Regulatory Matters (Narrative) (Details) (USD $)	1 Months Ended								9 Months Ended	12 Months Ended	9 Months Ended	1 Months Ended					9 Months Ended	1 Months Ended	0 Months Ended	1 Months Ended			1 Months Ended
	Sep. 30, 2013 MMBTU customer	May 31, 2013 bbl mi	Sep. 30, 2013 Minimum	Sep. 30, 2013 Maximum	May 31, 2012 Virginia Electric and Power Company	Mar. 31, 2010 Virginia Electric and Power Company	Jul. 31, 2008 Virginia Electric and Power Company Project	Apr. 30, 2008 Virginia Electric and Power Company	Sep. 30, 2013 Virginia Electric and Power Company Project	Dec. 31, 2012 Virginia Electric and Power Company Project	Sep. 30, 2013 Virginia Electric and Power Company Scenario, Forecast	Oct. 31, 2013 Virginia Electric and Power Company Virginia Regulation	Sep. 30, 2013 Virginia Electric and Power Company Virginia Regulation MW DSM_Program	Aug. 31, 2013 Virginia Electric and Power Company Virginia Regulation motion notice DSM_Program	Jul. 31, 2013 Virginia Electric and Power Company Virginia Regulation Part	Mar. 31, 2013 Virginia Electric and Power Company Virginia Regulation	Sep. 30, 2013 Virginia Electric and Power Company Virginia Regulation MW	Sep. 30, 2013 Virginia Electric and Power Company Virginia Regulation Bremo Power Station	Nov. 05, 2013 Virginia Electric and Power Company Virginia Regulation Subsequent Event	Oct. 31, 2013 Virginia Electric and Power Company Virginia Regulation Subsequent Event	Sep. 30, 2013 Virginia Electric and Power Company Virginia Regulation Other Current Liabilities	Sep. 30, 2013 Virginia Electric and Power Company Virginia Regulation Noncurrent Regulatory Liability	Aug. 31, 2013 Virginia Electric and Power Company Virginia Regulation Rider C1A	Aug. 31, 2013 Virginia Electric and Power Company Virginia Regulation Rider C2A	Jul. 31, 2008 Virginia Electric and Power Company 1.5% Incentive Rate For Projects Project	Jul. 31, 2008 Virginia Electric and Power Company 1.25% Incentive Rate For Projects Project
Regulatory Matters [Line Items]
ROE								11.40%									10.90%
Number of electric transmission projects							11			11															4	7
Incentive for 4 electric transmission enhancement projects							1.50%
Incentive for 7 electric transmission enhancement projects									1.25%
Number of electric transmission projects cancelled										1
Estimated cost of project abandonment										$ 7,000,000
Number of transmission projects approved									10
Estimated cost for electric transmission projects											852,000,000
Costs claimed to be unjust and excluded from transmission formula rate						223,000,000
Potential settlement required annual payment for 10 Years									250,000
Settlement payment duration					10 years
Earned ROE													10.30%			10.11%
Proposed base rate credit												9,000,000
Basis points below authorized ROE																	0.50%
Requested revenue requirement																			101,000,000				1,000,000	35,000,000
Combined spending cap inclusive of lost revenues														114,000,000
New DSM programs														3
Currently approved fuel factor rate (cents per kWh)																				0.02942
Requested fuel factor rate (cents per kWh)																				0.02572
Reduction in anticipated fuel recoveries																				140,000,000
Fuel recoveries																					20,000,000	47,000,000
Capacity (MW)													227				227
Proposed conversion expected cost																		53,000,000
Respondents who filed motions for reconsideration														3
Number of Filed Notices to Appeal Final Order														2
Requested ROE																			12.50%
Basis points enhancement to Roe																			1.00%
Number of parts of amendment															2
Cost of project	$ 42,000,000	$ 147,000,000
Capacity of project	185,000	27,000
Customers that have entered into binding agreement for full project capacity	4
Period for full project capacity			8 years	13 years
Length of pipeline		58