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Investments - Distribution of Fixed Maturity Securities by Expected Maturity (Details) - USD ($) $ in Millions | 6 Months Ended |
--- | --- | ---
Jun. 30, 2025 | Dec. 31, 2024
Amortized Cost, net |  |
Due in 1 year or less | $ 2,251.8 |
Due after 1 year through 5 years | 925.6 |
Due after 5 years through 10 years | 925.0 |
Due after 10 years through 20 years | 981.5 |
Due after 20 years | 763.5 |
Amortized Cost, net | 5,847.4 | $ 5,842.5
Fair Value |  |
Due in 1 year or less | 2,189.5 |
Due after 1 year through 5 years | 898.5 |
Due after 5 years through 10 years | 893.4 |
Due after 10 years through 20 years | 859.8 |
Due after 20 years | 612.1 |
Total | $ 5,453.3 | $ 5,387.9
Percent of Total Fair Value |  |
Due in 1 year Or less (percent) | 40.20% |
Due after 1 year through 5 years (percent) | 16.50% |
Due after 5 years through 10 years (percent) | 16.40% |
Due after 10 years through 20 years (percent) | 15.80% |
Due after 20 years (percent) | 11.20% |
Total (percent) | 100.00% |
Average option-adjusted duration, in years | 5 years 8 months 12 days |

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