FAIR VALUE MEASUREMENT (Details 2) (USD $) In Millions	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended			9 Months Ended		3 Months Ended	9 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2011 Interest rate contracts Derivatives	Sep. 30, 2010 Interest rate contracts Derivatives	Sep. 30, 2011 Interest rate contracts Derivatives	Sep. 30, 2010 Interest rate contracts Derivatives	Sep. 30, 2011 Foreign exchange contracts Derivatives	Sep. 30, 2010 Foreign exchange contracts Derivatives	Sep. 30, 2011 Foreign exchange contracts Derivatives	Sep. 30, 2010 Foreign exchange contracts Derivatives	Sep. 30, 2011 Equity contracts Derivatives	Sep. 30, 2010 Equity contracts Derivatives	Sep. 30, 2011 Equity contracts Derivatives	Sep. 30, 2010 Equity contracts Derivatives	Sep. 30, 2011 Commodity contracts Derivatives	Sep. 30, 2010 Commodity contracts Derivatives	Sep. 30, 2011 Commodity contracts Derivatives	Sep. 30, 2010 Commodity contracts Derivatives	Sep. 30, 2011 Credit derivatives Derivatives	Sep. 30, 2010 Credit derivatives Derivatives	Sep. 30, 2011 Credit derivatives Derivatives	Sep. 30, 2010 Credit derivatives Derivatives	Sep. 30, 2011 Federal funds sold and securities borrowed or purchased under agreements to resell	Sep. 30, 2010 Federal funds sold and securities borrowed or purchased under agreements to resell	Sep. 30, 2011 Federal funds sold and securities borrowed or purchased under agreements to resell	Sep. 30, 2010 Federal funds sold and securities borrowed or purchased under agreements to resell	Sep. 30, 2011 Mortgage-backed securities Trading account assets	Sep. 30, 2010 Mortgage-backed securities Trading account assets	Sep. 30, 2011 Mortgage-backed securities Trading account assets	Sep. 30, 2010 Mortgage-backed securities Trading account assets	Sep. 30, 2011 Prime Trading account assets	Sep. 30, 2010 Prime Trading account assets	Sep. 30, 2011 Prime Trading account assets	Sep. 30, 2010 Prime Trading account assets	Sep. 30, 2011 Alt-A Trading account assets	Sep. 30, 2010 Alt-A Trading account assets	Sep. 30, 2011 Alt-A Trading account assets	Sep. 30, 2010 Alt-A Trading account assets	Sep. 30, 2011 Subprime Trading account assets	Sep. 30, 2010 Subprime Trading account assets	Sep. 30, 2011 Subprime Trading account assets	Sep. 30, 2010 Subprime Trading account assets	Sep. 30, 2011 Non-U.S. residential Trading account assets	Sep. 30, 2010 Non-U.S. residential Trading account assets	Sep. 30, 2011 Non-U.S. residential Trading account assets	Sep. 30, 2010 Non-U.S. residential Trading account assets	Sep. 30, 2011 Asset-based financing Trading account assets	Sep. 30, 2010 Asset-based financing Trading account assets	Sep. 30, 2011 Asset-based financing Trading account assets	Sep. 30, 2010 Asset-based financing Trading account assets	Sep. 30, 2011 U.S. government-sponsored agency guaranteed Trading account assets	Sep. 30, 2010 U.S. government-sponsored agency guaranteed Trading account assets	Sep. 30, 2011 U.S. government-sponsored agency guaranteed Trading account assets	Sep. 30, 2010 U.S. government-sponsored agency guaranteed Trading account assets	Sep. 30, 2011 Commercial. Trading account assets	Sep. 30, 2010 Commercial. Trading account assets	Sep. 30, 2011 Commercial. Trading account assets	Sep. 30, 2010 Commercial. Trading account assets	Sep. 30, 2011 U.S. Treasury and federal agency securities Trading account assets	Sep. 30, 2010 U.S. Treasury and federal agency securities Trading account assets	Sep. 30, 2011 U.S. Treasury and federal agency securities Trading account assets	Sep. 30, 2010 U.S. Treasury and federal agency securities Trading account assets	Sep. 30, 2011 Agency obligations Trading account assets	Sep. 30, 2011 Agency obligations Trading account assets	Sep. 30, 2011 State and municipal securities Trading account assets	Sep. 30, 2010 State and municipal securities Trading account assets	Sep. 30, 2011 State and municipal securities Trading account assets	Sep. 30, 2010 State and municipal securities Trading account assets	Sep. 30, 2011 Foreign government Trading account assets	Sep. 30, 2010 Foreign government Trading account assets	Sep. 30, 2011 Foreign government Trading account assets	Sep. 30, 2010 Foreign government Trading account assets	Sep. 30, 2011 Corporate Trading account assets	Sep. 30, 2010 Corporate Trading account assets	Sep. 30, 2011 Corporate Trading account assets	Sep. 30, 2010 Corporate Trading account assets	Sep. 30, 2011 Equity securities Trading account assets	Sep. 30, 2010 Equity securities Trading account assets	Sep. 30, 2011 Equity securities Trading account assets	Sep. 30, 2010 Equity securities Trading account assets	Sep. 30, 2011 Other debt securities Trading account assets	Sep. 30, 2010 Other debt securities Trading account assets	Sep. 30, 2011 Other debt securities Trading account assets	Sep. 30, 2010 Other debt securities Trading account assets	Sep. 30, 2011 Trading account assets	Sep. 30, 2010 Trading account assets	Sep. 30, 2011 Trading account assets	Sep. 30, 2010 Trading account assets	Sep. 30, 2011 Derivatives	Sep. 30, 2010 Derivatives	Sep. 30, 2011 Derivatives	Sep. 30, 2010 Derivatives	Sep. 30, 2011 Mortgage-backed securities Investments:	Sep. 30, 2010 Mortgage-backed securities Investments:	Sep. 30, 2011 Mortgage-backed securities Investments:	Sep. 30, 2010 Mortgage-backed securities Investments:	Sep. 30, 2011 Prime Investments:	Sep. 30, 2010 Prime Investments:	Sep. 30, 2011 Prime Investments:	Sep. 30, 2010 Prime Investments:	Sep. 30, 2011 Alt-A Investments:	Sep. 30, 2010 Alt-A Investments:	Sep. 30, 2011 Alt-A Investments:	Sep. 30, 2010 Alt-A Investments:	Sep. 30, 2010 Subprime Investments:	Sep. 30, 2010 Subprime Investments:	Sep. 30, 2010 Non-U.S. residential Investments:	Sep. 30, 2011 Asset-based financing Investments:	Sep. 30, 2010 Asset-based financing Investments:	Sep. 30, 2011 Asset-based financing Investments:	Sep. 30, 2010 Asset-based financing Investments:	Sep. 30, 2011 U.S. government-sponsored agency guaranteed Investments:	Sep. 30, 2011 U.S. government-sponsored agency guaranteed Investments:	Sep. 30, 2010 U.S. government-sponsored agency guaranteed Investments:	Jun. 30, 2010 U.S. government-sponsored agency guaranteed Investments:	Sep. 30, 2011 Commercial. Investments:	Sep. 30, 2010 Commercial. Investments:	Sep. 30, 2011 Commercial. Investments:	Sep. 30, 2010 Commercial. Investments:	Sep. 30, 2010 U.S. Treasury and federal agency securities Investments:	Sep. 30, 2011 U.S. Treasury and federal agency securities Investments:	Sep. 30, 2010 U.S. Treasury and federal agency securities Investments:	Sep. 30, 2010 Agency obligations Investments:	Sep. 30, 2011 State and municipal securities Investments:	Sep. 30, 2010 State and municipal securities Investments:	Sep. 30, 2011 State and municipal securities Investments:	Sep. 30, 2010 State and municipal securities Investments:	Sep. 30, 2011 Foreign government Investments:	Sep. 30, 2010 Foreign government Investments:	Sep. 30, 2011 Foreign government Investments:	Sep. 30, 2010 Foreign government Investments:	Sep. 30, 2011 Corporate Investments:	Sep. 30, 2010 Corporate Investments:	Sep. 30, 2011 Corporate Investments:	Sep. 30, 2010 Corporate Investments:	Sep. 30, 2011 Equity securities Investments:	Sep. 30, 2010 Equity securities Investments:	Sep. 30, 2011 Equity securities Investments:	Sep. 30, 2010 Equity securities Investments:	Sep. 30, 2011 Other debt securities Investments:	Sep. 30, 2010 Other debt securities Investments:	Sep. 30, 2011 Other debt securities Investments:	Sep. 30, 2010 Other debt securities Investments:	Sep. 30, 2011 Non-marketable equity securities Investments:	Sep. 30, 2010 Non-marketable equity securities Investments:	Sep. 30, 2011 Non-marketable equity securities Investments:	Sep. 30, 2010 Non-marketable equity securities Investments:	Sep. 30, 2011 Investments:	Sep. 30, 2010 Investments:	Sep. 30, 2011 Investments:	Sep. 30, 2010 Investments:	Sep. 30, 2011 Loans.	Sep. 30, 2010 Loans.	Sep. 30, 2011 Loans.	Sep. 30, 2010 Loans.	Sep. 30, 2011 Mortgage servicing rights	Sep. 30, 2010 Mortgage servicing rights	Sep. 30, 2011 Mortgage servicing rights	Sep. 30, 2010 Mortgage servicing rights	Sep. 30, 2011 Other financial assets measured on a recurring basis	Sep. 30, 2010 Other financial assets measured on a recurring basis	Sep. 30, 2011 Other financial assets measured on a recurring basis	Sep. 30, 2010 Other financial assets measured on a recurring basis	Sep. 30, 2011 Interest-bearing deposits	Sep. 30, 2010 Interest-bearing deposits	Sep. 30, 2011 Interest-bearing deposits	Sep. 30, 2010 Interest-bearing deposits	Sep. 30, 2011 Federal funds purchased and securities loaned or sold under agreements to repurchase	Sep. 30, 2010 Federal funds purchased and securities loaned or sold under agreements to repurchase	Sep. 30, 2011 Federal funds purchased and securities loaned or sold under agreements to repurchase	Sep. 30, 2010 Federal funds purchased and securities loaned or sold under agreements to repurchase	Sep. 30, 2011 Securities sold, not yet purchased Trading account liabilities	Sep. 30, 2010 Securities sold, not yet purchased Trading account liabilities	Sep. 30, 2011 Securities sold, not yet purchased Trading account liabilities	Sep. 30, 2010 Securities sold, not yet purchased Trading account liabilities	Sep. 30, 2011 Short-term borrowings.	Sep. 30, 2010 Short-term borrowings.	Sep. 30, 2011 Short-term borrowings.	Sep. 30, 2010 Short-term borrowings.	Sep. 30, 2011 Long-term debt.	Sep. 30, 2010 Long-term debt.	Sep. 30, 2011 Long-term debt.	Sep. 30, 2010 Long-term debt.	Sep. 30, 2011 Other financial liabilities measured on a recurring basis	Sep. 30, 2010 Other financial liabilities measured on a recurring basis	Sep. 30, 2011 Other financial liabilities measured on a recurring basis	Sep. 30, 2010 Other financial liabilities measured on a recurring basis
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	$ 201	$ 575	$ (730)	$ (374)	$ (18)	$ 250	$ 164	$ (38)	$ (1,845)	$ (1,233)	$ (1,639)	$ (1,110)	$ (1,059)	$ (524)	$ (1,023)	$ (529)	$ 210	$ 2,073	$ 2,296	$ 5,159	$ 3,431	$ 6,518	$ 4,911	$ 1,127	$ 3,423	$ 6,122	$ 3,577	$ 13,764	$ 651	$ 610	$ 594	$ 384	$ 229	$ 451	$ 385	$ 387	$ 723	$ 1,885	$ 1,125	$ 8,998	$ 323	$ 234	$ 224	$ 572	$ 6,016	$ 5,176	$ 7,465	$ 3,825	$ 947	$ 758	$ 831	$ 972	$ 550	$ 2,184	$ 418	$ 2,451	$ 46		$ 72		$ 46	$ 72	$ 246	$ 57	$ 208	$ 222	$ 903	$ 386	$ 566	$ 459	$ 5,273	$ 5,237	$ 5,159	$ 7,801	$ 648	$ 533	$ 776	$ 640	$ 1,695	$ 1,047	$ 1,305	$ 13,231	$ 18,250	$ 18,558	$ 19,128	$ 39,942	$ (2,511)	$ 1,141	$ (932)	$ 3,108	$ 83	$ 2,364	$ 716	$ 1,540	$ 23	$ 772	$ 166	$ 736	$ 1	$ 205	$ 1	$ 55	$ 14	$ 1	$ 814	$ 4,475	$ 12,303	$ 5,424	$ 8,272	$ 59	$ 22	$ 2	$ 1		$ 558	$ 527	$ 746	$ 19	$ 17	$ 21	$ 1	$ 355	$ 457	$ 504	$ 217	$ 329	$ 282	$ 358	$ 270	$ 1,516	$ 1,271	$ 1,018	$ 1,257	$ 1,621	$ 2,238	$ 2,055	$ 2,513	$ 653	$ 891	$ 727	$ 560	$ 7,658	$ 6,561	$ 6,467	$ 6,753	$ 16,690	$ 26,386	$ 17,286	$ 21,403	$ 3,590	$ 3,668	$ 3,213	$ 213	$ 4,258	$ 4,894	$ 4,554	$ 6,530	$ 2,449	$ 3,089	$ 2,509	$ 1,101								$ 2,056																$ 13
Net realized/unrealized gains (losses) included in principal transactions, assets	7	(91)	(108)	574	29	(162)	142	182	212	(196)	409	(423)	225	(158)	378	(274)	1,681	33	1,098	(1,242)	209		80	509	(158)	221	139	124	9	23	93	56		15	11	45	7	146	(5)	182	(19)	29	18	2	(182)	11	386	(75)	(140)	(62)	(59)	(220)	(15)	70	81	59	7	2	9	2	7	9	4	13	56	24	4	6	11	17	(178)	170	(55)	104	(172)	14	(101)	30	(121)	(39)	(134)	(16)	(796)	398	311	210	2,154	(574)	1,919	(1,183)																																																																																			46
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets																																																																																											(27)	123	(21)	(464)	(2)	78	(1)	(35)	(1)	35	(1)	12	(1)	(2)		(2)	(34)	39	(70)	(17)	(15)	(1)		(7)	11	(4)	(438)			(21)		35		(12)	7	14	14	11	21	(120)	46	(84)	(33)	4	(1)	(53)	25	8	(41)	(3)	(14)	(130)	318	420	333	(218)	425	297	(216)	(164)	(38)	(317)	(178)	(1,327)	(778)	(1,426)	(1,976)	57	7	48	(20)
Transfers in and/or out of Level 3, assets	393	(37)	1,102	300	37	62	(98)	(36)	(126)	277	(191)	(5)	67	(5)	(33)	63	266	9	(1)	(866)	1,050	1,714	(301)	5,879	345	1,374	574	786	19	188	16	338	44	41	28	201	(196)	24	(133)	(601)	(80)	904	(48)	645	265	4,850	207	4,950	225	160	314	329	333	57	397	(126)	(48)	47	(45)	47	(48)	(45)	3	236	110	292	(30)	5	131	(181)	266	198	1,763	(341)	(81)	362	(250)	350	133	108	450	(147)	853	7,180	2,940	5,756	637	306	779	(544)	42	(1,519)	(582)	(429)	13	(539)	(109)	(469)		(153)		37	(13)	1	(814)	(23)	(4,918)	30	(100)		37			29		(510)	2		(15)			(4)	(233)	(59)		(60)	21	(36)	11	(11)	(294)	13	(58)	(5)	(12)	(34)	78		42	67	6	(24)	43	(862)	(65)	(85)	(6,870)	(1,478)	(557)	635	378	390	993					(56)	44	(100)	2,027												(103)
Purchases, issuances and settlements, assets		(214)		(267)		(19)		23		(89)		297		(112)		(59)		66		(870)		(52)		665		(2,389)		(9,346)		70		113		(156)		(282)		(702)		(7,226)		(826)		(878)		(1,783)		(446)		(11)		(236)		(764)		(837)		16		16				(1)		(233)		27		129		16		(1,943)		(58)		(169)		(23)		(11,975)		(4,195)		(23,967)		(368)		(876)		(161)		160		(78)		1		(65)		(82)					(192)		(943)						(18)		241	(1)		18			(224)		(224)		22		37		(112)		(255)		(99)		(490)		33		373		(632)		(731)		(1,366)		(2,055)		(87)		2,893		(140)		(578)		(442)		(410)												158
Purchases, assets	4		8		11		11		124		180				2										522		4,850		120		1,435		30		1,607		50		501		37		328		642		4,274		224		579		61		400				5			5	79		1,048		455		1,314		525		3,109		33		161		569		1,021		2,825		15,782		139		201		7		58				7									19		106		4	9			3		42						5		38		127		233		56		527								35		804		4,152		1,018		5,149				248								57
Issuance, assets																									35		35																						35		35																																35		35																																																																	847		1,876		125		230		142		380
Sales, assets	(4)		(15)		(2)		(2)		(57)		(217)		(8)		(68)										(624)		(5,519)		(135)		(1,468)		(57)		(1,773)		(95)		(961)		(87)		(348)		(1,039)		(5,249)		(177)		(529)		(73)		(440)		(5)		(41)		(5)	(41)	(101)		(1,191)		(337)		(640)		(889)		(3,182)		(162)		(320)		(158)		(524)		(3,315)		(16,666)		(71)		(302)		(39)		(105)		(17)		(46)											(447)			(7)			(22)		(52)			(2)			(3)		(83)		(4)		(67)		(37)		(54)		(4)		(13)		(285)		(287)		(616)		(1,733)		(988)		(2,791)		(18)		(18)						(114)		(172)
Settlements, assets	(66)		278		(23)		(183)		(225)		(459)		46		15		(182)		(1,418)						(82)		(195)		(4)		(10)		(7)		(19)				(38)						(2)		(1,383)		(47)		(104)		(24)		(24)														(387)		(318)		(2,115)						(4)		(4)		(406)		(4,084)		(450)		(1,767)		(1)		(1)		(1)		(1)									(223)		(906)																		(53)		(146)		(88)		(104)		(110)		(449)		(103)		(266)		(457)		(1,209)		(1,035)		(3,081)		(244)		(746)		(204)		(506)		(98)		(342)
Balance at end of period, asset	535	233	535	233	34	131	34	131	(1,917)	(1,241)	(1,917)	(1,241)	(729)	(799)	(729)	(799)	1,975	2,181	1,975	2,181	4,690	8,180	4,690	8,180	3,461	5,328	3,461	5,328	660	891	660	891	239	351	239	351	489	1,353	489	1,353	174	341	174	341	5,700	8,255	5,700	8,255	1,067	845	1,067	845	832	1,547	832	1,547		65		65			231	305	231	305	995	424	995	424	4,679	5,620	4,679	5,620	266	851	266	851	2,114	1,093	2,114	1,093	17,446	21,941	17,446	21,941	(102)	505	(102)	505	65	807	65	807	16	233	16	233		22		22				4,246	7,159	4,246	7,159	46	46	1	1	3	551	3	551	18		18	1	388		388		353	339	353	339	1,316	911	1,316	911	1,506	2,126	1,506	2,126	273	925	273	925	7,235	6,290	7,235	6,290	15,382	18,575	15,382	18,575	4,646	3,921	4,646	3,921	2,852	3,976	2,852	3,976	2,380	2,698	2,380	2,698
Unrealized gains (losses) still held, assets	115	(84)	258	504	(66)	(222)	(226)	173	(572)	(539)	(811)	(774)	253	(62)	(247)	(107)	1,750	(349)	2,101	(1,271)	157		79		(196)	170	4	208	2	3	43	4	1	(6)	1	11	44	29	98	82	(15)	3	(26)		(235)	42	(361)	(218)	(167)	(75)	(113)	(198)	(61)	216	1	309		(2)		(4)			9	18	2	17	(28)	(4)	(23)	(19)	(86)	213	(237)	74	(77)	62	(85)	84	3	4	1	8	(610)	503	(699)	150	1,480	(1,256)	1,075	(1,475)	(17)	3	(31)	3		3		3									121	5	(133)	(17)	(31)									(1)		35		(22)		11	14	2	5	(83)	17	289	6	(14)	(23)	(4)	(79)	(24)	(11)	(24)	29	(128)	323	111	277	(220)	444	326	107	(126)	56	(282)	(168)	(1,327)	(778)	(1,426)	(1,976)	63	211	91	(20)												13
Fair value, liabilities measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, liability																																																																																																																																																																		586	183	277	28	1,078	1,091	1,261	929	447	621	187	774	611	445	802	231	6,873	10,741	8,385	9,654	16	7	19	13
Net realized/unrealized gains (losses) included in principal transactions, liabilities																																																																																																																																																																						(39)	(40)	(28)	(138)	(83)	(6)	10		48	(26)	192	(18)	45	(187)	(54)	85
Net realized/unrealized gains (losses) included in locations other than principal transactions, liabilities																																																																																																																																																																		40	(10)	13	(8)													106	(67)	272	78	(1)	(1)	(18)	(20)
Transfers in and/or out of Level 3, liabilities																																																																																																																																																																		(124)	(35)	(73)	(41)	(19)	3	81	79	97	(34)	296		(377)	351	(255)	245	(271)	338	(687)	670	2		9
Purchases, issuances and settlements, liabilities																																																																																																																																																																			3		166		276		264		190				(5)		323		(801)		371		(8)		(33)
Purchases, liability																																																																																																																																																																																								1
Issuance, liability																																																																																																																																																																		37		281										354		522		215		865		1		13
Sales, liability																																																																																																																																																																								(165)		238		385												(1)
Settlements, liability																																																																																																																																																																				(13)				(107)		(141)		(134)		(66)		(403)		(355)		(2,034)		(13)		(52)
Balance at end of period, liability																																																																																																																																																																		459	161	459	161	1,098	1,410	1,098	1,410	724	783	724	783	474	817	474	817	6,311	10,532	6,311	10,532	7		7
Unrealized gains (losses) still held, liabilities																																																																																																																																																																		$ (45)	$ (29)	$ (101)	$ (36)		$ (29)		$ (5)	$ (14)	$ (32)	$ (24)		$ (1)	$ (32)	$ (6)	$ (16)	$ (50)	$ (199)	$ 69	$ (121)	$ (3)		$ (9)