Operating Segments - Dominion Energy (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Gain (loss) on investments	$ 294	$ 134
Charge in connection with settlement of an agreement	47
Charge in connection with settlement of an agreement, after tax	35
Operating Segments
Segment Reporting Information [Line Items]
After- tax net benefits (expenses)	124	304
Gain (loss) on investments	266	123
Gain (loss) on investments, after tax	$ 202	$ 90
Investment, Type [Extensible Enumeration]	Nuclear Decommissioning Trust Fund [Member]	Nuclear Decommissioning Trust Fund [Member]
Corporate and Other | Operating Segments
Segment Reporting Information [Line Items]
After- tax net benefits (expenses)	$ 48	$ 393
After- tax net benefits (expenses) for specific items	191	466
Contracted Energy | Operating Segments
Segment Reporting Information [Line Items]
Gain (loss) on investments, after tax	175	77
Loss related to economic hedging activities	61
Loss related to economic hedging activities after tax	47
Gain related to economic hedging activities		332
Gain related to economic hedging activities after tax		253
Charge in connection with settlement of an agreement	47
Charge in connection with settlement of an agreement, after tax	35
Dominion Energy Virginia | Operating Segments
Segment Reporting Information [Line Items]
Gain (loss) on investments, after tax	$ 27	$ 13
Investment, Type [Extensible Enumeration]	Nuclear Decommissioning Trust Fund [Member]	Nuclear Decommissioning Trust Fund [Member]
Charge for amortization of a regulatory asset, 2021 Triennial Review		$ 61
Charge for amortization of a regulatory asset, 2021 Triennial Review, after tax		$ 45