v3.26.1
Investment Securities - Significant Unobservable Inputs (Details) - USD ($)
$ in Millions
6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Quantitative information for Level 3 Fair Value Measurements Assets    
Other long-term investments $ 3,316.2 $ 2,958.5
Kudu’s Participation Contracts    
Quantitative information for Level 3 Fair Value Measurements Assets    
New and existing contracts deployed 43.3 201.7
Level 3 | Recent transaction    
Quantitative information for Level 3 Fair Value Measurements Assets    
Other long-term investments 10.4 250.4
Level 3 | Discounted cash flow | Kudu’s Participation Contracts    
Quantitative information for Level 3 Fair Value Measurements Assets    
Fair Value 1,344.6 1,285.0
Level 3 | Discounted cash flow | Bamboo SPV    
Quantitative information for Level 3 Fair Value Measurements Assets    
Fair Value 280.0  
Level 3 | Discounted cash flow | PassportCard/DavidShield    
Quantitative information for Level 3 Fair Value Measurements Assets    
Fair Value 170.0 170.0
Level 3 | Discounted cash flow | Bishop Street    
Quantitative information for Level 3 Fair Value Measurements Assets    
Fair Value 130.0  
Level 3 | Discounted cash flow | Private common shares and units    
Quantitative information for Level 3 Fair Value Measurements Assets    
Fair Value 57.5 56.9
Level 3 | Discounted cash flow | Private preferred securities    
Quantitative information for Level 3 Fair Value Measurements Assets    
Fair Value 36.9 35.6
Level 3 | Discounted cash flow | Private debt instruments    
Quantitative information for Level 3 Fair Value Measurements Assets    
Other long-term investments $ 10.0 $ 16.5
Level 3 | Discount Rate | Discounted cash flow | Bamboo SPV    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 16.00%  
Level 3 | Discount Rate | Discounted cash flow | PassportCard/DavidShield    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 24.00% 24.00%
Level 3 | Discount Rate | Discounted cash flow | Bishop Street    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 14.00%  
Level 3 | Discount Rate | Discounted cash flow | Private preferred securities    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 15.00% 8.00%
Level 3 | Discount Rate | Discounted cash flow | Private debt instruments    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 11.00%  
Level 3 | Discount Rate | Discounted cash flow | Minimum | Kudu’s Participation Contracts    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 16.00% 16.00%
Level 3 | Discount Rate | Discounted cash flow | Minimum | Private common shares and units    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 22.00% 22.00%
Level 3 | Discount Rate | Discounted cash flow | Minimum | Private debt instruments    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate   11.00%
Level 3 | Discount Rate | Discounted cash flow | Maximum | Kudu’s Participation Contracts    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 22.00% 25.00%
Level 3 | Discount Rate | Discounted cash flow | Maximum | Private common shares and units    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 35.00% 35.00%
Level 3 | Discount Rate | Discounted cash flow | Maximum | Private debt instruments    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate   12.00%
Level 3 | Terminal Cash Flow Exit Multiple | Discounted cash flow | Minimum | Kudu’s Participation Contracts    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 700.00% 700.00%
Level 3 | Terminal Cash Flow Exit Multiple | Discounted cash flow | Maximum | Kudu’s Participation Contracts    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 2200.00% 2200.00%
Level 3 | Terminal Revenue Growth Rate | Discounted cash flow | Bamboo SPV    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 4.00%  
Level 3 | Terminal Revenue Growth Rate | Discounted cash flow | PassportCard/DavidShield    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 4.00% 4.00%
Level 3 | Terminal Revenue Growth Rate | Discounted cash flow | Minimum | Private common shares and units    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 3.00% 3.00%
Level 3 | Terminal Revenue Growth Rate | Discounted cash flow | Maximum | Private common shares and units    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 4.00% 4.00%
Level 3 | Measurement Input, Pre-Tax Discount Rate | Discounted cash flow | Kudu’s Participation Contracts    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 18.00% 19.00%
Level 3 | Measurement, Input, Pre-Tax Terminal Cash Flow Exit Multiple | Discounted cash flow | Kudu’s Participation Contracts    
Quantitative information for Level 3 Fair Value Measurements Assets    
Discount rate 1400.00% 1400.00%