Fair Value Measurements (Details 1) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	$ 614	$ 623
Derivative assets	2,125	2,397
Netting adjustments	(1,295)	(1,452)
Total derivative assets	830	945
Accrued income and other assets	118	112
Total assets on a recurring basis at fair value	17,273	18,688
LIABILITIES MEASURED ON A RECURRING BASIS
Federal funds purchased and securities sold under repurchase agreements	394	292
Bank notes and other short-term borrowings, Short positions	324	337
Derivative liabilities	1,601	2,004
Netting adjustments	(847)	(978)
Total derivative liabilities	754	1,026
Accrued expense and other liabilities	8	45
Total liabilities on a recurring basis at fair value	1,480	1,700
Level 1 [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Bank notes and other short-term borrowings, Short positions	6
Derivative liabilities	64	79
Total derivative liabilities	64	79
Accrued expense and other liabilities		23
Total liabilities on a recurring basis at fair value	70	102
Level 2 [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Federal funds purchased and securities sold under repurchase agreements	394	292
Bank notes and other short-term borrowings, Short positions	318	337
Derivative liabilities	1,535	1,896
Total derivative liabilities	1,535	1,896
Accrued expense and other liabilities	8	22
Total liabilities on a recurring basis at fair value	2,255	2,547
Level 3 [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	2	29
Total derivative liabilities	2	29
Total liabilities on a recurring basis at fair value	2	29
Available-for-sale Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	14,633	16,012
Short-term investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	292	236
US Treasury and Government [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	336	353
Mortgage Backed Securities, Other [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	97	62
Mortgage Backed Securities, Other [Member] | Available-for-sale Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	714	778
Other Debt Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	36	108
Other Debt Securities [Member] | Available-for-sale Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	12	9
Total trading account securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	614	623
US States and Political Subdivisions Debt Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	122	81	[1]
US States and Political Subdivisions Debt Securities [Member] | Available-for-sale Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	62	63
Collateralized Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	23	19
Collateralized Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	13,845	15,162
Level 1 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	11	79
Derivative assets	73	86
Total derivative assets	73	86
Accrued income and other assets	1	7
Total assets on a recurring basis at fair value	115	192
Level 1 [Member] | Available-for-sale Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	12	9
Level 1 [Member] | Other Debt Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	11	79
Level 1 [Member] | Other Debt Securities [Member] | Available-for-sale Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	12	9
Level 1 [Member] | Total trading account securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	11	79
Level 2 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	602	509
Derivative assets	2,010	2,266
Total derivative assets	2,010	2,266
Accrued income and other assets	117	105
Total assets on a recurring basis at fair value	17,642	19,119
Level 2 [Member] | Available-for-sale Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	14,621	16,003
Level 2 [Member] | Short-term investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	292	236
Level 2 [Member] | US Treasury and Government [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	336	353
Level 2 [Member] | Mortgage Backed Securities, Other [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	96	27
Level 2 [Member] | Mortgage Backed Securities, Other [Member] | Available-for-sale Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	714	778
Level 2 [Member] | Other Debt Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	25	29
Level 2 [Member] | Total trading account securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	602	509
Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	122	81
Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member] | Available-for-sale Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	62	63
Level 2 [Member] | Collateralized Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	23	19
Level 2 [Member] | Collateralized Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	13,845	15,162
Level 3 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	1	35
Derivative assets	42	45
Total derivative assets	42	45
Total assets on a recurring basis at fair value	811	829
Level 3 [Member] | Mortgage Backed Securities, Other [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	1	35
Level 3 [Member] | Total trading account securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account assets	1	35
Other Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	786	760
Other Investments [Member] | Principal Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	729	709
Other Investments [Member] | Principal Direct Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	244	236
Other Investments [Member] | Principal Indirect Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	485	473
Other Investments [Member] | Equity and Mezzanine Direct Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	15	15
Other Investments [Member] | Equity and Mezzanine Indirect Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	42	36
Other Investments [Member] | Private Equity And Mezzanine Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	57	51
Other Investments [Member] | Level 1 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	18	11
Other Investments [Member] | Level 1 [Member] | Principal Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	18	11
Other Investments [Member] | Level 1 [Member] | Principal Direct Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	18	11
Other Investments [Member] | Level 3 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	768	749
Other Investments [Member] | Level 3 [Member] | Principal Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	711	698
Other Investments [Member] | Level 3 [Member] | Principal Direct Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	226	225
Other Investments [Member] | Level 3 [Member] | Principal Indirect Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	485	473
Other Investments [Member] | Level 3 [Member] | Equity and Mezzanine Direct Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	15	15
Other Investments [Member] | Level 3 [Member] | Equity and Mezzanine Indirect Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	42	36
Other Investments [Member] | Level 3 [Member] | Private Equity And Mezzanine Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities purchased under resale agreements	57	51
Interest rate [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	1,722	1,953
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	1,213	1,398
Interest rate [Member] | Level 2 [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	1,213	1,398
Interest rate [Member] | Level 2 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	1,686	1,915
Interest rate [Member] | Level 3 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	36	38
Foreign exchange [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	94	151
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	84	288
Foreign exchange [Member] | Level 1 [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	64	79
Foreign exchange [Member] | Level 2 [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	20	209
Foreign exchange [Member] | Level 1 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	73	86
Foreign exchange [Member] | Level 2 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	21	65
Energy and commodity [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	271	253
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	267	253
Energy and commodity [Member] | Level 2 [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	266	252
Energy and commodity [Member] | Level 3 [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	1	1
Energy and commodity [Member] | Level 2 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	271	253
Credit [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	35	37
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	34	62
Credit [Member] | Level 2 [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	33	34
Credit [Member] | Level 3 [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	1	28
Credit [Member] | Level 2 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	29	30
Credit [Member] | Level 3 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	6	7
Equity [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	3	3
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	3	3
Equity [Member] | Level 2 [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	3	3
Equity [Member] | Level 2 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	$ 3	$ 3

[1] Assumes conversion of stock options and/or Preferred Series A, as applicable.