Fair Value Measurements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013		Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets	$ 3,690		$ 3,181		$ 3,150		$ 3,690
Trading securities	27,336				28,894
Trading liabilities	9,349				10,875
Loss severity rate	1.8
Foreign currecy implied volatility	3.00%
Equity implied volatility	5.00%
Transfers Into Level 3	4		(47)
Long-term debt from Level 3 to Level 2	211		86
Transfers into level 3	68		(11)
Deferred fee on stand by letters of credit	45				46
Revaluation period	45 days
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency correlations	55.00%
Minimum [Member] | Loss Severity Rates [Member] | Residential Mortgage [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range of Inputs	70.00%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency correlations	55.00%
Maximum [Member] | Loss Severity Rates [Member] | Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range of Inputs	17.00%
Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets	694				1,320
Derivative Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets	392				782
Credit contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets	181		364	[1]	191	[1]	571	[1]
Transfers Into Level 3	0	[1]	(46)	[1]
Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	3,988				5,991
Trading liabilities	4,989				6,741
Deposits In Domestic Office [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt from Level 3 to Level 2	140		85
Transfers into level 3	68		(11)
Long-term Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt from Level 3 to Level 2	71		1
Transfers into level 3	$ 0		$ 0

[1] Level 3 net derivatives included derivative assets of $694 million and derivative liabilities of $392 million as of March 31, 2014 and derivative assets of $1,320 million and derivative liabilities of $782 million as of March 31, 2013.