Segment Reporting - Adjustments for Performance Fees, Performance Fee Related Compensation and Investment Income (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Investment income (loss)	$ (254.0)	$ 394.6	$ (81.5)	$ 1,424.4
Performance revenues related compensation expense	(92.2)	207.0	13.5	577.7
Net performance revenues	(154.6)	130.9	(99.5)	470.4
Adjustments
Segment Reporting Information [Line Items]
Performance revenues related compensation expense	252.2	42.0	242.1	(210.4)
Net performance revenues	329.7	140.0	344.1	(81.5)
Total Reportable Segments
Segment Reporting Information [Line Items]
Performance revenues related compensation expense	160.0	249.0	255.6	367.3
Net performance revenues	175.1	270.9	244.6	388.9
Performance allocations
Segment Reporting Information [Line Items]
Investment income (loss)	(246.8)	337.9	(86.0)	1,048.1
Performance allocations \| Adjustments
Segment Reporting Information [Line Items]
Investment income (loss)	581.9	182.0	586.2	(291.9)
Performance allocations \| Total Reportable Segments
Segment Reporting Information [Line Items]
Investment income (loss)	335.1	519.9	500.2	756.2
Principal investment income
Segment Reporting Information [Line Items]
Investment income (loss)	(7.2)	56.7	4.5	376.3
Principal investment income \| Adjustments
Segment Reporting Information [Line Items]
Investment income (loss)	29.3	(12.9)	41.4	(306.2)
Principal investment income \| Total Reportable Segments
Segment Reporting Information [Line Items]
Investment income (loss)	$ 22.1	$ 43.8	$ 45.9	$ 70.1