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		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[1]	$ 22	$ (7)	$ 90	$ 45
Amount of Gain (Loss) Reclassified From AOCI to Income		55	83	229	87
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2]	(16)	(69)	(258)	(24)
Commodity
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[1]	7	64	193	117
Amount of Gain (Loss) Reclassified From AOCI to Income		62	85	249	94
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2]	0	0	0	3
Commodity | Operating revenue
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income		64	87	266	103
Commodity | Purchased Gas
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income		(1)	(2)	(9)	(9)
Commodity | Electric Fuel and Other Energy-Related Purchases
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income		(1)		(8)
Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[1],[3]	3	(71)	(107)	(72)
Amount of Gain (Loss) Reclassified From AOCI to Income	[3]	(10)	(2)	(21)	(7)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2],[3]	(16)	(69)	(258)	(27)
Foreign currency
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[1],[4]	12		4
Amount of Gain (Loss) Reclassified From AOCI to Income	[4]	3		1
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[2],[4]	0		0
Virginia Electric and Power Company
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[5]	(2)	(9)	(26)	(4)
Amount of Gain (Loss) Reclassified From AOCI to Income		0	0	(1)	(1)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[6]	(16)	(69)	(258)	(24)
Virginia Electric and Power Company | Commodity
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[5]				0
Amount of Gain (Loss) Reclassified From AOCI to Income					(1)
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[6]				3
Virginia Electric and Power Company | Commodity | Electric Fuel and Other Energy-Related Purchases
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income					(1)
Virginia Electric and Power Company | Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[5],[7]	(2)	(9)	(26)	(4)
Amount of Gain (Loss) Reclassified From AOCI to Income	[7]	0	0	(1)	0
Increase (Decrease) in Derivatives Subject to Regulatory Treatment	[6],[7]	(16)	(69)	(258)	(27)
Dominion Gas Holdings, LLC
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[8]	12	4	(11)	2
Amount of Gain (Loss) Reclassified From AOCI to Income		3	3	5	4
Dominion Gas Holdings, LLC | Commodity
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[8]	0	11	(7)	10
Amount of Gain (Loss) Reclassified From AOCI to Income		1	3	6	4
Dominion Gas Holdings, LLC | Commodity | Operating revenue
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified From AOCI to Income		1	3	6	4
Dominion Gas Holdings, LLC | Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[8],[9]	0	(7)	(8)	(8)
Amount of Gain (Loss) Reclassified From AOCI to Income	[9]	(1)	$ 0	(2)	$ 0
Dominion Gas Holdings, LLC | Foreign currency
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	[8],[10]	12		4
Amount of Gain (Loss) Reclassified From AOCI to Income	[10]	$ 3		$ 1

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

[3] Amounts recorded in Dominion’s Consolidated Statements of Income are classified in interest and related charges.

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

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

[6] 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.

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

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

[9] Amounts recorded in Dominion Gas' Consolidated Statements of Income are classified in interest and related charges.

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