Operating Segments (Schedule of Segment Reporting Information, by Segment) (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Operating Revenue		$ 3,870	$ 3,938
Net Income From Discontinued Operations Including Noncontrolling Interests	[1],[2]	28	229
Net income (loss) attributable to Dominion Energy		1,008	(270)
Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		3,869	3,949
Adjustments & Eliminations
Segment Reporting Information [Line Items]
Operating Revenue		17	15
Net Income From Discontinued Operations Including Noncontrolling Interests		0	0
Net income (loss) attributable to Dominion Energy		0	0
Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		1	(11)
Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		(251)	(263)
Eliminations
Segment Reporting Information [Line Items]
Operating Revenue		(234)	(248)
Dominion Energy Virginia
Segment Reporting Information [Line Items]
Operating Revenue		1,985	1,935
Dominion Energy Virginia | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		1,987	1,938
Net Income From Discontinued Operations Including Noncontrolling Interests		0	0
Net income (loss) attributable to Dominion Energy		434	429
Dominion Energy Virginia | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		(2)	(3)
Gas Distribution
Segment Reporting Information [Line Items]
Operating Revenue		976	890
Gas Distribution | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		975	886
Net Income From Discontinued Operations Including Noncontrolling Interests		0	0
Net income (loss) attributable to Dominion Energy		251	224
Gas Distribution | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		1	4
Dominion Energy South Carolina
Segment Reporting Information [Line Items]
Operating Revenue		754	714
Dominion Energy South Carolina | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		752	713
Net Income From Discontinued Operations Including Noncontrolling Interests		0	0
Net income (loss) attributable to Dominion Energy		102	94
Dominion Energy South Carolina | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		2	1
Contracted Assets
Segment Reporting Information [Line Items]
Operating Revenue		289	296
Contracted Assets | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		268	288
Net Income From Discontinued Operations Including Noncontrolling Interests		0	51
Net income (loss) attributable to Dominion Energy		150	111
Contracted Assets | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		21	8
Corporate and Other
Segment Reporting Information [Line Items]
Operating Revenue		100	351
Corporate and Other | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue		(130)	109
Net Income From Discontinued Operations Including Noncontrolling Interests		28	178
Net income (loss) attributable to Dominion Energy		71	(1,128)
Corporate and Other | Intersegment revenue
Segment Reporting Information [Line Items]
Operating Revenue		$ 230	$ 242

[1] Includes income tax expense of $7 million and $31 million for the three months ended March 31, 2021 and 2020, respectively.

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