Fair Value Measurements (Net Change in the Assets and Liabilities Measured at Fair Value on a Recurring Basis and Included in the Level 3 Fair Value Category) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Total realized and unrealized gains (losses):
Included in earnings	$ (2)	$ (1)	$ 98	$ 1
The amount of gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to assets/liabilities still held at the reporting date	1	2	2	0
Level 3 | Commodity Transactions | Fair Value, Measurements, Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	3	2	(16)	25
Total realized and unrealized gains (losses):
Included in earnings	(2)	(1)	98	1
Included in other comprehensive income (loss)	4	(25)	7	11
Included in regulatory assets/liabilities	39	10	53	(17)
Settlements	5	3	(94)	(23)
Transfers out of Level 3	(2)	7	(1)	(1)
Ending balance	47	(4)	47	(4)
The amount of gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to assets/liabilities still held at the reporting date	1	2	2	0
Level 3 | Virginia Electric and Power Company | Commodity Transactions | Fair Value, Measurements, Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	7	(25)	(7)	2
Total realized and unrealized gains (losses):
Included in earnings	(2)	(4)	109	(9)
Included in regulatory assets/liabilities	39	10	53	(17)
Settlements	2	4	(109)	9
Ending balance	46	(15)	46	(15)
Level 3 | Dominion Gas Holdings, LLC | Commodity Transactions | Fair Value, Measurements, Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(3)	23	(6)	(12)
Total realized and unrealized gains (losses):
Included in earnings	(1)	0	(8)	2
Included in other comprehensive income (loss)	5	(23)	8	11
Settlements	0	0	7	(1)
Ending balance	$ 1	$ 0	$ 1	$ 0