Segment Reporting - Adjustments for Performance Fees, Performance Fee Related Compensation and Investment Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Investment income (loss)	$ 44.8	$ 1,898.0	$ 6,721.9
Performance revenues related compensation expense	1,103.7	719.9	2,961.0
Performance allocations
Segment Reporting Information [Line Items]
Investment income (loss)	(88.6)	1,327.5	6,084.6
Performance revenues related compensation expense	1,103.7	719.9	2,961.0
Net performance revenues	(1,192.3)	607.6	3,123.6
Performance allocations | Adjustments
Segment Reporting Information [Line Items]
Investment income (loss)	1,026.9	653.2	(3,146.0)
Performance revenues related compensation expense	(696.4)	262.3	(1,552.0)
Net performance revenues	1,723.3	390.9	(1,594.0)
Performance allocations | Total Reportable Segments
Segment Reporting Information [Line Items]
Investment income (loss)			2,938.6
Performance revenues related compensation expense			1,409.0
Net performance revenues			1,529.6
Performance allocations | Total Reportable Segments | Global Segments
Segment Reporting Information [Line Items]
Investment income (loss)	938.3	1,980.7
Performance revenues related compensation expense	407.3	982.2
Net performance revenues	531.0	998.5
Realized principal investment income
Segment Reporting Information [Line Items]
Investment income (loss)	133.4	570.5	637.3
Realized principal investment income | Adjustments
Segment Reporting Information [Line Items]
Investment income (loss)	(44.6)	(419.9)	(427.8)
Realized principal investment income | Total Reportable Segments
Segment Reporting Information [Line Items]
Investment income (loss)			$ 209.5
Realized principal investment income | Total Reportable Segments | Global Segments
Segment Reporting Information [Line Items]
Investment income (loss)	$ 88.8	$ 150.6