Consolidated Investment Products (Condensed Consolidating Balance Sheet Line Items Reflecting Impact Of Consolidation Of Investment Products Into The Condensed Consolidated Balance Sheets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Accounts receivable	$ 545.9	$ 500.8
Investments	885.4	839.7
Cash and cash equivalents of CIP	404.0	583.6
Investments of CIP	5,762.8	4,734.7
Other assets	92.0	182.1
Total assets	20,462.5	19,270.5
Accounts payable and accrued expenses	757.3	763.1
Debt of CIP	5,149.6	4,181.7
Other liabilities of CIP	280.9	461.8
Total liabilities	(11,177.2)	(10,293.2)
Retained Earnings (Accumulated Deficit)	3,926.0	3,361.9
Retained earnings appropriated for investors in CIP	17.6	104.3
Equity attributable to noncontrolling interests in consolidated entities	781.2	570.3
Total liabilities and equity	20,462.5	19,270.5
CLOs - VIEs [Member]
Accounts receivable	0	0
Investments	0	0
Cash and cash equivalents of CIP	378.8	542.3
Accounts receivable of CIP	155.7	56.3
Investments of CIP	5,063.5	4,237.3
Total assets	5,598.0	4,835.9
Debt of CIP	5,302.9	4,270.4
Other liabilities of CIP	277.4	461.4
Total liabilities	(5,580.3)	(4,731.8)
Retained Earnings (Accumulated Deficit)	20.3	12.5
Retained earnings appropriated for investors in CIP	17.6	104.3
Other equity attributable to common shareholders	(20.2)	(12.7)
Equity attributable to noncontrolling interests in consolidated entities	0	0
Total liabilities and equity	5,598.0	4,835.9
Other VIEs [Member]
Accounts receivable	0	0
Investments	0	0
Cash and cash equivalents of CIP	5.0	5.6
Accounts receivable of CIP	0.1	0.2
Investments of CIP	53.4	40.4
Total assets	58.5	46.2
Debt of CIP	0	0
Other liabilities of CIP	0.4	0.9
Total liabilities	(0.4)	(0.9)
Retained Earnings (Accumulated Deficit)	0	0
Retained earnings appropriated for investors in CIP	0	0
Other equity attributable to common shareholders	0	0
Equity attributable to noncontrolling interests in consolidated entities	58.1	45.3
Total liabilities and equity	58.5	46.2
VOEs [Member]
Accounts receivable	0	0
Investments	0	0
Cash and cash equivalents of CIP	21.5	35.7
Accounts receivable of CIP	5.5	1.8
Investments of CIP	730.2	512.2
Total assets	757.2	549.7
Debt of CIP	0	0
Other liabilities of CIP	6.9	3.0
Total liabilities	(6.9)	(3.0)
Retained Earnings (Accumulated Deficit)	0	0
Retained earnings appropriated for investors in CIP	0	0
Other equity attributable to common shareholders	0	0
Equity attributable to noncontrolling interests in consolidated entities	750.3	546.7
Total liabilities and equity	757.2	549.7
Adjustments [Member]
Accounts receivable	(3.8)	(3.4)
Investments	(94.9)	(55.3)
Cash and cash equivalents of CIP	(1.3)	0
Accounts receivable of CIP	0	0
Investments of CIP	(84.3)	(55.2)
Total assets	(184.3)	(113.9)
Debt of CIP	(153.3)	(88.7)
Other liabilities of CIP	(3.8)	(3.5)
Total liabilities	157.1	92.2
Retained Earnings (Accumulated Deficit)	0	0
Retained earnings appropriated for investors in CIP	0	0
Other equity attributable to common shareholders	0	0
Equity attributable to noncontrolling interests in consolidated entities	(27.2)	(21.7)
Total liabilities and equity	(184.3)	(113.9)
Impact of CIP [Member]
Accounts receivable	(3.8)	(3.4)
Investments	(94.9)	(55.3)
Cash and cash equivalents of CIP	404.0	583.6
Accounts receivable of CIP	161.3	58.3
Investments of CIP	5,762.8	4,734.7
Total assets	6,229.4	5,317.9
Debt of CIP	5,149.6	4,181.7
Other liabilities of CIP	280.9	461.8
Total liabilities	(5,430.5)	(4,643.5)
Retained Earnings (Accumulated Deficit)	20.3	12.5
Retained earnings appropriated for investors in CIP	17.6	104.3
Other equity attributable to common shareholders	(20.2)	(12.7)
Equity attributable to noncontrolling interests in consolidated entities	781.2	570.3
Total liabilities and equity	$ 6,229.4	$ 5,317.9