Consolidated Investment Products (VIE Balance Sheets Consolidated In Period) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Cash and cash equivalents of CIP	$ (257.9)	$ (363.3)
Accounts receivable and other assets of CIP	182.2	173.5
Investments of CIP	4,036.9	6,016.1
Total assets	23,502.8	25,073.2
Debt of CIP	3,529.6	5,437.0
Other liabilities of CIP	314.0	273.7
Total liabilities	15,460.1	16,210.2
Total equity	7,730.1	8,695.7	$ 9,085.1	$ 9,119.8
Total liabilities and equity	23,502.8	$ 25,073.2
CLOs - VIEs [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents of CIP	(151.0)		(209.2)
Accounts receivable and other assets of CIP	3.6		1.5
Investments of CIP	311.0		567.0
Total assets	465.6		777.7
Debt of CIP	414.4		601.4
Other liabilities of CIP	17.4		176.3
Total liabilities	431.8		777.7
Total equity	33.8		0.0
Total liabilities and equity	465.6		777.7
VOEs [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents of CIP			(10.0)
Accounts receivable and other assets of CIP			0.0
Investments of CIP			0.0
Total assets			10.0
Debt of CIP			0.0
Other liabilities of CIP			0.0
Total liabilities			0.0
Total equity			10.0
Total liabilities and equity			$ 10.0
Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member] | CLOs - VIEs [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents of CIP	(23.6)
Accounts receivable and other assets of CIP	12.2
Investments of CIP	196.1
Total assets	231.9
Debt of CIP	0.0
Other liabilities of CIP	13.1
Total liabilities	13.1
Total equity	218.8
Total liabilities and equity	$ 231.9