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	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Included in earnings	$ 97	$ (9)	$ (15)
The amount of total gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to assets still held at the reporting date	6	0	42
Commodity | Level 3
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
The amount of total gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to assets still held at the reporting date	6	0	42
Commodity | Level 3 | Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Beginnning balance	(16)	25	(71)
Included in earnings	97	(9)	(15)
Included in regulatory assets/liabilities	109	(9)	30
Included in other comprehensive income (loss)	7	1	101
Settlements	(88)	(23)	47
Transfers out of Level 3	(2)	(1)	(67)
Ending balance	107	(16)	25
Commodity | Virginia Electric and Power Company | Level 3 | Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Beginnning balance	(7)	2	(28)
Included in earnings	96	(17)	(50)
Included in regulatory assets/liabilities	109	(9)	30
Settlements	(96)	17	50
Ending balance	102	(7)	2
Commodity | Dominion Gas Holdings, LLC | Level 3 | Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Beginnning balance	(6)	(12)	(98)
Included in earnings	2	1	(15)
Included in other comprehensive income (loss)	10	3	86
Settlements	(4)	2	15
Ending balance	$ 2	$ (6)	$ (12)