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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 | 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)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Period Increase (Decrease) |  | 41 | 79 | 72 | 138
Debt Securities, Available-for-sale, Gain (Loss), Total |  | 26 | (107) | 75 | (287)
Foreign exchange |  | 27 | (186) | (104) | (55)
Gain (Loss) on Derivative |  | (41) | (128) | (181) | (232)
Other |  | 1 | (6) | (7) | (13)
Fixed Maturities [Member] |  |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Debt Securities, Available-for-Sale, Realized Gain (Loss), Excluding Other-than-temporary Impairment |  | 36 | 17 | 52 | 19
Debt Securities, Available-for-Sale, Realized Loss, Excluding Other-than-temporary Impairment |  | (106) | (113) | (247) | (272)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Period Increase (Decrease) |  | (8) | 8 | 32 | 10
Debt Securities, Available-For-Sale, Credit Impairment Charges Intent to Sell | [1] | (28) | (19) | (62) | (44)
Equity Securities |  |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Equity Securities, FV-NI, Realized Gain (Loss) |  | 21 | 28 | 24 | 39
Other Investments |  |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Net realized gains (losses) |  | 132 | 0 | 300 | 0
Alternative Investment |  |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Net realized gains (losses) |  | 49 | 20 | 80 | 35
Other derivative instruments |  |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | (3) | 2 | (5) | 1
Investment and embedded derivative instruments |  |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | $ (17) | $ (55) | $ (60) | $ (101)
[1] | Relates to certain securities we intended to sell and securities written to market entering default.

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