Equity (Schedule of Reclassifications out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating Revenue		$ (3,086)	$ (3,132)	$ (2,598)	$ (2,921)	$ (2,556)	$ (2,971)	$ (2,747)	$ (3,409)	$ (11,737)		$ (11,683)		$ (12,436)
Purchased gas										459		551		1,355
Electric fuel and other energy-related purchases										2,333		2,725		3,400
Interest and related charges										1,010		904		1,193
Other Income										(250)		(196)		(250)
Impairment										23		31		13
Income from continuing operations including noncontrolling interests before income taxes										(2,867)		(2,828)		(1,778)
Income tax expense										655		905		452
Other operations and maintenance										3,064		2,595		2,765
Dominion Gas Holdings, LLC
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating Revenue		(457)	(382)	(368)	(431)	(425)	(365)	(395)	(531)	(1,638)	[1]	(1,716)	[1]	(1,898)	[1]
Purchased gas	[1]									109		133		315
Interest and related charges	[1]									94		73		27
Other Income										(11)		(1)		(1)
Income from continuing operations including noncontrolling interests before income taxes										(607)		(740)		(846)
Income tax expense										215		283		334
Virginia Electric and Power Company
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating Revenue		$ (1,711)	$ (2,211)	$ (1,776)	$ (1,890)	$ (1,614)	$ (2,058)	$ (1,813)	$ (2,137)	(7,588)	[2]	(7,622)	[2]	(7,579)	[2]
Electric fuel and other energy-related purchases	[2]									1,973		2,320		2,406
Interest and related charges										461		443		411
Other Income										(56)		(68)		(93)
Impairment										3		4		2
Income from continuing operations including noncontrolling interests before income taxes										(1,945)		(1,746)		(1,406)
Income tax expense										727		659		$ 548
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										(259)		(176)
Income tax expense										100		68
Income from continuing operations including noncontrolling interests										(159)		(108)
Deferred (gains) and losses on derivatives-hedging activities: | Reclassification out of Accumulated Other Comprehensive Income | Dominion Gas Holdings, LLC
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations including noncontrolling interests before income taxes										15		(6)
Income tax expense										(6)		3
Income from continuing operations including noncontrolling interests										9		(3)
Deferred (gains) and losses on derivatives-hedging activities: | Reclassification out of Accumulated Other Comprehensive Income | Virginia Electric and Power Company
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations including noncontrolling interests before income taxes										1		1
Income tax expense										0		0
Income from continuing operations including noncontrolling interests										1		1
Deferred (gains) and losses on derivatives-hedging activities: | Commodity | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating Revenue										(330)		(203)
Purchased gas										13		15
Electric fuel and other energy-related purchases										10		1
Deferred (gains) and losses on derivatives-hedging activities: | Commodity | Reclassification out of Accumulated Other Comprehensive Income | Dominion Gas Holdings, LLC
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating Revenue										(4)		(6)
Deferred (gains) and losses on derivatives-hedging activities: | Commodity | Reclassification out of Accumulated Other Comprehensive Income | Virginia Electric and Power Company
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Electric fuel and other energy-related purchases												1
Deferred (gains) and losses on derivatives-hedging activities: | Interest rate | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and related charges										31		11
Deferred (gains) and losses on derivatives-hedging activities: | Interest rate | Reclassification out of Accumulated Other Comprehensive Income | Dominion Gas Holdings, LLC
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and related charges										2
Deferred (gains) and losses on derivatives-hedging activities: | Interest rate | Reclassification out of Accumulated Other Comprehensive Income | Virginia Electric and Power Company
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and related charges										1
Deferred (gains) and losses on derivatives-hedging activities: | Foreign currency | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income										17
Deferred (gains) and losses on derivatives-hedging activities: | Foreign currency | Reclassification out of Accumulated Other Comprehensive Income | Dominion Gas Holdings, LLC
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income										17
Unrealized (gains) and losses on investment securities: | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Realized (gain) loss on sale of securities										(66)		(110)
Impairment										23		31
Income from continuing operations including noncontrolling interests before income taxes										(43)		(79)
Income tax expense										15		29
Income from continuing operations including noncontrolling interests										(28)		(50)
Unrealized (gains) and losses on investment securities: | Reclassification out of Accumulated Other Comprehensive Income | Virginia Electric and Power Company
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Realized (gain) loss on sale of securities										(9)		(14)
Impairment										3		4
Income from continuing operations including noncontrolling interests before income taxes										(6)		(10)
Income tax expense										2		4
Income from continuing operations including noncontrolling interests										(4)		(6)
Unrecognized pension and other postretirement benefit costs:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrecognized pension and other postretirement benefit costs, before tax										56		86
Unrecognized pension and other postretirement benefit costs, income tax expense										(22)		(35)
Unrecognized pension and other postretirement benefit costs, net of tax										34		51
Unrecognized pension and other postretirement benefit costs: | Dominion Gas Holdings, LLC
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrecognized pension and other postretirement benefit costs, before tax										5		7
Unrecognized pension and other postretirement benefit costs, income tax expense										(2)		(3)
Unrecognized pension and other postretirement benefit costs, net of tax										3		4
Prior-service costs (credits) | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other operations and maintenance										(15)		(12)
Actuarial losses | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other operations and maintenance										71		98
Actuarial losses | Reclassification out of Accumulated Other Comprehensive Income | Dominion Gas Holdings, LLC
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other operations and maintenance										$ 5		$ 7

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

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