Income Taxes (Reconciliation of Income Taxes at the U.S. Statutory Federal Rate as Compared to the Income Tax Expense Recorded in Our Consolidated Statements of Income) (Details)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Operating Loss Carryforwards [Line Items]
U.S. statutory rate	35.00%	35.00%
Increases (reductions) resulting from:
State taxes, net of federal benefit	2.40%	4.40%
Investment and production tax credits	(1.80%)	(0.60%)
Valuation allowances	0.00%	(0.90%)
AFUDC - equity	(0.70%)	(0.90%)
Other, net	(0.90%)	(2.10%)
Effective tax rate	34.00%	34.90%
Virginia Electric and Power Company
Operating Loss Carryforwards [Line Items]
U.S. statutory rate	35.00%	35.00%
Increases (reductions) resulting from:
State taxes, net of federal benefit	2.80%	3.90%
Investment and production tax credits	(0.20%)	0.00%
Valuation allowances	0.00%	0.00%
AFUDC - equity	(1.10%)	(0.80%)
Other, net	(0.30%)	0.10%
Effective tax rate	36.20%	38.20%