Financial Instruments And Risk Management (Fair Value Of Derivative Instruments Derivatives In Fair Value Hedging Relationships) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	$ 42,648
Amount of Gain or (Loss) Recognized in Earnings on Hedging Items	(29,773)
Interest Expense [Member] | Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	42,648
Interest Expense [Member] | 2018 Senior Notes [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Hedging Items	$ (29,773)