Fair Value Measurement - Changes in level 3 recurring measurements (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Deposits [Member]
Liabilities
Beginning balance	$ 2,015	$ 1,651	$ 1,983	$ 1,418
Total realized/unrealized (gains)/losses	(110)	35	(105)	166
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	316	357	612	708
Settlements	(44)	(96)	(157)	(232)
Transfers into and/or out of level 3	13	(71)	(143)	(184)
Ending balance	2,190	1,876	2,190	1,876
Change in unrealized (gains)/losses related to financial instruments held	(110)	34	(97)	155
Other borrowed funds [Member]
Liabilities
Beginning balance	2,137	1,233	1,619	1,507
Total realized/unrealized (gains)/losses	(243)	(205)	(269)	(9)
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	2,389	425	4,151	809
Settlements	(1,695)	(333)	(2,919)	(1,178)
Transfers into and/or out of level 3	85	(13)	91	(22)
Ending balance	2,673	1,107	2,673	1,107
Change in unrealized (gains)/losses related to financial instruments held	33	(161)	74	(38)
Trading liabilities - Debt and equity instruments [Member]
Liabilities
Beginning balance	251	273	205	211
Total realized/unrealized (gains)/losses	(60)	(2)	(68)	(17)
Purchases	(374)	(695)	(1,859)	(1,400)
Sales	454	806	2,006	1,599
Issuances	0	0	0	0
Settlements	(21)	(17)	(34)	(28)
Transfers into and/or out of level 3	(146)	(5)	(146)	(5)
Ending balance	104	360	104	360
Change in unrealized (gains)/losses related to financial instruments held	(48)	(3)	(78)	(3)
Accounts payable and other liabilities [Member]
Liabilities
Beginning balance	33	46	36	51
Total realized/unrealized (gains)/losses	0	0	1	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(1)	(4)	(5)	(9)
Transfers into and/or out of level 3	0	0	0	0
Ending balance	32	42	32	42
Change in unrealized (gains)/losses related to financial instruments held	0	0	1	0
Beneficial interests issued by consolidated VIEs [Member]
Liabilities
Beginning balance	818	841	925	791
Total realized/unrealized (gains)/losses	59	2	25	47
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	30	18	51	54
Settlements	(44)	(116)	(138)	(147)
Transfers into and/or out of level 3	0	0	0	0
Ending balance	863	745	863	745
Change in unrealized (gains)/losses related to financial instruments held	54	3	26	12
Long-term debt
Liabilities
Beginning balance	9,084	9,553	8,476	10,310
Total realized/unrealized (gains)/losses	(430)	(191)	(905)	(52)
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	1,878	750	3,733	1,874
Settlements	(1,246)	(779)	(1,603)	(2,166)
Transfers into and/or out of level 3	(84)	(477)	(499)	(1,110)
Ending balance	9,202	8,856	9,202	8,856
Change in unrealized (gains)/losses related to financial instruments held	(292)	(133)	(321)	20
Collateralized Mortgage Backed Securities
Assets
Fair Value, Beginning balance	2,603	2,229	2,368	2,640
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	270	40	327	(17)
Purchases	439	105	1,266	314
Sales	(449)	(184)	(997)	(587)
Settlements	(76)	(83)	(172)	(130)
Transfers into and/or out of level 3	0	(9)	(5)	(122)
Fair Value, Ending Balance	2,787	2,098	2,787	2,098
Change in unrealized gains/(losses) related to financial instruments held	200	20	188	(36)
US Government Corporations and Agencies Securities [Member]
Assets
Fair Value, Beginning balance	819	79	498	86
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	106	(9)	140	(21)
Purchases	2	0	393	5
Sales	0	0	(79)	0
Settlements	(26)	0	(51)	0
Transfers into and/or out of level 3	0	0	0	0
Fair Value, Ending Balance	901	70	901	70
Change in unrealized gains/(losses) related to financial instruments held	114	(4)	153	(8)
Residential mortgage
Assets
Fair Value, Beginning balance	633	699	663	796
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	203	19	312	51
Purchases	135	87	434	179
Sales	(336)	(95)	(740)	(258)
Settlements	(20)	(39)	(49)	(75)
Transfers into and/or out of level 3	0	0	(5)	(22)
Fair Value, Ending Balance	615	671	615	671
Change in unrealized gains/(losses) related to financial instruments held	135	3	177	27
Commercial mortgage
Assets
Fair Value, Beginning balance	1,151	1,451	1,207	1,758
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	(39)	30	(125)	(47)
Purchases	302	18	439	130
Sales	(113)	(89)	(178)	(329)
Settlements	(30)	(44)	(72)	(55)
Transfers into and/or out of level 3	0	(9)	0	(100)
Fair Value, Ending Balance	1,271	1,357	1,271	1,357
Change in unrealized gains/(losses) related to financial instruments held	(49)	21	(142)	(55)
Debt Instruments [Member]
Assets
Fair Value, Beginning balance	20,583	28,098	23,662	30,910
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	351	(91)	260	497
Purchases	7,301	3,638	13,579	8,413
Sales	(4,660)	(3,344)	(10,564)	(7,362)
Settlements	(1,805)	(1,508)	(3,364)	(4,802)
Transfers into and/or out of level 3	477	(208)	(1,326)	(1,071)
Fair Value, Ending Balance	22,247	26,585	22,247	26,585
Change in unrealized gains/(losses) related to financial instruments held	294	(87)	91	292
US States and Political Subdivisions Debt Securities
Assets
Fair Value, Beginning balance	1,432	1,747	1,436	1,619
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	(23)	6	18	(1)
Purchases	52	9	53	329
Sales	(37)	(303)	(83)	(484)
Settlements	(203)	0	(203)	(4)
Transfers into and/or out of level 3	0	0	0	0
Fair Value, Ending Balance	1,221	1,459	1,221	1,459
Change in unrealized gains/(losses) related to financial instruments held	(22)	0	17	0
Foreign Government Debt Securities
Assets
Fair Value, Beginning balance	85	81	67	104
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	9	(5)	11	3
Purchases	333	138	634	343
Sales	(397)	(129)	(682)	(360)
Settlements	(4)	(15)	(4)	(20)
Transfers into and/or out of level 3	110	0	110	0
Fair Value, Ending Balance	136	70	136	70
Change in unrealized gains/(losses) related to financial instruments held	11	0	11	4
Corporate Debt Securities
Assets
Fair Value, Beginning balance	4,852	5,463	5,308	6,373
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	(41)	(53)	(124)	205
Purchases	2,251	1,620	5,178	3,936
Sales	(955)	(1,436)	(3,518)	(2,705)
Settlements	(822)	(238)	(1,447)	(2,205)
Transfers into and/or out of level 3	450	(122)	338	(370)
Fair Value, Ending Balance	5,735	5,234	5,735	5,234
Change in unrealized gains/(losses) related to financial instruments held	28	92	30	187
Trading Loans [Member]
Assets
Fair Value, Beginning balance	10,032	11,144	10,787	12,209
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	41	139	(131)	295
Purchases	3,782	1,312	5,408	2,213
Sales	(2,265)	(619)	(3,750)	(1,292)
Settlements	(688)	(985)	(1,391)	(1,930)
Transfers into and/or out of level 3	38	(76)	17	(580)
Fair Value, Ending Balance	10,940	10,915	10,940	10,915
Change in unrealized gains/(losses) related to financial instruments held	21	36	(229)	189
Asset Backed Securities Trading Account [Member]
Assets
Fair Value, Beginning balance	1,579	7,434	3,696	7,965
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	95	(218)	159	12
Purchases	444	454	1,040	1,278
Sales	(557)	(673)	(1,534)	(1,934)
Settlements	(12)	(187)	(147)	(513)
Transfers into and/or out of level 3	(121)	(1)	(1,786)	1
Fair Value, Ending Balance	1,428	6,809	1,428	6,809
Change in unrealized gains/(losses) related to financial instruments held	56	(235)	74	(52)
Total debt and equity instruments [Member]
Assets
Fair Value, Beginning balance	22,703	30,339	25,639	32,967
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	384	(160)	338	574
Purchases	7,466	3,743	13,909	8,575
Sales	(4,735)	(3,378)	(10,732)	(7,467)
Settlements	(1,913)	(1,558)	(3,510)	(4,896)
Transfers into and/or out of level 3	502	(210)	(1,237)	(977)
Fair Value, Ending Balance	24,407	28,776	24,407	28,776
Change in unrealized gains/(losses) related to financial instruments held	324	(118)	202	396
Equity securities
Assets
Fair Value, Beginning balance	1,172	1,248	1,114	1,177
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	(10)	(70)	(9)	(77)
Purchases	111	90	204	112
Sales	(57)	(30)	(148)	(57)
Settlements	(56)	0	(65)	(13)
Transfers into and/or out of level 3	(121)	(2)	(57)	94
Fair Value, Ending Balance	1,039	1,236	1,039	1,236
Change in unrealized gains/(losses) related to financial instruments held	(8)	(32)	(28)	(54)
Physical Commodities [Member]
Assets
Fair Value, Beginning balance	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0		0
Purchases	0		0
Sales	0		0
Settlements	0		0
Transfers into and/or out of level 3	16		16
Fair Value, Ending Balance	16		16
Change in unrealized gains/(losses) related to financial instruments held	0		0
Other Debt and Equity Instruments [Member]
Assets
Fair Value, Beginning balance	948	993	863	880
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	43	1	87	154
Purchases	54	15	126	50
Sales	(18)	(4)	(20)	(48)
Settlements	(52)	(50)	(81)	(81)
Transfers into and/or out of level 3	130	0	130	0
Fair Value, Ending Balance	1,105	955	1,105	955
Change in unrealized gains/(losses) related to financial instruments held	38	1	139	158
Total net derivative receivables [Member]
Assets
Fair Value, Beginning balance	1,774	3,557	1,893	6,238
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	(104)	2,362	818	749
Purchases	1,081	749	1,390	1,341
Sales	(1,164)	(699)	(1,438)	(1,332)
Settlements	(1,928)	(1,310)	(3,187)	(3,052)
Transfers into and/or out of level 3	(75)	27	108	742
Fair Value, Ending Balance	(416)	4,686	(416)	4,686
Change in unrealized gains/(losses) related to financial instruments held	584	948	48	(2,086)
Interest rate contract
Assets
Fair Value, Beginning balance	2,791	3,238	3,322	3,561
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	125	2,027	431	3,355
Purchases	46	191	115	300
Sales	(63)	(30)	(125)	(98)
Settlements	(989)	(1,711)	(1,847)	(3,055)
Transfers into and/or out of level 3	191	(23)	205	(371)
Fair Value, Ending Balance	2,101	3,692	2,101	3,692
Change in unrealized gains/(losses) related to financial instruments held	156	845	45	828
Credit derivatives
Assets
Fair Value, Beginning balance	1,317	4,808	1,873	7,732
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	(335)	168	(824)	(2,186)
Purchases	3	26	50	104
Sales	(1)	(25)	(1)	(43)
Settlements	(76)	(530)	(189)	(1,160)
Transfers into and/or out of level 3	13	1	12	1
Fair Value, Ending Balance	921	4,448	921	4,448
Change in unrealized gains/(losses) related to financial instruments held	(360)	249	(836)	(1,880)
Foreign exchange
Assets
Fair Value, Beginning balance	(1,516)	(1,060)	(1,750)	(1,263)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	161	(632)	45	(505)
Purchases	8	26	(7)	45
Sales	0	(20)	(3)	(178)
Settlements	137	201	513	419
Transfers into and/or out of level 3	(8)	(3)	(16)	(6)
Fair Value, Ending Balance	(1,218)	(1,488)	(1,218)	(1,488)
Change in unrealized gains/(losses) related to financial instruments held	71	(594)	(5)	(505)
Equity Contract
Assets
Fair Value, Beginning balance	(1,000)	(2,829)	(1,806)	(3,105)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	(350)	885	513	165
Purchases	1,024	520	1,221	853
Sales	(1,100)	(695)	(1,306)	(1,078)
Settlements	(588)	108	(810)	99
Transfers into and/or out of level 3	(277)	28	(103)	1,083
Fair Value, Ending Balance	(2,291)	(1,983)	(2,291)	(1,983)
Change in unrealized gains/(losses) related to financial instruments held	654	479	604	(405)
Commodity Contract
Assets
Fair Value, Beginning balance	182	(600)	254	(687)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	295	(86)	653	(80)
Purchases	0	(14)	11	39
Sales	0	71	(3)	65
Settlements	(412)	622	(854)	645
Transfers into and/or out of level 3	6	24	10	35
Fair Value, Ending Balance	71	17	71	17
Change in unrealized gains/(losses) related to financial instruments held	63	(31)	240	(124)
Available-for-sale Securities
Assets
Fair Value, Beginning balance	1,967	25,917	28,916	25,486
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	3	(260)	(15)	(164)
Total realized/ unrealized gains/(losses)	0	(315)	(4)	(304)
Purchases	7	2,082	407	3,431
Sales	0	(742)	(13)	(1,260)
Settlements	(25)	(628)	(97)	(1,155)
Transfers into and/or out of level 3	0	0	(27,260)	116
Fair Value, Ending Balance	1,949	26,314	1,949	26,314
Change in unrealized gains/(losses) related to financial instruments held	0	(352)	8	(348)
Asset backed Security Available for Sale [Member]
Assets
Fair Value, Beginning balance	1,130	25,448	28,024	24,958
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	(339)	5	(336)
Purchases	0	1,849	400	3,170
Sales	0	(649)	0	(1,147)
Settlements	(5)	(617)	(44)	(1,069)
Transfers into and/or out of level 3	0	0	(27,260)	116
Fair Value, Ending Balance	1,125	25,692	1,125	25,692
Change in unrealized gains/(losses) related to financial instruments held	0	(354)	5	(355)
Other Available For Sale Securities [Member]
Assets
Fair Value, Beginning balance	837	469	892	528
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	24	(9)	32
Purchases	7	233	7	261
Sales	0	(93)	(13)	(113)
Settlements	(20)	(11)	(53)	(86)
Transfers into and/or out of level 3	0	0	0	0
Fair Value, Ending Balance	824	622	824	622
Change in unrealized gains/(losses) related to financial instruments held	0	2	3	7
Loans [Member]
Assets
Fair Value, Beginning balance	2,064	1,766	2,282	1,647
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	6	546	(29)	576
Purchases	103	580	328	707
Sales	(7)	0	(56)	0
Settlements	(323)	(372)	(682)	(491)
Transfers into and/or out of level 3	0	0	0	81
Fair Value, Ending Balance	1,843	2,520	1,843	2,520
Change in unrealized gains/(losses) related to financial instruments held	9	536	(43)	563
Mortgage servicing rights [Member]
Assets
Fair Value, Beginning balance	7,949	8,039	7,614	7,223
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(1,119)	1,347	(523)
Purchases	655	526	1,339	1,099
Sales	(19)	0	(418)	0
Settlements	(288)	(328)	(547)	(681)
Transfers into and/or out of level 3	0	0	0	0
Fair Value, Ending Balance	9,335	7,118	9,335	7,118
Change in unrealized gains/(losses) related to financial instruments held	1,038	(1,119)	1,347	(523)
Private Equity Funds [Member]
Assets
Fair Value, Beginning balance	6,831	6,739	7,181	6,751
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	434	35	165	287
Purchases	122	348	203	459
Sales	(7)	(6)	(103)	(242)
Settlements	(275)	(368)	(341)	(507)
Transfers into and/or out of level 3	0	(46)	0	(46)
Fair Value, Ending Balance	7,105	6,702	7,105	6,702
Change in unrealized gains/(losses) related to financial instruments held	206	305	(188)	436
All other assets [Member]
Assets
Fair Value, Beginning balance	3,985	4,397	4,258	4,374
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	1	(59)	(25)	(223)
Purchases	83	276	135	632
Sales	(292)	(73)	(295)	(92)
Settlements	(97)	(93)	(393)	(243)
Transfers into and/or out of level 3	0	0	0	0
Fair Value, Ending Balance	3,680	4,448	3,680	4,448
Change in unrealized gains/(losses) related to financial instruments held	(11)	(52)	(41)	(218)
Fair Value, Measurements, Recurring [Member] | Total net derivative receivables [Member]
Assets
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings				749
Fair Value, Measurements, Recurring [Member] | Interest rate contract
Assets
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings				3,400
Fair Value, Measurements, Recurring [Member] | Credit derivatives
Assets
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings				(2,200)
Fair Value, Measurements, Recurring [Member] | Mortgage servicing rights [Member]
Assets
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	$ 1,038	$ (1,100)