Derivative Instruments and Other Financial Instruments Used For Hedging (Details 2) (Trading Account Activities [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Gain or (Loss) Recognized in Income on Derivative Instruments
Gain or (Loss) Recognized in Income on Derivative Instruments	$ 21	$ 25	$ 47	$ 53
Interest rate contracts [Member]
Gain or (Loss) Recognized in Income on Derivative Instruments
Gain or (Loss) Recognized in Income on Derivative Instruments	7	8	21	19
Equity contracts [Member]
Gain or (Loss) Recognized in Income on Derivative Instruments
Gain or (Loss) Recognized in Income on Derivative Instruments	4	5	9	13
Foreign exchange contracts [Member]
Gain or (Loss) Recognized in Income on Derivative Instruments
Gain or (Loss) Recognized in Income on Derivative Instruments	6	7	13	13
Commodity contracts [Member]
Gain or (Loss) Recognized in Income on Derivative Instruments
Gain or (Loss) Recognized in Income on Derivative Instruments	4	3	4	2
Credit Contracts [Member]
Gain or (Loss) Recognized in Income on Derivative Instruments
Gain or (Loss) Recognized in Income on Derivative Instruments		$ 2		$ 6