Significant Accounting Policies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounting Policy [Line Items]
Accrued unbilled revenue	$ 555	$ 411
Percentage of fuel currently subject to deferred fuel accounting	84.00%
Interest income	3		12
Reduction in interest expense	10	3	7
Income Tax Interest Income		8
Reduction in penalties (less than $1 million)		1	1
Accrued interest receivable	5	5
Interest and penalties payable	15	10
Income tax examination, penalties accrued	1	1
Accounts payable for checks outstanding	38	53
Margin assets	620	212
Margin liabilities	2	4
Capitalized interest costs	66	91	85
Inventory under LIFO method	7	24
Amount exceeded on LIFO basis	77	69
Virginia Electric and Power Company
Accounting Policy [Line Items]
Accrued unbilled revenue	395	348
Income Tax Interest Income			12
Income taxes payable	22
Noncurrent federal and state income taxes payable	28	36
Accounts payable for checks outstanding	21	30
Margin assets	11	18
Capitalized interest costs	33	31	31
AFUDC related to projects	32	37	20
State | Virginia Electric and Power Company
Accounting Policy [Line Items]
Income tax receivable	3
Non current income tax receivable	12
Federal | Virginia Electric and Power Company
Accounting Policy [Line Items]
Prepaid federal and state income taxes		$ 10