Commitments and Contingencies (Lease Commitments) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Loss Contingencies [Line Items]
2013	$ 79
2014	72
2015	64
2016	55
2017	63
Thereafter	161
Total	494
Virginia Electric and Power Company
Loss Contingencies [Line Items]
2013	26
2014	24
2015	19
2016	15
2017	11
Thereafter	26
Total	$ 121