Segment Reporting - Reconciliation of Fund Level Fee Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fund management fees
Segment Reporting Information [Line Items]
Fund management fees and incentive fees	$ 2,043.2	$ 2,030.1	$ 1,667.5
Fund management fees | Global Investment Solutions
Segment Reporting Information [Line Items]
Fund management fees and incentive fees	2,043.2	2,030.1	1,667.5
Total Reportable Segments | Global Investment Solutions
Segment Reporting Information [Line Items]
Fund management fees and incentive fees	246.0	222.9	228.9
Total Reportable Segments | Fund management fees
Segment Reporting Information [Line Items]
Fund management fees and incentive fees			1,654.6
Total Reportable Segments | Fund management fees | Global Investment Solutions
Segment Reporting Information [Line Items]
Fund management fees and incentive fees	242.4	222.9	228.4
Adjustments | Global Investment Solutions
Segment Reporting Information [Line Items]
Adjustments	(262.6)	(207.2)	(127.3)
Adjustments | Fund management fees
Segment Reporting Information [Line Items]
Fund management fees and incentive fees	$ (31.1)	$ (26.6)	$ (24.0)