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Commitments, Contingencies, And Guarantees (Net Realized Gains (Losses) Of Derivative Instrument Activity In Consolidated Statement Of Operations) (Detail) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | $ 54 | $ (163) | $ (178) | $ (1)
Foreign currency forward contracts |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | (17) | (247) | (95) | (515)
All Other Futures Contracts, Options and equities [Member] |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | 29 | 49 | 5 | 285
Convertible securities |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative | [1] | (3) | 0 | (2) | (2)
Investment And Embedded Derivative Instruments [Member] |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | 9 | (198) | (92) | (232)
Futures contracts on equities |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative | [2] | 52 | 54 | (80) | 240
Other Derivatives [Member] |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | (7) | (19) | (6) | (9)
Guaranteed Living Benefit And Other Derivative Instruments [Member] |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | $ 45 | $ 35 | $ (86) | $ 231
[1] | Includes embedded derivatives.
[2] | Related to MRB book of business.

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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4A -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4A + Details
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