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Investments (Net Realized Gains (Losses) And Losses Included In Net Realized Gains (Losses) And Other Comprehensive Income) (Detail) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2024 | Mar. 31, 2023
Gain (Loss) on Securities [Line Items] |  |  |
Net realized gains (losses) |  | $ (101) | $ (77)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Period Increase (Decrease) |  | 31 | 59
Debt Securities, Available-for-sale, Gain (Loss), Total |  | 49 | (180)
Foreign exchange |  | (131) | 131
Gain (Loss) on Derivative |  | (140) | (104)
Other |  | (8) | (7)
Fixed Maturities [Member] |  |  |
Gain (Loss) on Securities [Line Items] |  |  |
Debt Securities, Available-for-Sale, Realized Gain (Loss), Excluding Other-than-temporary Impairment |  | 16 | 2
Debt Securities, Available-for-Sale, Realized Loss, Excluding Other-than-temporary Impairment |  | (141) | (159)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Period Increase (Decrease) |  | 40 | 2
Debt Securities, Available-For-Sale, Credit Impairment Charges Intent to Sell | [1] | (34) | (25)
Equity Securities |  |  |
Gain (Loss) on Securities [Line Items] |  |  |
Equity Securities, FV-NI, Realized Gain (Loss) |  | 3 | 11
Other Investments |  |  |
Gain (Loss) on Securities [Line Items] |  |  |
Net realized gains (losses) |  | 168 | 0
Alternative Investment |  |  |
Gain (Loss) on Securities [Line Items] |  |  |
Net realized gains (losses) |  | 31 | 15
Other derivative instruments |  |  |
Gain (Loss) on Securities [Line Items] |  |  |
Gain (Loss) on Derivative |  | (2) | (1)
Investment and embedded derivative instruments |  |  |
Gain (Loss) on Securities [Line Items] |  |  |
Gain (Loss) on Derivative |  | $ (43) | $ (46)
[1] | Relates to certain securities we intended to sell and securities written to market entering default.

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