Quarterly Financial Data (Unaudited) (Quarterly Financial Data) (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Condensed Financial Statements Captions [Line Items]
Operating revenue	$ 3,521	$ 3,607	$ 3,106	$ 3,938	$ 3,895	$ 3,782	$ 3,443	$ 3,281	$ 14,172		$ 14,401		$ 11,199
Income (loss) from continuing operations	856	27	804	368	936	1,104	248	(744)	2,055		1,544		3,013
Net income (loss) from continuing operations including noncontrolling interests	815	112	869	(468)	820	947	(199)	(908)	1,328		660		2,097
Net income (loss) from discontinued operations including noncontrolling interest	(125)	19	(2,001)	229	190	38	257	231	(1,878)	[1],[2]	716	[1],[2]	452	[1],[2]
Net Income (Loss) Including Noncontrolling Interests	690	131	(1,132)	(239)	1,010	985	58	(677)	(550)		1,376		2,549
Net income (loss) attributable to Dominion Energy	$ 682	$ 356	$ (1,169)	$ (270)	$ 1,009	$ 975	$ 54	$ (680)	$ (401)		$ 1,358		$ 2,447
Basic EPS:
EPS from continuing operations - Basic	$ 0.98	$ 0.42	$ 1.01	$ (0.57)	$ 0.99	$ 1.14	$ (0.25)	$ (1.14)	$ 1.83		$ 0.79		$ 3.19
EPS from discontinued operations - Basic	(0.16)	(0.01)	(2.42)	0.23	0.22	0.05	0.32	0.28	(2.39)		0.87		0.55
EPS attributable to Dominion Energy - Basic	0.82	0.41	(1.41)	(0.34)	1.21	1.19	0.07	(0.86)	(0.56)		1.66		3.74
Diluted EPS:
EPS from continuing operations - Diluted	0.98	0.42	0.90	(0.57)	0.99	1.12	(0.25)	(1.14)	1.82		0.75		3.19
EPS from discontinued operations - Diluted	(0.16)	(0.01)	(2.42)	0.23	0.22	0.05	0.32	0.28	(2.39)		0.87		0.55
EPS attributable to Dominion Energy - Diluted	0.82	0.41	(1.52)	(0.34)	1.21	1.17	0.07	(0.86)	(0.57)		1.62		3.74
Dividends declared per common share	$ 0.6300	$ 0.9400	$ 0.9400	$ 0.9400	$ 0.9175	$ 0.9175	$ 0.9175	$ 0.9175	$ 3.45		$ 3.67		$ 3.34
Virginia Electric and Power Company
Condensed Financial Statements Captions [Line Items]
Operating revenue	$ 1,780	$ 2,248	$ 1,805	$ 1,930	$ 1,941	$ 2,264	$ 1,938	$ 1,965	$ 7,763	[3]	$ 8,108	[3]	$ 7,619	[3]
Income (loss) from continuing operations	497	687	635	(133)	659	820	238	122	1,686		1,839		2,071
Net income (loss) attributable to Dominion Energy	$ 336	$ 475	$ 490	$ (280)	$ 427	$ 602	$ 100	$ 20	$ 1,021		$ 1,149		$ 1,282
Preferred Class A
Diluted EPS:
Dividends declared per preferred share	$ 4.375	$ 4.375	$ 4.375	$ 4.375	$ 4.375	$ 4.375	$ 0.729
Preferred Class B
Diluted EPS:
Dividends declared per preferred share	$ 11.625	$ 11.625	$ 11.625	$ 11.625	$ 1.9375

[1] Includes income tax expense (benefit) of $(204) million, $142 million and $58 million for the years ended December 31, 2020, 2019 and 2018, respectively

[2] See Note 9 for amounts attributable to related parties

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