Fair Value Measurement - Changes in level 3 recurring measurements (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Deposits [Member]
Liabilities
Beginning balance	$ 773	$ 476	$ 1,235
Total realized/unrealized (gains)/losses	15	54	47
Purchases	0
Sales	0
Issuances	433
Settlements	(386)
Purchases, issuances, settlements, net		(86)	(870)
Transfers into and/or out of level 3	583	329	64
Ending balance	1,418	773	476
Change in unrealized (gains)/losses related to financial instruments held	4	(77)	(36)
Other borrowed funds [Member]
Liabilities
Beginning balance	1,384	542	101
Total realized/unrealized (gains)/losses	(244)	(242)	(73)
Purchases	0
Sales	0
Issuances	1,597
Settlements	(834)
Purchases, issuances, settlements, net		1,326	621
Transfers into and/or out of level 3	(396)	(242)	(107)
Ending balance	1,507	1,384	542
Change in unrealized (gains)/losses related to financial instruments held	(85)	445	9
Trading liabilities - Debt and equity instruments [Member]
Liabilities
Beginning balance	54	10	288
Total realized/unrealized (gains)/losses	17	2	64
Purchases	(533)
Sales	778
Issuances	0
Settlements	(109)
Purchases, issuances, settlements, net		19	(339)
Transfers into and/or out of level 3	4	23	(3)
Ending balance	211	54	10
Change in unrealized (gains)/losses related to financial instruments held	(7)	0	12
Accounts payable and other liabilities [Member]
Liabilities
Beginning balance	236	355	0
Total realized/unrealized (gains)/losses	(61)	(138)	(55)
Purchases	0
Sales	0
Issuances	0
Settlements	(124)
Purchases, issuances, settlements, net		19	410
Transfers into and/or out of level 3	0	0	0
Ending balance	51	236	355
Change in unrealized (gains)/losses related to financial instruments held	5	37	(29)
Beneficial interests issued by consolidated VIEs [Member]
Liabilities
Beginning balance	873	625	0
Total realized/unrealized (gains)/losses	17	(7)	344
Purchases	0
Sales	0
Issuances	580
Settlements	(679)
Purchases, issuances, settlements, net		87	(598)
Transfers into and/or out of level 3	0	168	879
Ending balance	791	873	625
Change in unrealized (gains)/losses related to financial instruments held	(15)	(76)	327
Long-term debt
Liabilities
Beginning balance	13,044	18,287	16,548
Total realized/unrealized (gains)/losses	60	(532)	1,367
Purchases	0
Sales	0
Issuances	2,564
Settlements	(3,218)
Purchases, issuances, settlements, net		(4,796)	(2,738)
Transfers into and/or out of level 3	(2,140)	85	3,110
Ending balance	10,310	13,044	18,287
Change in unrealized (gains)/losses related to financial instruments held	288	662	1,728
Total debt and equity instruments [Member]
Assets
Fair Value, Beginning balance	34,554	35,681	41,888
Total realized/ unrealized gains/(losses)	980	614	(604)
Purchases	20,904
Sales	(18,200)
Issuances	0
Settlements	(5,083)
Purchases, issuances, settlements, net		(517)	(9,307)
Transfers into and/or out of level 3	(188)	(1,224)	3,704
Fair Value, Ending Balance	32,967	34,554	35,681
Change in unrealized gains/(losses) related to financial instruments held	308	507	(1,919)
Total debt instruments [Member]
Assets
Fair Value, Beginning balance	31,939	32,284	38,814
Total realized/ unrealized gains/(losses)	665	270	(443)
Purchases	20,688
Sales	(17,620)
Issuances	0
Settlements	(4,636)
Purchases, issuances, settlements, net		635	(8,522)
Transfers into and/or out of level 3	(126)	(1,250)	2,435
Fair Value, Ending Balance	30,910	31,939	32,284
Change in unrealized gains/(losses) related to financial instruments held	(49)	9	(1,816)
Total mortgage-backed securities [Member]
Assets
Fair Value, Beginning balance	2,930	3,145	5,989
Total realized/ unrealized gains/(losses)	170	432	(1,062)
Purchases	1,532
Sales	(1,444)
Issuances	0
Settlements	(435)
Purchases, issuances, settlements, net		(704)	(508)
Transfers into and/or out of level 3	(113)	57	(1,274)
Fair Value, Ending Balance	2,640	2,930	3,145
Change in unrealized gains/(losses) related to financial instruments held	(27)	209	(1,222)
U.S. government agencies [Member]
Assets
Fair Value, Beginning balance	174	260	163
Total realized/ unrealized gains/(losses)	24	24	(38)
Purchases	28
Sales	(39)
Issuances	0
Settlements	(43)
Purchases, issuances, settlements, net		(107)	62
Transfers into and/or out of level 3	(58)	(3)	73
Fair Value, Ending Balance	86	174	260
Change in unrealized gains/(losses) related to financial instruments held	(51)	(31)	(38)
Residential - nonagency [Member]
Assets
Fair Value, Beginning balance	687	1,115	3,339
Total realized/ unrealized gains/(losses)	109	178	(782)
Purchases	708
Sales	(432)
Issuances	0
Settlements	(221)
Purchases, issuances, settlements, net		(564)	(245)
Transfers into and/or out of level 3	(55)	(42)	(1,197)
Fair Value, Ending Balance	796	687	1,115
Change in unrealized gains/(losses) related to financial instruments held	(9)	110	(871)
Commercial - nonagency [Member]
Assets
Fair Value, Beginning balance	2,069	1,770	2,487
Total realized/ unrealized gains/(losses)	37	230	(242)
Purchases	796
Sales	(973)
Issuances	0
Settlements	(171)
Purchases, issuances, settlements, net		(33)	(325)
Transfers into and/or out of level 3	0	102	(150)
Fair Value, Ending Balance	1,758	2,069	1,770
Change in unrealized gains/(losses) related to financial instruments held	33	130	(313)
Obligations of U.S. states and municipalities [Member]
Assets
Fair Value, Beginning balance	2,257	1,971	2,641
Total realized/ unrealized gains/(losses)	9	2	(22)
Purchases	807
Sales	(1,465)
Issuances	0
Settlements	(1)
Purchases, issuances, settlements, net		142	(648)
Transfers into and/or out of level 3	12	142	0
Fair Value, Ending Balance	1,619	2,257	1,971
Change in unrealized gains/(losses) related to financial instruments held	(11)	(30)	(123)
Non-U.S. government debt securities [Member]
Assets
Fair Value, Beginning balance	202	89	11
Total realized/ unrealized gains/(losses)	35	(36)	36
Purchases	552
Sales	(531)
Issuances	0
Settlements	(80)
Purchases, issuances, settlements, net		194	(22)
Transfers into and/or out of level 3	(74)	(45)	64
Fair Value, Ending Balance	104	202	89
Change in unrealized gains/(losses) related to financial instruments held	38	(8)	32
Corporate debt securities [Member]
Assets
Fair Value, Beginning balance	4,946	5,241	5,280
Total realized/ unrealized gains/(losses)	32	(325)	38
Purchases	8,080
Sales	(5,939)
Issuances	0
Settlements	(1,005)
Purchases, issuances, settlements, net		115	(3,416)
Transfers into and/or out of level 3	259	(85)	3,339
Fair Value, Ending Balance	6,373	4,946	5,241
Change in unrealized gains/(losses) related to financial instruments held	26	28	(72)
Loans [Member]
Assets
Fair Value, Beginning balance	13,144	13,218	17,091
Total realized/ unrealized gains/(losses)	329	(40)	(871)
Purchases	5,532
Sales	(3,873)
Issuances	0
Settlements	(2,691)
Purchases, issuances, settlements, net		1,296	(3,497)
Transfers into and/or out of level 3	(232)	(1,330)	495
Fair Value, Ending Balance	12,209	13,144	13,218
Change in unrealized gains/(losses) related to financial instruments held	142	(385)	(1,167)
Asset-backed securities [Member]
Assets
Fair Value, Beginning balance	8,460	8,620	7,802
Total realized/ unrealized gains/(losses)	90	237	1,438
Purchases	4,185
Sales	(4,368)
Issuances	0
Settlements	(424)
Purchases, issuances, settlements, net		(408)	(431)
Transfers into and/or out of level 3	22	11	(189)
Fair Value, Ending Balance	7,965	8,460	8,620
Change in unrealized gains/(losses) related to financial instruments held	(217)	195	736
Equity securities [Member]
Assets
Fair Value, Beginning balance	1,685	1,956	1,380
Total realized/ unrealized gains/(losses)	267	133	(149)
Purchases	180
Sales	(541)
Issuances	0
Settlements	(352)
Purchases, issuances, settlements, net		(351)	(512)
Transfers into and/or out of level 3	(62)	(53)	1,237
Fair Value, Ending Balance	1,177	1,685	1,956
Change in unrealized gains/(losses) related to financial instruments held	278	199	(51)
Other equity instruments [Member]
Assets
Fair Value, Beginning balance	930	1,441	1,694
Total realized/ unrealized gains/(losses)	48	211	(12)
Purchases	36
Sales	(39)
Issuances	0
Settlements	(95)
Purchases, issuances, settlements, net		(801)	(273)
Transfers into and/or out of level 3	0	79	32
Fair Value, Ending Balance	880	930	1,441
Change in unrealized gains/(losses) related to financial instruments held	79	299	(52)
Total net derivative receivables [Member]
Assets
Fair Value, Beginning balance	4,357	10,837	9,039
Total realized/ unrealized gains/(losses)	6,068	(507)	(11,473)
Purchases	1,767
Sales	(2,051)
Issuances	0
Settlements	(3,789)
Purchases, issuances, settlements, net		(6,004)	(3,428)
Transfers into and/or out of level 3	(114)	31	16,699
Fair Value, Ending Balance	6,238	4,357	10,837
Change in unrealized gains/(losses) related to financial instruments held	2,439	(1,313)	(10,902)
Interest rate
Assets
Fair Value, Beginning balance	2,836	2,040
Total realized/ unrealized gains/(losses)	5,205	3,057
Purchases	511
Sales	(219)
Issuances	0
Settlements	(4,534)
Purchases, issuances, settlements, net		(2,520)
Transfers into and/or out of level 3	(238)	259
Fair Value, Ending Balance	3,561	2,836
Change in unrealized gains/(losses) related to financial instruments held	1,497	487
Credit derivatives
Assets
Fair Value, Beginning balance	5,386	10,350
Total realized/ unrealized gains/(losses)	2,240	(1,757)
Purchases	22
Sales	(13)
Issuances	0
Settlements	116
Purchases, issuances, settlements, net		(3,102)
Transfers into and/or out of level 3	(19)	(105)
Fair Value, Ending Balance	7,732	5,386
Change in unrealized gains/(losses) related to financial instruments held	2,744	(1,048)
Foreign exchange
Assets
Fair Value, Beginning balance	(614)	1,082
Total realized/ unrealized gains/(losses)	(1,913)	(913)
Purchases	191
Sales	(20)
Issuances	0
Settlements	886
Purchases, issuances, settlements, net		(434)
Transfers into and/or out of level 3	207	(349)
Fair Value, Ending Balance	(1,263)	(614)
Change in unrealized gains/(losses) related to financial instruments held	(1,878)	(464)
Equity Contract [Member]
Assets
Fair Value, Beginning balance	(2,446)	(2,306)
Total realized/ unrealized gains/(losses)	(60)	(194)
Purchases	715
Sales	(1,449)
Issuances	0
Settlements	37
Purchases, issuances, settlements, net		(82)
Transfers into and/or out of level 3	98	136
Fair Value, Ending Balance	(3,105)	(2,446)
Change in unrealized gains/(losses) related to financial instruments held	(132)	(212)
Commodity
Assets
Fair Value, Beginning balance	(805)	(329)
Total realized/ unrealized gains/(losses)	596	(700)
Purchases	328
Sales	(350)
Issuances	0
Settlements	(294)
Purchases, issuances, settlements, net		134
Transfers into and/or out of level 3	(162)	90
Fair Value, Ending Balance	(687)	(805)
Change in unrealized gains/(losses) related to financial instruments held	208	(76)
Available-for-sale Securities [Member]
Assets
Fair Value, Beginning balance	14,287	13,193	12,391
Total realized/ unrealized gains/(losses)	(95)	(195)	(271)
Purchases	15,325
Sales	(1,476)
Issuances	0
Settlements	(2,555)
Purchases, issuances, settlements, net		1,226	1,414
Transfers into and/or out of level 3	0	63	(341)
Fair Value, Ending Balance	25,486	14,287	13,193
Change in unrealized gains/(losses) related to financial instruments held	(98)	(111)	(5)
Asset backed security [Member]
Assets
Fair Value, Beginning balance	13,775	12,732	11,447
Total realized/ unrealized gains/(losses)	(95)	(146)	(2)
Purchases	15,268
Sales	(1,461)
Issuances	0
Settlements	(2,529)
Purchases, issuances, settlements, net		1,189	1,112
Transfers into and/or out of level 3	0	0	175
Fair Value, Ending Balance	24,958	13,775	12,732
Change in unrealized gains/(losses) related to financial instruments held	(106)	(129)	(48)
Other available-for-sale securities [Member]
Assets
Fair Value, Beginning balance	512	461	944
Total realized/ unrealized gains/(losses)	0	(49)	(269)
Purchases	57
Sales	(15)
Issuances	0
Settlements	(26)
Purchases, issuances, settlements, net		37	302
Transfers into and/or out of level 3	0	63	(516)
Fair Value, Ending Balance	528	512	461
Change in unrealized gains/(losses) related to financial instruments held	8	18	43
Loans [Member]
Assets
Fair Value, Beginning balance	1,466	990	2,667
Total realized/ unrealized gains/(losses)	504	145	(448)
Purchases	326
Sales	(9)
Issuances	0
Settlements	(639)
Purchases, issuances, settlements, net		323	(1,906)
Transfers into and/or out of level 3	(1)	8	677
Fair Value, Ending Balance	1,647	1,466	990
Change in unrealized gains/(losses) related to financial instruments held	484	37	(488)
Mortgage servicing rights [Member]
Assets
Fair Value, Beginning balance	13,649	15,531	9,403
Total realized/ unrealized gains/(losses)	(7,119)	(2,268)	5,807
Purchases	2,603
Sales	0
Issuances	0
Settlements	(1,910)
Purchases, issuances, settlements, net		386	321
Transfers into and/or out of level 3	0	0	0
Fair Value, Ending Balance	7,223	13,649	15,531
Change in unrealized gains/(losses) related to financial instruments held	(7,119)	(2,268)	5,807
Private Equity Funds [Member]
Assets
Fair Value, Beginning balance	7,862	6,563	6,369
Total realized/ unrealized gains/(losses)	943	1,038	(407)
Purchases	1,452
Sales	(2,746)
Issuances	0
Settlements	(594)
Purchases, issuances, settlements, net		715	582
Transfers into and/or out of level 3	(166)	(454)	19
Fair Value, Ending Balance	6,751	7,862	6,563
Change in unrealized gains/(losses) related to financial instruments held	(242)	688	(369)
All other assets [Member]
Assets
Fair Value, Beginning balance	4,179	9,521	8,114
Total realized/ unrealized gains/(losses)	(54)	(113)	(676)
Purchases	938
Sales	(139)
Issuances	0
Settlements	(521)
Purchases, issuances, settlements, net		(5,132)	2,439
Transfers into and/or out of level 3	(29)	(97)	(356)
Fair Value, Ending Balance	4,374	4,179	9,521
Change in unrealized gains/(losses) related to financial instruments held	$ (83)	$ 37	$ (612)