Operating Segments - Dominion Energy (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Asset early retirement expense		$ 193	$ 125
Gain (loss) on investments		474	(505)	$ 639
Loss associated with sale of Kewaunee, after tax	$ 513
Charge for RGGI compliance cost, after tax	134
Charge in connection with comprehensive settlement agreement for fuel expenses, after-tax	$ 142
Charge for the write-off of certain previously deferred amounts		307	1,401	194
Operating Segments
Segment Reporting Information [Line Items]
After- tax net benefits (expenses)		405	(2,400)	(316)
Gain (loss) on investments		411	(559)	568
Gain (loss) on investments, after tax		$ 305	$ (451)	$ 445
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)		$ (166)	(1,300)	$ 873
After- tax net benefits (expenses) for specific items		251	(1,300)	991
Dominion Energy South Carolina Inc | Operating Segments
Segment Reporting Information [Line Items]
Litigation settlement expense				70
Litigation settlement expense, after tax				53
Charges associated with the settlement of the South Carolina electric base rate case				266
Charges associated with the settlement of the South Carolina electric base rate case, after tax				199
Benefit related to real estate transactions		28
Benefit related to real estate transactions, after tax		21
Dominion Energy Virginia | Operating Segments
Segment Reporting Information [Line Items]
Gain (loss) on investments, after tax		$ 43	$ (58)	$ 55
Investment, Type [Extensible Enumeration]		Nuclear Decommissioning Trust Fund [Member]	Nuclear Decommissioning Trust Fund [Member]	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
Benefit for change in expected CCRO reserve				$ 130
Benefit for change in expected CCRO reserve, after tax				97
Charges associated with budget process related to customer arrears				77
Charges associated with budget process related to customer arrears, after tax				57
Charge associated with storm damage and service restoration				68
Charge associated with storm damage and service restoration, after tax			87	50
Charge for amortization of a regulatory asset, 2021 Triennial Review		$ 244	243	61
Charge for amortization of a regulatory asset, 2021 Triennial Review, after tax		182	181	45
Easement charge related to CVOW Commercial Project		65
Easement charge related to CVOW Commercial Project, after tax		48
Charges for Dismantling cost			167
Charges for Dismantling cost, after tax			124
Loss from unbilled revenue reduction				151
Loss from unbilled revenue reduction, after tax				112
Net charge associated with settlement of the 2021 Triennial Review				125
Net charge associated with settlement of the 2021 Triennial Review, after tax				93
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
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		$ 262	$ (393)	$ 390
Investment, Type [Extensible Enumeration]		Nuclear Decommissioning Trust Fund [Member]	Nuclear Decommissioning Trust Fund [Member]	Nuclear Decommissioning Trust Fund [Member]
Loss associated with sale of Kewaunee			$ 649
Loss associated with sale of Kewaunee, after tax			513
Loss related to economic hedging activities				$ 337
Loss related to economic hedging activities, after tax				254
Net loss on the sale of non-wholly-owned nonregulated solar facilities				513
Net benefit on the sale of non-wholly-owned nonregulated solar facilities, after-tax				8
Charge associated with storm damage and service restoration, after tax			6
Charges related to revision of AROs		$ 83
Charges related to revision of AROs, after tax		60
Charge associated with revision in estimated recovery of spent nuclear fuel costs associated with the decommissioning of Kewaunee				44
Charge associated with revision in estimated recovery of spent nuclear fuel costs associated with the decommissioning of Kewaunee, after tax				$ 35
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