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v3.25.4

Investment Securities - Investment Holdings (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2025 | Dec. 31, 2024
U.S. Government and agency obligations |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Cost or Amortized Cost | $ 459.7 | $ 461.8
Gross Unrealized Gains | 1.3 | 1.1
Gross Unrealized Losses | (0.7) | (0.8)
Net Foreign Currency Gains (Losses) | 0.0 | 0.0
Carrying Value | 460.3 | 462.1
Debt securities issued by corporations |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Cost or Amortized Cost | 1,534.9 | 1,444.5
Gross Unrealized Gains | 13.5 | 4.6
Gross Unrealized Losses | (11.5) | (31.4)
Net Foreign Currency Gains (Losses) | 0.8 | (3.5)
Carrying Value | 1,537.7 | 1,414.2
Municipal obligations |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Cost or Amortized Cost |  | 3.2
Gross Unrealized Gains |  | 0.0
Gross Unrealized Losses |  | 0.0
Net Foreign Currency Gains (Losses) |  | 0.0
Carrying Value |  | 3.2
Mortgage and asset-backed securities |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Cost or Amortized Cost | 405.1 | 400.2
Gross Unrealized Gains | 4.2 | 0.2
Gross Unrealized Losses | (16.3) | (26.5)
Net Foreign Currency Gains (Losses) | 0.0 | 0.0
Carrying Value | 393.0 | 373.9
Collateralized loan obligations |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Cost or Amortized Cost | 343.9 | 237.3
Gross Unrealized Gains | 0.8 | 1.2
Gross Unrealized Losses | (0.1) | (0.2)
Net Foreign Currency Gains (Losses) | 2.4 | (1.6)
Carrying Value | 347.0 | 236.7
Foreign government and agency obligations |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Cost or Amortized Cost | 31.2 | 22.2
Gross Unrealized Gains | 0.0 | 0.0
Gross Unrealized Losses | (0.1) | (0.1)
Net Foreign Currency Gains (Losses) | 1.4 | (0.6)
Carrying Value | 32.5 | 21.5
Fixed maturity investments |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Cost or Amortized Cost | 2,774.8 | 2,569.2
Gross Unrealized Gains | 19.8 | 7.1
Gross Unrealized Losses | (28.7) | (59.0)
Net Foreign Currency Gains (Losses) | 4.6 | (5.7)
Carrying Value | $ 2,770.5 | $ 2,511.6

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