Derivative Financial Instruments - Gains and Losses on Derivative Instruments Held For Other Purpose (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives held for other purposes		$ (1,354)	$ 1,052
Loss on Instruments Designated at Fair Value and Related Derivatives [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives held for other purposes		(1,419)	1,059
Loss on Instruments Designated at Fair Value and Related Derivatives [Member] | Interest rate contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives held for other purposes		250	156
Loss on Instruments Designated at Fair Value and Related Derivatives [Member] | Foreign exchange contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives held for other purposes		(2)	(1)
Loss on Instruments Designated at Fair Value and Related Derivatives [Member] | Equity contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives held for other purposes		(1,698)	914
Loss on Instruments Designated at Fair Value and Related Derivatives [Member] | Credit contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives held for other purposes		37	0
Other Income (Loss) [Member] | Interest rate contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives held for other purposes		(3)	(1)
Other Income (Loss) [Member] | Credit contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives held for other purposes		51	(10)
Other Income (Loss) [Member] | Other Contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives held for other purposes	[1]	$ 11	$ (6)

[1] Consists of swap agreements entered into in conjunction with the sales of Visa Class B Shares.