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Investments - Additional Information (Details) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2024 USD ($) Security | Dec. 31, 2023 USD ($) Security
Summary of Investment Holdings [Line Items] |  |
Number of securities in unrealized loss position | Security | 1,059 | 1,063
Securities lending rate of collateral required | 1.02 |
Debt Securities |  |
Summary of Investment Holdings [Line Items] |  |
Assets held by insurance regulators | $ 14 | $ 14
Foreign government and agency securities |  |
Summary of Investment Holdings [Line Items] |  |
Securities lending rate of collateral required | 1.05 |
Loaned securities |  |
Summary of Investment Holdings [Line Items] |  |
Securities lending rate of collateral required | 1 |
Securities received as collateral | $ 18 | $ 61

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