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Investments - (Narrative) (Details) $ in Millions | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2025 USD ($) security | Sep. 30, 2025 USD ($) security | Dec. 31, 2024 USD ($) security
Investments [Abstract] |  |  |
Equity Securities at Fair Value | $ 12,547 | $ 12,547 | $ 11,185
Fair value of largest single common stock holding | $ 940 | $ 940 | $ 891
Largest equity holdings to total equity portfolio | 7.70% | 7.70% | 8.20%
Largest equity holdings to total investment portfolio | 3.10% | 3.10% | 3.20%
Allowance for credit loss on fixed-maturity | $ 41 | $ 41 | $ 33
Reductions in the allowance for credit losses for securities sold | $ (6) | $ (7) |
Number of fixed-maturity securities in a total unrealized loss position | security | 2,831 | 2,831 | 3,723
Fixed-maturity securities, total unrealized loss | $ 429 | $ 429 | $ 631
Number of fixed-maturity securities in continuous unrealized loss position and below 70 percent of amortized cost | 17 | 17 | 19
Fixed maturity investments, Percentage of amortized costs |  | 70.00% |

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