Financings And Capitalization (Issuance Of Common Stock) (Details) (Continuous Equity Program [Member], USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	9 Months Ended
	Jun. 30, 2012	Sep. 30, 2012
Continuous Equity Program [Member]
Aggregate sales price of an equity offering program		$ 50
Shares of common stock issued	650,235	1,413,160
Per share value of common stock issued	$ 23.07
Value of common stock issued	$ 15	$ 30