Income Taxes (Schedule of Unrecognized Tax Benefits) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1, 2013	$ 231	$ 293
Increases - prior period positions	14
Decreases - prior period positions	(91)
Current period positions	21
Settlements	(2)
Expiration of statutes of limitations	(4)
Balance at September 30, 2013	231	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	32	57
Increases - prior period positions	12
Decreases - prior period positions	(42)
Current period positions	7
Settlements	(2)
Expiration of statutes of limitations	0
Balance at September 30, 2013	$ 32	$ 57