Derivative Instruments (Details 2) (Customer-Related Positions [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2012 Y	Dec. 31, 2011 Y
Interest Rate Contracts [Member] | Receive fixed/pay floating swaps [Member]
Customer-related derivative positions of the company
Notional Value, Assets	$ 15,369	$ 16,230
Notional Value, Liabilities	741	523
Fair Value, Assets	1,063	1,216
Fair Value, Liabilities	2	1
Derivative Asset Average Remaining Maturity Period	5.01	4.98
Derivative Liability Average Remaining Maturity Period	4.29	2.52
Interest Rate Contracts [Member] | Pay fixed/receive floating swaps [Member]
Customer-related derivative positions of the company
Notional Value, Assets	886	99
Notional Value, Liabilities	15,319	16,206
Fair Value, Assets	3
Fair Value, Liabilities	1,032	1,182
Derivative Asset Average Remaining Maturity Period	5.26	1.81
Derivative Liability Average Remaining Maturity Period	4.99	5.10
Interest Rate Contracts [Member] | Purchased Option [Member]
Customer-related derivative positions of the company
Notional Value, Assets	2,659	2,660
Notional Value, Liabilities
Fair Value, Assets	30	26
Fair Value, Liabilities
Derivative Asset Average Remaining Maturity Period	5.98	6.11
Derivative Liability Average Remaining Maturity Period
Interest Rate Contracts [Member] | Written Option [Member]
Customer-related derivative positions of the company
Notional Value, Assets
Notional Value, Liabilities	2,659	2,660
Fair Value, Assets
Fair Value, Liabilities	30	26
Derivative Asset Average Remaining Maturity Period
Derivative Liability Average Remaining Maturity Period	5.98	6.11
Foreign Exchange Rate Contracts [Member] | Purchased Option [Member]
Customer-related derivative positions of the company
Notional Value, Assets	125	127
Notional Value, Liabilities
Fair Value, Assets	3	5
Fair Value, Liabilities
Derivative Asset Average Remaining Maturity Period	0.38	0.41
Derivative Liability Average Remaining Maturity Period
Foreign Exchange Rate Contracts [Member] | Written Option [Member]
Customer-related derivative positions of the company
Notional Value, Assets
Notional Value, Liabilities	125	127
Fair Value, Assets
Fair Value, Liabilities	3	5
Derivative Asset Average Remaining Maturity Period
Derivative Liability Average Remaining Maturity Period	0.38	0.41
Foreign Exchange Rate Contracts [Member] | Forwards, spots and swaps [Member]
Customer-related derivative positions of the company
Notional Value, Assets	8,938	7,982
Notional Value, Liabilities	8,108	8,578
Fair Value, Assets	378	369
Fair Value, Liabilities	$ 355	$ 360
Derivative Asset Average Remaining Maturity Period	0.46	0.54
Derivative Liability Average Remaining Maturity Period	0.54	0.49