Borrowings - Outstanding Loans Payable of Consolidated Funds (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2026	Dec. 31, 2025
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Borrowings	$ 9,837.2	$ 9,423.1
Level III
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Borrowings	9,837.2	9,423.1
Revolving credit facilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Borrowing Outstanding	41.5	63.0
Fair Value	$ 41.5	$ 63.0
Weighted Average Interest Rate	6.57%	6.68%
Weighted Average Remaining Maturity in Years	2 years 11 months 4 days	3 years 5 months 12 days
Borrowings	$ 41.5	$ 63.0
Loans Payable of Consolidated Funds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Borrowing Outstanding	10,897.4	10,567.4
Fair Value	10,804.4	10,426.0
Senior secured notes
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Borrowing Outstanding	10,480.2	9,994.8
Fair Value	$ 10,472.5	$ 9,972.1
Weighted Average Interest Rate	5.07%	5.09%
Weighted Average Remaining Maturity in Years	11 years 6 months 25 days	11 years 2 months 4 days
Borrowings		$ 937.5
Senior secured notes \| Level III
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Borrowings	$ 925.7	939.9
Subordinated notes
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Borrowing Outstanding	375.7	509.6
Fair Value	$ 290.4	$ 390.9
Weighted Average Remaining Maturity in Years	10 years 1 month 24 days	9 years 7 months 24 days