Operating Revenue (Schedule of Operating Revenue) (Parenthetical) (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		$ 3,470	$ 3,746	$ 7,793	$ 7,376
Other revenues	[1]	115	224	288	452
NGL Midstream | Transferred at a Point in Time
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		19	42	58	93
Renewable Energy Investment Tax Credits
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		7	4	11	7
Alternative Revenue Programs
Public Utilities General Disclosures [Line Items]
Other revenues		39	21	75	35
Dominion Energy Gas Holdings, LLC
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		509	529	1,064	1,094
Other revenues	[2]	1	1	2	2
Dominion Energy Gas Holdings, LLC | NGL Midstream | Transferred at a Point in Time
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		0	2	1	3
Virginia Electric and Power Company
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		1,765	1,914	3,674	3,866
Other revenues	[1],[2]	40	24	61	37
Virginia Electric and Power Company | Renewable Energy Investment Tax Credits
Public Utilities General Disclosures [Line Items]
Operating revenue from contracts with customers		5	2	8	3
Virginia Electric and Power Company | Alternative Revenue Programs
Public Utilities General Disclosures [Line Items]
Other revenues		$ 34	$ 18	$ 51	$ 26

[1] Amounts above include alternative revenue of $39 million and $21 million at Dominion Energy and $34 million and $18 million at Virginia Power for the three months ended June 30, 2020 and 2019, respectively, and $75 million and $35 million at Dominion Energy and $51 million and $26 million at Virginia Power for the six months ended June 30, 2020 and 2019, respectively.

[2] See Notes 10 and 19 for amounts attributable to related parties and affiliates.