v3.26.1
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, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Other derivative instruments        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative $ (8) $ (2) $ (17) $ (5)
Not Designated as Hedging Instrument [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative (173) 63 (252) 91
Not Designated as Hedging Instrument [Member] | Foreign currency forward contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative (60) 147 (168) 133
Not Designated as Hedging Instrument [Member] | Options/Futures/Forward contracts on notes and bonds        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative 5 7 (2) (2)
Not Designated as Hedging Instrument [Member] | Investment And Embedded Derivative Instruments [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative (55) 154 (170) 131
Not Designated as Hedging Instrument [Member] | Futures contracts on equities        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative [1] (110) (89) (65) (35)
Not Designated as Hedging Instrument [Member] | Other derivative instruments        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative (8) (2) (17) (5)
Not Designated as Hedging Instrument [Member] | Other Derivative Instruments [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivative $ (118) $ (91) $ (82) $ (40)
[1] Related to MRB book of business.