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Investments Schedule of Gains and Losses on Equity and Other Investments (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023
Gain (Loss) on Securities [Line Items] |  |  |  |
Net realized gains (losses) | $ 104 | $ (304) | $ 3 | $ (381)
Equity Securities |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Equity Securities, FV-NI, Realized Gain (Loss) | 21 | 28 | 24 | 39
Less: Net gains (losses) recognized from sales of securities | 14 | 2 | 11 | (3)
Unrealized Gain (Loss) on Investments | 7 | 26 | 13 | 42
Other Investments |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Net realized gains (losses) | 132 | 0 | 300 | 0
Less: Net gains (losses) recognized from sales of securities | 0 |  | 0 |
Unrealized Gain (Loss) on Investments | 132 |  | 300 |
Alternative Investment |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Net realized gains (losses) | 49 | 20 | 80 | 35
Less: Net gains (losses) recognized from sales of securities | 0 | 0 | 0 | 0
Unrealized Gain (Loss) on Investments | 49 | 20 | 80 | 35
Equity securities and other investments |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Net realized gains (losses) | 202 | 48 | 404 | 74
Less: Net gains (losses) recognized from sales of securities | 14 | 2 | 11 | (3)
Unrealized Gain (Loss) on Investments | $ 188 | $ 46 | $ 393 | $ 77

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