Summary of Significant Accounting Policies (Details 3) (USD $)	12 Months Ended
	Dec. 31, 2011 M	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Income taxes
The ownership percentage for which the entity files a consolidated federal income tax return, low end of range	80.00%
Total accruals for unrecognized tax benefits	$ 99,230,000	$ 111,594,000	$ 113,100,000	$ 129,157,000
Unrecognized tax benefits, if realized would have impacted effective tax rate	80,300,000	88,200,000
Cash and Cash Equivalents
Maximum maturity period of short-term and highly liquid interest bearing investments at time of purchase (in months)	3
Excess capital and undistributed earnings included in cash and cash equivalents	56,300,000
Restricted Assets
Restricted cash	185,794,000	116,734,000	159,659,000
Restricted short-term investments	129,599,000	114,903,000
Restricted deposits (included in other current assets)	20,453,000	21,302,000
Restricted long-term investments	7,956,000	84,950,000
Total	$ 343,802,000	$ 337,889,000