Equity (Schedule of Reclassifications out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating Revenue		$ 2,556	$ 2,971	$ 2,747	$ 3,409	$ 2,943	$ 3,050	$ 2,813	$ 3,630	$ 11,683		$ 12,436		$ 13,120
Purchased gas										551		1,355		1,331
Electric fuel and other energy-related purchases										2,725		3,400		3,885
Interest and related charges										904		1,193		877
Income from continuing operations including noncontrolling interests before income taxes										2,828		1,778		2,704
Income tax expense										(905)		(452)		(892)
Income from continuing operations including noncontrolling interests										1,923		1,326		1,812
Other income										196		250		265
Impairment										31		13		8
Deferred gains and losses on derivatives-hedging activities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations including noncontrolling interests before income taxes										(176)		152
Income tax expense										68		(59)
Income from continuing operations including noncontrolling interests										(108)		93
Unrealized gains and losses on investment securities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations including noncontrolling interests before income taxes										(79)		(87)
Income tax expense										29		33
Income from continuing operations including noncontrolling interests										(50)		(54)
Other income										(110)		(100)
Impairment										31		13
Unrecognized pension and other postretirement benefit costs | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations including noncontrolling interests before income taxes										86		57
Income tax expense										(35)		(24)
Income from continuing operations including noncontrolling interests										51		33
Prior-service costs (credits)										(12)		(12)
Actuarial losses										98		69
Commodity | Deferred gains and losses on derivatives-hedging activities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating Revenue										(203)		130
Purchased gas										15		13
Electric fuel and other energy-related purchases										1		(7)
Interest rate | Deferred gains and losses on derivatives-hedging activities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and related charges										11		16
Dominion Gas Holdings, LLC
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating Revenue		425	365	395	531	510	391	428	569	1,716	[1]	1,898	[1]	1,937	[1]
Purchased gas	[1]									133		315		323
Interest and related charges	[1]									73		27		28
Income from continuing operations including noncontrolling interests before income taxes										740		846		762
Income tax expense										(283)		(334)		(301)
Other income										24		22		28
Dominion Gas Holdings, LLC | Deferred gains and losses on derivatives-hedging activities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations including noncontrolling interests before income taxes										(6)		13
Income tax expense										3		(5)
Income from continuing operations including noncontrolling interests										(3)		8
Dominion Gas Holdings, LLC | Unrecognized pension and other postretirement benefit costs | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations including noncontrolling interests before income taxes										7		8
Income tax expense										(3)		(3)
Income from continuing operations including noncontrolling interests										4		5
Prior-service costs (credits)												1
Actuarial losses										7		7
Dominion Gas Holdings, LLC | Commodity | Deferred gains and losses on derivatives-hedging activities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating Revenue										(6)		(2)
Purchased gas												14
Dominion Gas Holdings, LLC | Interest rate | Deferred gains and losses on derivatives-hedging activities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and related charges												1
Virginia Electric and Power Company
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating Revenue		$ 1,614	$ 2,058	$ 1,813	$ 2,137	$ 1,814	$ 2,053	$ 1,729	$ 1,983	7,622	[2]	7,579	[2]	7,295	[2]
Electric fuel and other energy-related purchases	[2]									2,320		2,406		2,304
Interest and related charges										443		411		369
Income from continuing operations including noncontrolling interests before income taxes										1,746		1,406		1,797
Income tax expense										(659)		(548)		(659)
Other income										68		93		86
Impairment										4		2		$ 1
Virginia Electric and Power Company | Deferred gains and losses on derivatives-hedging activities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations including noncontrolling interests before income taxes										1		(5)
Income tax expense										0		2
Income from continuing operations including noncontrolling interests										1		(3)
Virginia Electric and Power Company | Unrealized gains and losses on investment securities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations including noncontrolling interests before income taxes										(10)		(10)
Income tax expense										4		4
Income from continuing operations including noncontrolling interests										(6)		(6)
Other income										(14)		(10)
Impairment										4
Virginia Electric and Power Company | Commodity | Deferred gains and losses on derivatives-hedging activities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Electric fuel and other energy-related purchases										$ 1		$ (5)

[1] See Note 24 for amounts attributable to related parties.

[2] See Note 24 for amounts attributable to affiliates.