Regulatory Matters (Narrative) (Detail) $ in Millions	1 Months Ended				12 Months Ended
	May 31, 2022 USD ($)	Apr. 30, 2022 USD ($)	Jan. 31, 2022 USD ($)	Sep. 30, 2021 USD ($) MW	Dec. 31, 2021 USD ($)		Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2008	Mar. 31, 2022 USD ($)
Public Utilities General Disclosures [Line Items]
Regulatory liabilities					$ 986	[1]				$ 830
Ohio Regulation | PIR Program
Public Utilities General Disclosures [Line Items]
Percentage of pipeline system replaced									25.00%
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					140		$ 231	$ 231
Proposed revenue requirement					137		118	118
Cumulative gross plant investment estimated cost					1,100		$ 952	$ 952
Ohio Regulation | Subsequent Event | PIR Program
Public Utilities General Disclosures [Line Items]
Increases of annual capital expenditures percentage		3.00%
Virginia Electric and Power Company
Public Utilities General Disclosures [Line Items]
Proposed cost of project				$ 1,400
Regulatory liabilities					$ 647	[2]				$ 460
Virginia Electric and Power Company | Utility Scale Solar Generation
Public Utilities General Disclosures [Line Items]
Targeted capacity provided by legislation | MW				661
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 | Virginia Regulation | Annual Fuel Factor | Subsequent Event
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	155
Estimated under-unrecovered balances	215,000
Virginia Electric and Power Company | Virginia Regulation | Annual Fuel Factor | Maximum | Subsequent Event
Public Utilities General Disclosures [Line Items]
Increase (decrease) in revenue requirement	1,300
Virginia Electric and Power Company | Virginia Regulation | Annual Fuel Factor | Minimum [Member] | Subsequent Event
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 | Subsequent Event | 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		$ 143
Questar Gas Company | Utah Regulation | Subsequent Event | 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%

[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.