Consolidated Investment Products (Fair Value Hierarchy Levels Of Investments Held And Notes Issued By Consolidated Investment Products) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
CLO notes	$ (9,644.1)	$ (8,443.4)
Fair Value Measurements [Member]
Private equity fund assets	100.8	125.0
Real estate investments		5.3
Total assets at fair value	4,514.6	4,550.6
Total liabilities at fair value	(4,003.1)	(3,899.4)
Quoted Prices in Active Markets for Identical Assets [Member]
Private equity fund assets	37.4	21.0
Real estate investments		0
Total assets at fair value	39.4	31.0
Total liabilities at fair value	0	0
Significant Other Observable Inputs [Member]
Private equity fund assets	4.8	9.9
Real estate investments		0
Total assets at fair value	3,968.4	3,916.7
Total liabilities at fair value	0	0
Significant Unobservable Inputs [Member]
Private equity fund assets	58.6	94.1
Real estate investments		5.3
Total assets at fair value	506.8	602.9
Total liabilities at fair value	(4,003.1)	(3,899.4)
Bank Loans [Member] | Fair Value Measurements [Member]
CLO collateral assets	3,795.1	3,709.3
Bank Loans [Member] | Quoted Prices in Active Markets for Identical Assets [Member]
CLO collateral assets	0	0
Bank Loans [Member] | Significant Other Observable Inputs [Member]
CLO collateral assets	3,795.1	3,709.3
Bank Loans [Member] | Significant Unobservable Inputs [Member]
CLO collateral assets	0	0
Bonds [Member] | Fair Value Measurements [Member]
CLO collateral assets	151.0	185.4
Bonds [Member] | Quoted Prices in Active Markets for Identical Assets [Member]
CLO collateral assets	0	0
Bonds [Member] | Significant Other Observable Inputs [Member]
CLO collateral assets	151.0	185.4
Bonds [Member] | Significant Unobservable Inputs [Member]
CLO collateral assets	0	0
Equity Securities [Member] | Fair Value Measurements [Member]
CLO collateral assets	17.5	12.1
Equity Securities [Member] | Quoted Prices in Active Markets for Identical Assets [Member]
CLO collateral assets	0	0
Equity Securities [Member] | Significant Other Observable Inputs [Member]
CLO collateral assets	17.5	12.1
Equity Securities [Member] | Significant Unobservable Inputs [Member]
CLO collateral assets	0	0
Investments in Other Private Equity Funds [Member] | Fair Value Measurements [Member]
Private equity fund assets		503.5
Investments in Other Private Equity Funds [Member] | Quoted Prices in Active Markets for Identical Assets [Member]
Private equity fund assets	0	0
Investments in Other Private Equity Funds [Member] | Significant Other Observable Inputs [Member]
Private equity fund assets	0	0
Investments in Other Private Equity Funds [Member] | Significant Unobservable Inputs [Member]
Private equity fund assets	448.2
Debt Securities Issued By U.S. Treasury [Member] | Fair Value Measurements [Member]
Private equity fund assets	2.0	10.0
Debt Securities Issued By U.S. Treasury [Member] | Quoted Prices in Active Markets for Identical Assets [Member]
Private equity fund assets	2.0	10.0
Debt Securities Issued By U.S. Treasury [Member] | Significant Other Observable Inputs [Member]
Private equity fund assets	0	0
Debt Securities Issued By U.S. Treasury [Member] | Significant Unobservable Inputs [Member]
Private equity fund assets	0	0
CLO Notes [Member] | Fair Value Measurements [Member]
CLO notes	(4,003.1)	(3,899.4)
CLO Notes [Member] | Quoted Prices in Active Markets for Identical Assets [Member]
CLO notes	0	0
CLO Notes [Member] | Significant Other Observable Inputs [Member]
CLO notes	0	0
CLO Notes [Member] | Significant Unobservable Inputs [Member]
CLO notes	$ (4,003.1)	$ (3,899.4)