Regulatory Matters (Narrative) (Detail) $ in Millions	1 Months Ended												3 Months Ended				9 Months Ended		12 Months Ended
	Nov. 30, 2022 USD ($)	Oct. 31, 2022 USD ($) MW	Sep. 30, 2022 USD ($)	Aug. 31, 2022 USD ($)	Jul. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)	May 31, 2022 USD ($)	Apr. 30, 2022 USD ($)	Jan. 31, 2022 USD ($)	Sep. 30, 2021 USD ($) MW	Jul. 31, 2021 USD ($)	Sep. 30, 2020 USD ($) mi	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2021 USD ($)		Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2008	Oct. 31, 2021 USD ($)
Public Utilities General Disclosures [Line Items]
Depreciation, depletion and amortization													$ 727			$ 621	$ 2,120	$ 1,833
Regulatory liabilities			$ 1,019										1,019				1,019			$ 986	[1]
North Carolina Regulation | Public Service Company Of North Carolina | Rider D
Public Utilities General Disclosures [Line Items]
Increase in gas cost			126				$ 56
Ohio Regulation | PIR Program
Public Utilities General Disclosures [Line Items]
Percentage of pipeline system replaced																								25.00%
Increases of annual capital expenditures percentage								3.00%
Total gross plant investment estimated cost																				225
Proposed revenue requirement																				273
Cumulative gross plant investment estimated cost																				2,200
Ohio Regulation | CEP Program
Public Utilities General Disclosures [Line Items]
Total gross plant investment estimated cost																				146		$ 231	$ 231
Proposed revenue requirement																				131		118	118
Cumulative gross plant investment estimated cost																				1,100		$ 952	$ 952
Ohio Regulation | PIPP Plus Program
Public Utilities General Disclosures [Line Items]
Projected deferred program costs																	22
Accumulated arrearages																	4
Ohio Regulation | UEX Rider
Public Utilities General Disclosures [Line Items]
Actual revenue requirement															$ 20
Public utilities, under-recovered accumulated bad debt expense															$ 7
Ohio Regulation | UEX Rider | Forecast
Public Utilities General Disclosures [Line Items]
Recovery of bad debt expense																			$ 13
Virginia Electric and Power Company
Public Utilities General Disclosures [Line Items]
Proposed cost of project																									$ 3,900
Depreciation, depletion and amortization													451			343	1,305	990
Regulatory liabilities			648										648				$ 648			$ 647	[2]
Virginia Electric and Power Company | Rider DSM
Public Utilities General Disclosures [Line Items]
Increase in customer usage tracker			$ 46
Virginia Electric and Power Company | Virginia Power North Carolina Fuel Filing
Public Utilities General Disclosures [Line Items]
Fuel Component of Electric Rates				$ 107
Increase in Fuel Component of Electric Rates				80
Virginia Electric and Power Company | Utility Scale Solar
Public Utilities General Disclosures [Line Items]
Proposed cost of project										$ 1,400						$ 1,400		$ 1,400
Targeted capacity provided by legislation | MW										661
Virginia Electric and Power Company | Utility Scale Solar | Subsequent Event
Public Utilities General Disclosures [Line Items]
Proposed cost of project		$ 1,200
Targeted capacity provided by legislation | MW		474
Virginia Electric and Power Company | Energy Storage
Public Utilities General Disclosures [Line Items]
Targeted capacity provided by legislation | MW										70
Virginia Electric and Power Company | Energy Storage | Subsequent Event
Public Utilities General Disclosures [Line Items]
Targeted capacity provided by legislation | MW		16
Virginia Electric and Power Company | CVOW Commercial Project
Public Utilities General Disclosures [Line Items]
Estimated cost										$ 1,100
Virginia Electric and Power Company | CVOW Commercial Project | Subsequent Event
Public Utilities General Disclosures [Line Items]
Proposed cost of project, sharing cost amount		$ 10,300
Proposed cost of project, sharing cost amount		13,700
Virginia Electric and Power Company | Virginia Regulation
Public Utilities General Disclosures [Line Items]
Depreciation, depletion and amortization													33
Depreciation and amortization after tax													$ 25
Virginia Electric and Power Company | Virginia Regulation | Impairment of Assets and Other Charges (Benefits)
Public Utilities General Disclosures [Line Items]
Impairment of assets and other charges (benefits)														$ 180
Asset impairment charges after tax														134
Virginia Electric and Power Company | Virginia Regulation | Annual Fuel Factor
Public Utilities General Disclosures [Line Items]
Total revenue requirement							$ 2,300
Rate year beginning							2022-07
Estimated under-recovered balances							$ 1,000
Increase (decrease) in revenue requirement							1,800
Fuel cost recognized														191
Fuel cost recognized after-tax														$ 142
Public utilities collection of requested under-recovered projected fuel expense period																	3 years
Public utilities collection of requested under-recovered projected fuel expense beginning date																	Jul. 01, 2022
Public utilities exclude from recovery through base rates one half of financing costs period																	3 years
Virginia Electric and Power Company | Virginia Regulation | Annual Fuel Factor | Maximum
Public Utilities General Disclosures [Line Items]
Increase (decrease) in revenue requirement							1,300
Virginia Electric and Power Company | Virginia Regulation | Annual Fuel Factor | Minimum
Public Utilities General Disclosures [Line Items]
Increase (decrease) in revenue requirement							1,200
Dominion Energy South Carolina Inc | South Carolina Regulation | Rider DSM
Public Utilities General Disclosures [Line Items]
Annual transportation cost rate adjustment, approval amount requested to recover amount									$ 60
Application date									2022-04
Dominion Energy South Carolina Inc | South Carolina Regulation | Cost Of Fuel
Public Utilities General Disclosures [Line Items]
Rate year beginning								2022-05
Application date								2022-04
Regulatory liabilities								$ 66
Increase (decrease) in annual base fuel component recoveries				$ 399				$ 143
Dominion Energy South Carolina Inc | South Carolina Regulation | Gas Rate Case
Public Utilities General Disclosures [Line Items]
Total revenue requirement						$ 553
Increase (decrease) in revenue requirement						$ 129
Dominion Energy South Carolina Inc | South Carolina Regulation | Gas Rate Case | Forecast
Public Utilities General Disclosures [Line Items]
Increase (decrease) in base rate revenue requirement	$ 16
Base rate increase in revenue required	$ 12
Dominion Energy South Carolina Inc | South Carolina Regulation | Subsequent Event | Gas Rate Case
Public Utilities General Disclosures [Line Items]
Total revenue requirement approved		549
Approved increase in revenue required		125
Hope Gas Inc | West Virginia Regulation | West Virginia Base Rate Case
Public Utilities General Disclosures [Line Items]
Increase (decrease) in revenue requirement												$ 28
Approved increase in revenue required											$ 13
Public Utilities distribution infrastructure gathering assets | mi												2,000
Return of equity percentage												10.25%
Approved return on equity percentage											9.54%	9.45%
Questar Gas Company | Utah Regulation
Public Utilities General Disclosures [Line Items]
Increase in gas cost					$ 94
Questar Gas Company | Utah Regulation | Base Rate Case
Public Utilities General Disclosures [Line Items]
Increase (decrease) in revenue requirement							$ 71
Percentage of earned return							10.30%
Authorized return percentage							9.50%
Questar Gas Company | Utah Regulation | Subsequent Event
Public Utilities General Disclosures [Line Items]
Increase in gas cost		$ 128

[1] Dominion Energy’s Consolidated Balance Sheet at December 31, 2021 has been derived from the audited Consolidated Balance Sheet at that date.

[2] Virginia Power’s Consolidated Balance Sheet at December 31, 2021 has been derived from the audited Consolidated Balance Sheet at that date.