Fair Value Measurements - Changes in Fair Value of Level 3 Assets and Liabilities (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	$ 3,150		$ 3,690
Fair Value Assets, Trading Revenue (Loss)	13	[1]	88	[1]
Fair Value Assets, Other Revenue	(12)	[1]	15	[1]
Fair Value Assets, Purchases	553		36
Fair Value Assets, Issuances	0		6
Fair Value Assets, Settlements	(29)		(600)
Transfers Into Level 3	4		(47)
Fair Value Assets, Transfers Out of Level 3	11		(7)
Fair Value Assets, Ending Balance	3,690		3,181
Fair Value Assets, Current Period Unrealized Gains (Losses)	(30)		51
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Beginning Balance	(3,234)		(3,065)
Fair Value Liability, Trading Revenue (Loss)	(31)	[1]	(71)	[1]
Fair Value Liability, Purchases	0		0
Fair Value Liability, Issuances	(68)		(614)
Fair Value Liability, Settlements	214		159
Transfers into level 3	(68)		11
Fair Value Liability, Transfers Out of Level 3	211		86
Fair Value Liability, Ending Balance	(2,976)		(3,494)
Fair Value Liability, Current Period Unrealized Gains (Losses)	(25)		(57)
Interest rate contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	1	[2]	7	[2]
Fair Value Assets, Trading Revenue (Loss)	0	[1],[2]	0	[1],[2]
Fair Value Assets, Other Revenue	0	[1],[2]	(1)	[1],[2]
Fair Value Assets, Purchases	0	[2]	0	[2]
Fair Value Assets, Issuances	0	[2]	0	[2]
Fair Value Assets, Settlements	0	[2]	0	[2]
Transfers Into Level 3	0	[2]	0	[2]
Fair Value Assets, Transfers Out of Level 3	0	[2]	0	[2]
Fair Value Assets, Ending Balance	1	[2]	6	[2]
Fair Value Assets, Current Period Unrealized Gains (Losses)	0	[2]	(1)	[2]
Foreign exchange contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	95	[2]	5	[2]
Fair Value Assets, Trading Revenue (Loss)	1	[1],[2]	15	[1],[2]
Fair Value Assets, Other Revenue	0	[1],[2]	0	[1],[2]
Fair Value Assets, Purchases	0	[2]	0	[2]
Fair Value Assets, Issuances	0	[2]	0	[2]
Fair Value Assets, Settlements	(6)	[2]	122	[2]
Transfers Into Level 3	0	[2]	(8)	[2]
Fair Value Assets, Transfers Out of Level 3	6	[2]	0	[2]
Fair Value Assets, Ending Balance	96	[2]	134	[2]
Fair Value Assets, Current Period Unrealized Gains (Losses)	1	[2]	137	[2]
Equity contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	3	[2]	(7)	[2]
Fair Value Assets, Trading Revenue (Loss)	19	[1],[2]	61	[1],[2]
Fair Value Assets, Other Revenue	0	[1],[2]	0	[1],[2]
Fair Value Assets, Purchases	0	[2]	0	[2]
Fair Value Assets, Issuances	0	[2]	0	[2]
Fair Value Assets, Settlements	(7)	[2]	(20)	[2]
Transfers Into Level 3	4	[2]	7	[2]
Fair Value Assets, Transfers Out of Level 3	5	[2]	(7)	[2]
Fair Value Assets, Ending Balance	24	[2]	34	[2]
Fair Value Assets, Current Period Unrealized Gains (Losses)	12	[2]	41	[2]
Precious metals contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	(2)	[2]
Fair Value Assets, Trading Revenue (Loss)	2	[1],[2]
Fair Value Assets, Other Revenue	0	[1],[2]
Fair Value Assets, Purchases	0	[2]
Fair Value Assets, Issuances	0	[2]
Fair Value Assets, Settlements	0	[2]
Transfers Into Level 3	0	[2]
Fair Value Assets, Transfers Out of Level 3	0	[2]
Fair Value Assets, Ending Balance	0	[2]
Fair Value Assets, Current Period Unrealized Gains (Losses)	0	[2]
Credit contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	191	[2]	571	[2]
Fair Value Assets, Trading Revenue (Loss)	(13)	[1],[2]	(49)	[1],[2]
Fair Value Assets, Other Revenue	0	[1],[2]	0	[1],[2]
Fair Value Assets, Purchases	0	[2]	0	[2]
Fair Value Assets, Issuances	0	[2]	0	[2]
Fair Value Assets, Settlements	3	[2]	(112)	[2]
Transfers Into Level 3	0	[2]	(46)	[2]
Fair Value Assets, Transfers Out of Level 3	0	[2]	0	[2]
Fair Value Assets, Ending Balance	181		364	[2]
Fair Value Assets, Current Period Unrealized Gains (Losses)	(28)	[2]	(197)	[2]
Collateralized debt obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	254		466
Fair Value Assets, Trading Revenue (Loss)	7	[1]	35	[1]
Fair Value Assets, Other Revenue	0	[1]	0	[1]
Fair Value Assets, Purchases	0		21
Fair Value Assets, Issuances	0		0
Fair Value Assets, Settlements	(3)		(41)
Transfers Into Level 3	0		0
Fair Value Assets, Transfers Out of Level 3	0		0
Fair Value Assets, Ending Balance	258		481
Fair Value Assets, Current Period Unrealized Gains (Losses)	7		35
Corporate and other domestic [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	2,260		1,861
Fair Value Assets, Trading Revenue (Loss)	(5)	[1]	7	[1]
Fair Value Assets, Other Revenue	0	[1]	0	[1]
Fair Value Assets, Purchases	553		15
Fair Value Assets, Issuances	0		0
Fair Value Assets, Settlements	0		(359)
Transfers Into Level 3	0		0
Fair Value Assets, Transfers Out of Level 3	0		0
Fair Value Assets, Ending Balance	2,808		1,524
Fair Value Assets, Current Period Unrealized Gains (Losses)	(6)		4
Foreign debt securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	0		299
Fair Value Assets, Trading Revenue (Loss)	0	[1]	(5)	[1]
Fair Value Assets, Other Revenue	0	[1]	0	[1]
Fair Value Assets, Purchases	0		0
Fair Value Assets, Issuances	0		0
Fair Value Assets, Settlements	0		0
Transfers Into Level 3	0		0
Fair Value Assets, Transfers Out of Level 3	0		0
Fair Value Assets, Ending Balance	0		294
Fair Value Assets, Current Period Unrealized Gains (Losses)	0		(5)
Government debt securities issued by foreign entities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	121		311
Fair Value Assets, Trading Revenue (Loss)	2	[1]	22	[1]
Fair Value Assets, Other Revenue	0	[1]	0
Fair Value Assets, Purchases	0		0
Fair Value Assets, Issuances	0		0
Fair Value Assets, Settlements	(6)		(190)
Transfers Into Level 3	0		0
Fair Value Assets, Transfers Out of Level 3	0		0
Fair Value Assets, Ending Balance	117		143
Fair Value Assets, Current Period Unrealized Gains (Losses)	(4)		19
Equity securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	0		9
Fair Value Assets, Trading Revenue (Loss)	0	[1]	2	[1]
Fair Value Assets, Other Revenue	0	[1]	0	[1]
Fair Value Assets, Purchases	0		0
Fair Value Assets, Issuances	0		0
Fair Value Assets, Settlements	0		0
Transfers Into Level 3	0		0
Fair Value Assets, Transfers Out of Level 3	0		0
Fair Value Assets, Ending Balance	0		11
Fair Value Assets, Current Period Unrealized Gains (Losses)	0		2
Mortgage servicing rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	227	[2],[3]	168	[2],[3]
Fair Value Assets, Trading Revenue (Loss)	0	[1],[2],[3]	0	[1],[2],[3]
Fair Value Assets, Other Revenue	(12)	[1],[2],[3]	16	[1],[2],[3]
Fair Value Assets, Purchases	0	[2],[3]	0	[2],[3]
Fair Value Assets, Issuances	0	[2],[3]	6	[2],[3]
Fair Value Assets, Settlements	(10)	[2],[3]	0	[2],[3]
Transfers Into Level 3	0	[2],[3]	0	[2],[3]
Fair Value Assets, Transfers Out of Level 3	0	[2],[3]	0	[2],[3]
Fair Value Assets, Ending Balance	205	[2],[3]	190	[2],[3]
Fair Value Assets, Current Period Unrealized Gains (Losses)	(12)	[2],[3]	16	[2],[3]
Deposits In Domestic Office [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Beginning Balance	(2,334)		(2,636)
Fair Value Liability, Trading Revenue (Loss)	(124)	[1]	(40)	[1]
Fair Value Liability, Purchases	0		0
Fair Value Liability, Issuances	(25)		(404)
Fair Value Liability, Settlements	167		108
Transfers into level 3	(68)		11
Fair Value Liability, Transfers Out of Level 3	140		85
Fair Value Liability, Ending Balance	(2,244)		(2,876)
Fair Value Liability, Current Period Unrealized Gains (Losses)	(23)		(32)
Long-term Debt [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Beginning Balance	(900)		(429)
Fair Value Liability, Trading Revenue (Loss)	93	[1]	(31)	[1]
Fair Value Liability, Purchases	0		0
Fair Value Liability, Issuances	(43)		(210)
Fair Value Liability, Settlements	47		51
Transfers into level 3	0		0
Fair Value Liability, Transfers Out of Level 3	71		1
Fair Value Liability, Ending Balance	(732)		(618)
Fair Value Liability, Current Period Unrealized Gains (Losses)	$ (2)		$ (25)

[1] Includes realized and unrealized gains and losses.

[2] 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.

[3] See Note 7, "Intangible Assets," for additional information.