Variable Interest Entities (Narrative) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) MW generator	Sep. 30, 2014 USD ($)
Virginia Electric and Power Company
Variable Interest Entities [Line Items]
Long term capacity contract non utility generators (generators) | generator			5
Aggregate generation capacity from long-term power and capacity contracts (MW) | MW			870
Remaining purchase commitments			$ 478
Payment for electric capacity	$ 52	$ 55	160	$ 166
Payment for electric energy	17	28	77	115
Shared services purchased	73	82	$ 239	246
Virginia Electric and Power Company | Minimum
Variable Interest Entities [Line Items]
Contracts expiry date start range			2015
Virginia Electric and Power Company | Maximum
Variable Interest Entities [Line Items]
Contracts expiry date start range			2021
Dominion Gas Holdings, LLC
Variable Interest Entities [Line Items]
Shared services purchased	$ 27	$ 27	$ 85	$ 78
Dominion Midstream Partners, LP | Iroquois | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entities [Line Items]
Ownership percentage			25.93%
Dominion Gas Holdings, LLC | Iroquois | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entities [Line Items]
Ownership percentage			24.72%