Related-Party Transactions (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Virginia Electric and Power Company
Related Party Transaction [Line Items]
Commodity purchases from affiliates		$ 272	$ 398
Services provided by affiliates	[1]	119	120
Virginia Electric and Power Company | Affiliated Entity
Related Party Transaction [Line Items]
Services provided to related parties		6	6
Dominion Energy Gas Holdings, LLC
Related Party Transaction [Line Items]
Commodity purchases from affiliates		3	3
Services provided by affiliates	[2]	35	33
Services provided to related parties	[3]	37	52
Other receivables	[4]	11		$ 13
Customer receivables from related parties				1
Affiliated notes receivable	[5]	15		16
Dominion Energy Gas Holdings, LLC | Affiliated Entity
Related Party Transaction [Line Items]
Services provided to related parties		15	$ 18
Imbalances receivable from affiliates		1		1
Imbalances payable to affiliates	[6]	$ 3		$ 13

[1] Includes capitalized expenditures of $33 million and $37 million for the three months ended March 31, 2019 and 2018, respectively.

[2] Includes capitalized expenditures of $5 million and $10 million for the three months ended March 31, 2019 and 2018, 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 deferred charges and other assets in Dominion Energy Gas’ Consolidated Balance Sheets.

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