Income Taxes (Earliest Tax Year) (Details)	12 Months Ended
	Dec. 31, 2011
Pennsylvania [Member]
Earliest Open Tax Year	2008
Connecticut [Member]
Earliest Open Tax Year	2007
Massachusetts [Member]
Earliest Open Tax Year	2007
Virginia [Member]
Earliest Open Tax Year	2008	[1]
West Virginia [Member]
Earliest Open Tax Year	2008

[1] Virginia is the only state considered major for Virginia Power's operations.