Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2019	Jul. 31, 2019
Document And Entity Information [Abstract]
Entity Registrant Name	Dominion Energy South Carolina, Inc.
Entity Central Index Key	0000091882
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		40,296,147
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-3375
Entity Tax Identification Number	570248695
Entity Address, Address Line One	400 Otarre Parkway
Entity Address, City or Town	Cayce
Entity Address, State or Province	South Carolina
Entity Address, Postal Zip Code	29033
City Area Code	803
Local Phone Number	217-9000

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
ASSETS
Utility plant in service	$ 12,986	$ 12,803
Accumulated depreciation and amortization	(4,750)	(4,581)
Construction work in progress	282	350
Nuclear fuel, net of accumulated amortization	193	211
Utility plant, net	8,711	8,783
Nonutility Property and Investments:
Nonutility property, net of accumulated depreciation	71	72
Assets held in trust, net-nuclear decommissioning	206	190
Other investments	0	1
Nonutility property and investments, net	277	263
Current Assets:
Cash and cash equivalents	5	377
Restricted cash and equivalents	117	0
Receivables, customer, net of allowance for uncollectible accounts	327	331
Affiliated and related party	19	359
Receivables, other	55	68
Inventories (at average cost):
Fuel	107	89
Materials and supplies	160	158
Prepayments	111	82
Regulatory assets	259	223
Other current assets	19	1
Total current assets	1,179	1,688
Deferred Debits and Other Assets:
Regulatory assets	3,759	4,046
Other	357	183
Total deferred debits and other assets	4,116	4,229
Total assets	14,283	14,963
CAPITALIZATION AND LIABILITIES
Common Stock - no par value	3,635	2,860
Retained earnings	72	1,279
Accumulated other comprehensive income (loss)	(4)	(3)
Total common equity	3,703	4,136
Noncontrolling interest	173	179
Total equity	3,876	4,315
Affiliated long-term debt	230	0
Long-term debt, net	3,934	5,132
Total long-term debt	4,164	5,132
Total capitalization	8,040	9,447
Current Liabilities:
Short-term borrowings	0	73
Current portion of long-term debt	7	14
Accounts payable	150	267
Affiliated and related party payables	368	347
Customer deposits and customer prepayments	75	73
Revenue subject to refund	14	77
Taxes accrued	163	228
Interest accrued	62	72
Regulatory liabilities	269	126
Reserves for litigation and regulatory proceedings	278	11
Other	62	42
Total current liabilities	1,448	1,330
Deferred Credits and Other Liabilities:
Deferred income taxes, net	555	989
Asset retirement obligations	498	542
Pension and other postretirement benefits	223	232
Regulatory liabilities	3,277	2,264
Other	227	143
Other affiliate	15	16
Total deferred credits and other liabilities	4,795	4,186
Commitments and Contingencies
Total capitalization and liabilities	$ 14,283	$ 14,963

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) shares in Millions, $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Utility plant, net	$ 8,711	$ 8,783
Receivables, customer, allowance for uncollectible accounts	7	4
Total current assets	1,179	1,688
Total deferred debits and other assets	$ 4,116	$ 4,229
Common Stock, Par Value	$ 0	$ 0
Common Stock, Shares, Outstanding	40.3	40.3
Variable Interest Entity, Primary Beneficiary [Member]
Utility plant, net	$ 690	$ 711
Total current assets	133	96
Total deferred debits and other assets	$ 34	$ 34

Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($)
$ in Millions

3 Months Ended

6 Months Ended

Jun. 30, 2019

Jun. 30, 2018

Jun. 30, 2019

Jun. 30, 2018

Operating Revenues:

Electric

^[1]

$ 621

$ 553

$ 141

$ 1,100

Gas

77

79

222

234

Total operating revenues

698

632

363

1,334

Operating Expenses

Fuel used in electric generation

^[1]

143

155

280

315

Purchased power

^[1]

12

15

20

67

Gas purchased for resale

^[1]

44

45

121

Other operations and maintenance

123

113

219

215

Other operations and maintenance - affiliated suppliers

72

51

120

95

Impairment of assets and other charges

100

0

371

4

Depreciation and amortization

115

81

217

161

Other taxes

^[1]

72

65

141

129

Total operating expenses

681

525

1,489

1,107

Operating income (loss)

17

107

(1,126)

227

Other income (expense), net

(9)

2

(14)

125

Interest charges, net of allowance for borrowed funds used during construction

63

76

136

152

Income (loss) before income tax expense (benefit)

(55)

33

(1,276)

200

Income tax expense (benefit)

15

2

(103)

41

Net Income (Loss) and Other Comprehensive Income (Loss)

(70)

31

(1,173)

159

Comprehensive Income Attributable to Noncontrolling Interest

8

5

14

9

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

$ (78)

$ 26

$ (1,187)

$ 150

[1]	See Note 14 for amounts attributable to affiliates.

Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Allowance for borrowed funds used during construction	$ 2	$ 3	$ 2	$ 5

Consolidated Statements of Cash Flows (Unaudited) - USD ($)
$ in Millions

6 Months Ended

Jun. 30, 2019

Jun. 30, 2018

Operating Activities

Net income (loss)

$ (1,173)

$ 159

Adjustments to reconcile net income (loss) to net cash provided by operating activities:

Impairment of assets and other charges

371

4

Provision for refunds to customers

950

0

Deferred income taxes, net

(434)

58

Depreciation and amortization

223

165

Amortization of nuclear fuel

27

Other adjustments

(4)

(7)

Changes in certain assets and liabilities:

Receivables - affiliated and related party

(3)

(12)

Income tax receivable

0

(8)

Inventories

(48)

(11)

Prepayments

(29)

(34)

Regulatory assets

187

(9)

Regulatory liabilities

195

(107)

Accounts payable

(72)

(19)

Accounts payable - affiliated and related party

17

8

Revenue subject to refund

(63)

156

Taxes accrued

(65)

(93)

Other assets

(138)

(131)

Other liabilities

59

55

Net cash provided by operating activities

0

201

Investing Activities

Property additions and construction expenditures

(226)

(464)

Proceeds from investments and sales of assets

12

31

Purchase of investments

(23)

(17)

Purchase of investments - affiliate

0

(113)

Proceeds from interest rate derivative contract settlement

0

115

Investment in affiliate, net

343

(75)

Net cash provided by (used in) investing activities

106

(523)

Financing Activities

Proceeds from issuance of debt

0

100

Proceeds from issuance of affiliated debt

230

0

Repayment of long-term debt, including redemption premiums

(1,247)

(170)

Dividend to parent

(30)

(156)

Contribution from parent

775

20

Contribution returned to parent

(20)

0

Money pool borrowings, net

4

150

Short-term borrowings, net

(73)

205

Net cash provided by (used in) financing activities

(361)

149

Net decrease in cash, restricted cash and equivalents

(255)

(173)

Cash, restricted cash and equivalents at beginning of period

377

395

Cash, restricted cash and equivalents at end of period

122

222

Noncash investing and financing activities:

Accrued construction expenditures

^[1]

39

19

Leases

^[1],[2]

$ 5

$ 0

[1]	See Note 1 for noncash investing and financing activities related to the adoption of a new accounting standard for leasing arrangements.
[2]	Includes $3 million of financing leases and $2 million of operating leases.

Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) $ in Millions	6 Months Ended
	Jun. 30, 2019 USD ($)
Statement Of Cash Flows [Abstract]
Financing leases	$ 3
Operating leases	$ 2

Consolidated Statements of Changes in Common Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Retained Earnings	AOCI	Noncontrolling Interest
Beginning balance at Dec. 31, 2017	$ 4,980	$ 2,860	$ 1,982	$ (4)	$ 142
Beginning balance (in shares) at Dec. 31, 2017		40
Total comprehensive income (loss) available (attributable) to common shareholder	159		150		9
Capital contribution from parent	20				20
Dividend to parent	(74)		(72)		(2)
Ending balance at Jun. 30, 2018	5,085	$ 2,860	2,060	(4)	169
Ending balance (in shares) at Jun. 30, 2018		40
Beginning balance at Mar. 31, 2018	5,034	$ 2,860	2,034	(4)	144
Beginning balance (in shares) at Mar. 31, 2018		40
Total comprehensive income (loss) available (attributable) to common shareholder	31		26		5
Capital contribution from parent	20				20
Ending balance at Jun. 30, 2018	5,085	$ 2,860	2,060	(4)	169
Ending balance (in shares) at Jun. 30, 2018		40
Beginning balance at Dec. 31, 2018	4,315	$ 2,860	1,279	(3)	179
Beginning balance (in shares) at Dec. 31, 2018		40
Cumulative-effect of change in accounting principle	0		1	(1)
Total comprehensive income (loss) available (attributable) to common shareholder	(1,173)		(1,187)		14
Capital contribution from parent	775	$ 775
Capital contribution returned to parent	(20)				(20)
Dividend to parent	(20)		(20)
Other	(1)		(1)
Ending balance at Jun. 30, 2019	3,876	$ 3,635	72	(4)	173
Ending balance (in shares) at Jun. 30, 2019		40
Beginning balance at Mar. 31, 2019	3,867	$ 3,535	151	(4)	185
Beginning balance (in shares) at Mar. 31, 2019		40
Total comprehensive income (loss) available (attributable) to common shareholder	(70)		(78)		8
Capital contribution from parent	100	$ 100
Capital contribution returned to parent	(20)				(20)
Other	(1)		(1)
Ending balance at Jun. 30, 2019	$ 3,876	$ 3,635	$ 72	$ (4)	$ 173
Ending balance (in shares) at Jun. 30, 2019		40

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2019

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Consolidation and Variable Interest Entities

DESC has determined that it has a controlling financial interest in each of GENCO and Fuel Company (which are considered to be VIEs) and, accordingly, DESC's Consolidated Financial Statements include, after eliminating intercompany balances and transactions, the accounts of DESC, GENCO and Fuel Company. 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, pursuant to a FERC-approved tariff, solely to DESC under the terms of a power purchase agreement and related operating agreement. The effects of these transactions are eliminated in consolidation. GENCO’s property (carrying value of $497 million) previously served as collateral for its long-term borrowings. In May 2019, GENCO redeemed its 5.49% senior secured notes and was able to release the first mortgage lien in June 2019 that had previously secured these notes. Fuel Company acquires, owns and provides financing for DESC’s nuclear fuel, certain fossil fuels and emission and other environmental allowances. See also Note 5.

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 14 for amounts attributable to affiliates.

Significant Accounting Policies

There have been no significant changes from Note 1 to the Consolidated Financial Statements in DESC's Annual Report on Form 10-K for the year ended December 31, 2018, with the exception of the item described below.

Leases

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

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

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

Recently Adopted Accounting Standards

In February 2016, the Financial Accounting Standards Board 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 12 for additional information.

Rate and Other Regulatory Matters

6 Months Ended

Jun. 30, 2019

Regulated Operations [Abstract]

Rate and Other Regulatory Matters

2. RATE AND OTHER REGULATORY MATTERS

Regulatory Matters Involving Potential Loss Contingencies

As a result of issues generated in the ordinary course of business, DESC is involved in various regulatory matters. Certain regulatory matters may ultimately result in a loss; however, as such matters are in an initial procedural phase, involve uncertainty as to the outcome of pending reviews or orders, and/or involve significant factual issues that need to be resolved, it is not possible for DESC to estimate a range of possible loss. For regulatory matters that DESC cannot estimate, a statement to this effect is made in the description of the matter. Other matters may have progressed sufficiently through the regulatory process such that DESC is able to estimate a range of possible loss. For regulatory matters that DESC is able to reasonably estimate a range of possible losses, an estimated range of possible loss is provided, in excess of the accrued liability (if any) for such matters. Any estimated range is based on currently available information, involves elements of judgment and significant uncertainties and may not represent DESC’s maximum possible loss exposure. The circumstances of such regulatory matters will change from time to time and actual results may vary significantly from the current estimate. For current matters not specifically reported below, management does not anticipate that the outcome from such matters would have a material effect on DESC’s financial position, liquidity or results of operations.

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 has determined to be services that are likely subject to FERC’s jurisdiction. DESC requested that the FERC accept the 2015 Task Order for filing to become effective in August 2019 and accept the refund analysis included in the filing. At June 30, 2019, DESC’s Consolidated Balance Sheets include reserves of $10 million included within revenue subject to refund for the potential refund of amounts collected under the 2015 Task Order as well as under two prior task orders commencing in 1995 and each covering ten-year periods. During the second quarter of 2019, DESC recorded a $6 million ($4 million after-tax) charge primarily within interest charges in DESC’s Consolidated Statements of Comprehensive Income (Loss). This matter is pending.

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 the

second quarter of 2018 DESC recorded a charge of $109 million ($82 million after-tax) to operating revenues in DESC’s Consolidated Statements of Comprehensive Income (Loss). The temporary rate reduction remained in effect until February 2019 when rates pursuant to the SCANA Merger Approval Order became effective.

Other Regulatory Matters

Other than the following matter, there have been no significant developments regarding the pending regulatory matters disclosed in Note 2 to the Consolidated Financial Statements in DESC's Annual Report on Form 10-K for the year ended December 31, 2018 or Note 2 to the Consolidated Financial Statements in DESC’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2019.

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 Natural Gas Rate Stabilization Act effective for the rate year beginning November 2019. This matter is pending.

Regulatory Assets and Regulatory Liabilities

Rate-regulated utilities recognize in their financial statements certain revenues and expenses in different periods than do other enterprises. As a result, DESC has recorded regulatory assets and regulatory liabilities which are summarized in the following tables. 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.

	June 30,		December 31,
(millions)	2019		2018
Regulatory assets:
NND Project costs	$	138	$	127
Deferred employee benefit plan costs		16		16
Other unrecovered plant		14		14
DSM programs		16		14
Other		75		52
Regulatory assets - current		259		223
NND Project costs		2,572		2,641
AROs		324		380
Deferred employee benefit plan costs		230		256
Deferred losses on interest rate derivatives		308		442
Other unrecovered plant		73		79
DSM programs		53		51
Environmental remediation costs		21		24
Deferred storm damage costs		34		35
Deferred transmission operating costs		27		15
Other		117		123
Regulatory assets - noncurrent		3,759		4,046
Total regulatory assets	$	4,018	$	4,269
Regulatory liabilities:
Monetization of guaranty settlement	$	67	$	61
Income taxes refundable through future rates		48		52
Reserve for refunds to electric utility customers		136		—
Other		18		13
Regulatory liabilities - current		269		126
Monetization of guaranty settlement		1,003		1,037
Income taxes refundable through future rates		826		607
Asset removal costs		552		541
Deferred gains on interest rate derivatives		77		75
Reserve for refunds to electric utility customers		813		—
Other		6		4
Regulatory liabilities - noncurrent		3,277		2,264
Total regulatory liabilities	$	3,546	$	2,390

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 discussed in Note 11. While such costs are not currently being recovered, management believes 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. In the future, as a result of deregulation, changes in state law, other changes in the regulatory environment or changes in accounting requirements or other adverse legislative or regulatory developments, DESC could be required to write off all or a portion of its regulatory assets and liabilities. Such an event could have a material effect on DESC's financial statements in the period the write-off would be recorded.

NND Project costs reflects expenditures associated with the NND Project, which pursuant to the SCANA Merger Approval Order, will be recovered from electric service customers over a 20-year period ending in 2039. See Note 11 for more information.

AROs represent deferred depreciation and accretion expense related to legal obligations associated with the future retirement of generation, transmission and distribution properties. The AROs primarily relate to DESC’s electric generating facilities, including Summer, and are expected to be recovered over the related property lives and periods of decommissioning which may range up to approximately 106 years.

Employee benefit plan costs have historically been recovered as they have been recorded under GAAP. Deferred employee benefit plan costs represent amounts of pension and other postretirement benefit costs which were accrued as liabilities and treated as regulatory assets pursuant to FERC guidance, and costs deferred pursuant to specific South Carolina Commission regulatory orders. DESC expects to recover deferred pension costs through utility rates over periods through 2044. DESC expects to recover other deferred benefit costs through utility rates, primarily over average service periods of participating employees up to 11 years.

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

Other unrecovered plant represents the carrying value of coal-fired generating units, including related materials and supplies inventory, retired from service prior to being fully depreciated. DESC is amortizing these amounts through cost of service rates over the units' previous estimated remaining useful lives through 2025. Unamortized amounts are included in rate base and are earning a current return.

DSM programs represent deferred costs associated with electric demand reduction programs, and such deferred costs are currently being recovered over five years through an approved rate rider.

Environmental remediation costs are associated with the assessment and clean-up of sites currently or formerly owned by DESC. Such remediation costs are expected to be recovered over periods of up to 16 years. See also Note 11.

Deferred storm damage costs represent storm restoration costs for which DESC expects to receive future recovery through customer rates.

Deferred transmission operating costs includes deferred depreciation and property taxes associated with certain transmission assets for which DESC expects recovery from customers through future rates. See also Note 11.

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

Monetization of guaranty settlement represents proceeds related to the monetization of the Toshiba Settlement. In accordance with the SCANA Merger Approval Order, this balance, net of amounts that may be required to satisfy certain liens, will be refunded to electric customers over a 20-year period ending in 2039. See Note 11.

Income taxes refundable through future rates includes (i) excess deferred income taxes arising from the remeasurement of deferred income taxes in connection with the enactment of the 2017 Tax Reform Act (certain of which are protected under normalization rules and will be amortized over the remaining lives of related property, and certain of which will be amortized to the benefit of customers over prescribed periods as instructed by regulators) and (ii) deferred income taxes arising from investment tax credits, offset by (iii) deferred income taxes that arise from utility operations that have not been included in customer rates (a portion of which relate to depreciation and are expected to be recovered over the remaining lives of the related property which may range up to 85 years). See also Note 6.

Reserve for refunds to electric utility customers reflects amounts previously collected from retail electric customers of DESC for the NND Project to be credited to customers over an estimated 11-year period in connection with the SCANA Merger Approval Order. See Note 11.

Asset removal costs represent estimated net collections through depreciation rates of amounts to be expended for the removal of assets in the future.

Revenue Recognition

6 Months Ended

Jun. 30, 2019

Revenues [Abstract]

Revenue Recognition

3. REVENUE RECOGNITION

DESC has disaggregated operating revenues by customer class as follows:

	Three Months Ended					Three Months Ended				Six Months Ended				Six Months Ended
	June 30, 2019					June 30, 2018				June 30, 2019				June 30, 2018
(millions)	Electric			Gas		Electric		Gas		Electric		Gas		Electric		Gas
Customer class:
Residential	$	281		$	31	$	243	$	34	$	10	$	109	$	495	$	120
Commercial		206			23		171		22		67		61		340		61
Industrial		100			19		106		21		18		45		191		45
Other		35			4		30		2		45		7		68		7
Revenues from contracts with customers		622			77		550		79		140		222		1,094		233
Other revenues		(1	)		—		3		—		1		—		6		1
Total Operating Revenues	$	621		$	77	$	553	$	79	$	141	$	222	$	1,100	$	234

Contract liabilities represent the obligation to transfer goods or services to a customer for which consideration has already been received from the customer. DESC had contract liability balances of $5 million and $4 million at June 30, 2019 and December 31, 2018, respectively. During the six months ended June 30, 2019, DESC recognized revenue of $3 million from the beginning contract liability balances as DESC fulfilled its obligations to provide service to its customers. Contract liabilities are recorded in customer deposits and customer prepayments in the Consolidated Balance Sheets.

Equity

6 Months Ended

Jun. 30, 2019

Stockholders Equity Note [Abstract]

Equity

4. EQUITY

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

In February 2019, DESC received an equity contribution of $675 million from its parent that was funded by Dominion Energy. DESC used these funds to redeem long-term debt. See Note 5.

In June 2019, DESC received an equity contribution of $100 million from its parent that was funded by Dominion Energy. DESC used these funds to repay intercompany credit agreement borrowings from Dominion Energy.

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 June 30, 2019 and December 31, 2018, retained earnings of $126 million and $115 million, respectively, 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 June 30, 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. There have been no other significant changes to dividend restrictions affecting DESC described in Note 4 to the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2018.

Long-Term and Short-Term Debt and Liquidity

6 Months Ended

Jun. 30, 2019

Debt Disclosure [Abstract]

Long-Term and Short-Term Debt and Liquidity

5. LONG-TERM AND SHORT-TERM DEBT AND LIQUIDITY

Long-term Debt

In February 2019, DESC launched tender offers for certain of its first mortgage bonds pursuant to which it purchased first mortgage bonds having an aggregate purchase price equal to $1.2 billion. DESC incurred a loss on reacquired debt of $187 million in connection with these tender offers, which is recorded in other deferred debits on the Consolidated Balance Sheets.

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.

Liquidity

In March 2019, DESC became a co-borrower under Dominion Energy's $6 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:

(millions)

Facility Limit

Outstanding

Commercial Paper

Outstanding

Letters of Credit

At June 30, 2019

$

1,000

$

—

$

—

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 June 30, 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.

(millions)

Facility Limit⁽¹⁾

Outstanding

Commercial Paper

Outstanding

Letters of Credit

At December 31, 2018

$

1,200

$

73

$

—

(1)	Included $500 million related to Fuel Company. In February 2019, Fuel Company's commercial paper program and its credit facility were terminated.

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 to issue short-term indebtedness (pursuant to Section 204 of the Federal Power Act). DESC may issue unsecured promissory notes, commercial paper and direct loans 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 to issue short-term indebtedness not to exceed $200 million outstanding with maturity dates of one year or less. The authorities described herein will expire in April 2020, which reflects a one-year authorization period rather than the two-year period DESC and GENCO had requested. In granting the authorization for a shorter period, FERC cited certain regulatory and legislative proceedings at the state level, as well as certain legal proceedings, arising from the NND Project that could affect DESC's and GENCO's circumstances. Were adverse developments to occur with respect to these uncertainties, the ability of DESC or GENCO to secure renewal of this short-term borrowing authority may be adversely impacted.

DESC is obligated with respect to an aggregate of $68 million of industrial revenue bonds which are secured by letters of credit issued by TD Bank N.A. These letters of credit expire, subject to renewal, in the fourth quarter of 2019.

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 June 30, 2019, DESC had borrowings outstanding under this credit agreement totaling $61 million, which are recorded in affiliated and related party payables in DESC’s Consolidated Balance Sheets. For the three and six months ended June 30, 2019, DESC recorded interest charges of less than $1 million.

DESC participated in a utility money pool with SCANA and another regulated subsidiary of SCANA through April 2019. Fuel Company and GENCO remained in the utility money pool. Money pool borrowings and investments bear interest at short-term market rates. For the three and six months ended June 30, 2019, DESC recorded interest income from money pool transactions of $3 million and $6 million, respectively, and for the same periods DESC recorded interest expense from money pool transactions of $3 million and $6 million, respectively. Interest income and interest expense for the corresponding periods in 2018 were not significant. DESC had outstanding money pool borrowings due to an affiliate of $224 million and investments due from an affiliate of $9 million at June 30, 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.

Income Taxes

6 Months Ended

Jun. 30, 2019

Income Tax Disclosure [Abstract]

Income Taxes

6. INCOME TAXES

DESC’s effective tax rate for the six months ended June 30, 2019 is 8.1% compared to 20.5% for the six months ended June 30, 2018. Variances in the effective tax rate are primarily driven by charges resulting from the SCANA Combination. In connection with the SCANA Merger Approval Order, 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 income tax expense of $198 million in satisfaction of this commitment.

In the first quarter, DESC’s unrecognized tax benefits increased by $51 million and income tax expense increased by $40 million related to a state income tax position taken in prior years. In the second quarter, DESC’s unrecognized tax benefits increased by $24 million and income tax expense increased by $23 million primarily related to a federal income tax position taken in prior years.

As of June 30, 2019, there have been no other material changes in DESC’s unrecognized tax benefits. See Note 6 to the Consolidated Financial Statements in DESC's Annual Report on Form 10-K for the year ended December 31, 2018 for a discussion of these unrecognized tax benefits and potential changes due to the SCANA Combination.

DESC has significant federal and state net operating loss carryforward-related deferred tax assets where the utilization of these tax benefits may be limited in future periods due to the SCANA Combination. For the period ended June 30, 2019, DESC has concluded a valuation allowance is not required on these deferred tax assets. If DESC concludes a valuation allowance is required in future periods, the impact could be material.

The 2017 Tax Reform Act limits the deductibility of interest expense to 30% of adjusted taxable income for certain businesses, with any disallowed interest carried forward indefinitely. Subject to additional guidance in yet to be finalized regulations, DESC expects its interest expense to be deductible in 2019.

Derivative Financial Instruments

6 Months Ended

Jun. 30, 2019

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Derivative Financial Instruments

7. DERIVATIVE FINANCIAL INSTRUMENTS

DESC’s accounting policies, objectives, and strategies for using derivative instruments are discussed in Note 7 in the Consolidated Financial Statements in DESC’s Annual Report on Form 10-K for the year ended December 31, 2018. Derivative assets and liabilities are presented gross on the Consolidated Balance Sheets and are measured at fair value. See Note 8 for further information about fair value measurements and associated valuation methods for derivatives. Derivative contracts include over-the-counter transactions, which are bilateral contracts that are transacted directly with a third party. In general, most over-the-counter transactions are subject to collateral requirements.

Pursuant to regulatory orders, interest rate derivatives entered into by DESC after October 2013 have not been 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 expense or have been applied as otherwise directed by the South Carolina Commission. See Note 15 regarding the settlement gains realized in the first quarter of 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:

	June 30, 2019								December 31, 2018
	Gross Amounts Not Offset in the Consolidated Balance Sheet								Gross Amounts Not Offset in the Consolidated Balance Sheet
(millions)	Gross Liabilities Presented in the Consolidated Balance Sheet		Financial Instruments		Cash Collateral Paid		Net Amounts		Gross Liabilities Presented in the Consolidated Balance Sheet		Financial Instruments		Cash Collateral Paid		Net Amounts
Interest rate contracts:
Over-the-counter	$	19	$	—	$	19	$	—	$	11	$	—	$	11	$	—
Total derivatives	$	19	$	—	$	19	$	—	$	11	$	—	$	11	$	—

Volumes

The following table presents the volume of derivative activity at June 30, 2019. These volumes are based on open derivative positions and represent the combined absolute value of their long and short positions.

		Current				Noncurrent
Interest rate⁽¹⁾		$	—			$	71,400,000

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

Fair Value and Gains and Losses on Derivative Instruments

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

(millions)	Fair Value - Derivatives under Hedge Accounting		Fair Value - Derivatives not under Hedge Accounting		Total Fair Value
At June 30, 2019
Current Liabilities
Interest rate	$	1	$	1	$	2
Total current derivative liabilities⁽¹⁾		1		1		2
Noncurrent Liabilities
Interest rate		11		6		17
Total noncurrent derivative liabilities⁽²⁾		11		6		17
Total derivative liabilities	$	12	$	7	$	19
At December 31, 2018
Current Liabilities
Interest rate	$	1	$	—	$	1
Total current derivative liabilities⁽¹⁾		1		—		1
Noncurrent Liabilities
Interest rate		7		3		10
Total noncurrent derivative liabilities⁽²⁾		7		3		10
Total derivative liabilities	$	8	$	3	$	11

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

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

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

Derivatives in Cash Flow Hedging Relationships

(millions)	Gain (loss) Reclassified from Deferred Accounts into Income			Increase (Decrease) in Derivatives Subject to Regulatory Treatment⁽¹⁾
Three Months Ended June 30, 2019
Derivative type and location of gains (losses):
Interest rate⁽²⁾	$	—		$	—
Total	$	—		$	—
Three Months Ended June 30, 2018
Derivative type and location of gains (losses):
Interest rate⁽²⁾	$	(1	)	$	—
Total	$	(1	)	$	—
Six Months Ended June 30, 2019
Derivative type and location of gains (losses):
Interest rate⁽²⁾	$	—		$	(2	)
Total	$	—		$	(2	)
Six Months Ended June 30, 2018
Derivative type and location of gains (losses):
Interest rate⁽²⁾	$	(1	)	$	2
Total	$	(1	)	$	2

(1)	Represents net derivative activity deferred into and amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/ liabilities have no associated effect in the Consolidated Statements of Comprehensive Income (Loss).

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

Derivatives Not designated as Hedging Instruments

(millions)	Increase (Decrease) in Derivatives Subject to Regulatory Treatment⁽¹⁾						Amount of Gain (Loss) Recognized in Income on Derivatives⁽²⁾
Three Months Ended June 30,	2019			2018		Location	2019		2018
Derivative type and location of gains (losses):
Interest rate contracts:						Interest charges	$	—	$	(1	)
						Other income		—		—
Total interest rate contracts	$	(2	)	$	—		$	—	$	(1	)
Six Months Ended June 30,
Derivative type and location of gains (losses):
Interest rate contracts:						Interest charges	$	—	$	(1	)
						Other income		—		115
Total interest rate contracts	$	(3	)	$	65		$	—	$	114

(1)	Represents net derivative activity deferred into and amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/liabilities have no associated effect in the Consolidated Statements of Comprehensive Income (Loss).

(2)	^{Includes derivative activity amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/liabilities have no associated effect in the Consolidated Statements of Comprehensive Income (Loss).}

Credit Risk Considerations

Certain derivative contracts contain contingent credit features. These features may include (i) material adverse change clauses or payment acceleration clauses that could result in immediate payments or (ii) the posting of letters of credit or termination of the derivative contract before maturity if specific events occur, such as a credit rating downgrade below investment grade or failure to post collateral.

Derivative Contracts with Credit Contingent Features

(millions)	June 30, 2019		December 31, 2018
in Net Liability Position
Aggregate fair value of derivatives in net liability position	$	19	$	11
Fair value of collateral already posted		19		11
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	$	—	$	—

Fair Value Measurements, Including Derivatives

6 Months Ended

Jun. 30, 2019

Fair Value Disclosures [Abstract]

Fair Value Measurements, Including Derivatives

8. 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, and to a lesser extent, broker quotes. When evaluating pricing information, DESC considers the ability to transact at the quoted price. Periodically, inputs to valuation models are reviewed and revised as needed, based on historical information, updated market data, market liquidity and relationships, and changes in third-party sources.

The inputs and assumptions used in measuring fair value for interest rate derivative contracts include the following:

•	Interest rate curves

•	Credit quality of counterparties and DESC

•	Notional value

•	Credit enhancements

•	Time value

Levels

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

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

•

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

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

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

Recurring Fair Value Measurements

Fair value measurements are separately disclosed by level within the fair value hierarchy.

All of DESC's interest rate swap agreements were in a liability position for all periods presented. Such agreements are valued using discounted cash flow models with independently sourced data, and are considered to be Level 2 fair value measurements. The fair value of these derivatives at June 30, 2019 was $19 million, and at December 31, 2018 was $11 million.

Fair Value of Financial Instruments

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

June 30, 2019

December 31, 2018

(millions)

Carrying

Amount

Estimated

Fair Value⁽¹⁾

Carrying

Amount

Estimated

Fair Value⁽²⁾

Long-term debt⁽³⁾

$

4,171

$

4,982

$

5,146

$

5,470

(1)

Fair value is estimated using market prices, where available, and interest rates currently available for issuance of debt with similar terms and remaining maturities. All fair value measurements are classified as Level 2. The carrying amount of debt issuances with short-term maturities and variable rates refinanced at current market rates is a reasonable estimate of their fair value.

(2)

Fair value is estimated based on net present value calculations using independently sourced market data that incorporate a developed discount rate using similarly rated long-term debt, along with benchmark interest rates. All fair value measurements are classified as Level 2. The carrying amount of debt issuances with short-term maturities and variable rates refinanced at current market rates is a reasonable estimate of their fair value.

(3)	Carrying amount includes amounts which represent the unamortized debt issuance costs and discount or premium.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Utility Plant and Nonutility Property

6 Months Ended

Jun. 30, 2019

Utility Plant And Non Utility Property [Abstract]

Utility Plant and Nonutility Property

9. UTILITY PLANT AND NONUTILITY PROPERTY

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. DESC expects the transaction to close in the third quarter of 2019 and estimates the transaction to result in a $7 million ($5 million after-tax) gain. Pursuant to the agreement, upon closing DESC expects to enter into a commission agreement with the buyer under which the buyer will compensate DESC in connection with the right to use DESC’s brand in marketing materials and other services over a ten-year term.

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 in Summer is 66.7%. 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 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.

Employee Benefit Plans

6 Months Ended

Jun. 30, 2019

Compensation And Retirement Disclosure [Abstract]

Employee Benefit Plans

10. EMPLOYEE BENEFIT PLANS

Components of net periodic benefit cost recorded by DESC were as follows:

(millions)	Pension Benefits						Other Postretirement Benefits
Three Months Ended June 30,	2019			2018			2019		2018
Service cost	$	3		$	4		$	—	$	1
Interest cost		7			7			2		2
Expected return on assets		(10	)		(12	)		—		—
Amortization of actuarial losses		3			3			—		1
Curtailment⁽¹⁾		6			—			3		—
Net periodic benefit cost	$	9		$	2		$	5	$	4
Six Months Ended June 30,
Service cost	$	7		$	8		$	1	$	2
Interest cost		15			15			4		4
Expected return on assets		(20	)		(24	)		—		—
Amortization of actuarial losses		7			5			—		1
Curtailment⁽¹⁾		6			—			3		—
Net periodic benefit cost	$	15		$	4		$	8	$	7

(1) Related to a voluntary retirement program.

No significant contribution to the pension trust is expected for the remainder of 2019 based on current market conditions and assumptions, nor is a limitation on benefit payments expected to apply. DESC recovers current pension costs through either a rate rider that may be adjusted annually for retail electric operations or through cost of service rates for gas operations.

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 the second quarter of 2019, upon the determinations made concerning the number of employees that elected to participate in the program, DESC recorded a charge of $62 million ($47 million after-tax), of which $50 million was included within other operations and maintenance expense, $3 million within other taxes and $9 million within other income (expense), net.

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 remeasurement is expected to increase the net periodic benefit cost for 2019 by approximately $1 million, excluding the impacts of curtailments. 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.

Commitments And Contingencies

6 Months Ended

Jun. 30, 2019

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

11. 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

In July 2019, the EPA published the ACE Rule, which repeals and replaces the Clean Power Plan. The ACE Rule only applies to coal-fired steam electric generating units greater than or equal to 25 MW. The 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, which plans must be approved by the EPA. DESC is currently evaluating the ACE Rule for potential impact at its coal fired units and expects any costs incurred to comply with such rule to be recoverable through rates. 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.

In July 2011, the EPA issued the CSAPR to reduce emissions of SO₂and NO_X from power plants in the eastern half of the U.S. The CSAPR replaces the Clean Air Interstate Rule and requires a total of 28 states to reduce annual SO₂ emissions and annual ozone season NO_X emissions to assist in attaining the ozone and fine particle National Ambient Air Quality Standards. The rule establishes an emissions cap for SO₂and NO_X and limits the trading for emission allowances by separating affected states into two groups with no trading between the groups. The State of South Carolina has chosen to remain in the CSAPR program, even though recent court rulings exempted the state. This allows the state to remain compliant with regional haze standards. Air quality control installations that DESC has already completed have positioned them to comply with the existing allowances set by the CSAPR. Any costs incurred to comply with CSAPR are expected to be recoverable through rates.

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 due to plant retirements, conversions and enhancements.

The CWA provides for the imposition of effluent limitations that require treatment for wastewater discharges. Under the CWA, compliance with applicable limitations is achieved under state-issued NPDES permits such that, as a facility’s NPDES permit is renewed, any new effluent limitations would be incorporated. The ELG Rule was final in September 2015, after which state regulators are required to modify facility NPDES permits to match more restrictive standards, which would require facilities to retrofit with new wastewater treatment technologies. Compliance dates varied by type of wastewater, and some were based on a facility's five-year permit cycle and thus could range from 2018 to 2023. However, the ELG Rule is under reconsideration by the EPA and has been stayed administratively. The EPA has decided to conduct a new rulemaking that could result in revisions to certain flue gas desulfurization wastewater and bottom ash transport water requirements in the ELG Rule. Accordingly, in September 2017 the EPA finalized a rule that postpones compliance dates under the ELG Rule to a range from November 2020 to December 2023. The EPA indicates that the new rulemaking process may take up to three years to complete, such that any revisions to the ELG Rule likely would not be final until the summer of 2020. While DESC expects that wastewater treatment technology retrofits will be required at Williams and Wateree generating stations, any costs incurred to comply with the ELG Rule are expected to be recoverable through rates.

The CWA Section 316(b) Existing Facilities Rule became effective in October 2014. This rule establishes national requirements for the location, design, construction and capacity of cooling water intake structures at existing facilities that reflect the best technology

available for minimizing the adverse environmental impacts of impingement and entrainment. 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. Any costs incurred to comply with this rule are expected to be recoverable through rates.

The EPA's final rule for CCR became effective in the fourth quarter of 2015. This rule regulates CCR as a non-hazardous waste under Subtitle D of the Resource Conservation and Recovery Act and imposes certain requirements on ash storage ponds and other CCR management facilities at certain of DESC's coal-fired generating facilities. DESC has already closed or has begun the process of closure of all of its ash storage ponds and has previously recognized AROs for such ash storage ponds under existing requirements. DESC does not expect the incremental compliance costs associated with this rule to be significant and expect to recover such costs in future rates.

DESC is responsible for four decommissioned MGP sites in South Carolina which contain residues of by-product chemicals. These sites are in various stages of investigation, remediation and monitoring under work plans approved by or under review by SCDHEC and the EPA. DESC anticipates that major remediation activities at all of these sites will continue at least through 2022 and will cost an additional $10 million. In February 2019, SCDHEC directed DESC to pursue a stakeholder-developed modified removal action plan for one site (Congaree River). DESC is developing an engineering design for this plan, which would require permits from the U.S. Army Corps of Engineers and others and further approvals before it could be implemented. If DESC receives the necessary permits and approvals for this plan, remediation cost for the Congaree River site would increase by $8 million. DESC cannot predict if or when such permits or approvals will be received. Major remediation activities are accrued in other within deferred credits and other liabilities on the Consolidated Balance Sheets. DESC expects to recover any cost arising from the remediation of MGP sites through rates. At June 30, 2019, deferred amounts, net of amounts previously recovered through rates and insurance settlements, totaled $23 million and are included in regulatory assets.

Abandoned NND Project

A description of events and circumstances leading up to DESC's abandonment of the NND Project and subsequent regulatory, legislative, legal and investigative proceedings, as well as related impairments of NND Project and other costs are described in Note 11 in DESC's Annual Report on Form 10-K for the year ended December 31, 2018.

SCANA Merger Approval Order

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

•	A charge of $105 million ($79 million net of tax) related to certain assets that had been constructed in connection with the NND Project for which DESC committed to forgo recovery.

•

A regulatory liability for refunds and restitution of amounts previously collected from retail electric customers of $1.0 billion pre-tax ($756 million net of tax), recorded as a reduction in operating revenue, which will be credited to customers over an estimated 11 years. In addition, a previously existing regulatory liability of $1.0 billion will be credited to customers over 20 years. These refunds include amounts to be refunded to customers related to the monetization of guaranty settlement described in Note 2.

•	A regulatory liability for refunds to natural gas customers totaling $2 million pre-tax ($2 million net of tax).

•	A tax charge of $198 million related to $264 million of regulatory assets for which DESC committed to forgo recovery.

Further, except for rate adjustments for fuel and environmental costs, DSM costs, and other rates routinely adjusted on an annual or biannual basis, DESC will freeze retail electric base rates at current levels until January 1, 2021.

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 June 30, 2019, such investment in these assets included $323 million within utility plant, net and $27 million within regulatory assets, which amount represents certain deferred operating costs. The South Carolina Commission approved deferral of these operating costs related to the investment until recovery of the transmission capital costs and associated deferred operating costs is addressed in a future rate proceeding. DESC believes these transmission capital and deferred operating costs are probable of recovery; however, if the South Carolina Commission were to disallow recovery of or a reasonable return on all or a portion of them, an impairment charge equal to the disallowed costs may be required.

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 $278 million included within reserves for litigation and regulatory proceedings at June 30, 2019. During the three and six months ended June 30, 2019 the Consolidated Statements of Comprehensive Income (Loss) includes charges of $100 million ($75 million after-tax) and $266 million ($200 million after-tax), respectively, included within impairment of assets and other charges.

Ratepayer Class Actions

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

In December 2018, the State Court of Common Pleas in Hampton County entered an order granting preliminary approval of a class action settlement and a stay of pre-trial proceedings in the DESC Ratepayer Case. The settlement agreement, contingent upon the closing of the SCANA Combination, provided that SCANA and DESC would establish an escrow account and proceeds from the escrow account would be distributed to the class members, after payment of certain taxes, attorneys' fees and other expenses and administrative costs. The escrow account would include (1) up to $2.0 billion, net of a credit of up to $2.0 billion in future electric bill relief, which would inure to the benefit of the escrow account in favor of class members over a period of time established by the South Carolina Commission in its order related to matters before the South Carolina Commission related to the NND Project, (2) a cash payment of $115 million and (3) the transfer of certain DESC-owned real estate or sales proceeds from the sale of such properties, which counsel for the DESC Ratepayer Class estimate to have an aggregate value between $60 million and $85 million. At the closing of the SCANA Combination, SCANA and DESC funded the cash payment portion of the escrow account. The court held a fairness hearing on the settlement in May 2019. In June 2019, the court entered an order granting final approval of the settlement, which order became effective July 2019. In July 2019, DESC transferred $117 million representing the cash payment, plus accrued interest, to the plaintiffs. In addition, property with a net recorded value of $42 million will be transferred to the plaintiffs as soon as practicable 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. 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 claims are similar to the Santee Cooper Ratepayer 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 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. 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 plantiffs who were not certified as part of the class action filed a separate case. In those cases, the plaintiffs allege, among other things, that SCANA, 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 $75 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 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.

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.

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 are 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. DESC does not believe that the claims asserted related to the IAA Period will exceed the amounts previously funded for the currently asserted IAA-related claims, whether relating to claims already paid or those remaining to be paid. DESC intends to oppose any previously unasserted claim that is asserted against it, whether directly or indirectly by a claim through 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.

Leases

6 Months Ended

Jun. 30, 2019

Leases [Abstract]

Leases

12. LEASES

At June 30, 2019, DESC had the following lease assets and liabilities recorded in the Consolidated Balance Sheets:

(millions)	June 30, 2019
Lease assets:
Operating lease assets⁽¹⁾	$	20
Finance lease assets⁽²⁾		28
Total lease assets	$	48
Lease liabilities:
Operating lease - current⁽³⁾	$	2
Operating lease - noncurrent⁽⁴⁾		16
Finance lease - current⁽⁵⁾		7
Finance lease - noncurrent⁽⁶⁾		22
Total lease liabilities	$	47

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

(2)	^{Included in utility plant, net, in the Consolidated Balance Sheets, net of $20 million of accumulated amortization at June 30, 2019.}

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

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

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

(6)	^{Included in long-term debt in the Consolidated Balance Sheets.}

For the three and six months ended June 30, 2019, total lease cost consisted of the following:

	Three Months Ended		Six Months Ended
(millions)	June 30, 2019		June 30, 2019
Finance lease cost:
Amortization	$	2	$	4
Interest		—		—
Operating lease cost		—		1
Short-term lease cost		1		1
Variable lease cost		—		—
Total lease cost	$	3	$	6

For the six months ended June 30, 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:

	Six Months Ended
(millions)	June 30, 2019
Operating cash flows from finance leases	$	—
Operating cash flows from operating leases		2
Financing cash flows from finance leases		4

At June 30, 2019, the weighted average remaining lease term and weighted average discount rate for finance and operating leases were as follows:

	June 30, 2019
Weighted average remaining lease term - finance leases	5 years
Weighted average remaining lease term - operating leases	21 years
Weighted average discount rate - finance leases		2.97	%
Weighted average discount rate - operating leases		4.53	%

Lease liabilities have the following scheduled maturities:

(millions)	Operating			Finance
2019	$	2		$	4
2020		2			8
2021		2			6
2022		1			5
2023		1			3
After 2023		22			5
Total undiscounted lease payments		30			31
Present value adjustment		(12	)		(2	)
Present value of lease liabilities	$	18		$	29

Operating Segments

6 Months Ended

Jun. 30, 2019

Segment Reporting [Abstract]

Operating Segments

13. OPERATING SEGMENTS

Operating segments include Electric Operations and Gas Distribution and are organized primarily on the basis of products and services sold.

In connection with the SCANA Combination, effective January 2019, reportable segments were changed to include a Corporate and Other segment and to utilize comprehensive income (loss) as the measure of segment profitability. The Corporate and Other segment includes specific items attributable to DESC's operating segments that are not included in profit measures evaluated by executive management in assessing the segments' performance or in allocating resources. Corresponding amounts in prior periods have been recast to conform to the current presentation.

In the six months ended June 30, 2019, DESC reported after-tax net expenses of $1.3 billion for specific items in the Corporate and Other segment, with $1.4 billion attributable to its operating segments.

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

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

•	$266 million ($200 million after-tax) of charges associated with litigation, attributable to Electric Operations;

•	A $198 million tax charge for $264 million of income tax-related regulatory assets for which DESC committed to forgo recovery, attributable to Electric Operations;

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

•	$72 million ($60 million after-tax) of merger and integration-related costs associated with the SCANA Combination, including a $62 million ($47 million after-tax) charge related to a voluntary retirement program, attributable to:

•

Electric Operations ($55 million after-tax); and

•

Gas Distribution ($5 million after-tax); and

•	$63 million tax charges for changes in unrecognized tax benefits, attributable to Electric Operations.

(millions)	External Revenue			Comprehensive Income (Loss) Available (Attributable) to Common Shareholder
Three Months Ended June 30, 2019
Electric Operations	$	620		$	104
Gas Distribution		78			(8	)
Corporate and Other		—			(166	)
Adjustments/Eliminations		—			(8	)
Consolidated Total	$	698		$	(78	)

Three Months Ended June 30, 2018
Electric Operations	$	553		$	30
Gas Distribution		79			(3	)
Corporate and Other		—			4
Adjustments/Eliminations		—			(5	)
Consolidated Total	$	632		$	26

Six Months Ended June 30, 2019
Electric Operations	$	1,147		$	152
Gas Distribution		225			14
Corporate and Other		(1,009	)		(1,339	)
Adjustments/Eliminations		—			(14	)
Consolidated Total	$	363		$	(1,187	)

Six Months Ended June 30, 2018
Electric Operations	$	1,100		$	130
Gas Distribution		234			29
Corporate and Other		—			—
Adjustments/Eliminations		—			(9	)
Consolidated Total	$	1,334		$	150

Affiliated Transactions

6 Months Ended

Jun. 30, 2019

Affiliated and Related Party Transactions

14. AFFILIATED AND RELATED PARTY TRANSACTIONS

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

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

DESS, on behalf of itself and its parent company, 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 Income (Loss).

	Three Months Ended June 30,				Six Months Ended June 30,
(millions)	2019		2018		2019		2018
Purchases of coal from affiliate	$	34	$	45	$	62	$	77
Sales of coal to affiliate		34		45		62		77
Purchases of fuel used in electric generation from affiliate		10		29		43		60
Direct and allocated costs from services company affiliate⁽¹⁾		82		76		140		135
Operating Revenues - Electric from sales to affiliate		1		1		2		2
Operating Expenses - Other taxes from affiliate		1		1		3		3

(1)	^{Includes capitalized expenditures of $11 million for both the three months ended June 30, 2019 and 2018, and $20 million and $19 million for the six months ended June 30, 2019 and 2018, respectively.}

(millions)	June 30, 2019		December 31, 2018
Receivable from Canadys Refined Coal, LLC	$	10	$	7
Payable to Canadys Refined Coal, LLC		10		7
Payable to SCANA Energy Marketing, Inc.		—		14
Payable to DESS		63		38

In connection with the SCANA Combination, purchases from certain entities owned by Dominion Energy became affiliated transactions. During the three and six months ended June 30, 2019, DESC purchased electricity generated by two such affiliates, Ridgeland Solar Farm I, LLC and Moffett Solar 1, LLC, totaling $3 million and $4 million, respectively, which is recorded as purchased power in the Consolidated Statements of Comprehensive Income (Loss). At June 30, 2019, DESC had accounts payable balances to these affiliates totaling $1 million. In addition, during the three and six months ended June 30, 2019, DESC incurred demand and transportation charges from Dominion Energy Carolina Gas Transmission, LLC totaling $17 million and $32 million, respectively, of which $6 million and $9 million, respectively, is recorded as fuel used in electric generation and $11 million and $23 million, respectively, is recorded as gas purchased for resale in the Consolidated Statements of Comprehensive Income (Loss). At June 30, 2019, DESC had an accounts payable balance due to this affiliate totaling $5 million.

Borrowings from an affiliate are described in Note 5.

Other Income (Expense), Net

6 Months Ended

Jun. 30, 2019

Income Statement [Abstract]

Other Income (Expense), Net

15. OTHER INCOME (EXPENSE), NET

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

	Three Months Ended June 30,						Six Months Ended June 30,
(millions)	2019			2018			2019			2018
Revenues from contracts with customers	$	2		$	2		$	3		$	3
Other income		2			4			6			130
Other expense		(15	)		(5	)		(25	)		(12	)
Allowance for equity funds used during construction		2			1			2			4
Other income (expense), net	$	(9	)	$	2		$	(14	)	$	125

Other income in 2018 includes gains from the settlement of interest rate derivatives of $115 million (see Note 7). Non-service cost components of pension and other postretirement benefits are included in other expense.

Summary of Significant Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Jun. 30, 2019
Accounting Policies [Abstract]
Basis of Consolidation and Variable Interest Entities	Basis of Consolidation and Variable Interest Entities DESC has determined that it has a controlling financial interest in each of GENCO and Fuel Company (which are considered to be VIEs) and, accordingly, DESC's Consolidated Financial Statements include, after eliminating intercompany balances and transactions, the accounts of DESC, GENCO and Fuel Company. 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, pursuant to a FERC-approved tariff, solely to DESC under the terms of a power purchase agreement and related operating agreement. The effects of these transactions are eliminated in consolidation. GENCO’s property (carrying value of $497 million) previously served as collateral for its long-term borrowings. In May 2019, GENCO redeemed its 5.49% senior secured notes and was able to release the first mortgage lien in June 2019 that had previously secured these notes. Fuel Company acquires, owns and provides financing for DESC’s nuclear fuel, certain fossil fuels and emission and other environmental allowances. See also Note 5. 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 14 for amounts attributable to affiliates. Significant Accounting Policies There have been no significant changes from Note 1 to the Consolidated Financial Statements in DESC's Annual Report on Form 10-K for the year ended December 31, 2018, with the exception of the item described below.
Leases	Leases DESC leases certain assets including vehicles, real estate, office equipment and other assets under both operating and finance leases. For operating leases, rent expense is recognized on a straight-line basis over the term of the lease agreement, subject to regulatory framework. Rent expense associated with operating leases, short-term leases and variable leases is primarily recorded in other operations and maintenance expense in the Consolidated Statements of Comprehensive Income (Loss). Rent expense associated with finance leases results in the separate presentation of interest expense on the lease liability and amortization expense of the related right-of-use asset in the Consolidated Statements of Comprehensive Income (Loss). Amortization expense and interest charges associated with finance leases are recorded in depreciation and amortization and interest charges, respectively, in the Consolidated Statements of Comprehensive Income (Loss) or deferred within regulatory assets in the Consolidated Balance Sheets. Certain leases include one or more options to renew, with renewal terms that can extend the lease from one to 70 years. The exercise of renewal options is solely at DESC's discretion and is included in the lease term if the option is reasonably certain to be exercised. A right-of-use asset and corresponding lease liability for leases with original lease terms of one year or less are not included in the Consolidated Balance Sheets, unless such leases contain renewal options that DESC is reasonably certain will be exercised. The determination of the discount rate utilized has a significant impact on the calculation of the present value of the lease liability included in the Consolidated Balance Sheets. For DESC’s leased assets, the discount rate implicit in the lease is generally unable to be determined from a lessee perspective. As such, DESC uses internally-developed incremental borrowing rates as a discount rate in the calculation of the present value of the lease liability. The incremental borrowing rates are determined based on an analysis of DESC's publicly available secured borrowing rates over various lengths of time that most closely corresponds to DESC's lease maturities.
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards In February 2016, the Financial Accounting Standards Board 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 12 for additional information.

Rate and Other Regulatory Matters (Tables)

6 Months Ended

Jun. 30, 2019

Regulated Operations [Abstract]

Schedule of Regulatory Assets and Liabilities

	June 30,		December 31,
(millions)	2019		2018
Regulatory assets:
NND Project costs	$	138	$	127
Deferred employee benefit plan costs		16		16
Other unrecovered plant		14		14
DSM programs		16		14
Other		75		52
Regulatory assets - current		259		223
NND Project costs		2,572		2,641
AROs		324		380
Deferred employee benefit plan costs		230		256
Deferred losses on interest rate derivatives		308		442
Other unrecovered plant		73		79
DSM programs		53		51
Environmental remediation costs		21		24
Deferred storm damage costs		34		35
Deferred transmission operating costs		27		15
Other		117		123
Regulatory assets - noncurrent		3,759		4,046
Total regulatory assets	$	4,018	$	4,269
Regulatory liabilities:
Monetization of guaranty settlement	$	67	$	61
Income taxes refundable through future rates		48		52
Reserve for refunds to electric utility customers		136		—
Other		18		13
Regulatory liabilities - current		269		126
Monetization of guaranty settlement		1,003		1,037
Income taxes refundable through future rates		826		607
Asset removal costs		552		541
Deferred gains on interest rate derivatives		77		75
Reserve for refunds to electric utility customers		813		—
Other		6		4
Regulatory liabilities - noncurrent		3,277		2,264
Total regulatory liabilities	$	3,546	$	2,390

Revenue Recognition (Tables)

6 Months Ended

Jun. 30, 2019

Revenue Recognition And Deferred Revenue [Abstract]

Disaggregation of Revenue

DESC has disaggregated operating revenues by customer class as follows:

	Three Months Ended					Three Months Ended				Six Months Ended				Six Months Ended
	June 30, 2019					June 30, 2018				June 30, 2019				June 30, 2018
(millions)	Electric			Gas		Electric		Gas		Electric		Gas		Electric		Gas
Customer class:
Residential	$	281		$	31	$	243	$	34	$	10	$	109	$	495	$	120
Commercial		206			23		171		22		67		61		340		61
Industrial		100			19		106		21		18		45		191		45
Other		35			4		30		2		45		7		68		7
Revenues from contracts with customers		622			77		550		79		140		222		1,094		233
Other revenues		(1	)		—		3		—		1		—		6		1
Total Operating Revenues	$	621		$	77	$	553	$	79	$	141	$	222	$	1,100	$	234

Long-Term and Short-Term Debt and Liquidity (Tables)

6 Months Ended

Jun. 30, 2019

Debt Disclosure [Abstract]

Schedule of Line of Credit Facilities

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

(millions)

Facility Limit

Outstanding

Commercial Paper

Outstanding

Letters of Credit

At June 30, 2019

$

1,000

$

—

$

—

(millions)

Facility Limit⁽¹⁾

Outstanding

Commercial Paper

Outstanding

Letters of Credit

At December 31, 2018

$

1,200

$

73

$

—

(1)	Included $500 million related to Fuel Company. In February 2019, Fuel Company's commercial paper program and its credit facility were terminated.

Derivative Financial Instruments (Tables)

6 Months Ended

Jun. 30, 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:

	June 30, 2019								December 31, 2018
	Gross Amounts Not Offset in the Consolidated Balance Sheet								Gross Amounts Not Offset in the Consolidated Balance Sheet
(millions)	Gross Liabilities Presented in the Consolidated Balance Sheet		Financial Instruments		Cash Collateral Paid		Net Amounts		Gross Liabilities Presented in the Consolidated Balance Sheet		Financial Instruments		Cash Collateral Paid		Net Amounts
Interest rate contracts:
Over-the-counter	$	19	$	—	$	19	$	—	$	11	$	—	$	11	$	—
Total derivatives	$	19	$	—	$	19	$	—	$	11	$	—	$	11	$	—

Schedule of Volume of Derivative Activity

The following table presents the volume of derivative activity at June 30, 2019. These volumes are based on open derivative positions and represent the combined absolute value of their long and short positions.

		Current				Noncurrent
Interest rate⁽¹⁾		$	—			$	71,400,000

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

Fair Value of Derivatives

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

(millions)	Fair Value - Derivatives under Hedge Accounting		Fair Value - Derivatives not under Hedge Accounting		Total Fair Value
At June 30, 2019
Current Liabilities
Interest rate	$	1	$	1	$	2
Total current derivative liabilities⁽¹⁾		1		1		2
Noncurrent Liabilities
Interest rate		11		6		17
Total noncurrent derivative liabilities⁽²⁾		11		6		17
Total derivative liabilities	$	12	$	7	$	19
At December 31, 2018
Current Liabilities
Interest rate	$	1	$	—	$	1
Total current derivative liabilities⁽¹⁾		1		—		1
Noncurrent Liabilities
Interest rate		7		3		10
Total noncurrent derivative liabilities⁽²⁾		7		3		10
Total derivative liabilities	$	8	$	3	$	11

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

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

Derivatives in Cash Flow Hedging Relationships

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

Derivatives in Cash Flow Hedging Relationships

(millions)	Gain (loss) Reclassified from Deferred Accounts into Income			Increase (Decrease) in Derivatives Subject to Regulatory Treatment⁽¹⁾
Three Months Ended June 30, 2019
Derivative type and location of gains (losses):
Interest rate⁽²⁾	$	—		$	—
Total	$	—		$	—
Three Months Ended June 30, 2018
Derivative type and location of gains (losses):
Interest rate⁽²⁾	$	(1	)	$	—
Total	$	(1	)	$	—
Six Months Ended June 30, 2019
Derivative type and location of gains (losses):
Interest rate⁽²⁾	$	—		$	(2	)
Total	$	—		$	(2	)
Six Months Ended June 30, 2018
Derivative type and location of gains (losses):
Interest rate⁽²⁾	$	(1	)	$	2
Total	$	(1	)	$	2

(1)	Represents net derivative activity deferred into and amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/ liabilities have no associated effect in the Consolidated Statements of Comprehensive Income (Loss).

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

Derivatives Not Designated as Hedging Instruments

(millions)	Increase (Decrease) in Derivatives Subject to Regulatory Treatment⁽¹⁾						Amount of Gain (Loss) Recognized in Income on Derivatives⁽²⁾
Three Months Ended June 30,	2019			2018		Location	2019		2018
Derivative type and location of gains (losses):
Interest rate contracts:						Interest charges	$	—	$	(1	)
						Other income		—		—
Total interest rate contracts	$	(2	)	$	—		$	—	$	(1	)
Six Months Ended June 30,
Derivative type and location of gains (losses):
Interest rate contracts:						Interest charges	$	—	$	(1	)
						Other income		—		115
Total interest rate contracts	$	(3	)	$	65		$	—	$	114

(1)	Represents net derivative activity deferred into and amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/liabilities have no associated effect in the Consolidated Statements of Comprehensive Income (Loss).

(2)	^{Includes derivative activity amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/liabilities have no associated effect in the Consolidated Statements of Comprehensive Income (Loss).}

Derivative Contracts with Credit Contingent Features

(millions)	June 30, 2019		December 31, 2018
in Net Liability Position
Aggregate fair value of derivatives in net liability position	$	19	$	11
Fair value of collateral already posted		19		11
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	$	—	$	—

- Definition

Tabular disclosure of credit derivatives which includes information by sellers of credit derivatives, about each credit derivative, or each group of similar credit derivatives, including (a) the nature of the credit derivative - its term, how it arose, the events or circumstances that would require the seller to perform under the credit derivative, and the current status of the payment/performance risk of the credit derivative; (b) the maximum potential amount of future payments (undiscounted) the seller could be required to make under the credit derivative; (c) the current fair value of the credit derivative; and (d) the nature of any recourse provisions under the credit derivative, and any assets held either as collateral or by third parties. A credit derivative is a derivative instrument (1) in which one or more of its underlyings are related to the credit risk of a specified entity (or a group of entities) or an index based on the credit risk of a group of entities and (2) that exposes the seller to potential loss from credit-risk-related events specified in the contract. Examples of credit derivatives within the scope of this paragraph include, but are not limited to, credit default swaps, credit spread options, and credit index products; also includes a hybrid instrument that has an embedded credit derivative (for example, but not limited to, a credit-linked note).

+ References + Details

Fair Value Measurements, Including Derivatives (Tables)

6 Months Ended

Jun. 30, 2019

Fair Value Disclosures [Abstract]

Schedule of Carrying Values and Estimated Fair Values of Debt Instruments

For financial instruments that are not recorded at fair value, the carrying amounts and estimated fair values are as follows:

June 30, 2019

December 31, 2018

(millions)

Carrying

Amount

Estimated

Fair Value⁽¹⁾

Carrying

Amount

Estimated

Fair Value⁽²⁾

Long-term debt⁽³⁾

$

4,171

$

4,982

$

5,146

$

5,470

(1)

Fair value is estimated using market prices, where available, and interest rates currently available for issuance of debt with similar terms and remaining maturities. All fair value measurements are classified as Level 2. The carrying amount of debt issuances with short-term maturities and variable rates refinanced at current market rates is a reasonable estimate of their fair value.

(2)

Fair value is estimated based on net present value calculations using independently sourced market data that incorporate a developed discount rate using similarly rated long-term debt, along with benchmark interest rates. All fair value measurements are classified as Level 2. The carrying amount of debt issuances with short-term maturities and variable rates refinanced at current market rates is a reasonable estimate of their fair value.

(3)	Carrying amount includes amounts which represent the unamortized debt issuance costs and discount or premium.

Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2019

Compensation And Retirement Disclosure [Abstract]

Net Periodic Benefit Cost (Credit)

Components of net periodic benefit cost recorded by DESC were as follows:

(millions)	Pension Benefits						Other Postretirement Benefits
Three Months Ended June 30,	2019			2018			2019		2018
Service cost	$	3		$	4		$	—	$	1
Interest cost		7			7			2		2
Expected return on assets		(10	)		(12	)		—		—
Amortization of actuarial losses		3			3			—		1
Curtailment⁽¹⁾		6			—			3		—
Net periodic benefit cost	$	9		$	2		$	5	$	4
Six Months Ended June 30,
Service cost	$	7		$	8		$	1	$	2
Interest cost		15			15			4		4
Expected return on assets		(20	)		(24	)		—		—
Amortization of actuarial losses		7			5			—		1
Curtailment⁽¹⁾		6			—			3		—
Net periodic benefit cost	$	15		$	4		$	8	$	7

(1) Related to a voluntary retirement program.

Leases (Tables)

6 Months Ended

Jun. 30, 2019

Leases [Abstract]

Schedule Of Lease Assets and Liabilities Recorded in Consolidated Balance Sheets

At June 30, 2019, DESC had the following lease assets and liabilities recorded in the Consolidated Balance Sheets:

(millions)	June 30, 2019
Lease assets:
Operating lease assets⁽¹⁾	$	20
Finance lease assets⁽²⁾		28
Total lease assets	$	48
Lease liabilities:
Operating lease - current⁽³⁾	$	2
Operating lease - noncurrent⁽⁴⁾		16
Finance lease - current⁽⁵⁾		7
Finance lease - noncurrent⁽⁶⁾		22
Total lease liabilities	$	47

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

(2)	^{Included in utility plant, net, in the Consolidated Balance Sheets, net of $20 million of accumulated amortization at June 30, 2019.}

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

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

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

(6)	^{Included in long-term debt in the Consolidated Balance Sheets.}

Summary of Total Lease Cost

For the three and six months ended June 30, 2019, total lease cost consisted of the following:

	Three Months Ended		Six Months Ended
(millions)	June 30, 2019		June 30, 2019
Finance lease cost:
Amortization	$	2	$	4
Interest		—		—
Operating lease cost		—		1
Short-term lease cost		1		1
Variable lease cost		—		—
Total lease cost	$	3	$	6

Cash Paid for Amounts Included in Measurement of Lease Liabilities

For the six months ended June 30, 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:

	Six Months Ended
(millions)	June 30, 2019
Operating cash flows from finance leases	$	—
Operating cash flows from operating leases		2
Financing cash flows from finance leases		4

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

At June 30, 2019, the weighted average remaining lease term and weighted average discount rate for finance and operating leases were as follows:

	June 30, 2019
Weighted average remaining lease term - finance leases	5 years
Weighted average remaining lease term - operating leases	21 years
Weighted average discount rate - finance leases		2.97	%
Weighted average discount rate - operating leases		4.53	%

Schedule of Maturity Analysis of Operating and Finance Lease Liabilities

Lease liabilities have the following scheduled maturities:

(millions)	Operating			Finance
2019	$	2		$	4
2020		2			8
2021		2			6
2022		1			5
2023		1			3
After 2023		22			5
Total undiscounted lease payments		30			31
Present value adjustment		(12	)		(2	)
Present value of lease liabilities	$	18		$	29

Operating Segments (Tables)

6 Months Ended

Jun. 30, 2019

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment

(millions)	External Revenue			Comprehensive Income (Loss) Available (Attributable) to Common Shareholder
Three Months Ended June 30, 2019
Electric Operations	$	620		$	104
Gas Distribution		78			(8	)
Corporate and Other		—			(166	)
Adjustments/Eliminations		—			(8	)
Consolidated Total	$	698		$	(78	)

Three Months Ended June 30, 2018
Electric Operations	$	553		$	30
Gas Distribution		79			(3	)
Corporate and Other		—			4
Adjustments/Eliminations		—			(5	)
Consolidated Total	$	632		$	26

Six Months Ended June 30, 2019
Electric Operations	$	1,147		$	152
Gas Distribution		225			14
Corporate and Other		(1,009	)		(1,339	)
Adjustments/Eliminations		—			(14	)
Consolidated Total	$	363		$	(1,187	)

Six Months Ended June 30, 2018
Electric Operations	$	1,100		$	130
Gas Distribution		234			29
Corporate and Other		—			—
Adjustments/Eliminations		—			(9	)
Consolidated Total	$	1,334		$	150

Affiliated Transactions (Tables)

6 Months Ended

Jun. 30, 2019

Schedule of Affiliated Transactions

Amounts expensed are primarily recorded in other operations and maintenance - affiliated suppliers and other income (expense), net in the Consolidated Statements of Comprehensive Income (Loss).

	Three Months Ended June 30,				Six Months Ended June 30,
(millions)	2019		2018		2019		2018
Purchases of coal from affiliate	$	34	$	45	$	62	$	77
Sales of coal to affiliate		34		45		62		77
Purchases of fuel used in electric generation from affiliate		10		29		43		60
Direct and allocated costs from services company affiliate⁽¹⁾		82		76		140		135
Operating Revenues - Electric from sales to affiliate		1		1		2		2
Operating Expenses - Other taxes from affiliate		1		1		3		3

(1)	^{Includes capitalized expenditures of $11 million for both the three months ended June 30, 2019 and 2018, and $20 million and $19 million for the six months ended June 30, 2019 and 2018, respectively.}

Schedule of Affiliated Transactions

(millions)	June 30, 2019		December 31, 2018
Receivable from Canadys Refined Coal, LLC	$	10	$	7
Payable to Canadys Refined Coal, LLC		10		7
Payable to SCANA Energy Marketing, Inc.		—		14
Payable to DESS		63		38

Other Income (Expense), Net (Tables)

6 Months Ended

Jun. 30, 2019

Income Statement [Abstract]

Components of Other Income (Expense), Net

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

	Three Months Ended June 30,						Six Months Ended June 30,
(millions)	2019			2018			2019			2018
Revenues from contracts with customers	$	2		$	2		$	3		$	3
Other income		2			4			6			130
Other expense		(15	)		(5	)		(25	)		(12	)
Allowance for equity funds used during construction		2			1			2			4
Other income (expense), net	$	(9	)	$	2		$	(14	)	$	125

Summary of Significant Accounting Policies (Narrative) (Detail)
$ in Millions

6 Months Ended

Jun. 30, 2019

USD ($)

MW

May 31, 2019

Jan. 01, 2019

USD ($)

Dec. 31, 2018

USD ($)

Carrying value of property

$ 71

$ 72

Option to extend, existence, operating lease

true

Operating lease, right of use asset

$ 20

^[1]

$ 19

Operating lease liability

$ 18

$ 19

Minimum [Member]

Power Generation Capacity Megawatts | MW

25

1 year

70 years

Power Generation Capacity Megawatts | MW

605

Carrying value of property

$ 497

Genco | 5.49% Senior Secured Note Due 2024

Debt instrument, interest rate

5.49%

[1]	Included in other deferred debits and other assets in the Consolidated Balance Sheets.

Rate and Other Regulatory Matters (Narrative) (Detail) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Rate And Other Regulatory Matters [Line Items]
Interest charges			$ 63	$ 76	$ 136	$ 152
Operating expense			681	525	$ 1,489	$ 1,107
South Carolina Commission order, revenue requirement under RSA	$ 437
South Carolina Commission order, increase in natural gas rates under RSA	$ 7
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
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
NND Project Costs [Member]
Rate And Other Regulatory Matters [Line Items]
Electric service customers over period					20 years
End period for recovery					2039
Asset Retirement Obligation Costs [Member]
Rate And Other Regulatory Matters [Line Items]
Recovery period of regulatory asset					106 years
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
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
Reserve For Refunds To Electric Utility Customers [Member]
Rate And Other Regulatory Matters [Line Items]
Electric service customers over period					11 years
FERC
Rate And Other Regulatory Matters [Line Items]
Reserves included within revenue subject to refund			10
Interest charges			6
Interest charge, after tax			$ 4

Rate and Other Regulatory Matters (Schedule of Regulatory Assets) (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Regulatory Assets
Regulatory assets, current	$ 259	$ 223
Regulatory assets, noncurrent	3,759	4,046
Total regulatory assets	4,018	4,269
NND Project Costs [Member]
Regulatory Assets
Regulatory assets, current	138	127
Regulatory assets, noncurrent	2,572	2,641
Deferred Employee Benefit Plan Costs [Member]
Regulatory Assets
Regulatory assets, current	16	16
Regulatory assets, noncurrent	230	256
Other Unrecovered Plant [Member]
Regulatory Assets
Regulatory assets, current	14	14
Regulatory assets, noncurrent	73	79
Demand Side Management Programs [Member]
Regulatory Assets
Regulatory assets, current	16	14
Regulatory assets, noncurrent	53	51
Other Regulatory Assets [Member]
Regulatory Assets
Regulatory assets, current	75	52
Regulatory assets, noncurrent	117	123
Asset Retirement Obligation Costs [Member]
Regulatory Assets
Regulatory assets, noncurrent	324	380
Deferred Losses On Interest Rate Derivatives [Member]
Regulatory Assets
Regulatory assets, noncurrent	308	442
Environmental Remediation Costs [Member]
Regulatory Assets
Regulatory assets, noncurrent	21	24
Deferred Storm Damage Costs [Member]
Regulatory Assets
Regulatory assets, noncurrent	34	35
Deferred Transmission Operating Costs [Member] [Domain]
Regulatory Assets
Regulatory assets, noncurrent	$ 27	$ 15

Rate and Other Regulatory Matters (Schedule of Regulatory Liabilities) (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Regulatory Liabilities
Regulatory liability, current	$ 269	$ 126
Regulatory liability, noncurrent	3,277	2,264
Total regulatory liabilities	3,546	2,390
Reserve For Refunds To Electric Utility Customers [Member]
Regulatory Liabilities
Regulatory liability, current	136	0
Regulatory liability, noncurrent	813	0
Monetization Of Guaranty Settlement [Member]
Regulatory Liabilities
Regulatory liability, current	67	61
Regulatory liability, noncurrent	1,003	1,037
Income Taxes Refundable Through Future Rates [Member]
Regulatory Liabilities
Regulatory liability, current	48	52
Regulatory liability, noncurrent	826	607
Other Regulatory Liability [Member]
Regulatory Liabilities
Regulatory liability, current	18	13
Regulatory liability, noncurrent	6	4
Asset Retirement Obligation Costs [Member]
Regulatory Liabilities
Regulatory liability, noncurrent	552	541
Deferred Gains On Interest Rate Derivatives [Member]
Regulatory Liabilities
Regulatory liability, noncurrent	$ 77	$ 75

Revenue Recognition (Disaggregation of Revenue) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating revenue from contracts with customers	$ 2	$ 2	$ 3	$ 3
Total operating revenues	698	632	363	1,334
Residential [Member] \| Electric Operations
Operating revenue from contracts with customers	281	243	10	495
Residential [Member] \| Gas Distribution
Operating revenue from contracts with customers	31	34	109	120
Commercial [Member] \| Electric Operations
Operating revenue from contracts with customers	206	171	67	340
Commercial [Member] \| Gas Distribution
Operating revenue from contracts with customers	23	22	61	61
Industrial [Member] \| Electric Operations
Operating revenue from contracts with customers	100	106	18	191
Industrial [Member] \| Gas Distribution
Operating revenue from contracts with customers	19	21	45	45
Other \| Electric Operations
Operating revenue from contracts with customers	35	30	45	68
Other \| Gas Distribution
Operating revenue from contracts with customers	4	2	7	7
Electric Operations
Operating revenue from contracts with customers	622	550	140	1,094
Other revenues	(1)	3	1	6
Total operating revenues	621	553	141	1,100
Gas Distribution
Operating revenue from contracts with customers	77	79	222	233
Other revenues	0	0	0	1
Total operating revenues	$ 77	$ 79	$ 222	$ 234

Revenue Recognition (Narrative) (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
Contract liability balances	$ 5	$ 4
Revenue recognized from contract liability balances	$ 3

Equity (Narrative) (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		6 Months Ended
	Jun. 30, 2019	Feb. 28, 2019	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Stockholders Equity Note [Abstract]
Common stock, par value	$ 0		$ 0
Common stock, shares authorized	50,000,000		50,000,000
Shares, issued	40,300,000		40,300,000
Common stock, shares outstanding	40,300,000		40,300,000		40,300,000
Preferred stock, par value	$ 0		$ 0
Preferred stock, shares authorized	20,000,000		20,000,000
Preferred stock, shares issued	1,000		1,000
Preferred stock, shares outstanding	1,000		1,000
Contributions from parent	$ 100	$ 675	$ 775	$ 20
Retained earnings, restricted	$ 126		$ 126		$ 115

Long-Term and Short-Term Debt and Liquidity (Narrative) (Detail) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended
	May 31, 2019	Apr. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019	Feb. 28, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Aggregate purchase price of first mortgage bonds								$ 1,200,000,000
Loss on reacquired debt					$ 187,000,000
Redemption of remaining principal outstanding plus accrued interest					1,247,000,000	$ 170,000,000
Equity capital contribution returned to parent					$ 20,000,000	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
Commercial paper maturity period		2020-04
Interest charges			$ 63,000,000	$ 76,000,000	$ 136,000,000	$ 152,000,000
Interest income from money pool transactions			3,000,000		6,000,000
Interest expense from money pool transactions			3,000,000		6,000,000
Money pool borrowings due to affiliates			224,000,000		224,000,000				$ 282,000,000
Investments due from affiliates			9		9				$ 353,000,000
Maximum [Member]
Debt Instrument [Line Items]
Short term commercial paper maturity period		1 year
Letters of Credit
Debt Instrument [Line Items]
Facility limit			1,000,000,000.0		1,000,000,000.0
Dominion Energy
Debt Instrument [Line Items]
Short-term borrowings outstanding, maximum		$ 900,000,000
Short-term borrowings outstanding			61,000,000		61,000,000
Dominion Energy \| Maximum [Member]
Debt Instrument [Line Items]
Interest charges			1,000,000		1,000,000
Current Joint Revolving Credit Facility
Debt Instrument [Line Items]
Facility limit			1,000,000,000		1,000,000,000
Current Joint Revolving Credit Facility \| Dominion Energy
Debt Instrument [Line Items]
Facility limit							$ 6,000,000,000
Line of Credit Facility
Debt Instrument [Line Items]
Facility limit			500,000,000		500,000,000
Letters of Credit
Debt Instrument [Line Items]
Debt instrument, face amount			$ 68,000,000		68,000,000
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
3.05% Promissory Note due in May 2024 \| Genco
Debt Instrument [Line Items]
Debt instrument, face amount	$ 230,000,000
Debt instrument, interest rate	3.05%
Debt instrument, maturity date	2024-05
5.49% Senior Secured Note Due 2024 \| Genco
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 and Liquidity (Schedule of Line of Credit Facilities) (Detail) - USD ($)	Jun. 30, 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		$ 1,200,000,000
Outstanding Commercial Paper		73,000,000
Outstanding Letters of Credit		$ 0

Long-Term and Short-Term Debt and Liquidity (Schedule of Line of Credit Facilities) (Parenthetical) (Detail) $ in Millions	Dec. 31, 2018 USD ($)
Fuel Company
Debt Instrument [Line Items]
Facility limit	$ 500

Income Taxes (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
Income Taxes (Narrative) (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Taxes [Line Items]
Effective tax rate, percent				8.10%	20.50%
Effective tax rate, state and local income taxes, amount				$ 198
Income tax expense (benefit)	$ 15		$ 2	$ (103)	$ 41
Percentage of deductibility of interest expense				30.00%
State \| Prior Years
Income Taxes [Line Items]
Unrecognized tax benefits	24	$ 51		$ 24
Income tax expense (benefit)	$ 23	$ 40

Derivative Financial Instruments (Offsetting Liabilities) (Detail) - USD ($) $ in Millions	Jun. 30, 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)

Jun. 30, 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

[1]	Maturity is determined based on final settlement period.

Derivative Financial Instruments (Fair Value of Derivatives) (Detail) - USD ($)
$ in Millions

Jun. 30, 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

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

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

[1]	Current derivative liabilities are presented in other current liabilities in the Consolidated Balance Sheets.
[2]	Noncurrent derivative liabilities are presented in other deferred credits and other liabilities in the Consolidated Balance Sheets.

Derivative Financial Instruments (Derivatives in Cash Flow Hedging Relationships) (Detail) - Cash Flow Hedging [Member] - USD ($)
$ in Millions

3 Months Ended

6 Months Ended

Jun. 30, 2019

Jun. 30, 2018

Jun. 30, 2019

Jun. 30, 2018

Derivative [Line Items]

Gain (loss) Reclassified from Deferred Accounts into Income

$ 0

$ (1)

$ 0

$ (1)

Increase (Decrease) in Derivatives Subject to Regulatory Treatment

^[1]

0

(2)

2

Interest Rate Contract [Member]

Derivative [Line Items]

Gain (loss) Reclassified from Deferred Accounts into Income

^[2]

0

(1)

0

(1)

Increase (Decrease) in Derivatives Subject to Regulatory Treatment

^[1],[2]

$ 0

$ (2)

$ 2

[1]	Represents net derivative activity deferred into and amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/ liabilities have no associated effect in the Consolidated Statements of Comprehensive Income (Loss).
[2]	Amounts recorded in DESC’s Consolidated Statements of Comprehensive Income (Loss) are classified in interest charges.

Derivative Financial Instruments (Derivatives Not Designated as Hedging Instruments) (Detail) - Not Designated as Hedging Instrument [Member] - USD ($)
$ in Millions

3 Months Ended

6 Months Ended

Jun. 30, 2019

Jun. 30, 2018

Jun. 30, 2019

Jun. 30, 2018

Derivative [Line Items]

Increase (Decrease) in Derivatives Subject to Regulatory Treatment

^[1]

$ (2)

$ 0

$ (3)

$ 65

Amount of gain (loss) recognized in income on derivatives

^[2]

0

(1)

0

114

Other Income [Member]

Derivative [Line Items]

Amount of gain (loss) recognized in income on derivatives

^[2]

0

115

Interest Rate Contract [Member] | Interest Charges [Member]

Derivative [Line Items]

Amount of gain (loss) recognized in income on derivatives

^[2]

$ 0

$ (1)

$ 0

$ (1)

[1]	Represents net derivative activity deferred into and amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/liabilities have no associated effect in the Consolidated Statements of Comprehensive Income (Loss).
[2]	Includes derivative activity amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/liabilities have no associated effect in the Consolidated Statements of Comprehensive Income (Loss).

Derivative Financial Instruments (Derivative Contracts with Credit Contingent Features) (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Aggregate fair value of derivatives in net liability position	$ 19	$ 11
Fair value of collateral already posted	19	11
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	$ 0	$ 0

Fair Value Measurements, Including Derivatives (Narrative) (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Interest Rate Contract [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total liabilities	$ 19	$ 11

Fair Value Measurements, Including Derivatives (Schedule of Carrying Values and Estimated Fair Values of Debt Instruments) (Detail) - USD ($)
$ in Millions

Jun. 30, 2019

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Long-term debt, carrying amount

^[1]

$ 4,171

$ 5,146

Long-term debt, estimated fair value

^[1]

$ 4,982

^[2]

$ 5,470

^[3]

[1]

Carrying amount includes amounts which represent the unamortized debt issuance costs and discount or premium.

[2]

(1)

Fair value is estimated using market prices, where available, and interest rates currently available for issuance of debt with similar terms and remaining maturities. All fair value measurements are classified as Level 2. The carrying amount of debt issuances with short-term maturities and variable rates refinanced at current market rates is a reasonable estimate of their fair value.

[3]

(2)

Fair value is estimated based on net present value calculations using independently sourced market data that incorporate a developed discount rate using similarly rated long-term debt, along with benchmark interest rates. All fair value measurements are classified as Level 2. The carrying amount of debt issuances with short-term maturities and variable rates refinanced at current market rates is a reasonable estimate of their fair value.

Utility Plant and Nonutility Property (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended
	May 31, 2019	Sep. 30, 2019	Jun. 30, 2019
Utility Plant And Non Utility Property [Line Items]
Total consideration from sale of assets	$ 7
Contractual term of agreement to use brand			10 years
Summer
Utility Plant And Non Utility Property [Line Items]
Percentage of direct expenses			66.70%
Percentage of ownership interest	66.70%
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
Warranty Service Contract Assets \| Scenario Forecast
Utility Plant And Non Utility Property [Line Items]
Expected gain on sale of assets		$ 7
Expected gain on sale of assets, after tax		$ 5

Employee Benefit Plans (Net Periodic Benefit Cost (Credit) (Detail) - USD ($)
$ in Millions

3 Months Ended

6 Months Ended

Jun. 30, 2019

Jun. 30, 2018

Jun. 30, 2019

Jun. 30, 2018

Pension Benefits

Components of Net Periodic Benefit Cost

Service cost

$ 3

$ 4

$ 7

$ 8

Interest cost

7

15

Expected return on assets

(10)

(12)

(20)

(24)

Amortization of actuarial losses

3

7

5

Curtailment

^[1]

6

0

6

0

Net periodic benefit cost

9

2

15

4

Employee Benefit Plans (Narrative) (Detail) $ in Millions	6 Months Ended
Employee Benefit Plans (Narrative) (Detail) $ in Millions	Jun. 30, 2019 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Expected pension contributions for remaining fiscal year	No
Voluntary retirement program related charges	$ 62
Voluntary retirement program related charges net of tax	47
Increase in pension benefit obligation	16
Increase in accumulated postretirement benefit obligation	10
Increase in fair value of pension plan assets	27
Increase in net periodic benefit cost	$ 1
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate percentage	4.07%
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate percentage	4.08%
Other Operations and Maintenance Expense
Defined Benefit Plan Disclosure [Line Items]
Voluntary retirement program related charges	$ 50
Other Taxes
Defined Benefit Plan Disclosure [Line Items]
Voluntary retirement program related charges	3
Other Income (Expense), Net
Defined Benefit Plan Disclosure [Line Items]
Voluntary retirement program related charges	$ 9

Commitments and Contingencies (Narrative) (Detail)	1 Months Ended				3 Months Ended		6 Months Ended
Commitments and Contingencies (Narrative) (Detail)	Jul. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jul. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) State MW	Mar. 31, 2019 USD ($)	Jun. 30, 2019 USD ($) State Product MW	Jun. 30, 2018 USD ($)
Loss Contingencies [Line Items]
Number of states required to reduce emissions under CSAPR \| State					28		28
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		23,000,000
Impairment of assets and other charges						$ 105,000,000	371,000,000	$ 4,000,000
Asset impairment charges after tax						79,000,000
Customer refundable fees, alternative plan		$ 2,390,000,000			3,546,000,000		3,546,000,000
Regulatory liability for refunds to natural gas customers						2,000,000
Regulatory liability for refunds to natural gas customers, net of 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					323,000,000		323,000,000
Transmission assets related to BLRA regulatory assets					27,000,000		27,000,000
Reserves		11,000,000			278,000,000		278,000,000
Legal expense					100,000,000		266,000,000
Legal expense, net of taxes					75,000,000		200,000,000
Escrow amount		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		115,000,000
Amount claimed by plantiffs in legal matter			$ 75,000,000
Proportionate ownership share in project			100.00%	100.00%
Proposed assessment amount from SCDOR audit				$ 410,000,000
Estimate of aggregate amount of subcontractor and vendor liens filed							285,000,000
Reduction of liens filed							$ 60,000,000
Percentage share of reduction of liens filed							55.00%
Nuclear Insurance
Maximum liability protection per nuclear incident amount							$ 14,000,000,000.0
Amount of coverage purchased from commercial insurance pools					450,000,000		450,000,000
Maximum assessment for premiums on insurance policy							92,000,000
Maximum liability protection per nuclear incident amount per year							$ 14,000,000
Inflation adjustment period for nuclear insurance							5 years
NEIL maximum insurance coverage to nuclear facility for property damage and outage costs					2,750,000,000		$ 2,750,000,000
NEIL maximum insurance coverage to nuclear facility for property damage and outage costs from non-nuclear event							2,330,000,000
NEIL aggregate maximum loss for any single loss occurrence					$ 2,750,000,000		2,750,000,000
NEIL maximum retrospective premium assessment							24,000,000
EMANI maximum insurance coverage for Summer station unit 1 for property damage and outage costs from non-nuclear event							415,000,000
EMANI maximum retrospective premium assessment							2,000,000
Dominion Energy South Carolina, Inc.
Loss Contingencies [Line Items]
Estimate of aggregate amount of subcontractor and vendor liens filed							$ 33,000,000
Subsequent Event
Loss Contingencies [Line Items]
Cash payment related to Ratepayer Case	$ 117,000,000
Property with net value transferred	$ 42,000,000
DESC Ratepayer Case
Loss Contingencies [Line Items]
Customer refundable fees, alternative plan						1,000,000,000.0
Customer refund fees alternative plan net of 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
Minimum [Member]
Loss Contingencies [Line Items]
Power Generation Capacity Megawatts \| MW					25		25
Estimated aggregate value of certain real estate		60,000,000
Maximum [Member]
Loss Contingencies [Line Items]
Estimated aggregate value of certain real estate		$ 85,000,000
Nuclear Insurance
Amount that could be assessed for each licensed reactor					$ 138,000,000		$ 138,000,000
Amount that could be assessed for each licensed reactor per reactor							$ 21,000,000

Leases (Schedule Of Lease Assets and Liabilities Recorded in Consolidated Balance Sheets) (Parenthetical) (Detail) $ in Millions	Jun. 30, 2019 USD ($)
Utility Plant, Net
Finance lease assets, accumulated amortization	$ 20

Leases (Schedule of Maturity Analysis of Operating and Finance Lease Liabilities) (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Jan. 01, 2019
Operating Lease Liabilities, Payments Due [Abstract]
Maturity of operating lease liabilities, 2019	$ 2
Maturity of operating lease liabilities, 2020	2
Maturity of operating lease liabilities, 2021	2
Maturity of operating lease liabilities, 2022	1
Maturity of operating lease liabilities, 2023	1
Maturity of operating lease liabilities, after 2023	22
Maturity of operating lease liabilities, total undiscounted lease payments	30
Operating lease liabilities, present value adjustment	(12)
Present value of operating lease liabilities	18	$ 19
Finance Lease Liabilities, Payments, Due [Abstract]
Maturity of finance lease liabilities, 2019	4
Maturity of finance lease liabilities, 2020	8
Maturity of finance lease liabilities, 2021	6
Maturity of finance lease liabilities, 2022	5
Maturity of finance lease liabilities, 2023	3
Maturity of finance lease liabilities, after 2023	5
Maturity of finance lease liabilities, total undiscounted lease payments	31
Finance lease liabilities, present value adjustment	(2)
Present value of finance lease liabilities	$ 29

Affiliated Transactions (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Related Party Transaction [Line Items]
Purchases from affiliates, fuel used in electric generation	$ 10	$ 29	$ 43	$ 60
Canadys Refined Coal [Member]
Related Party Transaction [Line Items]
Ownership percentage	40.00%		40.00%
Purchases from affiliates	$ 34	$ 45	$ 62	$ 77
Solar Affiliates [Member]
Related Party Transaction [Line Items]
Purchases from affiliates	3		4
Accounts payable to affiliates	1		1
Dominion Energy Carolina Gas Transmission LLC [Member]
Related Party Transaction [Line Items]
Purchases from affiliates	17		32
Accounts payable to affiliates	5		5
Purchases from affiliates, fuel used in electric generation	6		9
Purchases from affiliates, gas purchased for resale	$ 11		$ 23

Leases (Summary of Total Lease Cost) (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Finance lease cost:
Finance lease cost, amortization	$ 2	$ 4
Finance lease cost, interest	0	0
Operating lease cost	0	1
Short-term lease cost	1	1
Variable lease cost	0	0
Total lease cost	$ 3	$ 6

Affiliated Transactions (Schedule of Affiliated Transactions - Balance Sheet) (Detail) - USD ($) $ in Millions	Jun. 30, 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	63	38
Canadys Refined Coal [Member]
Related Party Transaction [Line Items]
Receivable from Canadys Refined Coal, LLC	10	7
Payable to Canadys Refined Coal, LLC	$ 10	$ 7