v3.25.2
Variable and voting interest entities - Total Assets and Maximum Exposure to Loss for Unconsolidated Variable Interest Entities (Details) - Variable Interest Entity, Not Primary Beneficiary, Excluding Investments In Related Party Investment Funds - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Variable Interest Entity [Line Items]    
Carrying Amount $ 242.2 $ 223.8
Maximum Exposure to Loss 345.9 346.5
Debt securities    
Variable Interest Entity [Line Items]    
Carrying Amount 38.3 21.1
Maximum Exposure to Loss 79.5 79.3
Other long-term investments    
Variable Interest Entity [Line Items]    
Carrying Amount 203.9 202.7
Maximum Exposure to Loss $ 266.4 $ 267.2