Derivative Financial Instruments - Notional Value of Derivative Contracts (Detail) - USD ($) $ in Millions		Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Total		$ 4,252,577	$ 4,135,130
Interest rate contracts [Member]
Derivative [Line Items]
Total		2,969,329	2,805,579
Interest Rate Futures and Forwards [Member]
Derivative [Line Items]
Total		628,410	501,635
Interest Rate Swap [Member]
Derivative [Line Items]
Total		2,206,367	2,142,183
Interest Rate Options Written [Member]
Derivative [Line Items]
Total		60,280	74,741
Interest Rate Options Purchased [Member]
Derivative [Line Items]
Total		74,272	87,020
Foreign exchange contracts [Member]
Derivative [Line Items]
Total		1,069,497	1,105,971
Foreign Exchange Swaps, Futures and Forwards [Member]
Derivative [Line Items]
Total		986,358	965,301
Foreign Exchange Options Written [Member]
Derivative [Line Items]
Total		22,651	52,845
Foreign Exchange Options Purchased [Member]
Derivative [Line Items]
Total		23,180	53,260
Foreign Exchange Spot [Member]
Derivative [Line Items]
Total		37,308	34,565
Commodities, equities and precious metals contracts [Member]
Derivative [Line Items]
Total		111,281	99,682
Commodities, Equities and Precious Metals, Swaps, Futures and Forwards [Member]
Derivative [Line Items]
Total		53,523	49,555
Commodities, Equities and Precious Metals Options Written [Member]
Derivative [Line Items]
Total		22,995	19,495
Commodities, Equities and Precious Metals Options Purchased [Member]
Derivative [Line Items]
Total		34,763	30,632
Credit contracts [Member]
Derivative [Line Items]
Total		101,880	123,714
Other Contract [Member]
Derivative [Line Items]
Total	[1]	$ 590	$ 184

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