Financial Instruments (Net investment hedges in foreign operations) (Details) (Net Investment Hedge [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net investment hedges in foreign operation
Hedge ineffectiveness gain (loss)	$ (187)	$ (260)	$ (353)	$ (480)
Foreign Exchange Contract [Member]
Net investment hedges in foreign operation
Gain (loss) recognized in AOCI	412	1,853	2,517	351
Gain (loss) reclassified from AOCI into earnings	$ 15	$ (2)	$ (109)	$ (12)