Fair Value Disclosure (Activity for Interest Rate Swap Liabilities Classified as Level 3 Fair Value Measurements) (Details) (USD $)	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2010		Mar. 31, 2010	Jun. 30, 2010		Dec. 31, 2009
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance	$ 359,716,000		$ 352,267,000	$ 359,716,000		$ 300,040,000
Settlements	(178,248,000)			(235,674,000)
Less: total gains (losses) included in earnings	113,802,000	[1]		186,506,000	[1]
Less: total gains (losses) included in other comprehensive income (loss)	71,895,000			108,844,000
Fair value, liabilities measured on recurring basis, change in unrealized gain (loss) included in other income still held at the reporting date	$ 88,100,000			$ 123,600,000

[1] Includes $88.1 million and $123.6 million, respectively, for the three and six months ended June 30, 2010, of losses that are attributable to the change in unrealized gains or losses relating to liabilities still held at the reporting date.