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Investments - Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments (Details) - USD ($) $ in Millions | 3 Months Ended
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Mar. 31, 2026 | Mar. 31, 2025
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |
Realized gains (losses) on securities | $ (18) | $ 3
Net of tax |  |
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |
Realized gains (losses) on securities before impairments | (11) | 8
Impairment allowance on securities | (4) | (6)
Realized gains (losses) on securities | (15) | 2
Change in unrealized | (78) | 61
Total pretax |  |
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |
Realized gains (losses) on securities before impairments | (13) | 10
Impairment allowance on securities | (5) | (7)
Realized gains (losses) on securities | (18) | 3
Change in unrealized | (98) | 76
Fixed maturities |  |
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |
Realized gains (losses) on securities before impairments | (1) | 1
Impairment allowance on fixed maturity securities | (5) | (7)
Realized gains (losses) on securities | (6) | (6)
Change in unrealized | (98) | 76
Equity securities |  |
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |
Realized gains (losses) on securities before impairments | (12) | 9
Realized gains (losses) on securities | (12) | 9
Change in unrealized | 0 | 0
Mortgage loans and other investments |  |
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |
Realized gains (losses) on securities before impairments | 0 | 0
Impairment allowance on mortgage loans and other investments | 0 | 0
Realized gains (losses) on securities | 0 | 0
Change in unrealized | 0 | 0
Total tax effects |  |
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |
Realized gains (losses) on securities before impairments | 2 | (2)
Impairment allowance on securities | 1 | 1
Realized gains (losses) on securities | 3 | (1)
Change in unrealized | $ 20 | $ (15)

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