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Investment Information - Net realized gains and losses (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Available for sale securities: |  |  |  |  |
Available for sale securities, gross gains on investment sales |  | $ 103 | $ 104 | $ 223 | $ 167
Available for sale securities, gross losses on investment sales |  | (59) | (50) | (228) | (205)
Equity securities, at fair value: |  |  |  |  |
Net realized gains (losses) on sales during the period |  | 15 | 15 | 69 | 31
Net unrealized gains (losses) on equity securities still held at reporting date |  | 79 | 58 | 113 | 147
Allowance for credit losses: |  |  |  |  |
Allowance for credit losses - investments related |  | 4 | 6 | (4) | 4
Allowance for credit losses - underwriting related |  | (9) | 2 | (10) | 0
Derivative instruments | [1] | 30 | 125 | 292 | 116
Other (2) | [2] | 7 | 4 | (80) | 225
Net realized gains (losses) |  | 210 | 169 | 442 | 358
Fixed maturities |  |  |  |  |
Available for sale securities: |  |  |  |  |
Change in fair value of assets and liabilities accounted for using the fair value option |  | 11 | 25 | 33 | 23
Other investments |  |  |  |  |
Available for sale securities: |  |  |  |  |
Change in fair value of assets and liabilities accounted for using the fair value option |  | 29 | (120) | 31 | (150)
Short term investments |  |  |  |  |
Available for sale securities: |  |  |  |  |
Change in fair value of assets and liabilities accounted for using the fair value option |  | $ 0 | $ 0 | $ 3 | $ 0
[1] | See note 10 for information on the Company’s derivative instruments.
[2] | Amounts in the 2025 periods primarily include losses related to the sale of certain alternative investments accounted for under the equity method.

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- Definition Includes realized gains and losses on debt securities accounted for as available for sale, realized and unrealized changes in the fair value of equity securities and assets and liabilities accounted for using the fair value option, realized and unrealized gains and losses on derivative instruments and changes in the allowance for credit losses on financial assets, and all other. + References No definition available. + Details
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- Definition Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-9 + Details
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