Derivatives and Hedge Accounting Activities (Schedule of Offsetting Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	$ 335	$ 782
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	335	782
Total derivatives, not subject to a master netting or similar arrangement	8	12
Gross Amounts of Recognized Liabilities, Total	343	794
Derivative liabilities	343	794
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	141	348
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Paid	0	196
Net Amounts	194	238
Interest rate | Over-the-counter
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	183	202
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	183	202
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	22	16
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Paid	0	0
Net Amounts	161	186
Commodity | Over-the-counter
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	70	87
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	70	87
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	37	34
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Paid	0	1
Net Amounts	33	52
Commodity | Exchange
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	82	493
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	82	493
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	82	298
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Paid	0	195
Net Amounts	0	0
Virginia Electric and Power Company
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	64	80
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	64	80
Total derivatives, not subject to a master netting or similar arrangement	22	7
Gross Amounts of Recognized Liabilities, Total	86	87
Derivative liabilities	86	87
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	13	4
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Paid	0	0
Net Amounts	51	76
Virginia Electric and Power Company | Interest rate | Over-the-counter
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	59	72
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	59	72
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	10	0
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Paid	0	0
Net Amounts	49	72
Virginia Electric and Power Company | Commodity | Over-the-counter
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	5	8
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	5	8
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	3	4
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Paid	0	0
Net Amounts	2	4
Dominion Gas Holdings, LLC
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	14	9
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	14	9
Derivative liabilities	14	9
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	0	0
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Paid	0	0
Net Amounts	14	9
Dominion Gas Holdings, LLC | Interest rate | Over-the-counter
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	14	9
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	14	9
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	0	0
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Paid	0	0
Net Amounts	$ 14	$ 9