Commitments and Contingencies (Details) (USD $)	6 Months Ended
Jun. 30, 2012	Dec. 31, 2011
Commitments and Contingencies (Textual) [Abstract]
Claims for damages	$ 800,000,000
Accrued incentives (fund level)	1,751,326,000	1,686,967,000
Compensation expense related to accrued incentives (fund level)	680,729,000	659,256,000
Capital commitments	328,637,000	266,541,000
Commitments	110,035,000	521,994,000
Aggregate potential investment commitments	$ 316,492,000	$ 367,930,000

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

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