Commitments and Contingencies (Narrative) (Detail)		1 Months Ended																		12 Months Ended
	Oct. 31, 2014 MGD	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	May 31, 2022 shares	Dec. 31, 2021 USD ($)	Aug. 31, 2021 shares	Jul. 31, 2021 USD ($) shares	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Oct. 31, 2020	Sep. 30, 2020 USD ($)	Aug. 31, 2020 USD ($)	Nov. 30, 2019 gal	Jul. 31, 2019 USD ($)	Aug. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Aug. 31, 2017 USD ($)	Apr. 30, 2017 Petition	Aug. 31, 2016 T	Dec. 31, 2022 USD ($) Facility Indicator Product MGD	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2018 USD ($)	Mar. 31, 2020 USD ($)
Loss Contingencies [Line Items]
Measurement of groundwater withdrawals | gal													3,000,000
Number of manufacturing gas plant decommissioned sites that contain residues of byproduct chemicals | Product																				4
Estimated environmental remediation activities at manufacturing gas plant sites																				$ 21,000,000
Environmental remediation costs recognized in regulatory assets																				$ 38,000,000
Number of facilities inactive subject to final rule | Facility																				3
Settlement payable by all																								$ 520,000,000
Reserves for litigation and regulatory proceedings					$ 211,000,000															$ 94,000,000	$ 211,000,000
Insurance receivables					85,000,000															68,000,000	85,000,000
Contested amount for filed liens in Fairfield country															$ 285,000,000
Impairment of assets and other charges																				4,000,000	311,000,000	$ (14,000,000)
Settlement payable by company							$ 99,000,000										$ 100,000,000							$ 320,000,000
Proportionate ownership share in project																100.00%	100.00%
Proposed assessment amount from SCDOR audit																$ 410,000,000
Litigation settlement expense awarded									$ 165,000,000
Real estate transfer to satisfy obligation under settlement			$ 51,000,000
Customer refundable fees, alternative plan					3,181,000,000															3,036,000,000	3,181,000,000
Energy payments under power purchase contracts					73,000,000				64,000,000											75,000,000	73,000,000	64,000,000
Nuclear Insurance
Loss Contingencies [Line Items]
Maximum liability protection per nuclear incident amount																				13,700,000,000
Maximum liability each nuclear plant is insured against																				450,000,000
Amount that could be assessed for each licensed reactor																				138,000,000
Amount that could be assessed for each licensed reactor per year																				$ 20,000,000
Inflation adjustment period for nuclear insurance																				5 years
NEIL maximum insurance coverage to nuclear facility for property damage and outage costs																				$ 1,060,000,000.00
NEIL maximum insurance coverage to nuclear facility for property damage and outage costs from non-nuclear event																				1,000,000
NEIL aggregate maximum loss for any single loss occurrence																				1,060,000,000.00
NEIL maximum retrospective premium assessment																				11,000,000
EMANI maximum insurance coverage for Summer station unit 1 for property damage and outage costs from non-nuclear event																				$ 1,000,000
SCANA
Loss Contingencies [Line Items]
Payment of civil monetary penalty									25,000,000
SCANA and DESC
Loss Contingencies [Line Items]
Payment of disgorgement and prejudgment interest									$ 112,500,000
N N D Project
Loss Contingencies [Line Items]
Jointly owned utility plant, proportionate ownership share																				55.00%
Summer [Member]
Loss Contingencies [Line Items]
Proceeds from legal settlements of share of claims incurred in previous year																				$ 1,000,000	1,000,000	4,000,000
SCDOR
Loss Contingencies [Line Items]
Value of certain utility and non-utility properties to be conveyed																				3,000,000
Non utility property fair value		$ 28,000,000
DESC Ratepayer Case
Loss Contingencies [Line Items]
Property with net value transferred					8,000,000							$ 22,000,000
Conveyance of property with net recorded value											$ 3,000,000
Property with net value transferred, cash contribution											38,500,000
Cash payment														$ 117,000,000									$ 115,000,000
Escrow account																							2,000,000,000.0
Credit in future electric rate relief																							2,000,000,000.0
Common Stock | Dominion Energy
Loss Contingencies [Line Items]
Common stock issued to satisfy the settlement											$ 322,000,000											322,000,000
Litigation settlement through cash								$ 43,000,000
Litigation settlement through stock issuance | shares				900,000		600,000	1,400,000
Common Stock | Dominion Energy | SCDOR
Loss Contingencies [Line Items]
Common stock issued to satisfy the settlement																				72,000,000	45,000,000
Dominion Energy South Carolina, Inc. | SCDOR
Loss Contingencies [Line Items]
Gain on expected conveyed value of utility and non-utility properties upon approval																				20,000,000
DESC Summer | Nuclear Insurance
Loss Contingencies [Line Items]
Amount that could be assessed for each licensed reactor																				92,000,000
Amount that could be assessed for each licensed reactor per year																				14,000,000
Impairment of Assets and Other Charges | Dominion Energy South Carolina, Inc.
Loss Contingencies [Line Items]
Impairment of assets and other charges																					70,000,000	97,000,000
Impairment of assets and other charges, after-tax																					53,000,000	$ 73,000,000
Other Income (Expense), Net | SCDOR
Loss Contingencies [Line Items]
Gain from transferred non utility property																				19,000,000
Gain from transferred non utility property, after tax																				$ 14,000,000
Unfavorable Regulatory Action | CWA
Loss Contingencies [Line Items]
Electric generating stations with water withdrawals with heightened entrainment analysis under CWA | MGD	2,000,000
Number of mandatory facility specific factors | Indicator																				5
Number of optional facility specific factors | Indicator																				6
Personal Injury or Wrongful Death Cases
Loss Contingencies [Line Items]
Reserves for litigation and regulatory proceedings					$ 85,000,000															$ 68,000,000	$ 85,000,000
Minimum [Member] | DESC Ratepayer Case
Loss Contingencies [Line Items]
Proceeds from sale of property																							60,000,000
Maximum [Member] | DESC Ratepayer Case
Loss Contingencies [Line Items]
Proceeds from sale of property																							$ 85,000,000
Virginia Electric and Power Company | Unfavorable Regulatory Action | CWA
Loss Contingencies [Line Items]
Number of DESC facilities subject to final regulations | Facility																				5
Carbon Regulations
Loss Contingencies [Line Items]
Significant emission rate per year CO2 equivalent | T																			75,000
EPA | Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Electric generating stations with water withdrawals under CWA | MGD																				125,000,000
EPA | Unfavorable Regulatory Action | CWA | Final Rule to Revise Effluent Limitations Guidelines for Steam Electric Power Generating Category
Loss Contingencies [Line Items]
Number of separate petitions for reconsideration granted | Petition																		2
EPA | Minimum [Member] | Unfavorable Regulatory Action | CWA | Final Rule to Revise Effluent Limitations Guidelines for Steam Electric Power Generating Category
Loss Contingencies [Line Items]
Loss contingencies individual circumstances period										2021
EPA | Maximum [Member] | Unfavorable Regulatory Action | CWA | Final Rule to Revise Effluent Limitations Guidelines for Steam Electric Power Generating Category
Loss Contingencies [Line Items]
Loss contingencies individual circumstances period										2028
Environmental Protection Agency And State Regulatory Agencies | Hydroelectric Facilities
Loss Contingencies [Line Items]
Number of DESC hydroelectric facilities subject to regulations | Facility																				5