Regulatory Matters (Narrative) (Details) (USD $)	1 Months Ended						3 Months Ended	12 Months Ended	3 Months Ended			1 Months Ended	3 Months Ended	24 Months Ended	3 Months Ended	1 Months Ended							12 Months Ended
	Mar. 31, 2013 Scenario, Forecast Sabinsville to Morrisville Project Dekatherm	Mar. 31, 2013 Scenario, Forecast Tioga Area Expansion Project Dekatherm	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	Mar. 31, 2013 Virginia Electric and Power Company Project	Dec. 31, 2012 Virginia Electric and Power Company Project	Mar. 31, 2013 Virginia Electric and Power Company Scenario, Forecast	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	Mar. 31, 2013 Virginia Electric and Power Company Virginia Regulation MW	Mar. 31, 2013 Virginia Electric and Power Company Virginia Regulation	Dec. 31, 2012 Virginia Electric and Power Company Virginia Regulation	Mar. 31, 2013 Virginia Electric and Power Company Virginia Regulation Base Roe	Apr. 25, 2013 Virginia Electric and Power Company Virginia Regulation Rider C1A April 2014 Subsequent Event	Apr. 25, 2013 Virginia Electric and Power Company Virginia Regulation Rider C2A April 2014 Subsequent Event	Apr. 25, 2013 Virginia Electric and Power Company Virginia Regulation Riders C1A And C2A Low Income Program April 2014 Subsequent Event	Apr. 25, 2013 Virginia Electric and Power Company Virginia Regulation Riders C1A And C2A Air Conditioner Cycling Program April 2014 Subsequent Event	Mar. 31, 2013 Virginia Electric and Power Company Virginia Regulation Rider S April 2013	Mar. 31, 2013 Virginia Electric and Power Company Virginia Regulation Rider B April 2013	Feb. 28, 2013 East Ohio Ohio Regulation	Dec. 31, 2008 East Ohio Ohio Regulation
Regulatory Matters [Line Items]
Authorized ROE						11.40%							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
Actual ROE														10.11%
Basis points performance incentive as provided for by regulation act															0.50%
Percentage of earnings that exceeded an ROE													60.00%
Requested authorized ROE													11.50%
Approved revenue requirement																4,000,000	23,000,000
Cost cap																		14,000,000
Period for DSM programs																		2 years	3 years
Revenue requirement																				248,000,000	12,000,000
Percentage of energy output purchased												100.00%
Energy output of customer owned solar distributed generation facilities												3
Fixed price of energy output purchased												0.15
Period to purchase energy output												5 years
Percentage of pipeline system to be replaced																							20.00%
Proposed PIR total gross plant investment																						148,000,000
Cumulative gross plant investment																						511,000,000
Proposed revenue requirement																						$ 67,000,000
Capacity of project	92,000	270,000