Derivative Financial Instruments - Notional Value of Derivative Contracts (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Derivative [Line Items]
Total	$ 4,635,158	$ 4,829,655
Interest rate contracts [Member]
Derivative [Line Items]
Total	3,071,747	3,338,215
Interest rate contracts [Member] | Futures and forwards [Member]
Derivative [Line Items]
Total	166,415	87,406
Interest rate contracts [Member] | Swaps [Member]
Derivative [Line Items]
Total	2,733,613	3,096,382
Interest rate contracts [Member] | Options written [Member]
Derivative [Line Items]
Total	79,440	70,903
Interest rate contracts [Member] | Options purchased [Member]
Derivative [Line Items]
Total	92,279	83,524
Foreign exchange contracts [Member]
Derivative [Line Items]
Total	1,259,180	1,160,973
Foreign exchange contracts [Member] | Options written [Member]
Derivative [Line Items]
Total	95,635	117,088
Foreign exchange contracts [Member] | Options purchased [Member]
Derivative [Line Items]
Total	92,147	118,350
Foreign exchange contracts [Member] | Swaps, futures and forwards [Member]
Derivative [Line Items]
Total	1,006,234	866,835
Foreign exchange contracts [Member] | Spot [Member]
Derivative [Line Items]
Total	65,164	58,700
Commodity and Equity Contract [Member]
Derivative [Line Items]
Total	87,426	89,730
Commodity and Equity Contract [Member] | Options written [Member]
Derivative [Line Items]
Total	15,821	18,015
Commodity and Equity Contract [Member] | Options purchased [Member]
Derivative [Line Items]
Total	26,794	23,452
Commodity and Equity Contract [Member] | Swaps, futures and forwards [Member]
Derivative [Line Items]
Total	44,811	48,263
Credit contracts [Member]
Derivative [Line Items]
Total	$ 216,805	$ 240,737