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Investments - Contractual Maturities of Bonds (Details) - USD ($) $ in Millions | Mar. 31, 2025 | Dec. 31, 2024
--- | --- | ---
Cost or Amortized Cost |  |
Due in one year or less | $ 309.7 |
Due after one year through five years | 344.2 |
Due after five years through ten years | 0.2 |
Due after ten years | 0.0 |
Cost or Amortized Cost | 654.1 | $ 607.1
Fair Value |  |
Due in one year or less | 310.1 |
Due after one year through five years | 345.3 |
Due after five years through ten years | 0.2 |
Due after ten years | 0.0 |
Fair Value | $ 655.6 | $ 607.4

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