Quarterly Financial and Common Stock Data (Unaudited) (Quarterly Financial and Common Stock Data) (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Operating revenue	$ 4,475	$ 4,269	$ 3,970	$ 3,858	$ 3,361	$ 3,451	$ 3,088	$ 3,466	$ 16,572	[1]	$ 13,366	[1]	$ 12,586	[1]
Income (loss) from operations	1,221	1,314	461	(482)	834	1,150	742	875	2,514		3,601		3,937
Net income including noncontrolling interests	1,010	985	58	(677)	662	883	478	526	1,376		2,549		3,120
Net income (loss)	$ 1,009	$ 975	$ 54	$ (680)	$ 641	$ 854	$ 449	$ 503	$ 1,358		$ 2,447		$ 2,999
Net income attributable to Dominion Energy — Basic	$ 1.22	$ 1.19	$ 0.07	$ (0.86)	$ 0.97	$ 1.31	$ 0.69	$ 0.77	$ 1.66		$ 3.74		$ 4.72
Net income attributable to Dominion Energy — Diluted	1.21	1.17	0.05	(0.86)	0.97	1.30	0.69	0.77	1.62		3.74		4.72
Dividends declared per common share	$ 0.9175	$ 0.9175	$ 0.9175	$ 0.9175	$ 0.835	$ 0.835	$ 0.835	$ 0.835	$ 3.67		$ 3.34		$ 3.035
Virginia Electric and Power Company
Condensed Financial Statements, Captions [Line Items]
Operating revenue	$ 1,941	$ 2,264	$ 1,938	$ 1,965	$ 1,810	$ 2,232	$ 1,829	$ 1,748	$ 8,108	[2]	$ 7,619	[2]	$ 7,556	[2]
Income (loss) from operations	659	820	238	122	418	756	533	364	1,839		2,071		2,732
Net income (loss)	427	602	100	20	239	520	339	184	1,149		1,282		1,540
Dominion Energy Gas Holdings, LLC
Condensed Financial Statements, Captions [Line Items]
Operating revenue	571	502	530	566	566	533	508	389	2,169	[3]	1,996	[3]	1,523	[3]
Income (loss) from operations	276	202	179	247	228	302	90	167	904		787		552
Net income including noncontrolling interests	292	175	149	226	72	242	129	213	842		656		829
Net income from continuing operations	276	130	123	172	182	209	84	157
Net income (loss) from discontinued operations	16	45	26	54	(110)	33	45	56
Net income (loss)	$ 261	$ 151	$ 119	$ 190	$ 27	$ 191	$ 83	$ 180	$ 721		$ 481		$ 703
Preferred Class A
Condensed Financial Statements, Captions [Line Items]
Dividends declared per preferred share	$ 4.375	$ 4.375	$ 0.729
Preferred Class B
Condensed Financial Statements, Captions [Line Items]
Dividends declared per preferred share	$ 1.9375

[1] See Note 9 for amounts attributable to related parties.

[2] See Note 25 for amounts attributable to affiliates.

[3] See Note 25 for amounts attributable to related parties.