v3.26.1
Derivative Financial Instruments - Gains and Losses on Hedged Items in Fair Value Hedges (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivatives $ 84 $ 52 $ 133 $ (65)
Gain (Loss) on Hedged Items (9) (7) 8 127
Asset-backed securities available-for-sale | Interest rate contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivatives 178 (20) 295 (197)
Gain (Loss) on Hedged Items 29 228 110 572
Deposits | Interest rate contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivatives   36 5 44
Gain (Loss) on Hedged Items   (28) (21) (59)
Long-term debt | Interest rate contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) on Derivatives (94) 36 (167) 88
Gain (Loss) on Hedged Items $ (38) $ (207) $ (81) $ (386)