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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
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Mar. 31, 2024 | Mar. 31, 2023
Realized and Unrealized Investment Gains Losses [Line Items] |  |
Total change in unrealized investment (losses) gains | $ (89,297) | $ 232,021
Income tax benefit (expense) | 19,175 | (51,222)
Noncontrolling interests | 0 | (1)
Total change in unrealized gains | (70,122) | 180,798
Debt securities |  |
Realized and Unrealized Investment Gains Losses [Line Items] |  |
Total change in unrealized investment (losses) gains | (88,594) | 227,116
Fixed maturity securities with allowance for expected credit losses |  |
Realized and Unrealized Investment Gains Losses [Line Items] |  |
Total change in unrealized investment (losses) gains | 987 | 3,456
Investment funds |  |
Realized and Unrealized Investment Gains Losses [Line Items] |  |
Total change in unrealized investment (losses) gains | (1,703) | 1,936
Other |  |
Realized and Unrealized Investment Gains Losses [Line Items] |  |
Total change in unrealized investment (losses) gains | $ 13 | $ (487)

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