Regulatory Assets and Liabilities (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Public Utilities, General Disclosures [Line Items]
Regulatory assets past expenditures not earning return	$ 289
Period for which expenditures are expected to be recovered	2 years
Virginia Electric and Power Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets past expenditures not earning return	$ 269
Dominion Gas Holdings, LLC
Public Utilities, General Disclosures [Line Items]
Regulatory assets past expenditures not earning return	$ 18