Fair Values Of Financial Instruments (Fair Value And Carrying Value Of Preferred Stocks And Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Fair Values Of Financial Instruments [Abstract]
Preferred stocks with mandatory redemption requirements, Carrying Amount	$ 22,036	$ 22,794
Long-term debt (excluding capital lease obligations), Carrying Amount	5,366,642	5,424,492
Preferred stocks with mandatory redemption requirements, Fair Value	26,458	25,475
Long-term debt (excluding capital lease obligations), Fair Value	$ 6,230,547	$ 5,841,448