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				6 Months Ended
		Jun. 30, 2022		Jun. 30, 2021		Jun. 30, 2022	Jun. 30, 2021
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[1]	$ 39		$ (21)		$ 72	$ 31
Amount of Gain (Loss) Reclassified From AOCI to Income		(14)		(16)		(28)	(33)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2]	354		(219)		633	189
Virginia Electric and Power Company
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[3]	33		(17)		59	26
Amount of Gain (Loss) Reclassified From AOCI to Income				0		(1)	(1)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[4]	353		(221)		632	186
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]	39	[6]	(21)	[6]	72	31
Amount of Gain (Loss) Reclassified From AOCI to Income		(14)	[6]	(16)	[6]	(28)	(32)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2]	354	[6]	(219)	[6]	633	189
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]	33		(17)		59	26
Amount of Gain (Loss) Reclassified From AOCI to Income	[7]			0		(1)	(1)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[4],[7]	$ 353		$ (221)		$ 632	$ 186

[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.