Operating Segments (Schedule of Segment Reporting Information, by Segment) (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Operating Revenue		$ 3,038	$ 3,106	$ 6,908	$ 7,044
Net income (loss) attributable to Dominion Energy		285	(1,169)	1,293	(1,439)
Net Income (Loss) From Discontinued Operations Including Noncontrolling Interests	[1],[2]	26	(2,001)	54	(1,772)
Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		3,037	3,112	6,906	7,061
Adjustments & Eliminations
Segment Reporting Information [Line Items]
Operating Revenue		11	12	28	27
Net income (loss) attributable to Dominion Energy		0	0	0	0
Net Income (Loss) From Discontinued Operations Including Noncontrolling Interests		0	0	0	0
Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		1	(6)	2	(17)
Adjustments & Eliminations
Segment Reporting Information [Line Items]
Operating Revenue		(250)	(248)	(501)	(511)
Eliminations
Segment Reporting Information [Line Items]
Operating Revenue		(239)	(236)	(473)	(484)
Dominion Energy Virginia
Segment Reporting Information [Line Items]
Operating Revenue		1,747	1,814	3,732	3,749
Dominion Energy Virginia | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		1,752	1,818	3,739	3,756
Net income (loss) attributable to Dominion Energy		431	437	865	866
Net Income (Loss) From Discontinued Operations Including Noncontrolling Interests		0	0	0	0
Dominion Energy Virginia | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		(5)	(4)	(7)	(7)
Gas Distribution
Segment Reporting Information [Line Items]
Operating Revenue		455	402	1,431	1,292
Gas Distribution | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		453	400	1,428	1,286
Net income (loss) attributable to Dominion Energy		95	87	346	311
Net Income (Loss) From Discontinued Operations Including Noncontrolling Interests		0	0	0	0
Gas Distribution | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		2	2	3	6
Dominion Energy South Carolina
Segment Reporting Information [Line Items]
Operating Revenue		681	635	1,435	1,349
Dominion Energy South Carolina | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		679	634	1,431	1,347
Net income (loss) attributable to Dominion Energy		84	75	186	169
Net Income (Loss) From Discontinued Operations Including Noncontrolling Interests		0	0	0	0
Dominion Energy South Carolina | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		2	1	4	2
Contracted Assets
Segment Reporting Information [Line Items]
Operating Revenue		274	249	563	545
Contracted Assets | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		257	234	525	522
Net income (loss) attributable to Dominion Energy		104	72	254	183
Net Income (Loss) From Discontinued Operations Including Noncontrolling Interests		0	51	0	102
Contracted Assets | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		17	15	38	23
Corporate and Other
Segment Reporting Information [Line Items]
Operating Revenue		120	242	220	593
Corporate and Other | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		(115)	14	(245)	123
Net income (loss) attributable to Dominion Energy		(429)	(1,840)	(358)	(2,968)
Net Income (Loss) From Discontinued Operations Including Noncontrolling Interests		26	(2,052)	54	(1,874)
Corporate and Other | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		$ 235	$ 228	$ 465	$ 470

[1] Includes income tax expense (benefit) of $4 million and $(593) million for the three months ended June 30, 2021 and 2020, respectively, and $11 million and $(562) million for the six months ended June 30, 2021 and 2020, respectively.

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