Commitments and Contingencies (Schedule of Nuclear Insurance Coverage) (Details) (USD $) In Billions, unless otherwise specified	Jun. 30, 2013
Millstone
Loss Contingencies [Line Items]
Coverage	$ 1.70
Kewaunee
Loss Contingencies [Line Items]
Coverage	1.06
Surry And North Anna
Loss Contingencies [Line Items]
Blanket property limit	0
Virginia Electric and Power Company | Surry
Loss Contingencies [Line Items]
Coverage	1.70	[1]
Virginia Electric and Power Company | North Anna
Loss Contingencies [Line Items]
Coverage	$ 1.70	[1]

[1] Surry and North Anna share a blanket property limit of $450 million.