Investments - Schedule of Performance Allocations Included in Revenues (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Investments [Line Items]
Total	$ 477.4	$ 112.4	$ 731.6	$ 709.1
Corporate Private Equity
Schedule of Investments [Line Items]
Total	291.6	(53.8)	852.2	161.5
Real Assets
Schedule of Investments [Line Items]
Total	45.0	54.6	(126.2)	313.6
Global Credit
Schedule of Investments [Line Items]
Total	16.3	4.1	(24.0)	28.2
Investment Solutions
Schedule of Investments [Line Items]
Total	$ 124.5	$ 107.5	$ 29.6	$ 205.8