Income Taxes (Unrecognized Tax Benefits) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1	$ 222	$ 293	$ 347
Increases-prior period positions	24	17	28
Decreases-prior period positions	(26)	(99)	(106)
Increases-current period positions	16	30	43
Decreases-current period positions	0	(5)	0
Settlements with tax authorities	0	(2)	(4)
Expiration of statutes of limitations	(91)	(12)	(15)
Balance at December 31	145	222	293
Virginia Electric and Power Company
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1	39	57	114
Increases-prior period positions	2	12	4
Decreases-prior period positions	(16)	(42)	(80)
Increases-current period positions	11	14	24
Decreases-current period positions	0	0	0
Settlements with tax authorities	0	(2)	(4)
Expiration of statutes of limitations	0	0	(1)
Balance at December 31	36	39	57
Dominion Gas Holdings, LLC
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1	29	30	30
Increases-prior period positions	0	0	0
Decreases-prior period positions	0	(1)	0
Increases-current period positions	0	0	0
Decreases-current period positions	0	0	0
Settlements with tax authorities	0	0	0
Expiration of statutes of limitations	0	0	0
Balance at December 31	$ 29	$ 29	$ 30