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, 2021		Jun. 30, 2020	Jun. 30, 2021		Jun. 30, 2020
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[1]	$ (21)		$ 6	$ 31		$ (353)
Amount of Gain (Loss) Reclassified From AOCI to Income		(16)		(7)	(33)		(36)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2]	(219)		14	189		(550)
Virginia Electric and Power Company
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[3]	(17)		2	26		(59)
Amount of Gain (Loss) Reclassified From AOCI to Income				(1)	(1)		(1)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[4]	(221)		13	186		(552)
Commodity contracts
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income				9	(1)		13
Commodity contracts | Operating Revenue
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income				8			14
Commodity contracts | Discontinued operations
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income				1			2
Commodity contracts | Purchased Gas
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income					(1)		(3)
Interest rate contracts
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[1]	(21)	[5]		31	[5]	(336)
Amount of Gain (Loss) Reclassified From AOCI to Income		(16)	[5]	(22)	(32)	[5]	(49)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2]	(219)	[5]	14	189	[5]	(550)
Interest rate contracts | Virginia Electric and Power Company
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[3],[6]	(17)		2	26		(59)
Amount of Gain (Loss) Reclassified From AOCI to Income	[6]			(1)	(1)		(1)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[4],[6]	$ (221)		13	$ 186		(552)
Interest rate contracts | Interest and Related Charges
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income				(18)			(43)
Interest rate contracts | Discontinued operations
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income				(4)			(6)
Foreign Exchange Contract
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	[1],[7]			6			$ (17)
Amount of Gain (Loss) Reclassified From AOCI to Income	[7]			$ 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 Statement of Income are classified in interest and related charges.

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

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