Derivative Financial Instruments - Gains and Losses on Derivative Instruments Designated and Qualifying As Hedging Instruments in Cash Flow Hedges (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI on Derivatives	$ 41	$ 85
Gain (Loss) Reclassified From AOCI into Income	(7)	(45)
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI on Derivatives	(1)	0
Foreign exchange contracts | Net interest income
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Reclassified From AOCI into Income	0	0
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI on Derivatives	42	85
Interest rate contracts | Net interest income
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Reclassified From AOCI into Income	$ (7)	$ (45)