Segment Reporting - Reconciliation of Income Before Provision for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Loss before provision for income taxes	$ (529.1)	$ 175.4	$ 560.3	$ 1,189.0
Adjustments:
Other non-operating (income) expense	(9.9)	(39.6)	(11.7)	(14.0)
Net (income) loss attributable to non-controlling interests in consolidated entities	152.4	(53.2)	(657.5)	(747.4)
Reconciling Items
Adjustments:
Equity-based compensation issued in conjunction with the initial public offering, acquisitions and strategic investments	54.5	56.3	202.1	209.7
Acquisition related charges, including amortization of intangibles and impairment	209.6	24.5	247.9	166.6
Other non-operating (income) expense	(9.9)	(39.6)	(11.7)	(14.0)
Tax benefit (expense) associated with performance fee compensation	(5.1)	15.0	(19.4)	(23.5)
Net (income) loss attributable to non-controlling interests in consolidated entities	152.4	(53.2)	(657.5)	(747.4)
Other adjustments	(0.8)	2.4	2.2	1.5
Net performance fees	25.1	15.9	76.6	3.3
Operating Segments
Adjustments:
Economic Net Income (Loss)	(128.4)	180.8	323.9	781.9
Net performance fees	(148.6)	139.2	282.4	669.0
Investment Income (Loss)	(6.3)	3.5	(23.3)	(9.1)
Equity-based compensation	30.8	23.8	91.0	57.3
Fee Related Earnings	57.3	61.9	155.8	179.3
Realized performance fees, net of related compensation	177.2	97.8	688.3	469.2
Realized investment income (loss)	9.2	(2.7)	(66.7)	14.1
Distributable Earnings	$ 243.7	$ 157.0	$ 777.4	$ 662.6