Fair Value Measurements (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	$ 623	$ 985
Derivative assets	2,397	2,304
Netting adjustments	(1,452)	(1,298)
Total derivative assets	945	1,006
Accrued income and other assets	112	77
Total assets on a recurring basis at fair value	18,688	25,322
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Federal funds purchased and securities sold under repurchase agreements	292	572
Bank notes and other short-term borrowings, Short positions	337	395
Derivative liabilities	2,004	2,107
Netting adjustments	(978)	(965)
Total derivative liabilities	1,026	1,142
Accrued expense and other liabilities	45	66
Total liabilities on a recurring basis at fair value	1,700	2,175
Level 1 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Federal funds purchased and securities sold under repurchase agreements	0	0
Bank notes and other short-term borrowings, Short positions	0	0
Derivative liabilities	79	82
Netting adjustments	0	0
Total derivative liabilities	79	82
Accrued expense and other liabilities	23	0
Total liabilities on a recurring basis at fair value	102	82
Level 2 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Federal funds purchased and securities sold under repurchase agreements	292	572
Bank notes and other short-term borrowings, Short positions	337	395
Derivative liabilities	1,896	2,024
Netting adjustments	0	0
Total derivative liabilities	1,896	2,024
Accrued expense and other liabilities	22	66
Total liabilities on a recurring basis at fair value	2,547	3,057
Level 3 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Federal funds purchased and securities sold under repurchase agreements	0	0
Bank notes and other short-term borrowings, Short positions	0	0
Derivative liabilities	0	1
Netting adjustments	0	0
Total derivative liabilities	29	1
Accrued expense and other liabilities	0	0
Total liabilities on a recurring basis at fair value	29	1
Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	16,012	21,933
Short-term investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	236	373
US Treasury and Government [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	353	501
US Treasury and Government [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements		8
Mortgage Backed Securities, Other [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	62	138
Mortgage Backed Securities, Other [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	778	1,069
Other Debt Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	108	235
Other Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	9	19
Total trading account securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	623	974
Commercial Loan [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	0	11
US States and Political Subdivisions Debt Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	81	66
US States and Political Subdivisions Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	63	172
Collateralized Mortgage Backed Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	19	34
Collateralized Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	15,162	20,665
Level 1 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	79	145
Derivative assets	86	92
Netting adjustments	0	0
Total derivative assets	86	92
Accrued income and other assets	7	1
Total assets on a recurring basis at fair value	192	251
Level 1 [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	9	13
Level 1 [Member] | Short-term investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Level 1 [Member] | US Treasury and Government [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	0	0
Level 1 [Member] | US Treasury and Government [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements		0
Level 1 [Member] | Mortgage Backed Securities, Other [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	0	0
Level 1 [Member] | Mortgage Backed Securities, Other [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Level 1 [Member] | Other Debt Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	79	145
Level 1 [Member] | Other Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	9	13
Level 1 [Member] | Total trading account securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	79	145
Level 1 [Member] | Commercial Loan [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	0	0
Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	0	0
Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Level 1 [Member] | Collateralized Mortgage Backed Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	0	0
Level 1 [Member] | Collateralized Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Level 2 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	509	818
Derivative assets	2,266	2,124
Netting adjustments	0	0
Total derivative assets	2,266	2,124
Accrued income and other assets	105	76
Total assets on a recurring basis at fair value	19,119	25,311
Level 2 [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	16,003	21,920
Level 2 [Member] | Short-term investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	236	373
Level 2 [Member] | US Treasury and Government [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	353	501
Level 2 [Member] | US Treasury and Government [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements		8
Level 2 [Member] | Mortgage Backed Securities, Other [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	27	137
Level 2 [Member] | Mortgage Backed Securities, Other [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	778	1,069
Level 2 [Member] | Other Debt Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	29	69
Level 2 [Member] | Other Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	6
Level 2 [Member] | Total trading account securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	509	807
Level 2 [Member] | Commercial Loan [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	0	11
Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	81	66
Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	63	172
Level 2 [Member] | Collateralized Mortgage Backed Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	19	34
Level 2 [Member] | Collateralized Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	15,162	20,665
Level 3 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	35	22
Derivative assets	45	88
Netting adjustments	0	0
Total derivative assets	45	88
Accrued income and other assets	0	0
Total assets on a recurring basis at fair value	829	1,058
Level 3 [Member] | Available-for-sale Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Level 3 [Member] | Short-term investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Level 3 [Member] | US Treasury and Government [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	0	0
Level 3 [Member] | Mortgage Backed Securities, Other [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Total trading account assets	35	1
Level 3 [Member] | Other Debt Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Total trading account assets	0	21
Level 3 [Member] | Total trading account securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	35	22
Level 3 [Member] | Commercial Loan [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Total trading account assets	0	0
Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Total trading account assets	0	0
Level 3 [Member] | Collateralized Mortgage Backed Securities [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Total trading account assets	0	0
Other Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	760	948
Other Investments [Member] | Principal Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	709	898
Other Investments [Member] | Principal Direct Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	236	372
Other Investments [Member] | Principal Indirect Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	473	526
Other Investments [Member] | Equity and Mezzanine Direct Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	15	20
Other Investments [Member] | Equity and Mezzanine Indirect Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	36	30
Other Investments [Member] | Private Equity And Mezzanine Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	51	50
Other Investments [Member] | Level 1 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	11	0
Other Investments [Member] | Level 1 [Member] | Principal Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	11	0
Other Investments [Member] | Level 1 [Member] | Principal Direct Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	11	0
Other Investments [Member] | Level 1 [Member] | Principal Indirect Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Other Investments [Member] | Level 1 [Member] | Equity and Mezzanine Direct Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Other Investments [Member] | Level 1 [Member] | Equity and Mezzanine Indirect Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Other Investments [Member] | Level 1 [Member] | Private Equity And Mezzanine Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Other Investments [Member] | Level 2 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Other Investments [Member] | Level 2 [Member] | Principal Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Other Investments [Member] | Level 2 [Member] | Principal Direct Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Other Investments [Member] | Level 2 [Member] | Principal Indirect Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Other Investments [Member] | Level 2 [Member] | Equity and Mezzanine Direct Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Other Investments [Member] | Level 2 [Member] | Equity and Mezzanine Indirect Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Other Investments [Member] | Level 2 [Member] | Private Equity And Mezzanine Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	0	0
Other Investments [Member] | Level 3 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	749	948
Other Investments [Member] | Level 3 [Member] | Principal Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	698	898
Other Investments [Member] | Level 3 [Member] | Principal Direct Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	225	372
Other Investments [Member] | Level 3 [Member] | Principal Indirect Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	473	526
Other Investments [Member] | Level 3 [Member] | Equity and Mezzanine Direct Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	15	20
Other Investments [Member] | Level 3 [Member] | Equity and Mezzanine Indirect Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	36	30
Other Investments [Member] | Level 3 [Member] | Private Equity And Mezzanine Investments [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Securities purchased under resale agreements	51	50
Interest rate [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	1,953	1,766
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	1,398	1,335
Interest rate [Member] | Level 1 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	0	0
Interest rate [Member] | Level 2 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	1,398	1,335
Interest rate [Member] | Level 3 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	0	0
Interest rate [Member] | Level 1 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	0	0
Interest rate [Member] | Level 2 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	1,915	1,691
Interest rate [Member] | Level 3 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	38	75
Foreign exchange [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	151	180
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	288	405
Foreign exchange [Member] | Level 1 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	79	82
Foreign exchange [Member] | Level 2 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	209	323
Foreign exchange [Member] | Level 3 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	0	0
Foreign exchange [Member] | Level 1 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	86	92
Foreign exchange [Member] | Level 2 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	65	88
Foreign exchange [Member] | Level 3 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	0	0
Energy and commodity [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	253	318
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	253	335
Energy and commodity [Member] | Level 1 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	0	0
Energy and commodity [Member] | Level 2 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	252	335
Energy and commodity [Member] | Level 3 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	1	0
Energy and commodity [Member] | Level 1 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	0	0
Energy and commodity [Member] | Level 2 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	253	317
Energy and commodity [Member] | Level 3 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	0	1
Credit [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	37	39
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	62	31
Credit [Member] | Level 1 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	0	0
Credit [Member] | Level 2 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	34	30
Credit [Member] | Level 3 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	28	1
Credit [Member] | Level 1 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	0	0
Credit [Member] | Level 2 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	30	27
Credit [Member] | Level 3 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	7	12
Equity [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	3	1
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	3	1
Equity [Member] | Level 1 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	0	0
Equity [Member] | Level 2 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	3	1
Equity [Member] | Level 3 [Member]
Fair Value Liabilities Measured on Recurring Basis, Obligations [Abstract]
Derivative liabilities	0	0
Equity [Member] | Level 1 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	0	0
Equity [Member] | Level 2 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	3	1
Equity [Member] | Level 3 [Member]
Fair Value Assets Measured on Recurring Basis, Obligations [Abstract]
Derivative assets	$ 0	$ 0