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Net Investment (Losses) Gains (Change in Unrealized Gains (Losses) of Available For Sales Securities) (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Realized and Unrealized Investment Gains Losses [Line Items] |  |  |  |
Total change in unrealized investment gains | $ 87,749 | $ 480,768 | $ 431,462 | $ 370,831
Income tax expense | (15,836) | (99,775) | (91,011) | (73,298)
Noncontrolling interests | 0 | 0 | (1) | 1
Total change in unrealized gains | 71,913 | 380,993 | 340,450 | 297,534
Debt securities |  |  |  |
Realized and Unrealized Investment Gains Losses [Line Items] |  |  |  |
Total change in unrealized investment gains | 111,755 | 463,418 | 447,977 | 363,430
Fixed maturity securities with allowance for expected credit losses |  |  |  |
Realized and Unrealized Investment Gains Losses [Line Items] |  |  |  |
Total change in unrealized investment gains | (23,621) | 11,166 | (23,694) | 4,470
Investment funds |  |  |  |
Realized and Unrealized Investment Gains Losses [Line Items] |  |  |  |
Total change in unrealized investment gains | (266) | 6,152 | 7,340 | 3,112
Other |  |  |  |
Realized and Unrealized Investment Gains Losses [Line Items] |  |  |  |
Total change in unrealized investment gains | $ (119) | $ 32 | $ (161) | $ (181)

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