Derivatives and Hedge Accounting Activities (Gains and Losses on Derivatives in Cash Flow Hedging Relationships) (Detail) - Cash Flow Hedges - USD ($) $ in Millions		3 Months Ended				9 Months Ended
		Sep. 30, 2022		Sep. 30, 2021		Sep. 30, 2022	Sep. 30, 2021
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[1]	$ 14		$ (2)		$ 86	$ 29
Amount of Gain (Loss) Reclassified From AOCI to Income		(16)		(14)		(44)	(47)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2]	182		9		815	198
Virginia Electric and Power Company
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[3]	18		(2)		77	24
Amount of Gain (Loss) Reclassified From AOCI to Income		(1)		(1)		(2)	(2)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[4]	182		8		814	194
Commodity Contract
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income	[5]						(1)
Interest Rate Contract
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[1]	14	[6]	(2)	[6]	86	29
Amount of Gain (Loss) Reclassified From AOCI to Income		(16)	[6]	(14)	[6]	(44)	(46)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2]	182	[6]	9	[6]	815	198
Interest Rate Contract | Virginia Electric and Power Company
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[3],[7]	18		(2)		77	24
Amount of Gain (Loss) Reclassified From AOCI to Income	[7]	(1)		(1)		(2)	(2)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[4],[7]	$ 182		$ 8		$ 814	$ 194

[1] Amounts deferred into AOCI have no associated effect in Dominion Energy’s Consolidated Statements of Income.

[2] Represents net derivative activity deferred into and amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/liabilities have no associated effect in Dominion Energy’s Consolidated Statements of Income.

[3] Amounts deferred into AOCI have no associated effect in Virginia Power’s Consolidated Statements of Income.

[4] Represents net derivative activity deferred into and amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/liabilities have no associated effect in Virginia Power’s Consolidated Statements of Income.

[5] Amounts recorded in Dominion Energy’s Consolidated Statement of Income are classified in purchased gas.

[6] Amounts recorded in Dominion Energy’s Consolidated Statement of Income are classified in interest and related charges.

[7] Amounts recorded in Virginia Power’s Consolidated Statements of Income are classified in interest and related charges.