Operating Segments - Dominion Energy (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Gain (loss) on investments				$ 395	$ 308
Charge for the write-off of certain previously deferred amounts	$ 67		$ 37	97	135
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)				74	370
Gain (loss) on investments				350	281
Gain (loss) on investments, after tax				$ 271	$ 208
Investment, Type [Extensible Enumeration]	Nuclear Decommissioning Trust Fund [Member]		Nuclear Decommissioning Trust Fund [Member]	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)				$ (34)	$ 559
After- tax net benefits (expenses) for specific items				200	739
Contracted Energy | Operating Segments
Segment Reporting Information [Line Items]
Gain (loss) on investments, after tax				236	178
Loss related to economic hedging activities				167
Loss related to economic hedging activities after tax				127
Gain related to economic hedging activities					342
Gain related to economic hedging activities after tax					260
Charge in connection with settlement of an agreement				47
Charge in connection with settlement of an agreement, after tax				35
Charge for impairment of nonregulated renewable natural gas facilities				33
Charge for impairment of nonregulated renewable natural gas facilities after tax				25
Dominion Energy Virginia | Operating Segments
Segment Reporting Information [Line Items]
Gain (loss) on investments, after tax				$ 35	$ 30
Investment, Type [Extensible Enumeration]	Nuclear Decommissioning Trust Fund [Member]		Nuclear Decommissioning Trust Fund [Member]	Nuclear Decommissioning Trust Fund [Member]	Nuclear Decommissioning Trust Fund [Member]
Charge for amortization of a regulatory asset, 2021 Triennial Review					$ 122
Charge for amortization of a regulatory asset, 2021 Triennial Review, after tax					91
Dominion Energy Virginia | Deferred amounts related to certain riders | Operating Segments
Segment Reporting Information [Line Items]
Charge for the write-off of certain previously deferred amounts					36
Charge for the write-off of certain previously deferred amounts, after tax					27
Dominion Energy South Carolina | Operating Segments
Segment Reporting Information [Line Items]
Benefit related to real estate transactions					31
Benefit related to real estate transactions, after tax					$ 23