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Investments - Schedule of Corporate Debt Securities by Industry Group (Details) | Sep. 30, 2025 | Dec. 31, 2024
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Debt Securities, Available-for-sale [Line Items] |  |
Corporate debt securities as component of total (in percent) | 100.00% | 100.00%
Financial |  |
Debt Securities, Available-for-sale [Line Items] |  |
Corporate debt securities as component of total (in percent) | 39.00% | 40.00%
Consumer |  |
Debt Securities, Available-for-sale [Line Items] |  |
Corporate debt securities as component of total (in percent) | 28.00% | 26.00%
Utilities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Corporate debt securities as component of total (in percent) | 11.00% | 11.00%
Industrial |  |
Debt Securities, Available-for-sale [Line Items] |  |
Corporate debt securities as component of total (in percent) | 9.00% | 9.00%
Communications |  |
Debt Securities, Available-for-sale [Line Items] |  |
Corporate debt securities as component of total (in percent) | 6.00% | 7.00%
Technology |  |
Debt Securities, Available-for-sale [Line Items] |  |
Corporate debt securities as component of total (in percent) | 6.00% | 7.00%
Basic materials |  |
Debt Securities, Available-for-sale [Line Items] |  |
Corporate debt securities as component of total (in percent) | 1.00% | 0.00%

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