Fair Value Measurements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended						6 Months Ended						3 Months Ended				6 Months Ended														3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended						6 Months Ended		12 Months Ended		6 Months Ended		12 Months Ended		6 Months Ended		12 Months Ended		6 Months Ended	12 Months Ended	6 Months Ended		12 Months Ended		6 Months Ended	12 Months Ended	6 Months Ended		12 Months Ended		6 Months Ended		12 Months Ended		6 Months Ended		12 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2014 Minimum [Member] Loss Severity Rates [Member] Residential Mortgage [Member]	Jun. 30, 2014 Maximum [Member] Loss Severity Rates [Member] Commercial Loan [Member]	Jun. 30, 2014 Derivatives [Member]	Jun. 30, 2013 Derivatives [Member]	Jun. 30, 2014 Derivative Liabilities [Member]	Jun. 30, 2013 Derivative Liabilities [Member]	Jun. 30, 2014 Credit contracts [Member]		Jun. 30, 2013 Credit contracts [Member]		Jun. 30, 2014 Credit contracts [Member]		Jun. 30, 2013 Credit contracts [Member]		Mar. 31, 2014 Credit contracts [Member]		Dec. 31, 2013 Credit contracts [Member]		Mar. 31, 2013 Credit contracts [Member]		Dec. 31, 2012 Credit contracts [Member]		Jun. 30, 2014 Derivatives [Member]	Dec. 31, 2013 Derivatives [Member]	Jun. 30, 2014 Deposits In Domestic Office [Member]	Jun. 30, 2013 Deposits In Domestic Office [Member]	Jun. 30, 2014 Deposits In Domestic Office [Member]	Jun. 30, 2013 Deposits In Domestic Office [Member]	Jun. 30, 2014 Long-term Debt [Member]	Jun. 30, 2013 Long-term Debt [Member]	Jun. 30, 2014 Long-term Debt [Member]	Jun. 30, 2013 Long-term Debt [Member]	Jun. 30, 2014 Foreign Government Debt Securities [Member]	Jun. 30, 2013 Foreign Government Debt Securities [Member]	Jun. 30, 2014 Foreign Government Debt Securities [Member]	Jun. 30, 2013 Foreign Government Debt Securities [Member]	Mar. 31, 2014 Foreign Government Debt Securities [Member]	Dec. 31, 2013 Foreign Government Debt Securities [Member]	Mar. 31, 2013 Foreign Government Debt Securities [Member]	Dec. 31, 2012 Foreign Government Debt Securities [Member]	Jun. 30, 2014 Foreign exchange contracts [Member] Option pricing model [Member] Minimum [Member] Foreign Exchange Volatility And Correlation Of Basket Of Currencies [Member]		Dec. 31, 2013 Foreign exchange contracts [Member] Option pricing model [Member] Minimum [Member] Foreign Exchange Volatility And Correlation Of Basket Of Currencies [Member]		Jun. 30, 2014 Foreign exchange contracts [Member] Option pricing model [Member] Maximum [Member] Foreign Exchange Volatility And Correlation Of Basket Of Currencies [Member]		Dec. 31, 2013 Foreign exchange contracts [Member] Option pricing model [Member] Maximum [Member] Foreign Exchange Volatility And Correlation Of Basket Of Currencies [Member]		Jun. 30, 2014 Deposits In Domestic Offices [Member] Option adjusted discounted cash flows [Member] Minimum [Member] Equity / Equity Index volatility [Member]		Dec. 31, 2013 Deposits In Domestic Offices [Member] Option adjusted discounted cash flows [Member] Minimum [Member] Equity / Equity Index volatility [Member]		Jun. 30, 2014 Deposits In Domestic Offices [Member] Option adjusted discounted cash flows [Member] Minimum [Member] Equity / Equity and Equity / Index correlation [Member]	Dec. 31, 2013 Deposits In Domestic Offices [Member] Option adjusted discounted cash flows [Member] Minimum [Member] Equity / Equity and Equity / Index correlation [Member]	Jun. 30, 2014 Deposits In Domestic Offices [Member] Option adjusted discounted cash flows [Member] Maximum [Member] Equity / Equity Index volatility [Member]		Dec. 31, 2013 Deposits In Domestic Offices [Member] Option adjusted discounted cash flows [Member] Maximum [Member] Equity / Equity Index volatility [Member]		Jun. 30, 2014 Deposits In Domestic Offices [Member] Option adjusted discounted cash flows [Member] Maximum [Member] Equity / Equity and Equity / Index correlation [Member]	Dec. 31, 2013 Deposits In Domestic Offices [Member] Option adjusted discounted cash flows [Member] Maximum [Member] Equity / Equity and Equity / Index correlation [Member]	Jun. 30, 2014 Equity contracts [Member] Option pricing model [Member] Minimum [Member] Equity / Equity Index volatility [Member]		Dec. 31, 2013 Equity contracts [Member] Option pricing model [Member] Minimum [Member] Equity / Equity Index volatility [Member]		Jun. 30, 2014 Equity contracts [Member] Option pricing model [Member] Minimum [Member] Equity / Equity and Equity / Index correlation [Member]		Dec. 31, 2013 Equity contracts [Member] Option pricing model [Member] Minimum [Member] Equity / Equity and Equity / Index correlation [Member]		Jun. 30, 2014 Equity contracts [Member] Option pricing model [Member] Maximum [Member] Equity / Equity Index volatility [Member]		Dec. 31, 2013 Equity contracts [Member] Option pricing model [Member] Maximum [Member] Equity / Equity Index volatility [Member]		Jun. 30, 2014 Equity contracts [Member] Option pricing model [Member] Maximum [Member] Equity / Equity and Equity / Index correlation [Member]		Dec. 31, 2013 Equity contracts [Member] Option pricing model [Member] Maximum [Member] Equity / Equity and Equity / Index correlation [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets	$ 3,581	$ 2,615	$ 3,581	$ 2,615	$ 3,690	$ 3,150	$ 3,181	$ 3,690			$ 538	$ 985	$ 222	$ 740	$ 257		$ 225	[1]	$ 257		$ 225	[1]	$ 181	[1]	$ 191	[1]	$ 364	[1]	$ 571	[1]											$ 0	$ 135	$ 0	$ 135	$ 117	$ 121	$ 143	$ 311
Trading securities	25,156		25,156			28,894																									4,354	5,991
Trading liabilities	8,815		8,815			10,875																									5,007	6,741
Loss severity rate			1.8
Foreign currency implied volatility			3.00%
Equity implied volatility			5.00%
Transfers Into Level 3	2	0	6	(46)											0	[1]	0	[1]	0	[1]	(46)	[1]												(177)		(160)					0	0	0	0
Long-term debt from Level 3 to Level 2	131	344	342	425																													104	165	244	244	27	179	98	181
Transfer out of level 3	107	15	98	21											(114)	[1]	0	[1]	(114)	[1]	0	[1]																			119	0	119	0
Transfers into level 3	27	177	95	160																													27		95		0	0	0	0
Range of Inputs									70.00%	27.00%																																							8.00%	[2]	11.00%	[2]	14.00%	[2]	16.00%	[2]	9.00%	[2],[3]	6.00%	[2],[3]	47.00%	50.00%	41.00%	[2],[3]	69.00%	[2],[3]	60.00%	58.00%	9.00%	[2]	6.00%	[2]	52.00%	[2]	50.00%	[2]	41.00%	[2]	69.00%	[2]	54.00%	[2]	58.00%	[2]
Deferred fee on stand by letters of credit	$ 41		$ 41			$ 46
Revaluation period			45 days

[1] Level 3 net derivatives included derivative assets of $538 million and derivative liabilities of $222 million as of June 30, 2014 and derivative assets of $985 million and derivative liabilities of $740 million as of June 30, 2013.

[2] We are the client-facing entity and we enter into identical but opposite derivatives to transfer the resultant risks to our affiliates. With the exception of counterparty credit risks, we are market neutral. The corresponding intra-group derivatives are presented as equity derivatives and foreign exchange derivatives in the table.

[3] Structured deposits and structured notes contain embedded derivative features whose fair value measurements contain significant Level 3 inputs.