Derivative Financial Instruments - Notional Value of Derivative Contracts (Detail) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Total	$ 4,231,145	$ 4,212,040
Interest rate contracts [Member]
Derivative [Line Items]
Total	2,742,962	2,748,778
Interest Rate Futures and Forwards [Member]
Derivative [Line Items]
Total	133,631	149,413
Interest Rate Swap [Member]
Derivative [Line Items]
Total	2,428,463	2,453,526
Interest Rate Options Written [Member]
Derivative [Line Items]
Total	83,275	65,747
Interest Rate Options Purchased [Member]
Derivative [Line Items]
Total	97,593	80,092
Foreign exchange contracts [Member]
Derivative [Line Items]
Total	1,212,131	1,186,671
Foreign Exchange Swaps, Futures and Forwards [Member]
Derivative [Line Items]
Total	1,035,435	980,811
Foreign Exchange Options Written [Member]
Derivative [Line Items]
Total	73,401	81,132
Foreign Exchange Options Purchased [Member]
Derivative [Line Items]
Total	74,122	82,004
Foreign Exchange Spot [Member]
Derivative [Line Items]
Total	29,173	42,724
Commodities, equities and precious metals contracts [Member]
Derivative [Line Items]
Total	93,196	88,521
Commodities, Equities and Precious Metals, Swaps, Futures and Forwards [Member]
Derivative [Line Items]
Total	48,754	35,546
Commodities, Equities and Precious Metals Options Written [Member]
Derivative [Line Items]
Total	18,787	19,601
Commodities, Equities and Precious Metals Options Purchased [Member]
Derivative [Line Items]
Total	25,655	33,374
Credit contracts [Member]
Derivative [Line Items]
Total	$ 182,856	$ 188,070