Consolidated Investment Products (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Jun. 02, 2010
Variable Interest Entity [Line Items]
Percentage of VIE general partnership interest	1.00%
Number of Investment Trusts Entered into Contingent Support Agreements	2
Total assets	$ 19,347,000,000	$ 20,444,100,000
Consolidated appropriated retained earnings due to acquisition			149,400,000
Real Estate Funds Assets		385,900,000
Other Noncontrolling Interests		363,600,000
Pay interest at Libor or Euribor plus	13.00%
Collateral assets, default percentage	1.00%	2.00%
Outstanding balance on the notes issued by consolidated CLOs exceeds their fair value by approximately	1,000,000,000	1,200,000,000
Notes issued by collateralized loan obligations terms of arrangements interest rate margin spread low	0.21%
Notes issued by collateralized loan obligations terms of arrangements interest rate margin spread high	7.25%
Notes issued by collateralized loan obligations cumulative average default rate range minimum	1.00%
Notes issued by collateralized loan obligations cumulative average default rate range maximum	5.00%
CLO [Member]
Variable Interest Entity [Line Items]
Total assets			805,400,000
Weighted average maturity (years)	9.3
Gain (loss) on derivative instruments, net, pretax	9,200,000	7,900,000
Senior Secured Bank Loans And Bonds [Member] | CLO [Member]
Variable Interest Entity [Line Items]
Fair value, option, aggregate differences, long-term debt instruments	701,000,000	261,000,000
Swap [Member] | VIEs [Member]
Variable Interest Entity [Line Items]
Derivative instruments, number of open swap agreements	70	105
Derivative instruments, open swap agreements, notional value	$ 123,300,000	$ 168,400,000
Minimum [Member] | Private Equity Funds [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Terms (in years)	7 years
Maximum [Member] | Private Equity Funds [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Terms (in years)	12 years