Derivatives and Hedge Accounting Activities (Schedule of Offsetting Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	$ 445	$ 782
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Total derivatives, not subject to a master netting or similar arrangement	8	12
Derivative Liabilities	453	794
Derivative, Collateral, Right to Reclaim Securities	302	348
Derivative, Collateral, Right to Reclaim Cash	25	196
Net Amounts	118	238
Interest rate | Over-the-counter
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	108	202
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Derivative, Collateral, Right to Reclaim Securities	25	16
Derivative, Collateral, Right to Reclaim Cash	0	0
Net Amounts	83	186
Commodity | Over-the-counter
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	65	87
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Derivative, Collateral, Right to Reclaim Securities	30	34
Derivative, Collateral, Right to Reclaim Cash	0	1
Net Amounts	35	52
Commodity | Exchange
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	272	493
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Derivative, Collateral, Right to Reclaim Securities	247	298
Derivative, Collateral, Right to Reclaim Cash	25	195
Net Amounts	0	0
Virginia Electric and Power Company
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	18	80
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Total derivatives, not subject to a master netting or similar arrangement	3	7
Derivative Liabilities	21	87
Derivative, Collateral, Right to Reclaim Securities	8	4
Derivative, Collateral, Right to Reclaim Cash	0	0
Net Amounts	10	76
Virginia Electric and Power Company | Interest rate | Over-the-counter
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	16	72
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Derivative, Collateral, Right to Reclaim Securities	6	0
Derivative, Collateral, Right to Reclaim Cash	0	0
Net Amounts	10	72
Virginia Electric and Power Company | Commodity | Over-the-counter
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	2	8
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Derivative, Collateral, Right to Reclaim Securities	2	4
Derivative, Collateral, Right to Reclaim Cash	0	0
Net Amounts	0	4
Dominion Gas Holdings, LLC
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	15	9
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Derivative, Collateral, Right to Reclaim Securities	6	0
Derivative, Collateral, Right to Reclaim Cash	0	0
Net Amounts	9	9
Dominion Gas Holdings, LLC | Interest rate | Over-the-counter
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	9	9
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	0	0
Net Amounts	9	9
Dominion Gas Holdings, LLC | Commodity | Over-the-counter
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	6	0
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Derivative, Collateral, Right to Reclaim Securities	6	0
Derivative, Collateral, Right to Reclaim Cash	0	0
Net Amounts	$ 0	$ 0