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Fair Value of Financial Instruments Additional Information (Detail) - USD ($) $ in Millions | Mar. 31, 2023 | Dec. 31, 2022
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Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis |  |
Ceded Policy Loans | $ 3,259.5 | $ 3,312.5
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 | 26.70% |
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 | 57.30% |
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 | 14.90% |
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 | 73.30% |
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 | 1.10% |

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