Operating Segments - Dominion Energy (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Asset early retirement expense	$ 129	$ 165
Gain (loss) on investments	(505)	639	$ 412
Operating Segments
Segment Reporting Information [Line Items]
After- tax net benefits (expenses)	(2,800)	(493)	(1,200)
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
Operating Segments | Nuclear Decommissioning Trust Fund
Segment Reporting Information [Line Items]
Gain (loss) on investments	559	568	335
Gain (loss) on investments, after tax	451	445	264
Corporate and Other | Operating Segments
Segment Reporting Information [Line Items]
After- tax net benefits (expenses)	(2,600)	(99)	(3,700)
After- tax net benefits (expenses) for specific items	(2,500)	97	(3,400)
Dominion Energy South Carolina Inc | Operating Segments
Segment Reporting Information [Line Items]
Litigation settlement expense		70	117
Litigation settlement expense, after tax		53	93
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
Dominion Energy Virginia | Operating Segments
Segment Reporting Information [Line Items]
Charge for expected CCRO			130
Charge for expected CCRO, net of tax			97
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
Amortization of regulatory asset	243	61
Amortization of regulatory asset after tax	181	45
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
Charges associated with legislation enacted related to customer arrears			127
Charges associated with legislation enacted related to customer arrears, net of tax			94
Write-off of inventory charge, after tax	14
Dominion Energy Virginia | Operating Segments | Nuclear Decommissioning Trust Fund
Segment Reporting Information [Line Items]
Gain (loss) on investments, after tax	(58)	55	27
Dominion Energy Virginia | Operating Segments | Electric Generation Facilities
Segment Reporting Information [Line Items]
Asset early retirement expense			751
Asset early retirement expense after tax			564
Gas Distribution | Operating Segments
Segment Reporting Information [Line Items]
Benefit (loss) associated with sale of hope	22
Benefit (loss) associated with sale of hope after tax	(78)
Contracted Assets | Operating Segments
Segment Reporting Information [Line Items]
Charges associated with impairment of nonregulated solar generation facilities	1,500
Charges associated with impairment of nonregulated solar generation facilities net of tax	1,100
Charge associated with the sale of Fowler Ridge			221
Charge associated with the sale of Fowler Ridge, net of tax			171
Loss associated with sale of Kewaunee	649
Loss associated with sale of Kewaunee, after tax	513
Loss related to economic hedging activities		347
Loss related to economic hedging activities, after tax		261
Net loss on the sale of non-wholly-owned nonregulated solar facilities		211
Net loss on the sale of non-wholly-owned nonregulated solar facilities after tax		161
Charge associated with storm damage and service restoration, after tax	6
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
Charge associated with certain nonregulated solar generation facilities			405
Charge associated with certain nonregulated solar generation facilities, net of tax			325
Gain related to economic hedging activities	165
Gain related to economic hedging activities after tax	133
Write-off of inventory charge, after tax	16
Contracted Assets | Operating Segments | Nuclear Decommissioning Trust Fund
Segment Reporting Information [Line Items]
Gain (loss) on investments, after tax	$ (393)	$ 390	$ 237