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, 2013		Mar. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	$ 3,690		$ 4,157
Fair Value Assets, Trading Revenue (Loss)	(88)	[1]	226	[1]
Fair Value Assets, Other Revenue	(15)	[1]	0	[1]
Purchases	36		83
Fair Value Assets, Issuances	6		8
Fair Value Assets, Settlements	(600)		(123)
Transfers Into Level 3	(47)		(3)
Fair Value Assets, Transfers Out of Level 3	(7)		(12)
Fair Value Assets, Ending Balance	3,181		3,884
Fair Value Assets, Current Period Unrealized Gains (Losses)	51		(235)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Beginning Balance	(3,065)		(2,953)
Fair Value Liability, Trading Revenue (Loss)	(71)	[1]	57	[1]
Fair Value Liability, Purchases	0		0
Fair Value Liability, Issuances	(614)		(376)
Fair Value Liability, Settlements	159		85
Fair Value Liability, Transfers Into Level 3	11		3
Fair Value Liability, Transfers Out of Level 3	86		174
Fair Value Liability, Ending Balance	(3,494)		(3,124)
Fair Value Liability, Current Period Unrealized Gains (Losses)	(57)		(41)
Interest rate contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	7	[2]	9	[2]
Fair Value Assets, Other Revenue	1	[1],[2]	0	[1],[2]
Fair Value Assets, Settlements			0	[2]
Fair Value Assets, Ending Balance	6	[3]	9	[2]
Fair Value Assets, Current Period Unrealized Gains (Losses)	(1)	[2]	0	[2]
Foreign exchange contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	5	[2]	(1)	[2]
Fair Value Assets, Trading Revenue (Loss)	(15)	[1],[2]	1	[1],[2]
Fair Value Assets, Other Revenue	0	[1],[2]
Fair Value Assets, Issuances	0	[2]
Fair Value Assets, Settlements	122	[2]
Transfers Into Level 3	(8)		(3)	[2]
Fair Value Assets, Transfers Out of Level 3	0	[2]
Fair Value Assets, Ending Balance	134	[3]	(5)	[2]
Fair Value Assets, Current Period Unrealized Gains (Losses)	137	[2]	(1)	[2]
Equity contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	(7)	[2]	(83)	[2]
Fair Value Assets, Trading Revenue (Loss)	(61)	[1],[2]	(50)	[1],[2]
Fair Value Assets, Other Revenue	0	[1],[2]
Fair Value Assets, Settlements	(20)	[2]	(19)	[2]
Transfers Into Level 3	7	[2]	0	[2]
Fair Value Assets, Transfers Out of Level 3	(7)	[2]	(1)	[2]
Fair Value Assets, Ending Balance	34	[3]	(53)	[2]
Fair Value Assets, Current Period Unrealized Gains (Losses)	41	[2]	27	[2]
Credit contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	571	[2]	1,353	[2]
Fair Value Assets, Trading Revenue (Loss)	49	[1],[2]	375	[1],[2]
Fair Value Assets, Other Revenue	0	[1],[2]
Fair Value Assets, Settlements	(112)	[2]	6	[2]
Transfers Into Level 3	(46)	[2]
Fair Value Assets, Transfers Out of Level 3	0	[2]	0	[2]
Fair Value Assets, Ending Balance	364	[3]	984	[2]
Fair Value Assets, Current Period Unrealized Gains (Losses)	(197)	[2]	(346)	[2]
Collateralized debt obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	466		703
Fair Value Assets, Trading Revenue (Loss)	(35)	[1]	(39)	[1]
Fair Value Assets, Other Revenue	0	[1]
Purchases	21		1
Fair Value Assets, Settlements	(41)		(82)
Transfers Into Level 3	0
Fair Value Assets, Ending Balance	481		661
Fair Value Assets, Current Period Unrealized Gains (Losses)	35		33
Corporate and other domestic [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	1,861		1,679
Fair Value Assets, Trading Revenue (Loss)	(7)	[1]	(20)	[1]
Fair Value Assets, Other Revenue	0	[1]
Purchases	15		82
Fair Value Assets, Settlements	(359)		(28)
Fair Value Assets, Ending Balance	1,524		1,753
Fair Value Assets, Current Period Unrealized Gains (Losses)	4		20
Foreign debt securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	299		253
Fair Value Assets, Trading Revenue (Loss)	5	[1]	(41)	[1]
Fair Value Assets, Other Revenue	0	[1]
Purchases	0
Fair Value Assets, Settlements	0
Transfers Into Level 3	0
Fair Value Assets, Ending Balance	294		294
Fair Value Assets, Current Period Unrealized Gains (Losses)	(5)		41
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	311
Fair Value Assets, Trading Revenue (Loss)	(22)	[1]
Fair Value Assets, Other Revenue	0	[1]
Purchases	0
Fair Value Assets, Settlements	(190)
Fair Value Assets, Ending Balance	143
Fair Value Assets, Current Period Unrealized Gains (Losses)	19
Equity securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	9		13
Fair Value Assets, Trading Revenue (Loss)	(2)	[1]	0	[1]
Fair Value Assets, Other Revenue	0	[1]
Fair Value Assets, Settlements	0		0
Fair Value Assets, Ending Balance	11		13
Fair Value Assets, Current Period Unrealized Gains (Losses)	2		3
Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance			11	[3]
Fair Value Assets, Transfers Out of Level 3			(11)	[3]
Fair Value Assets, Ending Balance			0	[3]
Fair Value Assets, Current Period Unrealized Gains (Losses)			(12)	[3]
Mortgage servicing rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	168	[4]	220	[4]
Fair Value Assets, Other Revenue	(16)	[1],[4]	0	[1],[4]
Fair Value Assets, Issuances	6	[4]	8	[4]
Fair Value Assets, Settlements			0	[4]
Fair Value Assets, Ending Balance	190	[4]	228	[4]
Fair Value Assets, Current Period Unrealized Gains (Losses)	16	[4]	0	[4]
Deposits In Domestic Office [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Beginning Balance	(2,636)		(2,867)
Fair Value Liability, Trading Revenue (Loss)	(40)	[1]	56	[1]
Fair Value Liability, Purchases	0		0
Fair Value Liability, Issuances	(404)		(287)
Fair Value Liability, Settlements	108		82
Fair Value Liability, Transfers Into Level 3	11		3
Fair Value Liability, Transfers Out of Level 3	85		161
Fair Value Liability, Ending Balance	(2,876)		(2,964)
Fair Value Liability, Current Period Unrealized Gains (Losses)	(32)		(41)
Long-term Debt [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Beginning Balance	(429)		(86)
Fair Value Liability, Trading Revenue (Loss)	(31)	[1]	1	[1]
Fair Value Liability, Purchases	0		0
Fair Value Liability, Issuances	(210)		(89)
Fair Value Liability, Settlements	51		3
Fair Value Liability, Transfers Into Level 3	0		0
Fair Value Liability, Transfers Out of Level 3	1		13
Fair Value Liability, Ending Balance	(618)		(160)
Fair Value Liability, Current Period Unrealized Gains (Losses)	$ (25)		$ 0

[1] Includes realized and unrealized gains and losses.

[2] Level 3 net derivatives included derivative assets of $1.3 billion and derivative liabilities of $782 million as of March 31, 2013 and derivative assets of $2.0 billion and derivative liabilities of $2.2 billion as of March 31, 2012.

[3]

[4] See Note 8, “Intangible Assets,” for additional information.