Financial Instruments (Free-standing derivatives) (Details) (Free Standing Derivatives [Member], USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Free standing derivatives
Gain (loss) on derivatives	$ (1,579)	$ 814
Interest Rate Contract [Member]
Free standing derivatives
Gain (loss) on derivatives	(132)	(22)
Foreign Exchange Contract [Member]
Free standing derivatives
Gain (loss) on derivatives	(1,443)	782
Other Contract [Member]
Free standing derivatives
Gain (loss) on derivatives	$ (4)	$ 54