v3.26.1
Fair Value Measurement - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Assets    
Subtotal $ 14,844.4  
Investments measured at net asset value   $ 13,107.9
Liabilities    
Loans payable of Consolidated Funds 10,156.7 9,423.1
Total 10,160.4 9,427.5
Foreign currency forward contracts    
Liabilities    
Foreign currency forward contracts 3.7 4.4
Revolving Credit Facility    
Liabilities    
Loans payable of Consolidated Funds 51.0 63.0
Senior Notes    
Liabilities    
Loans payable of Consolidated Funds 940.9 939.4
Equity securities | Consolidated VIEs    
Assets    
Investments measured at net asset value 726.4 989.4
Investments In CLOs and other    
Assets    
Investments 510.9  
Fair Value, Inputs, Level 1, 2 and 3    
Assets    
Subtotal 12,447.8 11,767.3
Fair Value, Inputs, Level 1, 2 and 3 | Foreign currency forward contracts    
Assets    
Foreign currency forward contracts 0.4 4.8
Fair Value, Inputs, Level 1, 2 and 3 | Investments of Consolidated Funds    
Assets    
Investments 11,936.5 11,186.0
Fair Value, Inputs, Level 1, 2 and 3 | Equity securities    
Assets    
Investments 965.6 1,245.0
Fair Value, Inputs, Level 1, 2 and 3 | Bonds    
Assets    
Investments 756.2 691.2
Fair Value, Inputs, Level 1, 2 and 3 | Loans    
Assets    
Investments 10,214.7 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 309.9 349.0
Fair Value, Inputs, Level 1, 2 and 3 | Other investments    
Assets    
Investments 201.0 227.5
Level I    
Assets    
Subtotal 163.4 244.0
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 0.0
Liabilities    
Foreign currency forward contracts 0.0 0.0
Level I | Investments of Consolidated Funds    
Assets    
Investments 73.7 132.0
Level I | Equity securities    
Assets    
Investments 73.7 132.0
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 89.7 112.0
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 37.1 43.9
Liabilities    
Loans payable of Consolidated Funds 0.0 0.0
Total 3.7 4.4
Level II | Foreign currency forward contracts    
Assets    
Foreign currency forward contracts 0.4 4.8
Liabilities    
Foreign currency forward contracts 3.7 4.4
Level II | Investments of Consolidated Funds    
Assets    
Investments 16.4 18.2
Level II | Equity securities    
Assets    
Investments 16.4 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 20.3 20.9
Level II | Investments in CLOs    
Assets    
Investments 0.0 0.0
Level II | Other investments    
Assets    
Investments 20.3 20.9
Level III    
Assets    
Subtotal 12,247.3 11,479.4
Liabilities    
Loans payable of Consolidated Funds 10,156.7 9,423.1
Total 10,156.7 9,423.1
Level III | Foreign currency forward contracts    
Assets    
Foreign currency forward contracts 0.0 0.0
Liabilities    
Foreign currency forward contracts 0.0 0.0
Level III | Investments of Consolidated Funds    
Assets    
Investments 11,846.4 11,035.8
Level III | Equity securities    
Assets    
Investments 875.5 1,094.8
Investments measured at net asset value 98.3 63.0
Level III | Bonds    
Assets    
Investments 756.2 691.2
Level III | Loans    
Assets    
Investments 10,214.7 9,249.8
Level III | Investments In CLOs and other    
Assets    
Investments 400.9 443.6
Level III | Investments in CLOs    
Assets    
Investments 309.9 349.0
Level III | Other investments    
Assets    
Investments 91.0 94.6
Fair Value Measured at NAV    
Assets    
Investments measured at net asset value 2,396.6 1,340.6
Fair Value Measured at NAV | Investments of Consolidated Funds    
Assets    
Investments $ 2,400.0 $ 1,300.0