Operating Segments - Dominion Energy (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Gain (loss) on investments	$ 134	$ (113)
Operating Segments
Segment Reporting Information [Line Items]
After- tax net benefits (expenses)	272	(269)
Operating Segments | Nuclear Decommissioning Trust Funds
Segment Reporting Information [Line Items]
Gain (loss) on investments	123	(125)
Gain (loss) on investments, after tax	90	(102)
Corporate and Other | Operating Segments
Segment Reporting Information [Line Items]
After- tax net benefits (expenses)	86	(311)
After- tax net benefits (expenses) for specific items	148	(289)
Contracted Assets | Operating Segments
Segment Reporting Information [Line Items]
Loss related to economic hedging activities		66
Gain related to economic hedging activities	291
Loss related to economic hedging activities after tax		47
Gain related to economic hedging activities after tax	221
Contracted Assets | Operating Segments | Nuclear Decommissioning Trust Funds
Segment Reporting Information [Line Items]
Gain (loss) on investments, after tax	77	(90)
Dominion Energy Virginia | Operating Segments
Segment Reporting Information [Line Items]
Charge associated with storm damage and service restoration		94
Charge associated with storm damage and service restoration, after tax		70
Charge for amortization of a regulatory asset, 2021 Triennial Review	61	61
Charge for amortization of a regulatory asset, 2021 Triennial Review, after tax	45	45
Dominion Energy Virginia | Operating Segments | Nuclear Decommissioning Trust Funds
Segment Reporting Information [Line Items]
Gain (loss) on investments, after tax	$ 13	$ (12)