Derivatives and Hedge Accounting Activities (Gains and Losses on Derivatives in Cash Flow Hedging Relationships) (Detail) - Cash Flow Hedges - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020	Dec. 31, 2019
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[1]	$ 21		$ (320)	$ (145)
Amount of Gain (Loss) Reclassified From AOCI to Income		(61)		(302)	83
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2]	135		(332)	(255)
Virginia Electric and Power Company
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[3]	17		(37)	(30)
Amount of Gain (Loss) Reclassified From AOCI to Income		(3)		(2)	(1)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[4]	130		(338)	(259)
Commodity
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[1]				125
Amount of Gain (Loss) Reclassified From AOCI to Income				23	143
Commodity | Purchased Gas
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income		(1)	[5]	(4)	(3)
Commodity | Operating Revenue
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income				25	142
Commodity | Discontinued operations
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income				2	4
Interest rate
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[1]	21	[6]	(309)	(252)
Amount of Gain (Loss) Reclassified From AOCI to Income		(60)	[6]	(319)	(54)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2]	135	[6]	(332)	(255)
Interest rate | Virginia Electric and Power Company
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[3],[7]	17		(37)	(30)
Amount of Gain (Loss) Reclassified From AOCI to Income	[7]	(3)		(2)	(1)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[4],[7]	$ 130		(338)	(259)
Interest rate | Discontinued operations
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income				(236)	(5)
Interest rate | Interest and Related Charges
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income				(83)	(49)
Foreign currency exchange rate
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[1],[8]			(11)	(18)
Amount of Gain (Loss) Reclassified From AOCI to Income	[8]			$ (6)	$ (6)

[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 Statements of Income are classified in purchased gas.

[6] Amounts recorded in Dominion Energy’s Consolidated Statements 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.

[8] Amounts recorded in Dominion Energy’s Consolidated Statements of Income are classified in discontinued operations.