Derivatives and Hedge Accounting Activities (Schedule of Offsetting Assets) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	$ 648		$ 883
Total derivatives, not subject to a master netting or similar arrangement	1		7
Derivative Assets	649	[1]	890	[1]
Gross Amounts Offset in the Consolidated Balance Sheet	0	[1]	0	[1]
Financial Instruments	543		568
Cash Collateral Received	0		0
Net Amounts	105		315
Interest rate | Over-the-counter
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	73		137
Gross Amounts Offset in the Consolidated Balance Sheet	0		0
Financial Instruments	43		0
Cash Collateral Received	0		0
Net Amounts	30		137
Commodity | Over-the-counter
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	203		240
Gross Amounts Offset in the Consolidated Balance Sheet	0		0
Financial Instruments	132		63
Cash Collateral Received	0		0
Net Amounts	71		177
Commodity | Exchange
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	372		506
Gross Amounts Offset in the Consolidated Balance Sheet	0		0
Financial Instruments	368		505
Cash Collateral Received	0		0
Net Amounts	4		1
Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	17		53
Total derivatives, not subject to a master netting or similar arrangement	1		0
Derivative Assets	18		53
Gross Amounts Offset in the Consolidated Balance Sheet	0		0
Financial Instruments	4		4
Cash Collateral Received	0		0
Net Amounts	13		49
Virginia Electric and Power Company | Interest rate | Over-the-counter
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	0		48
Gross Amounts Offset in the Consolidated Balance Sheet	0		0
Financial Instruments	0		0
Cash Collateral Received	0		0
Net Amounts	0		48
Virginia Electric and Power Company | Commodity | Over-the-counter
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	14		4
Gross Amounts Offset in the Consolidated Balance Sheet	0		0
Financial Instruments	4		4
Cash Collateral Received	0		0
Net Amounts	10		0
Virginia Electric and Power Company | Commodity | Exchange
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	3		1
Gross Amounts Offset in the Consolidated Balance Sheet	0		0
Financial Instruments	0		0
Cash Collateral Received	0		0
Net Amounts	$ 3		$ 1

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