Commitments and Contingencies (Environmental Matters) (Narrative) (Details) (USD $)	1 Months Ended				12 Months Ended		1 Months Ended				1 Months Ended	3 Months Ended
	Jun. 30, 2013	Feb. 28, 2013 T	Apr. 30, 2012 MW	Sep. 30, 2011 Party	Dec. 31, 2013 Site	Dec. 31, 2012 T	Jul. 31, 2011 Clean Air Act Group MW State	Dec. 31, 2013 Clean Air Act	Apr. 25, 2013 Clean Air Act	Dec. 31, 2013 Remedial options	Dec. 31, 2011 Virginia Electric and Power Company	Dec. 31, 2013 Virginia Electric and Power Company Site
Loss Contingencies [Line Items]
Charge reflecting plant balances not expected to be recovered											$ 228,000,000	$ 26,000,000
Charge reflecting plant balances not expected to be recovered, net of tax											139,000,000	16,000,000
Number of states under EPA Replacement Rule							28
Emissions of fossil fuel fired electric generating units			25				25
Number of groups of affected states							2
Estimate of possible loss								13,000,000	3,000,000
Amount of environmental mitigation projects									10,000,000
Number of parties ordered specific remedial action				22
Maximum civil penalties per day					37,500
Number of former manufactured gas plant sites					17							3
Preliminary costs for options under evaluation for the site, minimum										1,000,000
Preliminary costs for options under evaluation for the site, maximum										$ 22,000,000
Percentage Reduction In CO2 Emissions		10.00%
CO2 Emissions Cap		91,000,000				165,000,000
Percent further emission reduction goals in participating state power plant CO2 emissions					2.50%
National GHC reduction goal, percentage	17.00%
Period for consideration of CO2 emissions for biomass projects					3 years