Operating Segments - Dominion Energy (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Gain (loss) on investments	$ (116)	$ 294
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)	(151)	124
Gain (loss) on investments	(132)	266
Gain (loss) on investments, after tax	$ (95)	$ 202
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)	$ (176)	$ (185)
After- tax net benefits (expenses) for specific items	(157)	(44)
Contracted Energy | Operating Segments
Segment Reporting Information [Line Items]
Gain (loss) on investments, after tax	(84)	175
Gain (loss) related to economic hedging activities	28	(61)
Gain (loss) related to economic hedging activities after tax	21	(47)
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	$ (11)	$ 27
Investment, Type [Extensible Enumeration]	Nuclear Decommissioning Trust Fund [Member]	Nuclear Decommissioning Trust Fund [Member]
Share of costs not expected to be recovered from customers on the CVOW commercial project	$ 23
Share of costs not expected to be recovered from customers on the CVOW commercial project, after tax	17
Loss associated with severe weather events	82
Loss associated with severe weather events, after-tax	$ 61