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Investment Information - Narrative (Details) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 USD ($) lots | Dec. 31, 2022 USD ($) lots
Continuous unrealized loss, qualitative disclosures: |  |
Number of positions in an unrealized loss position (lots) | lots | 7,100 | 9,810
Total number of positions (lots) | lots | 15,720 | 12,590
Largest single loss | $ | $ 6 | $ 7
Equity securities, at fair value | $ | $ 1,186 | $ 860
Equity Method Investment, Financial Statement, Reported Amounts [Abstract] |  |
Investments, time lag for reporting - low end of range | 1 month |
Investments, time lag for reporting - high end of range | 3 months |

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