v3.26.3
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, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Other derivative instruments        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative $ 5 $ (9) $ (12) $ (14)
Not Designated as Hedging Instrument [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative 227 (153) (25) (62)
Not Designated as Hedging Instrument [Member] | Foreign currency forward contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative 276 (82) 108 51
Not Designated as Hedging Instrument [Member] | Options/Futures/Forward contracts on notes and bonds        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative (43) (3) (45) (5)
Not Designated as Hedging Instrument [Member] | Investment And Embedded Derivative Instruments [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative 233 (85) 63 46
Not Designated as Hedging Instrument [Member] | Futures contracts on equities        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative [1] (11) (59) (76) (94)
Not Designated as Hedging Instrument [Member] | Other derivative instruments        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative 5 (9) (12) (14)
Not Designated as Hedging Instrument [Member] | Other Derivative Instruments [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative $ (6) $ (68) $ (88) $ (108)
[1] Related to MRB book of business.