Operating Segments (Schedule of Segment Reporting Information, by Segment) (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Operating Revenue	[1]	$ 3,585	$ 3,970	$ 8,081	$ 7,828
Net income (loss)		(1,169)	54	(1,439)	(626)
Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Operating Revenue	[2]	1,805	1,938	3,735	3,903
Net income (loss)		490	100	210	120
Dominion Energy Gas Holdings, LLC
Segment Reporting Information [Line Items]
Operating Revenue	[3]	510	530	1,066	1,096
Net income (loss)		(198)	119	(29)	309
Net Income from discontinued operations		0	26	0	80
Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		(315)	(484)	(656)	(819)
Operating revenue			32
Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		3,585	3,970	8,081	7,828
Adjustments & Eliminations
Segment Reporting Information [Line Items]
Operating Revenue		(1)		(1)
Eliminations
Segment Reporting Information [Line Items]
Operating Revenue		(316)	(452)	(657)	(819)
Dominion Energy Virginia
Segment Reporting Information [Line Items]
Operating Revenue		1,818	1,945	3,756	3,946
Net income (loss)		437	393	866	754
Dominion Energy Virginia | Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Operating Revenue		1,805	1,938	3,735	3,932
Net income (loss)		435	393	862	751
Dominion Energy Virginia | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		(4)	(2)	(7)	(6)
Dominion Energy Virginia | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		1,814	1,943	3,749	3,940
Gas, Transmission & Storage
Segment Reporting Information [Line Items]
Operating Revenue		528	664	1,172	1,647
Net income (loss)		184	177	405	399
Gas, Transmission & Storage | Dominion Energy Gas Holdings, LLC
Segment Reporting Information [Line Items]
Operating Revenue		510	530	1,066	1,096
Net income (loss)		163	116	337	254
Net Income from discontinued operations			0		0
Gas, Transmission & Storage | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		49	91	106	146
Gas, Transmission & Storage | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		577	755	1,278	1,793
Gas Distribution
Segment Reporting Information [Line Items]
Operating Revenue		400	397	1,287	1,314
Net income (loss)		87	66	312	271
Gas Distribution | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		2	3	5	7
Gas Distribution | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		402	400	1,292	1,321
Dominion Energy South Carolina
Segment Reporting Information [Line Items]
Operating Revenue		634	701	1,347	1,390
Net income (loss)		75	95	169	166
Dominion Energy South Carolina | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		1	2	2	2
Dominion Energy South Carolina | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		635	703	1,349	1,392
Contracted Generation
Segment Reporting Information [Line Items]
Operating Revenue		238	249	524	601
Net income (loss)		21	13	80	115
Contracted Generation | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		5	4	9	7
Contracted Generation | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		243	253	533	608
Corporate and Other
Segment Reporting Information [Line Items]
Operating Revenue		(32)	(18)	(4)	(1,070)
Net income (loss)		(1,973)	(690)	(3,271)	(2,331)
Corporate and Other | Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Operating Revenue		0	0	0	(29)
Net income (loss)		55	(293)	(652)	(631)
Corporate and Other | Dominion Energy Gas Holdings, LLC
Segment Reporting Information [Line Items]
Operating Revenue		0	0	0	0
Net income (loss)		(361)	3	(366)	55
Net Income from discontinued operations			26		80
Corporate and Other | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		262	386	541	663
Corporate and Other | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		$ 230	$ 368	$ 537	$ (407)

[1] See Note 10 for amounts attributable to related parties.

[2] See Note 19 for amounts attributable to affiliates.

[3] See Note 19 for amounts attributable to related parties.