Financial Instruments (Free-standing derivatives) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Free Standing Derivatives [Member]
Free standing derivatives
Gain (loss) on derivatives	$ (2,132)	$ 677
Interest Rate Contract [Member]
Free standing derivatives
Gain (loss) on derivatives	(64)	(23)
Foreign Exchange Contract [Member]
Free standing derivatives
Gain (loss) on derivatives	(2,076)	701
Other Contract [Member]
Free standing derivatives
Gain (loss) on derivatives	$ 8	$ (1)