Quarterly Financial and Common Stock Data (Unaudited) (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Mar. 31, 2014
Condensed Financial Statements, Captions [Line Items]
After tax charges associated with liability management exercise				$ 172
Charge recognized, net of tax					$ 191	$ 193
Virginia Electric and Power Company
Condensed Financial Statements, Captions [Line Items]
Charge related to settlement offer, net of tax				74
Charge recognized, net of tax					$ 191
Virginia Electric and Power Company | Deferred Fuel Costs | Virginia Regulation
Condensed Financial Statements, Captions [Line Items]
Write off of deferred fuel cost, net of tax	$ 52
Virginia Electric and Power Company | Facilities Subject to Coal Combustion Residual Final Rule
Condensed Financial Statements, Captions [Line Items]
Charge related to settlement offer, net of tax	32		$ 28
Dominion Gas Holdings, LLC
Condensed Financial Statements, Captions [Line Items]
After tax gain from agreement to convey development rights				$ 36
Dominion Gas Holdings, LLC | Oil and Gas Properties
Condensed Financial Statements, Captions [Line Items]
After tax gain on sale	$ 43	$ 29