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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
--- | ---
Mar. 31, 2024 | Mar. 31, 2023
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (Loss) on Derivative |  | $ (140) | $ (104)
Foreign currency forward contracts |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (Loss) on Derivative |  | (52) | (51)
All Other Futures Contracts, Options and equities [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (Loss) on Derivative |  | 6 | 5
Convertible securities |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (Loss) on Derivative | [1] | 3 | 0
Investment And Embedded Derivative Instruments [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (Loss) on Derivative |  | (43) | (46)
Futures contracts on equities |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (Loss) on Derivative | [2] | (95) | (57)
Other Derivative Instruments [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (Loss) on Derivative |  | (97) | (58)
Other derivative instruments |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (Loss) on Derivative |  | $ (2) | $ (1)
[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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