Commitments and Contingencies (Nuclear Operations) (Narrative) (Details) $ in Millions	1 Months Ended	12 Months Ended
	Nov. 30, 2013 $ / kWh	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Loss Contingencies [Line Items]
Amount of coverage purchased from commercial insurance pools		$ 375
Amount that could be assessed for each licensed reactor		127
Amount that could be assessed for each licensed reactor per reactor		19
Maximum assessment for premiums on insurance policy		84
Maximum assessment for insurance policy		23
Current fee per kWh for electricity paid by civilian nuclear power generators | $ / kWh	1
Waste fee recognized		16
Spent Nuclear Fuel
Loss Contingencies [Line Items]
Receivables		87	$ 69
Millstone Unit 1
Loss Contingencies [Line Items]
Minimum financial assurance			2,900
Surry and North Anna
Loss Contingencies [Line Items]
Settlement amount		8	27
Millstone
Loss Contingencies [Line Items]
Settlement amount		17	17
Kewaunee
Loss Contingencies [Line Items]
Settlement amount		7
Virginia Electric and Power Company
Loss Contingencies [Line Items]
Maximum assessment for premiums on insurance policy		48
Maximum assessment for insurance policy		10
Waste fee recognized		10
Virginia Electric and Power Company | Spent Nuclear Fuel
Loss Contingencies [Line Items]
Receivables		$ 54	41
Virginia Electric and Power Company | Kewaunee
Loss Contingencies [Line Items]
Minimum financial assurance			$ 1,800