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Investment Securities - Significant Unobservable Inputs (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Other long-term investments | $ 1,998.2 | $ 1,488.0
Level 3 | Recent transaction |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Other long-term investments | 19.0 | 41.1
Level 3 | Discounted cash flow |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Other long-term investments | $ 15.5 | $ 9.6
Level 3 | Discounted cash flow | Discount Rate |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate |  | 11.00%
Level 3 | Discounted cash flow | Discount Rate | Minimum |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate | 11.00% |
Level 3 | Discounted cash flow | Discount Rate | Maximum |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate | 12.00% |
Kudu’s Participation Contracts |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
New and existing contracts deployed | $ 163.8 | $ 99.8
Kudu’s Participation Contracts | Level 3 | Discounted cash flow |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Fair Value | $ 890.5 | $ 695.9
Kudu’s Participation Contracts | Level 3 | Discounted cash flow | Discount Rate | Minimum |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate | 18.00% | 18.00%
Kudu’s Participation Contracts | Level 3 | Discounted cash flow | Discount Rate | Maximum |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate | 25.00% | 25.00%
Kudu’s Participation Contracts | Level 3 | Discounted cash flow | Terminal Cash Flow Exit Multiple | Minimum |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate | 700.00% | 700.00%
Kudu’s Participation Contracts | Level 3 | Discounted cash flow | Terminal Cash Flow Exit Multiple | Maximum |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate | 2200.00% | 1600.00%
Kudu’s Participation Contracts | Level 3 | Discounted cash flow | Measurement Input, Pre-Tax Discount Rate |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate | 20.00% | 21.00%
Kudu’s Participation Contracts | Level 3 | Discounted cash flow | Measurement, Input, Pre-Tax Terminal Cash Flow Exit Multiple |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate | 1300.00% | 1200.00%
Kudu’s Participation Contracts | Level 3 | Probability weighted expected return method |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Fair Value | $ 69.1 | $ 189.0
PassportCard/DavidShield | Level 3 | Discounted cash flow |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Fair Value | $ 150.0 | $ 135.0
PassportCard/DavidShield | Level 3 | Discounted cash flow | Discount Rate |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate | 24.00% | 24.00%
PassportCard/DavidShield | Level 3 | Discounted cash flow | Terminal Revenue Growth Rate |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate | 4.00% | 4.00%
Elementum Holdings, L.P. | Level 3 | Discounted cash flow |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Fair Value | $ 35.0 | $ 30.0
Elementum Holdings, L.P. | Level 3 | Discounted cash flow | Discount Rate |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate | 21.00% | 21.00%
Elementum Holdings, L.P. | Level 3 | Discounted cash flow | Terminal Revenue Growth Rate |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate | 4.00% | 4.00%
Preferred securities | Level 3 | Discounted cash flow |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Fair Value | $ 28.2 |
Preferred securities | Level 3 | Discounted cash flow | Discount Rate |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |
Discount Rate | 8.00% |

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