Summary Of Significant Accounting Policies (Effective AFUDC Rate) (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accounting Policies [Abstract]
Effective AFUDC rate	7.62%	7.91%	8.25%	[1]

[1] ate was effective from January 1, 2010 to November 30, 2010. Effective December 1, 2010, the rate was changed to 7.91%.