Derivative Financial Instruments - Notional Value of Derivative Contracts (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Total	$ 4,361,069	$ 4,212,040
Interest rate contracts [Member]
Derivative [Line Items]
Total	2,868,314	2,748,778
Interest Rate Futures and Forwards [Member]
Derivative [Line Items]
Total	421,519	149,413
Interest Rate Swap [Member]
Derivative [Line Items]
Total	2,245,350	2,453,526
Interest Rate Options Written [Member]
Derivative [Line Items]
Total	91,443	65,747
Interest Rate Options Purchased [Member]
Derivative [Line Items]
Total	110,002	80,092
Foreign exchange contracts [Member]
Derivative [Line Items]
Total	1,227,930	1,186,671
Foreign Exchange Swaps, Futures and Forwards [Member]
Derivative [Line Items]
Total	1,055,428	980,811
Foreign Exchange Options Written [Member]
Derivative [Line Items]
Total	72,066	81,132
Foreign Exchange Options Purchased [Member]
Derivative [Line Items]
Total	73,007	82,004
Foreign Exchange Spot [Member]
Derivative [Line Items]
Total	27,429	42,724
Commodities, equities and precious metals contracts [Member]
Derivative [Line Items]
Total	121,310	88,521
Commodities, Equities and Precious Metals, Swaps, Futures and Forwards [Member]
Derivative [Line Items]
Total	73,915	35,546
Commodities, Equities and Precious Metals Options Written [Member]
Derivative [Line Items]
Total	17,466	19,601
Commodities, Equities and Precious Metals Options Purchased [Member]
Derivative [Line Items]
Total	29,929	33,374
Credit contracts [Member]
Derivative [Line Items]
Total	$ 143,515	$ 188,070