Related-Party Transactions (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Virginia Electric and Power Company
Related Party Transaction [Line Items]
Commodity purchases from affiliates		$ 211	$ 272
Services provided by affiliates	[1]	121	119
Virginia Electric and Power Company | Affiliated Entity
Related Party Transaction [Line Items]
Services provided to related parties		5	6
Dominion Energy Gas Holdings, LLC
Related Party Transaction [Line Items]
Commodity purchases from affiliates		64	67
Services provided by affiliates	[2]	43	45
Services provided to related parties	[3]	32	$ 45
Other receivables	[4]	8		$ 7
Other deferred charges and other assets		11		12
Dominion Energy Gas Holdings, LLC | Affiliated Entity
Related Party Transaction [Line Items]
Services provided to related parties		3
Imbalances receivable from affiliates				8
Imbalances payable to affiliates	[5]	$ 2		$ 1

[1] Includes capitalized expenditures of $34 million and $33 million for the three months ended March 31, 2020 and 2019, respectively.

[2] Includes capitalized expenditures of $3 million and $6 million for the three months ended March 31, 2020 and 2019, respectively. 

[3] Amounts primarily attributable to Atlantic Coast Pipeline, a related-party VIE.

[4] Represents amounts due from Atlantic Coast Pipeline, a related-party VIE.

[5] Amounts are presented in other current liabilities in Dominion Energy Gas’ Consolidated Balance Sheets.