Financial Instruments (Net investment hedges in foreign operations) (Details) (Net Investment Hedge [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Net investment hedges in foreign operation
Hedge ineffectiveness gain (loss)	$ (166)	$ (220)
Foreign Exchange Contract [Member]
Net investment hedges in foreign operation
Gain (loss) recognized in AOCI	2,105	(1,502)
Gain (loss) reclassified from AOCI into earnings	$ (124)	$ (10)