Variable Interest Entities (Narrative) (Details) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2016 USD ($) MW generator	Mar. 31, 2015 USD ($)	Dec. 31, 2015 generator
Dominion Midstream Partners, LP
Variable Interest Entities [Line Items]
Ownership interest percentage of limited partner interests	64.60%
Variable Interest Entity, Primary Beneficiary | Partnership Interest | Merchant Solar Projects
Variable Interest Entities [Line Items]
Ownership percentage	67.00%
Variable Interest Entity, Primary Beneficiary | Dominion Midstream Partners, LP | Partnership Interest
Variable Interest Entities [Line Items]
Ownership interest percentage of limited partner interests	64.60%
Variable Interest Entity, Not Primary Beneficiary | Jointly Owned Natural Gas Pipeline | Atlantic Coast Pipeline | Pipelines | Gas Distribution
Variable Interest Entities [Line Items]
Ownership percentage	45.00%
Variable Interest Entity, Not Primary Beneficiary | Virginia Electric and Power Company
Variable Interest Entities [Line Items]
Long term capacity contract non utility generators (generators) | generator	3		5
Number of expired non-utility generators | generator			2
Aggregate generation capacity from long-term power and capacity contracts (MW) | MW	418
Remaining purchase commitments	$ 394
Payment for electric capacity	37	$ 53
Payment for electric energy	7	37
Shared services purchased	$ 114	83
Variable Interest Entity, Not Primary Beneficiary | Virginia Electric and Power Company | Minimum
Variable Interest Entities [Line Items]
Contracts expiry date start range	2017
Variable Interest Entity, Not Primary Beneficiary | Virginia Electric and Power Company | Maximum
Variable Interest Entities [Line Items]
Contracts expiry date start range	2021
Variable Interest Entity, Not Primary Beneficiary | Dominion Gas Holdings, LLC
Variable Interest Entities [Line Items]
Shared services purchased	$ 35	$ 28