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Investments Schedule of Gains and Losses on Equity and Other Investments (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Gain (Loss) on Securities [Line Items] |  |  |  |
Net realized gains (losses) | $ 283 | $ 198 | $ 327 | $ 201
Equity Securities |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Equity Securities, FV-NI, Realized Gain (Loss) | 396 | 123 | 596 | 147
Less: Net gains (losses) recognized from sales of securities | 59 | (6) | 79 | 5
Unrealized Gain (Loss) on Investments | 337 | 129 | 517 | 142
Other Investments |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Net realized gains (losses) | 82 | 152 | 103 | 452
Less: Net gains (losses) recognized from sales of securities | 0 | 2 | 4 | 2
Unrealized Gain (Loss) on Investments | 82 | 150 | 99 | 450
Private equities |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Net realized gains (losses) | 48 | (41) | 31 | 39
Less: Net gains (losses) recognized from sales of securities | 0 | 0 | 0 | 0
Unrealized Gain (Loss) on Investments | 48 | (41) | 31 | 39
Equity securities, Private equities and Other investments |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Net realized gains (losses) | 526 | 234 | 730 | 638
Less: Net gains (losses) recognized from sales of securities | 59 | (4) | 83 | 7
Unrealized Gain (Loss) on Investments | $ 467 | $ 238 | $ 647 | $ 631

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