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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 | 6 Months Ended
--- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2025 | Jun. 30, 2024
Other derivative instruments |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | $ (2) | $ (3) | $ (5) | $ (5)
Not Designated as Hedging Instrument [Member] |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | 63 | (41) | 91 | (181)
Not Designated as Hedging Instrument [Member] | Foreign currency forward contracts |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | 147 | (28) | 133 | (80)
Not Designated as Hedging Instrument [Member] | Options/Futures/Forward contracts on notes and bonds |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | 7 | 12 | (2) | 18
Not Designated as Hedging Instrument [Member] | Convertible securities |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative | [1] | 0 | (1) | 0 | 2
Not Designated as Hedging Instrument [Member] | Investment And Embedded Derivative Instruments [Member] |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | 154 | (17) | 131 | (60)
Not Designated as Hedging Instrument [Member] | Futures contracts on equities |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative | [2] | (89) | (21) | (35) | (116)
Not Designated as Hedging Instrument [Member] | Other derivative instruments |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | (2) | (3) | (5) | (5)
Not Designated as Hedging Instrument [Member] | Other Derivative Instruments [Member] |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |
Gain (Loss) on Derivative |  | $ (91) | $ (24) | $ (40) | $ (121)
[1] | Includes embedded derivatives.
[2] | Related to MRB book of business.

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