Income Taxes (Schedule of Unrecognized Tax Benefits) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1, 2013	$ 262	$ 293
Increases - prior period positions	2
Decreases - prior period positions	(42)
Current period positions	15
Settlements	(2)
Expiration of statutes of limitations	(4)
Balance at June 30, 2013	262	293
Virginia Electric and Power Company
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1, 2013	48	57
Increases - prior period positions	2
Decreases - prior period positions	(14)
Current period positions	5
Settlements	(2)
Expiration of statutes of limitations	0
Balance at June 30, 2013	$ 48	$ 57