Accumulated Other Comprehensive Income (Schedule of Reclassifications out of AOCI by Component Net of Tax) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Operating Revenue		$ 2,747	$ 2,813	$ 6,156		$ 6,443
Purchased gas		111	324	361		864
Electric fuel and other energy-related purchases		591	633	1,544		1,967
Interest and related charges		221	227	444		464
Other income		56	57	116		97
Income from operations including noncontrolling interests before income tax expense		608	224	1,447		795
Income tax expense		(190)	(63)	(489)		(249)
Dominion Gas Holdings, LLC
Accumulated Other Comprehensive Income (Loss) [Line Items]
Operating Revenue	[1]	395	428	926		997
Purchased gas	[1]	21	76	95		213
Interest and related charges		18	6	35	[1]	12	[1]
Other income		4	5	13		13
Income from operations including noncontrolling interests before income tax expense		139	153	402		420
Income tax expense		(54)	(60)	(156)		(163)
Deferred gains and losses on derivatives-hedging activities | Amounts reclassified from AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income from operations including noncontrolling interests before income tax expense		(102)	(22)	(4)		238
Income tax expense		41	6	2		(94)
Income from continuing operations including noncontrolling interests		(61)	(16)	(2)		144
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 operations including noncontrolling interests before income tax expense		(1)	5	(1)		12
Income tax expense		0	(2)	0		(4)
Income from continuing operations including noncontrolling interests		(1)	3	(1)		8
Unrealized gains and losses on investment securities | Amounts reclassified from AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other income		(25)	(13)	(64)		(33)
Impairment		5	2	11		4
Income from operations including noncontrolling interests before income tax expense		(20)	(11)	(53)		(29)
Income tax expense		8	4	20		11
Income from continuing operations including noncontrolling interests		(12)	(7)	(33)		(18)
Unrecognized pension and other postretirement benefit costs | Amounts reclassified from AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior service (credit) costs		(3)	(2)	(6)		(5)
Actuarial (gains) losses		24	17	49		34
Income from operations including noncontrolling interests before income tax expense		21	15	43		29
Income tax expense		(9)	(6)	(18)		(12)
Income from continuing operations including noncontrolling interests		12	9	25		17
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	1	4		4
Income from operations including noncontrolling interests before income tax expense		2	1	4		4
Income tax expense		(1)	0	(2)		(1)
Income from continuing operations including noncontrolling interests		1	1	2		3
Commodity contracts | Deferred gains and losses on derivatives-hedging activities | Amounts reclassified from AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Operating Revenue		(107)	(28)	(15)		241
Purchased gas		2	3	7		4
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		(1)	2	(1)		7
Purchased gas			3			5
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		$ 3	$ 3	$ 5		$ 6

[1] See Note 18 for amounts attributable to related parties.