Amount and Location in the Income Statement for Derivatives Designed as Cash Flow Hedges (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments in Cash Flow Hedging Relationships
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	$ (82)	$ 20	$ 264	$ 137
Derivative Instruments in Cash Flow Hedging Relationships | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	(2)	(2)	(3)	11
Derivative Instruments in Cash Flow Hedging Relationships | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	(80)	22	267	126
Non-derivative Instruments in Net Investment Hedging Relationships
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	(103)	(67)	47	6
Non-derivative Instruments in Net Investment Hedging Relationships | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives	$ (103)	$ (67)	$ 47	$ 6