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Fair Value of Financial Instruments Additional Information (Detail) - USD ($) $ in Millions | Dec. 31, 2025 | Dec. 31, 2024
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Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis |  |
Ceded Policy Loans | $ 3,353.8 | $ 3,313.6
Derivative Credit Risk Valuation Adjustment, Derivative Liabilities | 0.0 | 0.0
Derivative Credit Risk Valuation Adjustment, Derivative Assets | $ 0.0 | $ 0.0
Fair Value, Inputs, Level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis |  |
Percentage of Total Fair Value of Fixed Maturities Securities | 12.00% |
Fair Value, Inputs, Level 2 | Pricing Service |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis |  |
Percentage of Total Fair Value of Fixed Maturities Securities | 69.60% |
Fair Value, Inputs, Level 2 | Other Observable Market Data |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis |  |
Percentage of Total Fair Value of Fixed Maturities Securities | 17.40% |
Fair Value Inputs Other Than Level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis |  |
Percentage of Total Fair Value of Fixed Maturities Securities | 88.00% |
Fair Value Inputs Level 2 Or Level 3 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis |  |
Percentage of Total Fair Value of Fixed Maturities Securities | 1.00% |

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