Commitments and Contingencies (Guarantees, Surety Bonds and Letters of Credit) (Narrative) (Details) $ in Millions	Dec. 31, 2015 USD ($)
Guarantor Obligations [Line Items]
Exposure under guarantees	$ 6,562
Purchased surety bonds	92
Authorized issuance of standby letters of credit	59
Debt
Guarantor Obligations [Line Items]
Exposure under guarantees	27	[1]
Virginia Electric and Power Company
Guarantor Obligations [Line Items]
Purchased surety bonds	34
Virginia Electric and Power Company | Debt
Guarantor Obligations [Line Items]
Exposure under guarantees	14
Dominion Gas Holdings, LLC
Guarantor Obligations [Line Items]
Purchased surety bonds	23
Third Party and Equity Method Investee
Guarantor Obligations [Line Items]
Estimate of possible loss	74
Exposure under guarantees	$ 39

[1] Guarantee of debt of a DEI subsidiary. In the event of default by the subsidiary, Dominion would be obligated to repay such amounts.