Operating Segments - Dominion Energy (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Gain (loss) on investments			$ 669	$ 474	$ (505)
Gain (loss) on investments, after tax	$ 132	$ 202
Investment, Type [Extensible Enumeration]	Nuclear Decommissioning Trust Fund [Member]	Nuclear Decommissioning Trust Fund [Member]
Charge for the write-off of certain previously deferred amounts			600	307	1,401
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)			(132)	405	(2,400)
Gain (loss) on investments			565	411	(559)
Gain (loss) on investments, after tax			$ 434	$ 305	$ (451)
Investment, Type [Extensible Enumeration]			Nuclear Decommissioning Trust Fund [Member]	Nuclear Decommissioning Trust Fund [Member]	Nuclear Decommissioning Trust Fund [Member]
Charge associated with storm damage and service restoration					$ 125
Charge associated with storm damage and service restoration, after tax					93
Write-off of inventory charge					40
Write-off of inventory charge, after tax					30
Corporate and Other | Operating Segments
Segment Reporting Information [Line Items]
After- tax net benefits (expenses)			$ (644)	$ (129)	(1,400)
After- tax net benefits (expenses) for specific items			(268)	316	(1,500)
Dominion Energy South Carolina | Operating Segments
Segment Reporting Information [Line Items]
Benefit related to real estate transactions				28
Benefit related to real estate transactions, after tax				21
Charge in connection with the electric base rate case			58
Charge in connection with the electric base rate case, after tax			44
Dominion Energy Virginia | Operating Segments
Segment Reporting Information [Line Items]
Gain (loss) on investments, after tax			$ 62	43	(58)
Investment, Type [Extensible Enumeration]			Nuclear Decommissioning Trust Fund [Member]
Charge for RGGI compliance cost					213
Charge for RGGI compliance cost, after tax					159
Charge in connection with comprehensive settlement agreement for fuel expenses					191
Charge in connection with comprehensive settlement agreement for fuel expenses, after-tax					142
Charge associated with storm damage and service restoration, after tax					87
Charge for amortization of a regulatory asset, 2021 Triennial Review				244	243
Charge for amortization of a regulatory asset, 2021 Triennial Review, after tax				182	181
Share of costs not expected to be recovered from customers on the CVOW commercial project			$ 103
Share of costs not expected to be recovered from customers on the CVOW commercial project, after tax			77
Easement charge related to CVOW Commercial Project				65
Easement charge related to CVOW Commercial Project, after tax				48
Charges for Dismantling cost			40		167
Charges for Dismantling cost, after tax			30		124
Write-off of inventory charge, after tax					14
Charge related to the abandonment of certain regulated solar generation facilities and other facilities				25
Charge related to the abandonment of certain regulated solar generation facilities and other facilities, after tax				19
Charge related to write-off of certain early stage development costs			30
Charge related to write-off of certain early stage development costs after tax			22
Charge associated with an accrual for remediation costs			25
Charge associated with an accrual for remediation costs after tax			19
Dominion Energy Virginia | Operating Segments | Deferred rider costs for Virginia electric utility
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
Contracted Energy | Operating Segments
Segment Reporting Information [Line Items]
Charges associated with impairment of nonregulated solar generation facilities					829
Charges associated with impairment of nonregulated solar generation facilities net of tax					633
Gain (loss) on investments, after tax			372	262	(393)
Loss associated with sale of Kewaunee					649
Loss associated with sale of Kewaunee, after tax					513
Loss related to economic hedging activities			232
Loss related to economic hedging activities, after tax			176
Charge associated with storm damage and service restoration, after tax					6
Charges related to revision of AROs			122	83
Charges related to revision of AROs, after tax			89	60
Gain related to economic hedging activities				586	67
Gain related to economic hedging activities after tax				447	49
Write-off of inventory charge, after tax					$ 16
Charge related to impairment of certain property, plant and equipment				35
Charge related to impairment of certain property, plant and equipment, net of tax				$ 26
Charge for impairment of nonregulated renewable natural gas facilities			60
Charge for impairment of nonregulated renewable natural gas facilities after tax			46
Charge in connection with settlement of an agreement			47
Charge in connection with settlement of an agreement, after tax			$ 35