Regulatory Assets and Liabilities (Narrative) (Details) - Jun. 30, 2015 - USD ($) $ in Millions	Total
Public Utilities, General Disclosures [Line Items]
Regulatory assets past expenditures not earning return	$ 123
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	$ 105
Dominion Gas Holdings, LLC
Public Utilities, General Disclosures [Line Items]
Regulatory assets past expenditures not earning return	$ 18