Fair Value of Financial Instruments (Details 2) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Derivatives in Cash Flow Hedging Relationships [Member] | Interest rate swaps [Member]
Amount of pre-tax loss recognized in the condensed consolidated balance sheets as a component of other comprehensive income
Amount of Pre-Tax Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	$ (67,685)	$ (107,656)	$ (63,572)	$ (178,564)
Interest expense, net [Member]
Effective portion of the pre-tax loss reclassified from accumulated other comprehensive loss ("OCL') into interest expense on the condensed consolidated statements of income
Amount of Pre-Tax Loss Reclassified from AOCL into Income (Effective Portion)	$ 53,649	$ 55,009	$ 106,573	$ 108,173