Derivatives and Hedge Accounting Activities (Gains and Losses on Derivatives in Cash Flow Hedging Relationships) (Details) - Cash Flow Hedges - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[1]	$ 45	$ (18)	$ 115	$ 68
Amount of Gain (Loss) Reclassified From AOCI to Income		29	72	66	174
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2]	(42)	108	(34)	(241)
Virginia Electric and Power Company
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[3]	(5)	(10)	(5)	(24)
Amount of Gain (Loss) Reclassified From AOCI to Income		(1)	0	(1)	(1)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[4]	(42)	108	(34)	(241)
Dominion Energy Gas Holdings, LLC
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[5]	18	(13)	3	(23)
Amount of Gain (Loss) Reclassified From AOCI to Income		19	(2)	1	2
Commodity
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[1]	44	12	131	185
Amount of Gain (Loss) Reclassified From AOCI to Income		21	82	83	187
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2]	0	0	0	0
Commodity | Dominion Energy Gas Holdings, LLC
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[5]	2	(6)	4	(7)
Amount of Gain (Loss) Reclassified From AOCI to Income		1		(3)	4
Commodity | Operating revenue
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income		19	87	81	201
Commodity | Operating revenue | Dominion Energy Gas Holdings, LLC
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income		1		(3)	4
Commodity | Electric fuel and other energy-related purchases
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income		2	(3)	2	(6)
Commodity | Purchased Gas
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income			(2)		(8)
Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[1],[6]	(15)	(23)	(14)	(110)
Amount of Gain (Loss) Reclassified From AOCI to Income	[6]	(11)	(8)	(23)	(11)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2],[6]	(42)	108	(34)	(241)
Interest rate | Virginia Electric and Power Company
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[3],[7]	(5)	(10)	(5)	(24)
Amount of Gain (Loss) Reclassified From AOCI to Income	[7]	(1)	0	(1)	(1)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[4],[7]	(42)	108	(34)	(241)
Interest rate | Dominion Energy Gas Holdings, LLC
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[5],[8]	0			(9)
Amount of Gain (Loss) Reclassified From AOCI to Income	[8]	(1)		(2)
Foreign currency
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[1],[9]	16	(7)	(2)	(7)
Amount of Gain (Loss) Reclassified From AOCI to Income	[9]	19	(2)	6	(2)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2],[9]	0	0	0	0
Foreign currency | Dominion Energy Gas Holdings, LLC
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[5],[10]	16	(7)	(1)	(7)
Amount of Gain (Loss) Reclassified From AOCI to Income	[10]	$ 19	$ (2)	$ 6	$ (2)

[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 deferred into AOCI have no associated effect in Dominion Energy Gas' Consolidated Statements of Income.

[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 Gas' Consolidated Statements of Income are classified in interest and related charges

[9] Amounts recorded in Dominion Energy’s Consolidated Statements of Income are classified in other income.

[10] Amounts recorded in Dominion Energy Gas' Consolidated Statements of Income are classified in other income.