Derivative Instruments (Details 2) (Customer-Related Positions [Member], USD $) In Millions, unless otherwise specified	Jun. 30, 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	$ 16,547	$ 16,230
Notional Value, Liabilities	603	523
Fair Value, Assets	1,204	1,216
Fair Value, Liabilities	1	1
Derivative Asset Average Remaining Maturity Period	4.86	4.98
Derivative Liability Average Remaining Maturity Period	4.76	2.52
Interest Rate Contracts [Member] | Pay fixed/receive floating swaps [Member]
Customer-related derivative positions of the company
Notional Value, Assets	131	99
Notional Value, Liabilities	17,090	16,206
Fair Value, Assets	1
Fair Value, Liabilities	1,169	1,182
Derivative Asset Average Remaining Maturity Period	14.03	1.81
Derivative Liability Average Remaining Maturity Period	4.81	5.10
Interest Rate Contracts [Member] | Purchased Option [Member]
Customer-related derivative positions of the company
Notional Value, Assets	2,789	2,660
Notional Value, Liabilities	28
Fair Value, Assets	17	26
Derivative Asset Average Remaining Maturity Period	5.67	6.11
Derivative Liability Average Remaining Maturity Period	4.92
Interest Rate Contracts [Member] | Written Option [Member]
Customer-related derivative positions of the company
Notional Value, Assets	28
Notional Value, Liabilities	2,789	2,660
Fair Value, Liabilities	17	26
Derivative Asset Average Remaining Maturity Period	4.92
Derivative Liability Average Remaining Maturity Period	5.67	6.11
Foreign Exchange Rate Contracts [Member] | Purchased Option [Member]
Customer-related derivative positions of the company
Notional Value, Assets	305	127
Fair Value, Assets	10	5
Derivative Asset Average Remaining Maturity Period	0.57	0.41
Foreign Exchange Rate Contracts [Member] | Written Option [Member]
Customer-related derivative positions of the company
Notional Value, Liabilities	305	127
Fair Value, Liabilities	10	5
Derivative Liability Average Remaining Maturity Period	0.57	0.41
Foreign Exchange Rate Contracts [Member] | Forwards, spots and swaps [Member]
Customer-related derivative positions of the company
Notional Value, Assets	9,611	7,936
Notional Value, Liabilities	9,574	7,731
Fair Value, Assets	286	369
Fair Value, Liabilities	$ 266	$ 354
Derivative Asset Average Remaining Maturity Period	0.42	0.54
Derivative Liability Average Remaining Maturity Period	0.45	0.54