v3.26.3
Fair Value Measurement - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Assets    
Subtotal $ 14,139.4  
Investments measured at net asset value   $ 13,107.9
Liabilities    
Loans payable of Consolidated Funds 10,755.3 9,423.1
Total 10,757.3 9,427.5
Foreign currency forward contracts    
Liabilities    
Foreign currency forward contracts 2.0 4.4
Revolving Credit Facility    
Liabilities    
Loans payable of Consolidated Funds 33.9 63.0
Equity securities | Consolidated VIEs    
Assets    
Investments measured at net asset value 773.6 989.4
Fair Value, Inputs, Level 1, 2 and 3    
Assets    
Subtotal 12,456.1 11,767.3
Fair Value, Inputs, Level 1, 2 and 3 | Foreign currency forward contracts    
Assets    
Foreign currency forward contracts   4.8
Fair Value, Inputs, Level 1, 2 and 3 | Investments of Consolidated Funds    
Assets    
Investments 12,033.9 11,186.0
Fair Value, Inputs, Level 1, 2 and 3 | Equity securities    
Assets    
Investments 1,239.8 1,245.0
Fair Value, Inputs, Level 1, 2 and 3 | Bonds    
Assets    
Investments 760.2 691.2
Fair Value, Inputs, Level 1, 2 and 3 | Loans    
Assets    
Investments 10,033.9 9,249.8
Fair Value, Inputs, Level 1, 2 and 3 | Investments In CLOs and other    
Assets    
Investments   576.5
Fair Value, Inputs, Level 1, 2 and 3 | Investments in CLOs    
Assets    
Investments 293.3 349.0
Fair Value, Inputs, Level 1, 2 and 3 | Other investments    
Assets    
Investments 128.9 227.5
Level I    
Assets    
Subtotal 136.8 244.0
Liabilities    
Loans payable of Consolidated Funds 0.0 0.0
Total 0.0 0.0
Level I | Foreign currency forward contracts    
Assets    
Foreign currency forward contracts   0.0
Liabilities    
Foreign currency forward contracts 0.0 0.0
Level I | Investments of Consolidated Funds    
Assets    
Investments 47.1 132.0
Level I | Equity securities    
Assets    
Investments 47.1 132.0
Level I | Bonds    
Assets    
Investments 0.0 0.0
Level I | Loans    
Assets    
Investments 0.0 0.0
Level I | Investments In CLOs and other    
Assets    
Investments   112.0
Level I | Investments in CLOs    
Assets    
Investments 0.0 0.0
Level I | Other investments    
Assets    
Investments 89.7 112.0
Level II    
Assets    
Subtotal 38.9 43.9
Liabilities    
Loans payable of Consolidated Funds 0.0 0.0
Total 2.0 4.4
Level II | Foreign currency forward contracts    
Assets    
Foreign currency forward contracts   4.8
Liabilities    
Foreign currency forward contracts 2.0 4.4
Level II | Investments of Consolidated Funds    
Assets    
Investments 18.7 18.2
Level II | Equity securities    
Assets    
Investments 18.7 18.2
Level II | Bonds    
Assets    
Investments 0.0 0.0
Level II | Loans    
Assets    
Investments 0.0 0.0
Level II | Investments In CLOs and other    
Assets    
Investments   20.9
Level II | Investments in CLOs    
Assets    
Investments 0.0 0.0
Level II | Other investments    
Assets    
Investments 20.2 20.9
Level III    
Assets    
Subtotal 12,280.4 11,479.4
Liabilities    
Loans payable of Consolidated Funds 10,755.3 9,423.1
Total 10,755.3 9,423.1
Level III | Foreign currency forward contracts    
Assets    
Foreign currency forward contracts   0.0
Liabilities    
Foreign currency forward contracts 0.0 0.0
Level III | Investments of Consolidated Funds    
Assets    
Investments 11,968.1 11,035.8
Level III | Equity securities    
Assets    
Investments 1,174.0 1,094.8
Investments measured at net asset value 97.8 63.0
Level III | Bonds    
Assets    
Investments 760.2 691.2
Level III | Loans    
Assets    
Investments 10,033.9 9,249.8
Level III | Investments In CLOs and other    
Assets    
Investments   443.6
Level III | Investments in CLOs    
Assets    
Investments 293.3 349.0
Level III | Other investments    
Assets    
Investments 19.0 94.6
Fair Value Measured at NAV    
Assets    
Investments measured at net asset value 1,683.3 1,340.6
Fair Value Measured at NAV | Investments of Consolidated Funds    
Assets    
Investments $ 1,700.0 $ 1,300.0