Accrued Performance Fees - Components of Accrued Performance Fee (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Accrued performance fees	$ 2,988.6	$ 3,795.6
Corporate Private Equity
Segment Reporting Information [Line Items]
Accrued performance fees	2,096.9	2,932.6
Global Market Strategies
Segment Reporting Information [Line Items]
Accrued performance fees	78.3	129.9
Real Assets
Segment Reporting Information [Line Items]
Accrued performance fees	313.6	272.9
Investment Solutions
Segment Reporting Information [Line Items]
Accrued performance fees	$ 499.8	$ 460.2