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, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Total investment loss	$ 286.3	$ (254.0)	$ 202.4	$ (81.5)
Performance revenues related compensation expense	144.2	(92.2)	71.4	13.5
Net performance revenues	54.0	(154.6)	(30.2)	(99.5)
Adjustments
Segment Reporting Information [Line Items]
Performance revenues related compensation expense	(43.4)	252.2	285.2	242.1
Net performance revenues	1.7	329.7	227.9	344.1
Total Reportable Segments
Segment Reporting Information [Line Items]
Net performance revenues	55.7	175.1
Total Reportable Segments | Global Segments
Segment Reporting Information [Line Items]
Performance revenues related compensation expense	100.8	160.0	356.6	255.6
Net performance revenues	55.7	175.1	197.7	244.6
Performance revenues
Segment Reporting Information [Line Items]
Total investment loss	198.2	(246.8)	41.2	(86.0)
Performance revenues | Adjustments
Segment Reporting Information [Line Items]
Total investment loss	(41.7)	581.9	513.1	586.2
Performance revenues | Total Reportable Segments | Global Segments
Segment Reporting Information [Line Items]
Total investment loss	156.5	335.1	554.3	500.2
Principal investment income (loss)
Segment Reporting Information [Line Items]
Total investment loss	88.1	(7.2)	161.2	4.5
Principal investment income (loss) | Adjustments
Segment Reporting Information [Line Items]
Total investment loss	(61.5)	29.3	(100.9)	41.4
Principal investment income (loss) | Total Reportable Segments | Global Segments
Segment Reporting Information [Line Items]
Total investment loss	$ 26.6	$ 22.1	$ 60.3	$ 45.9