fair Value of Plan Assets |
Changes in Fair Value of Plan Assets
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| Schedule of Allocation of Plan Assets |
The pension plan asset allocation at December 31, 2019 and 2018 and the target allocation for 2020 are as follows:
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| Schedule of Fair Value Measurements By Category | At December 31, 2019 and 2018, fair value measurements, and the level within the fair value hierarchy in which the measurements fall, were as follows:
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| Schedule of Expected Benefit Payments |
Expected Benefit Payments
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| Components of Net Periodic Benefit Cost |
Components of Net Periodic Benefit Cost
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| 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:
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| 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:
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| Schedule of Assumptions Used in Determining Net Periodic Benefit Cost |
Significant assumptions used in determining net periodic benefit cost:
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| Schedule of Amounts in Regulatory Assets to be Recognized Over the Next Fiscal Year |
The estimated amounts to be amortized from regulatory assets into net periodic benefit cost in 2020 are as follows:
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Commitments and Contingencies (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Commitments And Contingencies Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Long-Term Purchase Agreements |
At December 31, 2019, 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.
|
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Leases (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Leases [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule Of Lease Assets and Liabilities Recorded in Consolidated Balance Sheets |
At December 31, 2019, DESC had the following lease assets and liabilities recorded in the Consolidated Balance Sheets:
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Summary of Total Lease Cost |
For the year ended December 31, 2019, total lease cost consisted of the following:
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Cash Paid for Amounts Included in Measurement of Lease Liabilities |
For the year ended December 31, 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:
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Summary of Weighted Average Remaining Lease Term And Discount Rate for Operating and Finance Leases |
At December 31, 2019, the weighted average remaining lease term and weighted average discount rate for finance and operating leases were as follows:
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Maturity Analysis of Operating and Finance Lease Liabilities |
Lease liabilities have the following scheduled maturities:
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Operating Segments (Tables) |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Segment Reporting [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Segment Reporting Information, by Segment |
The following table presents segment information pertaining to DESC’s operations:
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Utility Plant and Nonutility Property (Tables) |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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, 2019 and 2018 were as follows:
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Jointly Owned Utility Plants |
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Affiliated and Related Party Transactions (Tables) |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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 Loss.
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Affiliated Transactions |
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Other Income (Expense), Net (Tables) |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Income Statement [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Components of Other Income (Expense), Net |
Components of other income (expense), net are as follows:
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Quarterly Financial Information (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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, 2019 and 2018 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.
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Nature of Operations (Narrative) (Detail) - Segment |
3 Months Ended | 12 Months Ended |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2019 |
|
| Organization Consolidation And Presentation Of Financial Statements [Abstract] | ||
| Number of primary operating segments | 1 | 1 |
Summary of Significant Accounting Policies (Narrative) (Detail) |
12 Months Ended | |||||||
|---|---|---|---|---|---|---|---|---|
|
Jan. 01, 2019
USD ($)
|
Dec. 31, 2019
USD ($)
MW
|
Dec. 31, 2018
USD ($)
|
Dec. 31, 2017
USD ($)
|
Dec. 31, 2016
USD ($)
|
||||
| Significant Accounting Policies | ||||||||
| Carrying value of property | $ 69,000,000 | $ 72,000,000 | ||||||
| Public utilities, allowance for funds used during construction, rate | 4.30% | 7.00% | 3.90% | |||||
| Utilities operating expense, maintenance and operations, affiliate | $ 244,000,000 | $ 182,000,000 | $ 180,000,000 | |||||
| Turbine maintenance expense | 10,000,000 | 16,000,000 | ||||||
| Amount accrued annually for nuclear fuel outages | 17,000,000 | |||||||
| Nuclear refueling outage cost | 2,000,000 | 29,000,000 | ||||||
| Decommissioning liability, noncurrent | 646,000,000 | |||||||
| Payments to acquire investments to be held in decommissioning trust fund | 3,000,000 | |||||||
| Restricted cash and equivalent balances | 0 | 0 | $ 0 | |||||
| Cash held in escrow | 115,000,000 | |||||||
| Unbilled revenues | $ 114,000,000 | $ 129,000,000 | ||||||
| Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent | 21.00% | 21.00% | 35.00% | |||||
| Unrecognized tax benefits | $ 132,000,000 | $ 106,000,000 | $ 98,000,000 | $ 350,000,000 | ||||
| Interest expense | 18,000,000 | 8,000,000 | ||||||
| Interest income | 2,000,000 | 2,000,000 | ||||||
| Penalty expenses | 7,000,000 | |||||||
| Income taxes related to affiliated receivable | 21,000,000 | |||||||
| Margin liabilities with cash collateral | 0 | 0 | ||||||
| Margin assets with cash collateral | $ 19,000,000 | $ 11,000,000 | ||||||
| Option to extend, existence, operating lease | true | |||||||
| Operating lease, right of use asset | $ 19,000,000 | $ 23,000,000 | [1] | |||||
| Operating lease liability | 19,000,000 | $ 23,000,000 | ||||||
| Reclassification From AOCI to retained earnings | $ 1,000,000 | |||||||
| Minimum [Member] | ||||||||
| Significant Accounting Policies | ||||||||
| Lease renewal term | 1 year | |||||||
| Maximum [Member] | ||||||||
| Significant Accounting Policies | ||||||||
| Interest expense | 1,000,000 | |||||||
| Interest income | $ 1,000,000 | |||||||
| Lease renewal term | 70 years | |||||||
| Original term of leases | 1 year | |||||||
| Accounts Receivable | Credit Concentration Risk | ||||||||
| Significant Accounting Policies | ||||||||
| Concentration risk percentage | 10.00% | |||||||
| Turbine [Member] | ||||||||
| Significant Accounting Policies | ||||||||
| Utilities operating expense, maintenance and operations, affiliate | $ 18,000,000 | |||||||
| Genco | ||||||||
| Significant Accounting Policies | ||||||||
| Power Generation Capacity Megawatts | MW | 605 | |||||||
| Carrying value of property | $ 508,000,000 | |||||||
| ||||||||
Summary of Significant Accounting Policies (Schedule of Weighted Average Depreciation Rates) (Detail) |
12 Months Ended | |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Generation | ||
| Composite weighted average depreciation rates for utility plant | 2.50% | 2.61% |
| Transmission | ||
| Composite weighted average depreciation rates for utility plant | 2.57% | 2.74% |
| Distribution | ||
| Composite weighted average depreciation rates for utility plant | 2.41% | 2.41% |
| Storage | ||
| Composite weighted average depreciation rates for utility plant | 2.74% | 2.71% |
| General and other | ||
| Composite weighted average depreciation rates for utility plant | 3.22% | 3.18% |
Rate and Other Regulatory Matters (Narrative) (Detail) $ in Millions |
1 Months Ended | 3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Feb. 28, 2020
USD ($)
NuclearPlant
kV
mi
|
Jan. 31, 2020
USD ($)
|
Oct. 30, 2018
Petition
|
Oct. 31, 2019
USD ($)
|
Jun. 30, 2019
USD ($)
|
Jul. 31, 2018
USD ($)
|
Sep. 30, 2019
USD ($)
|
Jun. 30, 2019
USD ($)
|
Dec. 31, 2020
USD ($)
|
Dec. 31, 2019
USD ($)
|
Dec. 31, 2018
USD ($)
|
Dec. 31, 2017
USD ($)
|
|
| Rate And Other Regulatory Matters [Line Items] | ||||||||||||
| Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent | 21.00% | 21.00% | 35.00% | |||||||||
| Operating expense | $ 2,870 | $ 3,593 | $ 3,153 | |||||||||
| South Carolina Commission Order for Decrease of Total Fuel Cost Component of Retail Electric Rates to produce a projected under-recovery | 35 | |||||||||||
| South Carolina Commission Order, Annual DSM Program Rate Rider Recovery Amount | $ 30 | |||||||||||
| South Carolina Commission order, revenue requirement under RSA | $ 437 | |||||||||||
| South Carolina Commission order, increase in natural gas rates under RSA | $ 7 | |||||||||||
| South Carolina Commission order, revenue requirement approved under RSA | $ 436 | |||||||||||
| 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 | |||||||||||
| Subsequent Event | ||||||||||||
| Rate And Other Regulatory Matters [Line Items] | ||||||||||||
| DESC Pension Costs Rider approved by the South Carolina Commission | $ 11 | |||||||||||
| 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 | |||||||||||
| Demand Side Management Programs [Member] | ||||||||||||
| Rate And Other Regulatory Matters [Line Items] | ||||||||||||
| Recovery period of regulatory asset | 5 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 | |||||||||||
| 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 | |||||||||||
| Scenario Forecast | ||||||||||||
| Rate And Other Regulatory Matters [Line Items] | ||||||||||||
| South Carolina Commission Order for Decrease of Total Fuel Cost Component of Retail Electric Rates to produce a projected under-recovery | $ 44 | |||||||||||
| DESC | ||||||||||||
| Rate And Other Regulatory Matters [Line Items] | ||||||||||||
| Credits to Customer Related to Tax Act | $ 63 | $ 100 | ||||||||||
| South Carolina Commission Order, Number of Petitions Granted | Petition | 1 | |||||||||||
| DESC | Subsequent Event | ||||||||||||
| Rate And Other Regulatory Matters [Line Items] | ||||||||||||
| South Carolina Commission Order, Annual DSM Program Rate Rider Recovery Amount | $ 40 | |||||||||||
| DESC | Scenario Forecast | ||||||||||||
| Rate And Other Regulatory Matters [Line Items] | ||||||||||||
| Credits to Customer Related to Tax Act | $ 67 | |||||||||||
| Number of nuclear plants under development | NuclearPlant | 2 | |||||||||||
| Cost of anticipated project | $ 75 | |||||||||||
| DESC | Scenario Forecast | Transmission Project | ||||||||||||
| Rate And Other Regulatory Matters [Line Items] | ||||||||||||
| Cost of anticipated project | $ 30 | |||||||||||
| Transmission lines length of miles to be approved | mi | 28 | |||||||||||
| Transmission lines capacity | kV | 230 | |||||||||||
| Savannah River Site | ||||||||||||
| Rate And Other Regulatory Matters [Line Items] | ||||||||||||
| Interest charges (benefit) | $ (10) | $ 6 | ||||||||||
| Interest charges (benefit), after tax | $ (7) | $ 4 | ||||||||||
Rate and Other Regulatory Matters (Schedule of Regulatory Assets) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Regulatory Assets | ||||||||||||||||||||||||||||
| Regulatory assets, current | $ 271 | $ 224 | ||||||||||||||||||||||||||
| Regulatory assets, noncurrent | 3,892 | 4,060 | ||||||||||||||||||||||||||
| Total regulatory assets | 4,163 | 4,284 | ||||||||||||||||||||||||||
| NND Project Costs [Member] | ||||||||||||||||||||||||||||
| Regulatory Assets | ||||||||||||||||||||||||||||
| Regulatory assets, current | [1] | 138 | 127 | |||||||||||||||||||||||||
| Regulatory assets, noncurrent | [1] | 2,503 | 2,641 | |||||||||||||||||||||||||
| Deferred Employee Benefit Plan Costs [Member] | ||||||||||||||||||||||||||||
| Regulatory Assets | ||||||||||||||||||||||||||||
| Regulatory assets, current | [2] | 13 | 16 | |||||||||||||||||||||||||
| Regulatory assets, noncurrent | [2] | 196 | 256 | |||||||||||||||||||||||||
| Other Unrecovered Plant [Member] | ||||||||||||||||||||||||||||
| Regulatory Assets | ||||||||||||||||||||||||||||
| Regulatory assets, current | [3] | 14 | 14 | |||||||||||||||||||||||||
| Regulatory assets, noncurrent | [3] | 69 | 79 | |||||||||||||||||||||||||
| Demand Side Management Programs [Member] | ||||||||||||||||||||||||||||
| Regulatory Assets | ||||||||||||||||||||||||||||
| Regulatory assets, current | [4] | 17 | 14 | |||||||||||||||||||||||||
| Regulatory assets, noncurrent | [4] | 54 | 51 | |||||||||||||||||||||||||
| Asset Retirement Obligation Costs [Member] | ||||||||||||||||||||||||||||
| Regulatory Assets | ||||||||||||||||||||||||||||
| Regulatory assets, current | [5] | 28 | 0 | |||||||||||||||||||||||||
| Regulatory assets, noncurrent | [5] | 293 | 380 | |||||||||||||||||||||||||
| Cost Of Fuel Under-collections [Member] | ||||||||||||||||||||||||||||
| Regulatory Assets | ||||||||||||||||||||||||||||
| Regulatory assets, current | [6] | 13 | 13 | |||||||||||||||||||||||||
| Other Regulatory Assets [Member] | ||||||||||||||||||||||||||||
| Regulatory Assets | ||||||||||||||||||||||||||||
| Regulatory assets, current | 48 | 40 | ||||||||||||||||||||||||||
| Regulatory assets, noncurrent | [7] | 110 | 123 | |||||||||||||||||||||||||
| Cost of Reacquired Debt [Member] | ||||||||||||||||||||||||||||
| Regulatory Assets | ||||||||||||||||||||||||||||
| Regulatory assets, noncurrent | [8],[9] | 259 | 14 | |||||||||||||||||||||||||
| Deferred Losses On Interest Rate Derivatives [Member] | ||||||||||||||||||||||||||||
| Regulatory Assets | ||||||||||||||||||||||||||||
| Regulatory assets, noncurrent | [10] | 305 | 442 | |||||||||||||||||||||||||
| Environmental Remediation Costs [Member] | ||||||||||||||||||||||||||||
| Regulatory Assets | ||||||||||||||||||||||||||||
| Regulatory assets, noncurrent | [11] | 22 | 24 | |||||||||||||||||||||||||
| Deferred Storm Damage Costs [Member] | ||||||||||||||||||||||||||||
| Regulatory Assets | ||||||||||||||||||||||||||||
| Regulatory assets, noncurrent | [12] | 44 | 35 | |||||||||||||||||||||||||
| Deferred Transmission Operating Costs [Member] | ||||||||||||||||||||||||||||
| Regulatory Assets | ||||||||||||||||||||||||||||
| Regulatory assets, noncurrent | [13] | $ 37 | $ 15 | |||||||||||||||||||||||||
| ||||||||||||||||||||||||||||
Rate and Other Regulatory Matters (Schedule of Regulatory Liabilities) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Regulatory Liabilities | ||||||||||||
| Regulatory liability, current | $ 256 | $ 126 | ||||||||||
| Regulatory liability, noncurrent | 3,210 | 2,264 | ||||||||||
| Total regulatory liabilities | 3,466 | 2,390 | ||||||||||
| Monetization Of Guaranty Settlement [Member] | ||||||||||||
| Regulatory Liabilities | ||||||||||||
| Regulatory liability, current | [1] | 67 | 61 | |||||||||
| Regulatory liability, noncurrent | [1] | 970 | 1,037 | |||||||||
| Income Taxes Refundable Through Future Rates [Member] | ||||||||||||
| Regulatory Liabilities | ||||||||||||
| Regulatory liability, current | [2] | 16 | 52 | |||||||||
| Regulatory liability, noncurrent | [2] | 948 | 607 | |||||||||
| Asset Retirement Obligation Costs [Member] | ||||||||||||
| Regulatory Liabilities | ||||||||||||
| Regulatory liability, noncurrent | [3] | 552 | 541 | |||||||||
| Reserve For Refunds To Electric Utility Customers [Member] | ||||||||||||
| Regulatory Liabilities | ||||||||||||
| Regulatory liability, current | [4] | 143 | 0 | |||||||||
| Regulatory liability, noncurrent | [4] | 656 | 0 | |||||||||
| Other Regulatory Liability [Member] | ||||||||||||
| Regulatory Liabilities | ||||||||||||
| Regulatory liability, current | 30 | 13 | ||||||||||
| Regulatory liability, noncurrent | 13 | 4 | ||||||||||
| Deferred Gains On Interest Rate Derivatives [Member] | ||||||||||||
| Regulatory Liabilities | ||||||||||||
| Regulatory liability, noncurrent | [5] | $ 71 | $ 75 | |||||||||
| ||||||||||||
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, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|||
| Operating revenue from contracts with customers | $ 4 | $ 5 | $ 0 | ||
| Total Operating Revenues | [1] | 1,929 | 2,762 | $ 3,070 | |
| Electric Operations | |||||
| Operating revenue from contracts with customers | 1,516 | 2,315 | |||
| Other revenues | 9 | 12 | |||
| Total Operating Revenues | 1,525 | 2,327 | |||
| Gas Distribution | |||||
| Operating revenue from contracts with customers | 404 | 434 | |||
| Other revenues | 0 | 1 | |||
| Total Operating Revenues | 404 | 435 | |||
| Residential | Electric Operations | |||||
| Operating revenue from contracts with customers | 669 | 1,054 | |||
| Residential | Gas Distribution | |||||
| Operating revenue from contracts with customers | 194 | 208 | |||
| Commercial | Electric Operations | |||||
| Operating revenue from contracts with customers | 507 | 744 | |||
| Commercial | Gas Distribution | |||||
| Operating revenue from contracts with customers | 111 | 117 | |||
| Industrial | Electric Operations | |||||
| Operating revenue from contracts with customers | 224 | 385 | |||
| Industrial | Gas Distribution | |||||
| Operating revenue from contracts with customers | 81 | 92 | |||
| Other | Electric Operations | |||||
| Operating revenue from contracts with customers | 116 | 132 | |||
| Other | Gas Distribution | |||||
| Operating revenue from contracts with customers | $ 18 | $ 17 | |||
| |||||
Operating Revenue (Narrative) (Detail) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Disaggregation Of Revenue [Line Items] | ||
| Contract liability balances | $ 9 | $ 4 |
| Revenue recognized from contract liability balances | $ 3 | $ 4 |
| Minimum [Member] | ||
| Disaggregation Of Revenue [Line Items] | ||
| Service Contract, Term | 10 years | |
| Maximum [Member] | ||
| Disaggregation Of Revenue [Line Items] | ||
| Service Contract, Term | 15 years | |
Operating Revenue (Balance and Activity Related to Contract Costs Deferred as Regulatory Assets) (Detail) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Revenues [Abstract] | ||
| Beginning balance | $ 15 | $ 16 |
| Amortization | (2) | (1) |
| Ending balance | $ 13 | $ 15 |
Equity (Narrative) (Detail) - USD ($) $ / shares in Units, $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| 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 | $ 838 | $ 24 | $ 3 |
| Retained earnings, restricted | 115 | $ 115 | |
| Dominion Energy | |||
| Class Of Stock [Line Items] | |||
| Contributions from SCANA | $ 835 | ||
Long-Term and Short-Term Debt (Schedule of Debt) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
||||||
|---|---|---|---|---|---|---|---|---|
| Debt Instrument [Line Items] | ||||||||
| Weighted-average coupon rate | 3.82% | |||||||
| Total principal | $ 3,620 | $ 5,152 | ||||||
| Securities due within one year | 0 | (14) | ||||||
| Unamortized discount, premium and debt issuance costs, net | (32) | (36) | ||||||
| Finance leases | 27 | |||||||
| Total long-term debt | 3,608 | 5,132 | ||||||
| First Mortgage Bonds | ||||||||
| Debt Instrument [Line Items] | ||||||||
| Total principal | $ 3,267 | |||||||
| First Mortgage Bonds | DESC | ||||||||
| Debt Instrument [Line Items] | ||||||||
| Weighted-average coupon rate | [1],[2] | 5.42% | ||||||
| Total principal | [1] | $ 3,267 | 4,990 | |||||
| Tax Exempt Financings Variable Rate Due 2038 | DESC | ||||||||
| Debt Instrument [Line Items] | ||||||||
| Weighted-average coupon rate | [2] | 1.65% | ||||||
| Total principal | $ 35 | 35 | ||||||
| Tax Exempt Financings Variable Rate Due 2038 | Genco | ||||||||
| Debt Instrument [Line Items] | ||||||||
| Weighted-average coupon rate | [2] | 1.65% | ||||||
| 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 | [2] | 3.90% | ||||||
| Total principal | $ 54 | 54 | ||||||
| Other Debt | ||||||||
| Debt Instrument [Line Items] | ||||||||
| Total principal | $ 231 | |||||||
| Other Debt | DESC | ||||||||
| Debt Instrument [Line Items] | ||||||||
| Weighted-average coupon rate | [2] | 3.69% | ||||||
| Total principal | $ 1 | 0 | ||||||
| 5.49% Senior Secured Note Due 2024 | Genco | ||||||||
| Debt Instrument [Line Items] | ||||||||
| Total principal | $ 0 | 40 | ||||||
| 3.05% Affiliated Note Due 2024 | Genco | ||||||||
| Debt Instrument [Line Items] | ||||||||
| Weighted-average coupon rate | [2],[3] | 3.05% | ||||||
| Total principal | [3] | $ 230 | 0 | |||||
| Finance Lease | ||||||||
| Debt Instrument [Line Items] | ||||||||
| Finance leases | $ 20 | $ 30 | ||||||
| ||||||||
Long-Term and Short-Term Debt (Schedule of Debt) (Parenthetical) (Detail) - USD ($) $ in Millions |
1 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
May 31, 2019 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Debt Instrument [Line Items] | ||||
| Redemption of remaining principal outstanding plus accrued interest | $ 1,890 | $ 825 | $ 12 | |
| DESC | ||||
| Debt Instrument [Line Items] | ||||
| Aggregate purchase price of first mortgage bonds | $ 1,800 | |||
| 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% | |||
| 5.49% Senior Secured Note Due 2024 | Genco | ||||
| Debt Instrument [Line Items] | ||||
| Debt Instrument, Maturity Year | 2024 | |||
| Debt instrument, interest rate | 5.49% | |||
| Redemption of remaining principal outstanding plus accrued interest | $ 33 | |||
| 3.05% Affiliated Note Due 2024 | Genco | ||||
| Debt Instrument [Line Items] | ||||
| Debt Instrument, Maturity Year | 2024 | |||
| Debt instrument, interest rate | 3.05% | |||
Long-Term and Short-Term Debt (Schedule of Principal Payments of Long-Term Debt) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Debt Instrument [Line Items] | ||
| 2020 | $ 0 | |
| 2021 | 33 | |
| 2022 | 0 | |
| 2023 | 0 | |
| 2024 | 230 | |
| Thereafter | 3,357 | |
| Total | $ 3,620 | $ 5,152 |
| Weighted-average coupon, 2021 | 3.25% | |
| Weighted-average coupon, 2024 | 3.05% | |
| Weighted-average coupon, Thereafter | 5.34% | |
| Weighted-average coupon, Thereafter | 3.82% | |
| First Mortgage Bonds | ||
| Debt Instrument [Line Items] | ||
| 2020 | $ 0 | |
| 2021 | 33 | |
| 2022 | 0 | |
| 2023 | 0 | |
| 2024 | 0 | |
| Thereafter | 3,234 | |
| Total | 3,267 | |
| Tax Exempt Financings | ||
| Debt Instrument [Line Items] | ||
| 2020 | 0 | |
| 2021 | 0 | |
| 2022 | 0 | |
| 2023 | 0 | |
| 2024 | 0 | |
| Thereafter | 122 | |
| Total | 122 | |
| Other Debt | ||
| Debt Instrument [Line Items] | ||
| 2020 | 0 | |
| 2021 | 0 | |
| 2022 | 0 | |
| 2023 | 0 | |
| 2024 | 230 | |
| Thereafter | 1 | |
| Total | $ 231 |
Long-Term and Short-Term Debt (Narrative) (Detail) - USD ($) |
1 Months Ended | 12 Months Ended | |||||||
|---|---|---|---|---|---|---|---|---|---|
Jan. 31, 2020 |
May 31, 2019 |
Apr. 30, 2019 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Mar. 31, 2019 |
|||
| 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 | 6.88% | ||||||||
| Redemption of remaining principal outstanding plus accrued interest | $ 1,890,000,000 | $ 825,000,000 | $ 12,000,000 | ||||||
| Equity capital contribution returned to parent | $ 20,000,000 | $ 0 | 0 | ||||||
| Line of credit facility maturity date | 2023-03 | ||||||||
| Weighted average interest rate, outstanding commercial paper | 3.82% | ||||||||
| Commercial paper borrowing limit | $ 2,200,000,000 | ||||||||
| Interest charges | [1] | $ 260,000,000 | $ 303,000,000 | $ 288,000,000 | |||||
| Interest income from money pool transactions | 8,000,000 | 4,000,000 | |||||||
| Interest expense from money pool transactions | 8,000,000 | 4,000,000 | |||||||
| Money pool borrowings due to affiliates | 219,000,000 | 282,000,000 | |||||||
| Investments due from affiliates | 9,000,000 | $ 353,000,000 | |||||||
| Subsequent Event | |||||||||
| Debt Instrument [Line Items] | |||||||||
| Short term borrowing maturity period | 2 years | ||||||||
| 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 | 355,000,000 | ||||||||
| Interest charges | 3,000,000 | ||||||||
| Current Joint Revolving Credit Facility | |||||||||
| Debt Instrument [Line Items] | |||||||||
| Facility limit | 1,000,000,000 | ||||||||
| Current Joint Revolving Credit Facility | Dominion Energy | |||||||||
| Debt Instrument [Line Items] | |||||||||
| Facility limit | $ 6,000,000,000.0 | ||||||||
| Line of Credit Facility | |||||||||
| Debt Instrument [Line Items] | |||||||||
| Facility limit | 500,000,000 | ||||||||
| 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 | ||||||||
| |||||||||
Long-Term and Short-Term Debt (Schedule of Line of Credit Facilities) (Detail) - USD ($) |
Dec. 31, 2019 |
Dec. 31, 2018 |
||
|---|---|---|---|---|
| Current Joint Revolving Credit Facility | ||||
| Debt Instrument [Line Items] | ||||
| Facility limit | $ 1,000,000,000 | |||
| Outstanding Commercial Paper | 0 | |||
| Outstanding Letters of Credit | $ 0 | |||
| Previous Joint Revolving Credit Facility | ||||
| Debt Instrument [Line Items] | ||||
| Facility limit | [1] | $ 1,200,000,000 | ||
| Outstanding Commercial Paper | 73,000,000 | |||
| Outstanding Letters of Credit | $ 0 | |||
| ||||
Long-Term and Short-Term Debt (Schedule of Line of Credit Facilities) (Parenthetical) (Detail) |
Dec. 31, 2018
USD ($)
|
|---|---|
| Fuel Company | |
| Debt Instrument [Line Items] | |
| Facility limit | $ 500,000,000 |
Income Taxes (Narrative) (Detail) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Investments Owned Federal Income Tax Note [Line Items] | ||||
| Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent | 21.00% | 21.00% | 35.00% | |
| Increase in net operating loss utilization | $ 79 | |||
| Weighted average rate used to originate deferred tax liability | 35.00% | |||
| Deferred income taxes, net | $ (379) | $ (184) | $ (780) | |
| Regulatory liabilities | 265 | (360) | 899 | |
| Income tax reconciliation, tax reform remeasurement | 1 | |||
| Income tax reconciliation tax reform remeasurement of additional impairment charges. | 176 | |||
| Income tax reconciliation tax reform remeasurement of additional adjustments to deferred income taxes. | 23 | |||
| 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 | $ (10) | $ 31 | $ 13 |
| Income tax examination, description | The statute is closed for IRS examination of years prior to 2010, except for certain outstanding refund claims. The IRS has completed examinations of DESC’s federal returns through 2012. The IRS is currently examining DESC’s federal returns from 2013 through 2017. With few exceptions, DESC is no longer subject to state and local income tax examinations by tax authorities for years prior to 2012 | |||
| Decrease in Unrecognized Tax Benefits is Reasonably Possible | $ 65 | $ 65 | ||
| Maximum [Member] | ||||
| Investments Owned Federal Income Tax Note [Line Items] | ||||
| 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 | |||
Income Taxes (Details of Income Tax Expense for Continuing Operations Including Noncontrolling Interests) (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Current: | |||
| Federal | $ 0 | $ (16) | $ (410) |
| State | 34 | 0 | (18) |
| Total current expense (benefit) | 34 | (16) | (428) |
| Deferred: | |||
| Taxes before operating loss carryforwards, investment tax credits and tax reform | (90) | (216) | 262 |
| 2017 Tax Reform Act impact | 0 | (176) | (1) |
| Tax utilization expense of operating loss carryforwards | 102 | 46 | 0 |
| State | (57) | (52) | (2) |
| Total deferred expense (benefit) | (45) | (398) | 259 |
| Investment tax credit-amortization | (1) | (2) | (2) |
| Total income tax expense (benefit) | $ (12) | $ (416) | $ (171) |
Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Detail) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Income Tax Disclosure [Abstract] | |||
| U.S. statutory rate | 21.00% | 21.00% | 35.00% |
| Increases (reductions) resulting from: | |||
| State taxes, net of federal benefit | 3.90% | 3.80% | 2.30% |
| State investment tax credits | 0.00% | 0.30% | 1.50% |
| AFUDC - equity | 0.00% | 0.20% | 1.50% |
| Amortization of federal investment tax credits | 0.10% | 0.20% | 0.60% |
| Production tax credits | 0.40% | 0.90% | 2.30% |
| Domestic production activities deduction | 0.00% | 0.00% | 5.20% |
| Reversal of excess deferred income taxes | (1.40%) | 0.00% | 0.00% |
| Federal legislative change | 0.00% | 17.50% | 0.30% |
| NND Project impairment | (2.40%) | (2.30%) | 0.00% |
| Write-off of regulatory asset | (15.80%) | 0.00% | 0.00% |
| Changes in unrecognized tax benefits | (5.10%) | 0.00% | 0.00% |
| Other | 0.20% | (0.20%) | 1.20% |
| Effective tax rate | 0.90% | 41.40% | 49.90% |
Income Taxes (Schedule of Deferred Income Taxes) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Deferred income taxes: | ||
| Total deferred income tax assets | $ 1,258 | $ 971 |
| Total deferred income tax liabilities | 1,868 | 1,960 |
| Total net deferred income tax liabilities | 610 | 989 |
| Depreciation method and plant basis differences | 1,007 | 998 |
| Excess deferred income taxes | (231) | (148) |
| Unrecovered nuclear plant cost | 553 | 584 |
| DESC rate refund | (169) | (1) |
| Toshiba settlement | (219) | (231) |
| Nuclear decommissioning | (43) | (9) |
| Deferred state income taxes | 200 | 296 |
| Federal benefit of deferred state income taxes | (42) | (62) |
| Deferred fuel, purchased energy and gas costs | 7 | 1 |
| Pension benefits | 46 | 46 |
| Other postretirement benefits | (35) | (35) |
| Loss and credit carryforwards | (391) | (520) |
| Other | (73) | |
| Other | 70 | |
| Deferred Investment Tax Credits-Regulated Operations | 19 | 19 |
| Deferred income taxes and investment tax credits | $ 629 | $ 1,008 |
Income Taxes (Summary of Deductible Loss and Credit Carryforwards) (Detail) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2019
USD ($)
| |
| Investments Owned Federal Income Tax Note [Line Items] | |
| Loss and Credit Carryforwards, Deductible Amount | $ 3,056 |
| Loss and Credit Carryforwards, Deferred Tax Asset | 415 |
| Federal | |
| Investments Owned Federal Income Tax Note [Line Items] | |
| Loss Carryforwards, Deductible Amount | 1,207 |
| Loss Carryforwards, Deferred Tax Asset | $ 254 |
| 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 | $ 38 |
| Federal | Production and Other Credits | Minimum [Member] | |
| Investments Owned Federal Income Tax Note [Line Items] | |
| Credit Carryforwards, Expiration Period | 2031 |
| 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 | $ 1,849 |
| Loss Carryforwards, Deferred Tax Asset | $ 92 |
| 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 | $ 31 |
| 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 |
Income Taxes (Reconciliation of Unrecognized Tax Benefits Roll Forward) (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Income Tax Disclosure [Abstract] | |||
| Balance at January 1 | $ 106 | $ 98 | $ 350 |
| Increases-prior period positions | 76 | 8 | 0 |
| Decreases-prior period positions | (53) | 0 | (273) |
| Increases-current period positions | 3 | 0 | 21 |
| Balance at December 31 | $ 132 | $ 106 | $ 98 |
Derivative Financial Instruments (Offsetting Liabilities) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Derivative [Line Items] | ||
| Gross liabilities presented in the consolidated balance sheet | $ 19 | $ 11 |
| 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 | 19 | 11 |
| Gross amounts not offset in the consolidated balance sheet, net amounts | 0 | 0 |
| Interest Rate Contract [Member] | Over The Counter [Member] | ||
| Derivative [Line Items] | ||
| Gross liabilities presented in the consolidated balance sheet | 19 | 11 |
| 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 | 19 | 11 |
| Gross amounts not offset in the consolidated balance sheet, net amounts | $ 0 | $ 0 |
Derivative Financial Instruments (Schedule of Volume of Derivative Activity) (Detail) |
Dec. 31, 2019
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 | |||
| ||||
Derivative Financial Instruments (Fair Value of Derivatives) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
||||
|---|---|---|---|---|---|---|
| Derivative [Line Items] | ||||||
| Derivative Liability | $ 19 | $ 11 | ||||
| Other Current Liabilities [Member] | ||||||
| Derivative [Line Items] | ||||||
| Derivative Liability | [1] | 2 | 1 | |||
| Other Noncurrent Liabilities [Member] | ||||||
| Derivative [Line Items] | ||||||
| Derivative Liability | [2] | 17 | 10 | |||
| Interest Rate Contract [Member] | Other Current Liabilities [Member] | ||||||
| Derivative [Line Items] | ||||||
| Derivative Liability | 2 | 1 | ||||
| Interest Rate Contract [Member] | Other Noncurrent Liabilities [Member] | ||||||
| Derivative [Line Items] | ||||||
| Derivative Liability | 17 | 10 | ||||
| Designated as Hedging Instrument [Member] | ||||||
| Derivative [Line Items] | ||||||
| Derivative Liability | 12 | 8 | ||||
| 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] | 11 | 7 | |||
| 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 | 11 | 7 | ||||
| Not Designated as Hedging Instrument [Member] | ||||||
| Derivative [Line Items] | ||||||
| Derivative Liability | 7 | 3 | ||||
| Not Designated as Hedging Instrument [Member] | Other Current Liabilities [Member] | ||||||
| Derivative [Line Items] | ||||||
| Derivative Liability | [1] | 1 | 0 | |||
| Not Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member] | ||||||
| Derivative [Line Items] | ||||||
| Derivative Liability | [2] | 6 | 3 | |||
| Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Current Liabilities [Member] | ||||||
| Derivative [Line Items] | ||||||
| Derivative Liability | 1 | 0 | ||||
| Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Noncurrent Liabilities [Member] | ||||||
| Derivative [Line Items] | ||||||
| Derivative Liability | $ 6 | $ 3 | ||||
| ||||||
Derivative Financial Instruments (Derivatives in Cash Flow Hedging Relationships) (Detail) - Cash Flow Hedging [Member] - USD ($) $ in Millions |
12 Months Ended | ||||||
|---|---|---|---|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|||||
| Derivative [Line Items] | |||||||
| Gain (loss) Reclassified from Deferred Accounts into Income | $ 0 | $ (1) | $ (2) | ||||
| Increase (Decrease) in Derivatives Subject to Regulatory Treatment | [1] | 1 | 1 | (2) | |||
| Interest Rate Contract [Member] | |||||||
| Derivative [Line Items] | |||||||
| Gain (loss) Reclassified from Deferred Accounts into Income | [2] | 0 | (1) | (2) | |||
| Increase (Decrease) in Derivatives Subject to Regulatory Treatment | [1],[2] | $ 1 | $ 1 | $ (2) | |||
| |||||||
Derivative Financial Instruments (Derivatives Not Designated as Hedging Instruments) (Detail) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions |
12 Months Ended | ||||
|---|---|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|||
| Derivative [Line Items] | |||||
| Amount of Gain (Loss) Recognized in Income on Derivatives | [1] | $ (1) | $ 113 | $ (176) | |
| Interest Charges [Member] | Interest Rate Contract [Member] | |||||
| Derivative [Line Items] | |||||
| Amount of Gain (Loss) Recognized in Income on Derivatives | [1] | (1) | (2) | (3) | |
| Other Income [Member] | Interest Rate Contract [Member] | |||||
| Derivative [Line Items] | |||||
| Amount of Gain (Loss) Recognized in Income on Derivatives | [1] | 0 | 115 | 0 | |
| Impairment Loss [Member] | Interest Rate Contract [Member] | |||||
| Derivative [Line Items] | |||||
| Amount of Gain (Loss) Recognized in Income on Derivatives | [1] | $ 0 | $ 0 | $ (173) | |
| |||||
Fair Value Measurements, Including Derivatives (Schedule of Liabilities Measured at Fair Value on Recurring Basis) (Details) - Fair value, recurring - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Liabilities | ||
| Total liabilities | $ 19 | $ 11 |
| Interest Rate Contract [Member] | ||
| Liabilities | ||
| Total liabilities | 19 | 11 |
| Level 1 | ||
| Liabilities | ||
| Total liabilities | 0 | 0 |
| Level 1 | Interest Rate Contract [Member] | ||
| Liabilities | ||
| Total liabilities | 0 | 0 |
| Level 2 | ||
| Liabilities | ||
| Total liabilities | 19 | 11 |
| Level 2 | Interest Rate Contract [Member] | ||
| Liabilities | ||
| Total liabilities | 19 | 11 |
| Level 3 | ||
| Liabilities | ||
| Total liabilities | 0 | 0 |
| Level 3 | Interest Rate Contract [Member] | ||
| Liabilities | ||
| Total liabilities | $ 0 | $ 0 |
Fair Value Measurements, Including Derivatives (Schedule of Carrying Values and Estimated Fair Values of Debt Instruments) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Carrying Amount | ||||||||||
| Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||||||||||
| Long-term debt | [1] | $ 3,358 | $ 5,146 | |||||||
| Affiliated long-term debt | 230 | 0 | ||||||||
| Estimated Fair Value | ||||||||||
| Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||||||||||
| Long-term debt | [1] | 4,262 | [2] | 5,470 | [3] | |||||
| Affiliated long-term debt | $ 230 | [2] | $ 0 | [3] | ||||||
| ||||||||||
Asset Retirement Obligations (Narrative) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Asset Retirement Obligation Disclosure [Abstract] | ||
| Asset retirement obligation, other conditional obligations | $ 312 | |
| Assets held in trust, nuclear decommissioning | 214 | $ 190 |
| Asset retirement obligation, nuclear decommissioning | $ 177 |
Asset Retirement Obligations (Schedule of Reconciliation of the Carrying Amount of AROs) (Detail) - USD ($) $ in Millions |
12 Months Ended | |||
|---|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|||
| Asset Retirement Obligation Disclosure [Abstract] | ||||
| Beginning balance | $ 541 | $ 529 | ||
| Liabilities settled | (29) | (15) | ||
| Accretion expense | 23 | 23 | ||
| Revisions in estimated cash flows | [1] | (46) | 4 | |
| Ending balance | $ 489 | $ 541 | ||
| ||||
Employee Benefit Plans and Equity Compensation Plan (Narrative) (Detail) - USD ($) |
3 Months Ended | 12 Months Ended | ||||
|---|---|---|---|---|---|---|
Sep. 30, 2019 |
Jun. 30, 2019 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| 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 | $ 711,000,000 | $ 714,000,000 | ||||
| Defined benefit plan, annual rate of increase in the per capita cost of covered health care benefits | 6.60% | |||||
| Defined benefit plan, ultimate health care cost trend rate | 5.00% | |||||
| Defined benefit plan, effect of one percentage point increase on accumulated postretirement benefit obligation | 1,000,000 | |||||
| Defined benefit plan, effect of one percentage point decrease on accumulated postretirement benefit obligation | 1,000,000 | |||||
| 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, expected future employer contributions, next fiscal year, description | no | |||||
| 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 | 20,000,000 | $ 23,000,000 | |||
| 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% | |||||
| Summer | ||||||
| Defined Benefit Plan Disclosure [Line Items] | ||||||
| Defined benefit plan, shared costs deferred with joint ownership | 19,000,000 | $ 25,000,000 | ||||
| Maximum [Member] | ||||||
| Defined Benefit Plan Disclosure [Line Items] | ||||||
| Defined benefit plan, effect of one percentage point increase on accumulated postretirement benefit obligation | 1,000,000 | |||||
| Defined benefit plan, effect of one percentage point decrease on accumulated postretirement benefit obligation | $ 1,000,000 | |||||
| Pension Benefits | ||||||
| Defined Benefit Plan Disclosure [Line Items] | ||||||
| Discount rate percentage | 3.57% | 4.07% | 3.47% | 4.35% | ||
| Defined benefit plan, assumptions used calculating net periodic benefit cost, expected long-term rate of return on plan assets | 7.00% | 7.00% | 7.25% | |||
| Other Postretirement Benefits | ||||||
| Defined Benefit Plan Disclosure [Line Items] | ||||||
| Discount rate percentage | 4.08% | 3.52% | 4.38% | |||
| 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 | $ 15,000,000 | $ 12,000,000 | ||||
| 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 | |||||
Employee Benefit Plans and Equity Compensation Plan (Changes in Benefit Obligations) (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Pension Benefits | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Benefit obligation, January 1 | $ 732 | $ 793 | |
| Service cost | 15 | 17 | $ 18 |
| Interest cost | 28 | 29 | 32 |
| Plan participants’ contributions | 0 | 0 | |
| Actuarial (gain) loss | 47 | (46) | |
| Benefits paid | (21) | (19) | |
| Settlements | (80) | (42) | |
| Curtailment | 6 | 0 | |
| Amounts funded to parent | 0 | 0 | |
| Benefit obligation, December 31 | 727 | 732 | 793 |
| Other Postretirement Benefits | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Benefit obligation, January 1 | 187 | 217 | |
| Service cost | 3 | 4 | 4 |
| Interest cost | 9 | 8 | 9 |
| Plan participants’ contributions | 1 | 1 | |
| Actuarial (gain) loss | 22 | (31) | |
| Benefits paid | (13) | (11) | |
| Settlements | 0 | 0 | |
| Curtailment | 3 | 0 | |
| Amounts funded to parent | 2 | (1) | |
| Benefit obligation, December 31 | $ 214 | $ 187 | $ 217 |
Employee Benefit Plans and Equity Compensation Plan (Significant Assumptions Used to Determine Benefit Obligations) (Detail) |
Dec. 31, 2019 |
Sep. 30, 2019 |
Jun. 30, 2019 |
Dec. 31, 2018 |
|---|---|---|---|---|
| Pension Benefits | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Annual discount rate used to determine benefit obligation | 3.47% | 3.57% | 4.07% | 4.35% |
| Assumed annual rate of future salary increases for projected benefit obligation | 3.00% | 3.00% | ||
| Other Postretirement Benefits | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Annual discount rate used to determine benefit obligation | 3.52% | 4.08% | 4.38% |
Employee Benefit Plans and Equity Compensation Plan (Funded Status) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|---|
| Defined Benefit Plan Disclosure [Line Items] | |||
| Fair value of plan assets | $ 725 | $ 677 | $ 781 |
| Pension Benefits | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Fair value of plan assets | 725 | 676 | |
| Benefit obligation | 727 | 732 | 793 |
| Funded status | (2) | (56) | |
| Other Postretirement Benefits | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Benefit obligation | 214 | 187 | $ 217 |
| Funded status | $ (214) | $ (187) |
Employee Benefit Plans and Equity Compensation Plan (Amounts Recognized on Consolidated Balance Sheets) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Pension Benefits | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Noncurrent liability | $ (2) | $ (56) |
| Other Postretirement Benefits | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Current liability | (13) | (11) |
| Noncurrent liability | $ (201) | $ (177) |
Employee Benefit Plans and Equity Compensation Plan (Amounts Recognized in Accumulated Other Comprehensive Loss) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Pension Benefits | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Net actuarial loss | $ 2 | $ 3 |
| Other Postretirement Benefits | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Net actuarial loss | $ 2 | $ 1 |
Employee Benefit Plans and Equity Compensation Plan (Amounts Recognized in Regulatory Assets ) (Detail) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Pension Benefits | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Net actuarial loss | $ 125 | $ 202 |
| Prior service cost | 0 | 1 |
| Total | 125 | 203 |
| Other Postretirement Benefits | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Net actuarial loss | 29 | 9 |
| Total | $ 29 | $ 9 |
Employee Benefit Plans (Change in Fair Value of Plan Assets) (Detail) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Compensation And Retirement Disclosure [Abstract] | ||
| Fair value of plan assets, January 1 | $ 677 | $ 781 |
| Actual return (loss) on plan assets | 149 | (43) |
| Benefits paid | (21) | (61) |
| Settlements | (80) | 0 |
| Fair value of plan assets, December 31 | $ 725 | $ 677 |
Employee Benefit Plans (Pension Plan Asset Allocation and Target Allocation) (Detail) |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|---|
| Equity Securities | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Defined benefit Plan, Plan asset | 64.00% | 55.00% | |
| Fixed Income | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Defined benefit Plan, Plan asset | 35.00% | 34.00% | |
| Cash | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Defined benefit Plan, Plan asset | 1.00% | 0.00% | |
| Hedge Funds | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Defined benefit Plan, Plan asset | 0.00% | 11.00% | |
| Scenario Forecast | Equity Securities | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Defined benefit Plan, Target allocation plan asset | 45.00% | ||
| Scenario Forecast | Fixed Income | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Defined benefit Plan, Target allocation plan asset | 50.00% | ||
| Scenario Forecast | Cash | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Defined benefit Plan, Target allocation plan asset | 5.00% |
Employee Benefit Plans (Schedule of Fair Value Measurements By Category) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|---|
| Defined Benefit Plan Disclosure [Line Items] | |||
| Total assets in the fair value hierarchy | $ 725 | $ 677 | $ 781 |
| Common collective trust | 311 | 373 | |
| Joint venture interests | 0 | 77 | |
| Total investments | 725 | 677 | |
| Fair Value, Inputs, Level 2 | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Total assets in the fair value hierarchy | 414 | 227 | |
| Fair Value, Inputs, Level 2 | Mutual Funds | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Total assets in the fair value hierarchy | 152 | 99 | |
| Fair Value, Inputs, Level 2 | Short-term Investments | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Total assets in the fair value hierarchy | 0 | 19 | |
| Fair Value, Inputs, Level 2 | US Treasury securities | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Total assets in the fair value hierarchy | 3 | 7 | |
| Fair Value, Inputs, Level 2 | Corporate Debt Securities | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Total assets in the fair value hierarchy | 233 | 86 | |
| Fair Value, Inputs, Level 2 | Government and Other Debt Instruments | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Total assets in the fair value hierarchy | $ 26 | $ 16 |
Employee Benefit Plans (Expected Benefit Payments) (Detail) $ in Millions |
Dec. 31, 2019
USD ($)
|
|---|---|
| Pension Benefits | |
| Defined Benefit Plan Disclosure [Line Items] | |
| Defined benefit plan, expected benefit payments, 2020 | $ 70 |
| Defined benefit plan, expected benefit payments, 2021 | 37 |
| Defined benefit plan, expected benefit payments, 2022 | 48 |
| Defined benefit plan, expected benefit payments, 2023 | 46 |
| Defined benefit plan, expected benefit payments, 2024 | 46 |
| Defined benefit plan, expected benefit payments, 2025-2029 | 210 |
| Other Postretirement Benefits | |
| Defined Benefit Plan Disclosure [Line Items] | |
| Defined benefit plan, expected benefit payments, 2020 | 13 |
| Defined benefit plan, expected benefit payments, 2021 | 13 |
| Defined benefit plan, expected benefit payments, 2022 | 13 |
| Defined benefit plan, expected benefit payments, 2023 | 13 |
| Defined benefit plan, expected benefit payments, 2024 | 13 |
| Defined benefit plan, expected benefit payments, 2025-2029 | $ 69 |
Employee Benefit Plans (Components of Net Periodic Benefit Cost) (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Pension Benefits | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Service cost | $ 15 | $ 17 | $ 18 |
| Interest cost | 28 | 29 | 32 |
| Expected return on assets | (40) | (48) | (46) |
| Prior service cost amortization | 0 | 0 | 1 |
| Amortization of actuarial losses | 11 | 11 | 14 |
| Settlement loss | 16 | 0 | 0 |
| Curtailment | 6 | 0 | 0 |
| Net periodic benefit cost | 36 | 9 | 19 |
| Other Postretirement Benefits | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Service cost | 3 | 4 | 4 |
| Interest cost | 9 | 8 | 9 |
| Amortization of actuarial losses | 0 | 0 | 1 |
| Curtailment | 3 | 0 | 0 |
| Net periodic benefit cost | $ 15 | $ 12 | $ 14 |
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, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Pension Benefits | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Current year actuarial (gain) loss | $ (1) | $ 1 | $ 0 |
| Other Postretirement Benefits | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Current year actuarial (gain) loss | $ 1 | $ (1) | $ 1 |
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, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| 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 | $ (51) | $ 41 | $ (25) |
| Regulatory assets, amortization of actuarial losses, pension and other postretirement benefit plans, net of tax | (11) | (10) | (13) |
| Regulatory assets, amortization of prior service cost, pension and other postretirement benefit plans, net of tax | 0 | 0 | (1) |
| Regulatory assets, settlement loss, pension and other postretirement benefit plans, net of tax | (16) | 0 | 0 |
| Regulatory assets, total recognized in regulatory assets, pension and other postretirement benefit plans, net of tax | (78) | 31 | (39) |
| 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 | 20 | (26) | 7 |
| Regulatory assets, amortization of actuarial losses, pension and other postretirement benefit plans, net of tax | 0 | (1) | 0 |
| Regulatory assets, total recognized in regulatory assets, pension and other postretirement benefit plans, net of tax | $ 20 | $ (27) | $ 7 |
Employee Benefit Plans and Equity Compensation Plan (Schedule of Assumptions Used in Determining Net Periodic Benefit Cost) (Detail) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Defined Benefit Plan Disclosure [Line Items] | |||
| Ultimate health care cost trend rate | 5.00% | ||
| Pension Benefits | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Discount rate | 3.71% | 4.22% | |
| Expected return on plan assets | 7.00% | 7.00% | 7.25% |
| Rate of compensation increase | 3.00% | 3.00% | 3.00% |
| Pension Benefits | Minimum [Member] | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Discount rate | 3.57% | ||
| Pension Benefits | Maximum [Member] | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Discount rate | 4.38% | ||
| Other Postretirement Benefits | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Discount rate | 3.74% | 4.30% | |
| Health care cost trend rate | 6.60% | 7.00% | 6.60% |
| Ultimate health care cost trend rate | 5.00% | 5.00% | 5.00% |
| Year achieved | 2023 | 2023 | 2021 |
| Other Postretirement Benefits | Minimum [Member] | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Discount rate | 4.08% | ||
| Other Postretirement Benefits | Maximum [Member] | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Discount rate | 4.41% | ||
Employee Benefit Plans and Equity Compensation Plan (Schedule of Amounts in Regulatory Assets to be Recognized Over the Next Fiscal Year) (Detail) - Scenario Forecast $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2020
USD ($)
| |
| Pension Benefits | |
| Defined Benefit Plan Disclosure [Line Items] | |
| Defined benefit plan, future amortization of gain or loss from regulatory assets | $ 6 |
| Other Postretirement Benefits | |
| Defined Benefit Plan Disclosure [Line Items] | |
| Defined benefit plan, future amortization of gain or loss from regulatory assets | $ 1 |
Commitments and Contingencies (Narrative) (Detail) |
1 Months Ended | 3 Months Ended | 12 Months Ended | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Apr. 30, 2015
Facility
|
Oct. 31, 2014
MGD
Facility
|
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, 2019
USD ($)
Product
|
Dec. 31, 2018
USD ($)
|
Dec. 31, 2017
USD ($)
|
Feb. 28, 2020
USD ($)
|
|
| 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 | 8,000,000 | ||||||||||||||
| Environmental remediation costs recognized in regulatory assets | 23,000,000 | ||||||||||||||
| 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 | 576,000,000 | $ 1,376,000,000 | $ 1,118,000,000 | |||||||||||
| Impairment of assets and other charges, after-tax | 79,000,000 | ||||||||||||||
| Customer refundable fees, alternative plan | $ 2,390,000,000 | 2,390,000,000 | 3,466,000,000 | 2,390,000,000 | |||||||||||
| 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 | 345,000,000 | ||||||||||||||
| Transmission assets related to BLRA regulatory assets | 37,000,000 | ||||||||||||||
| Reserves for litigation and regulatory proceedings | 11,000,000 | 11,000,000 | 492,000,000 | 11,000,000 | |||||||||||
| Insurance receivables | 6,000,000 | ||||||||||||||
| Escrow amount | 115,000,000 | 115,000,000 | 115,000,000 | ||||||||||||
| Proposed settlement payable by company | $ 100,000,000 | ||||||||||||||
| Proportionate ownership share in project | 100.00% | 100.00% | |||||||||||||
| Proposed assessment amount from SCDOR audit | $ 410,000,000 | ||||||||||||||
| 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 | 24,000,000 | 24,000,000 | $ 37,000,000 | 24,000,000 | |||||||||||
| Nuclear Insurance | |||||||||||||||
| Loss Contingencies [Line Items] | |||||||||||||||
| Maximum liability each nuclear plant is insured against | $ 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 | ||||||||||||||
| 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 | ||||||||||||||
| 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 | ||||||||||||||
| Subsequent Event | |||||||||||||||
| Loss Contingencies [Line Items] | |||||||||||||||
| Proposed settlement payable by all | $ 520,000,000 | ||||||||||||||
| Proposed settlement payable by company | $ 320,000,000 | ||||||||||||||
| Maximum [Member] | Nuclear Insurance | |||||||||||||||
| Loss Contingencies [Line Items] | |||||||||||||||
| Maximum liability protection per nuclear incident amount | 14,000,000,000.0 | ||||||||||||||
| Amount that could be assessed for each licensed reactor | 138,000,000 | ||||||||||||||
| Amount that could be assessed for each licensed reactor per year | 21,000,000 | ||||||||||||||
| Dominion Energy South Carolina, Inc. | |||||||||||||||
| Loss Contingencies [Line Items] | |||||||||||||||
| Reduction of liens filed | 33,000,000 | ||||||||||||||
| DESC Summer | Maximum [Member] | Nuclear Insurance | |||||||||||||||
| Loss Contingencies [Line Items] | |||||||||||||||
| Amount that could be assessed for each licensed reactor | 92,000,000 | ||||||||||||||
| Amount that could be assessed for each licensed reactor per year | 14,000,000 | ||||||||||||||
| Impairment of Assets and Other Charges | Dominion Energy South Carolina, Inc. | |||||||||||||||
| Loss Contingencies [Line Items] | |||||||||||||||
| Impairment of assets and other charges | 590,000,000 | ||||||||||||||
| Impairment of assets and other charges, after-tax | $ 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 | $ 42,000,000 | ||||||||||||||
| DESC Ratepayer Case | Minimum [Member] | |||||||||||||||
| Loss Contingencies [Line Items] | |||||||||||||||
| Estimated aggregate fair value of certain real estate | 60,000,000 | ||||||||||||||
| DESC Ratepayer Case | Maximum [Member] | |||||||||||||||
| Loss Contingencies [Line Items] | |||||||||||||||
| Estimated aggregate fair value of certain real estate | $ 85,000,000 | ||||||||||||||
| Wrongful Death Suit of Estate of Jose Larios | Dominion Energy South Carolina, Inc. | |||||||||||||||
| Loss Contingencies [Line Items] | |||||||||||||||
| Litigation settlement expense awarded | $ 19,000,000 | ||||||||||||||
| NND Project | |||||||||||||||
| Loss Contingencies [Line Items] | |||||||||||||||
| Jointly owned utility plant, proportionate ownership share | 55.00% | ||||||||||||||
| Carbon Regulations [Member] | |||||||||||||||
| Loss Contingencies [Line Items] | |||||||||||||||
| Significant emission rate per year CO2 equivalent | T | 75,000 | ||||||||||||||
Commitments and Contingencies (Schedule of Long-Term Purchase Agreements) (Detail) $ in Millions |
Dec. 31, 2019
USD ($)
|
[1] | ||
|---|---|---|---|---|
| Commitments And Contingencies Disclosure [Abstract] | ||||
| Purchased electric capacity, 2020 | $ 59 | |||
| Purchased electric capacity, 2021 | 58 | |||
| Purchased electric capacity, 2022 | 57 | |||
| Purchased electric capacity, 2023 | 57 | |||
| Purchased electric capacity, 2024 | 57 | |||
| Purchased electric capacity, Thereafter | 661 | |||
| Purchased electric capacity, Total | $ 949 | |||
| ||||
Commitments and Contingencies (Schedule of Long-Term Purchase Agreements) (Parenthetical) (Detail) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2019
USD ($)
| |
| Solar Affiliates [Member] | |
| Long Term Purchase Commitment [Line Items] | |
| Purchases from affiliates | $ 234 |
Leases (Schedule Of Lease Assets and Liabilities Recorded in Consolidated Balance Sheets) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Jan. 01, 2019 |
Dec. 31, 2018 |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Leases [Abstract] | ||||||||||||||
| Operating lease assets | $ 23 | [1] | $ 19 | |||||||||||
| Finance lease assets | [2] | 26 | ||||||||||||
| Total lease assets | 49 | |||||||||||||
| Operating lease liabilities - current | [3] | 3 | ||||||||||||
| Operating lease liabilities - noncurrent | [4] | 20 | ||||||||||||
| Finance lease liabilities - current | [5] | 7 | ||||||||||||
| Finance lease liabilities - noncurrent | 20 | $ 0 | ||||||||||||
| Total lease liabilities | $ 50 | |||||||||||||
| ||||||||||||||
Leases (Schedule Of Lease Assets and Liabilities Recorded in Consolidated Balance Sheets) (Parenthetical) (Detail) $ in Millions |
Dec. 31, 2019
USD ($)
|
|---|---|
| Utility Plant, Net | |
| Finance lease assets, accumulated amortization | $ 24 |
Leases (Summary of Total Lease Cost) (Detail) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2019
USD ($)
| |
| Leases [Abstract] | |
| Finance lease cost, amortization | $ 7 |
| Finance lease cost, interest | 1 |
| Operating lease cost | 4 |
| Short-term lease cost | 1 |
| Total lease cost | $ 13 |
Leases (Cash Paid for Amounts Included in Measurement of Lease Liabilities) (Detail) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2019
USD ($)
| |
| Leases [Abstract] | |
| Operating cash flows from finance leases | $ 1 |
| Operating cash flows from operating leases | 3 |
| Financing cash flows from finance leases | $ 7 |
Leases (Summary of Weighted Average Remaining Lease Term And Discount Rate for Operating and Finance Leases) (Detail) |
Dec. 31, 2019 |
|---|---|
| Leases [Abstract] | |
| Weighted average remaining lease term - finance leases | 5 years |
| Weighted average remaining lease term - operating leases | 18 years |
| Weighted average discount rate - finance leases | 2.94% |
| Weighted average discount rate - operating leases | 3.94% |
Leases (Schedule of Maturity Analysis of Operating and Finance Lease Liabilities) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Jan. 01, 2019 |
|---|---|---|
| Operating Lease Liabilities, Payments Due [Abstract] | ||
| Maturity of operating lease liabilities, 2020 | $ 4 | |
| Maturity of operating lease liabilities, 2021 | 3 | |
| Maturity of operating lease liabilities, 2022 | 2 | |
| Maturity of operating lease liabilities, 2023 | 2 | |
| Maturity of operating lease liabilities, 2024 | 1 | |
| Maturity of operating lease liabilities, after 2024 | 23 | |
| Maturity of operating lease liabilities, total undiscounted lease payments | 35 | |
| Operating lease liabilities, present value adjustment | (12) | |
| Present value of operating lease liabilities | 23 | $ 19 |
| Finance Lease Liabilities, Payments, Due [Abstract] | ||
| Maturity of finance lease liabilities, 2020 | 8 | |
| Maturity of finance lease liabilities, 2021 | 7 | |
| Maturity of finance lease liabilities, 2022 | 5 | |
| Maturity of finance lease liabilities, 2023 | 4 | |
| Maturity of finance lease liabilities, 2024 | 2 | |
| Maturity of finance lease liabilities, after 2024 | 3 | |
| Maturity of finance lease liabilities, total undiscounted lease payments | 29 | |
| Finance lease liabilities, present value adjustment | (2) | |
| Present value of finance lease liabilities | $ 27 |
Operating Segments (Narrative) (Detail) $ in Millions |
3 Months Ended | 12 Months Ended | ||||||
|---|---|---|---|---|---|---|---|---|
|
Dec. 31, 2019
USD ($)
Segment
|
Jun. 30, 2019
USD ($)
|
Mar. 31, 2019
USD ($)
|
Dec. 31, 2018
USD ($)
|
Mar. 31, 2018
USD ($)
|
Dec. 31, 2019
USD ($)
Segment
|
Dec. 31, 2018
USD ($)
|
Dec. 31, 2017
USD ($)
|
|
| Segment Reporting Information [Line Items] | ||||||||
| Number of primary operating segments | Segment | 1 | 1 | ||||||
| Charge for refund of amounts from customers | $ 76 | $ 73 | $ 76 | $ 73 | ||||
| Charge for refund of amounts from customers, after tax | $ 756 | |||||||
| Litigation settlement expense, after tax | 240 | $ 75 | 118 | |||||
| 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 | 576 | 1,376 | $ 1,118 | ||||
| Asset impairment charge after-tax | $ 870 | $ 3 | 690 | |||||
| Operating Segment | Corporate and Other | ||||||||
| Segment Reporting Information [Line Items] | ||||||||
| After- tax net expenses | 1,600 | 917 | 690 | |||||
| Operating Segment | Dominion Energy South Carolina | ||||||||
| Segment Reporting Information [Line Items] | ||||||||
| Charge for refund of amounts from customers | 1,000 | 1,000 | ||||||
| Charge for refund of amounts from customers, after tax | 756 | |||||||
| Litigation settlement expense | 590 | |||||||
| Litigation settlement expense, after tax | 444 | |||||||
| 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 | 1,100 | ||||||
| Asset impairment charge after-tax | $ 870 | $ 690 | ||||||
Operating Segments - Schedule of Segment Information (Details) - USD ($) $ in Millions |
12 Months Ended | ||||
|---|---|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|||
| Segment Reporting Information [Line Items] | |||||
| Operating Revenue | [1] | $ 1,929 | $ 2,762 | $ 3,070 | |
| Depreciation and amortization | 450 | 327 | 312 | ||
| Interest charges | [1] | 260 | 303 | 288 | |
| Income tax expense (benefit) | (12) | (416) | (171) | ||
| Comprehensive income (loss) available (attributable) to common shareholder | (1,239) | (613) | (185) | ||
| Capital expenditures | 497 | 633 | 928 | ||
| Total assets | 14,301 | 14,963 | |||
| Operating Segment | Dominion Energy South Carolina | |||||
| Segment Reporting Information [Line Items] | |||||
| Operating Revenue | 2,937 | 2,763 | 3,070 | ||
| Depreciation and amortization | 452 | 327 | 312 | ||
| Interest charges | 247 | 306 | 288 | ||
| Income tax expense (benefit) | 163 | 98 | 257 | ||
| Comprehensive income (loss) available (attributable) to common shareholder | 408 | 304 | 505 | ||
| Capital expenditures | 497 | 633 | 928 | ||
| Total assets | 14,300 | 15,000 | |||
| Operating Segment | Corporate and Other | |||||
| Segment Reporting Information [Line Items] | |||||
| Operating Revenue | (1,008) | (1) | 0 | ||
| Depreciation and amortization | (2) | 0 | 0 | ||
| Interest charges | 13 | (3) | 0 | ||
| Income tax expense (benefit) | (175) | (514) | (428) | ||
| Comprehensive income (loss) available (attributable) to common shareholder | (1,647) | (917) | (690) | ||
| Capital expenditures | 0 | 0 | $ 0 | ||
| Total assets | $ 0 | $ 0 | |||
| |||||
Utility Plant and Nonutility Property - Property, Plant and Equipment (Details) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Property Plant And Equipment [Line Items] | ||
| Gross nonutility property | $ 75 | $ 73 |
| Generation | ||
| Property Plant And Equipment [Line Items] | ||
| Utility plant in service | 5,765 | 5,751 |
| Transmission | ||
| Property Plant And Equipment [Line Items] | ||
| Utility plant in service | 1,905 | 1,758 |
| Distribution | ||
| Property Plant And Equipment [Line Items] | ||
| Utility plant in service | 4,685 | 4,456 |
| Storage | ||
| Property Plant And Equipment [Line Items] | ||
| Utility plant in service | 73 | 74 |
| General and other | ||
| Property Plant And Equipment [Line Items] | ||
| Utility plant in service | 549 | 535 |
| Intangible | ||
| Property Plant And Equipment [Line Items] | ||
| Utility plant in service | 231 | 229 |
| Construction Work In Progress | ||
| Property Plant And Equipment [Line Items] | ||
| Utility plant in service | 339 | 350 |
| Nuclear Fuel | ||
| Property Plant And Equipment [Line Items] | ||
| Utility plant in service | 608 | 611 |
| Total Gross Utility Plant | ||
| Property Plant And Equipment [Line Items] | ||
| Utility plant in service | $ 14,155 | $ 13,764 |
Utility Plant and Nonutility Property (Narrative) (Details) - USD ($) $ in Millions |
1 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Aug. 31, 2019 |
May 31, 2019 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Utility Plant And Non Utility Property [Line Items] | ||||
| Amounts due from Santee Cooper for share of direct expenses | $ 119 | $ 68 | ||
| 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 | $ 50 | $ 46 | ||
| 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 |
Utility Plant and Nonutility Property - Schedule of Jointly Owned Utility Plants (Details) - Summer Unit 1 - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Property Plant And Equipment [Line Items] | ||
| Jointly owned utility plant, proportionate ownership share | 66.70% | 66.70% |
| Plant in service, jointly owned utility plant | $ 1,400 | $ 1,500 |
| Accumulated depreciation, jointly owned utility plant | 684 | 644 |
| Construction work in progress, jointly owned utility plant | $ 79 | $ 128 |
Affiliated and Related Party Transactions (Narrative) (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Related Party Transaction [Line Items] | |||
| Purchases from affiliates, fuel used in electric generation | $ 43 | $ 139 | $ 127 |
| Canadys Refined Coal [Member] | |||
| Related Party Transaction [Line Items] | |||
| Ownership percentage | 40.00% | ||
| Purchases from affiliates | $ 121 | 150 | $ 162 |
| Accounts payable to affiliates | 2 | 7 | |
| Accounts receivable to affiliates | 2 | $ 7 | |
| Solar Affiliates [Member] | |||
| Related Party Transaction [Line Items] | |||
| Purchases from affiliates | 234 | ||
| Solar Affiliates [Member] | SCANA Combination | |||
| Related Party Transaction [Line Items] | |||
| Purchases from affiliates | 8 | ||
| Solar Affiliates [Member] | Maximum [Member] | |||
| Related Party Transaction [Line Items] | |||
| Accounts payable to affiliates | 1 | ||
| Dominion Energy Carolina Gas Transmission LLC [Member] | |||
| Related Party Transaction [Line Items] | |||
| Purchases from affiliates | 63 | ||
| Accounts payable to affiliates | 5 | ||
| Purchases from affiliates, fuel used in electric generation | 19 | ||
| Purchases from affiliates, gas purchased for resale | 44 | ||
| Accounts receivable to affiliates | $ 1 | ||
Affiliated and Related Party Transactions (Schedule of Affiliated Transactions - Income Statement) (Detail) - USD ($) $ in Millions |
12 Months Ended | ||||
|---|---|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|||
| Related Party Transaction [Line Items] | |||||
| Purchases of fuel used in electric generation from affiliate | $ 43 | $ 139 | $ 127 | ||
| Operating Revenues – Electric from sales to affiliate | 4 | 5 | 5 | ||
| Operating Revenues – Gas from sales to affiliate | 1 | 1 | 1 | ||
| Operating Expenses – Other taxes from affiliate | 6 | 6 | 5 | ||
| DESS [Member] | |||||
| Related Party Transaction [Line Items] | |||||
| Direct and allocated costs from services company affiliate | [1] | 297 | 283 | 303 | |
| Canadys Refined Coal [Member] | |||||
| Related Party Transaction [Line Items] | |||||
| Purchases of coal from affiliate | 121 | 150 | 162 | ||
| Sales of coal to affiliate | $ 120 | $ 149 | $ 161 | ||
| |||||
Affiliated and Related Party Transactions (Schedule of Affiliated Transactions - Income Statement) (Parenthetical) (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| DESS [Member] | |||
| Related Party Transaction [Line Items] | |||
| Capitalized expenditures | $ 53 | $ 41 | $ 82 |
Affiliated and Related Party Transactions (Schedule of Affiliated Transactions - Balance Sheet) (Detail) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| SCANA Energy Marketing, Inc. [Member] | ||
| Related Party Transaction [Line Items] | ||
| Payable to affiliates | $ 0 | $ 14 |
| DESS [Member] | ||
| Related Party Transaction [Line Items] | ||
| Payable to affiliates | 76 | 38 |
| Public Service Company of North Carolina, Incorporated [Member] | ||
| Related Party Transaction [Line Items] | ||
| Payable to affiliates | 8 | 7 |
| Canadys Refined Coal [Member] | ||
| Related Party Transaction [Line Items] | ||
| Receivable from affiliates | 2 | 7 |
| Payable to affiliates | $ 2 | $ 7 |
Other Income (Expense), Net (Components of Other Income (Expense), Net) (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Condensed Statement Of Income Captions [Line Items] | |||
| Operating revenue from contracts with customers | $ 4 | $ 5 | $ 0 |
| Other income | 19 | 141 | 45 |
| Other expense | (57) | (28) | (32) |
| Allowance for equity funds used during construction | 1 | 11 | 15 |
| Other income (expense), net | $ (33) | 129 | $ 28 |
| 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 | ||
Quarterly Financial Information (Schedule of Quarterly Financial Information) (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 |
Sep. 30, 2019 |
Jun. 30, 2019 |
Mar. 31, 2019 |
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Quarterly Financial Information Disclosure [Abstract] | |||||||||||
| Operating revenue | $ 771 | $ 795 | $ 698 | $ (335) | $ 689 | $ 739 | $ 632 | $ 702 | |||
| Operating income (loss) | (76) | 261 | 17 | (1,143) | (1,271) | 212 | 107 | 121 | $ (941) | $ (831) | $ (83) |
| Total comprehensive income (loss) | (191) | 143 | (70) | (1,103) | (852) | 104 | 31 | 128 | $ (1,221) | $ (588) | $ (172) |
| Comprehensive income (loss) available (attributable) to common shareholder | $ (195) | $ 143 | $ (78) | $ (1,109) | $ (861) | $ 98 | $ 26 | $ 124 | |||
Quarterly Financial Information (Narrative) (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | |||||
|---|---|---|---|---|---|---|---|
Dec. 31, 2019 |
Jun. 30, 2019 |
Mar. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Litigation settlement expense, after tax | $ 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 | ||||||
| Impairment of assets and other charges | $ 695 | $ 1,376 | $ 1,118 | ||||
| NND Project Costs [Member] | |||||||
| Impairment of assets and other charges | $ 870 | ||||||