Fair Value Measurement - Level III Financial Liabilities Measured at Fair Value (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Realized and unrealized (gains) losses, net
Fair value, liability, recurring basis, unobservable input reconciliation, gain (loss), statement of income or comprehensive income	Net investment income (loss) of Consolidated Funds	Net investment income (loss) of Consolidated Funds	Net investment income (loss) of Consolidated Funds	Net investment income (loss) of Consolidated Funds
Level III | Loans Payable of Consolidated Funds
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 6,352.3	$ 5,647.9	$ 6,298.6	$ 5,491.6
Borrowings	3,000.2	869.2	3,546.9	869.8
Paydowns	(258.7)	(46.9)	(466.4)	(49.0)
Sales	(1,453.2)	(82.5)	(1,741.9)	(120.6)
Realized and unrealized (gains) losses, net
Included in earnings	5.8	(19.7)	95.2	121.7
Included in other comprehensive income	(23.0)	15.9	(109.0)	70.4
Balance, end of period	7,623.4	6,383.9	7,623.4	6,383.9
Changes in unrealized (gains) losses included in earnings related to financial liabilities still held at the reporting date	7.1	(18.1)	101.7	126.7
Changes in unrealized (gains) losses included in other comprehensive income related to financial liabilities still held at the reporting date	$ (27.1)	$ 16.1	$ (123.6)	$ 68.3