Accumulated Other Comprehensive Income (Schedule of Reclassifications out of AOCI by Component Net of Tax) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Operating Revenue	$ 3,409		$ 3,630
Purchased gas	250		540
Electric fuel and other energy-related purchases	953		1,334
Interest and related charges	223		237
Other income	60		40
Income from continuing operations including noncontrolling interests before income tax expense	839		571
Income tax expense	(299)		(186)
Dominion Gas Holdings, LLC
Accumulated Other Comprehensive Income (Loss) [Line Items]
Operating Revenue	531	[1]	569	[1]
Purchased gas	74	[1]	137	[1]
Interest and related charges	17		6
Other income	9		8
Income from continuing operations including noncontrolling interests before income tax expense	263		267
Income tax expense	(102)		(103)
Deferred gains and losses on derivatives-hedging activities | Amounts reclassified from AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income from continuing operations including noncontrolling interests before income tax expense	98		260
Income tax expense	(39)		(100)
Income from continuing operations including noncontrolling interests	59		160
Deferred gains and losses on derivatives-hedging activities | Amounts reclassified from AOCI | Dominion Gas Holdings, LLC
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income from continuing operations including noncontrolling interests before income tax expense			8
Income tax expense			(3)
Income from continuing operations including noncontrolling interests			5
Unrealized gains and losses on investment securities | Amounts reclassified from AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other income	(39)		(20)
Impairment	6		2
Income from continuing operations including noncontrolling interests before income tax expense	(33)		(18)
Income tax expense	12		7
Income from continuing operations including noncontrolling interests	(21)		(11)
Unrecognized pension and other postretirement benefit costs | Amounts reclassified from AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior service (credit) costs	(3)		(3)
Actuarial (gains) losses	25		17
Income from continuing operations including noncontrolling interests before income tax expense	22		14
Income tax expense	(9)		(6)
Income from continuing operations including noncontrolling interests	13		8
Unrecognized pension and other postretirement benefit costs | Amounts reclassified from AOCI | Dominion Gas Holdings, LLC
Accumulated Other Comprehensive Income (Loss) [Line Items]
Actuarial (gains) losses	2		2
Income from continuing operations including noncontrolling interests before income tax expense	2		2
Income tax expense	(1)		(1)
Income from continuing operations including noncontrolling interests	1		1
Commodity contracts | Deferred gains and losses on derivatives-hedging activities | Amounts reclassified from AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Operating Revenue	92		269
Purchased gas	5		1
Electric fuel and other energy-related purchases	(1)		(13)
Commodity contracts | Deferred gains and losses on derivatives-hedging activities | Amounts reclassified from AOCI | Dominion Gas Holdings, LLC
Accumulated Other Comprehensive Income (Loss) [Line Items]
Operating Revenue			6
Purchased gas			2
Interest rate contracts | Deferred gains and losses on derivatives-hedging activities | Amounts reclassified from AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and related charges	$ 2		$ 3

[1] See Note 17 for amounts attributable to related parties.