Derivative instruments (Details 2) (Derivatives in cash flow hedging relationships [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Location in the Consolidated Statements of Income and the effective portion of gain/(loss) reclassified from Accumulated Other Comprehensive Income into earnings for our derivative instruments designated as cash flow hedges contracts [Abstract]
Total	$ 134	$ (112)	$ 46
Foreign currency contracts [Member] \| Product sales [Member]
Location in the Consolidated Statements of Income and the effective portion of gain/(loss) reclassified from Accumulated Other Comprehensive Income into earnings for our derivative instruments designated as cash flow hedges contracts [Abstract]
The amount of gain (loss) recognized in product sales	74	(108)	47
Cross currency swap contracts [Member]
Location in the Consolidated Statements of Income and the effective portion of gain/(loss) reclassified from Accumulated Other Comprehensive Income into earnings for our derivative instruments designated as cash flow hedges contracts [Abstract]
The amount of gain (loss) recognized in interest and other income, net	61	(3)	0
Forward interest rate contracts [Member]
Location in the Consolidated Statements of Income and the effective portion of gain/(loss) reclassified from Accumulated Other Comprehensive Income into earnings for our derivative instruments designated as cash flow hedges contracts [Abstract]
The amount of gain (loss) recognized in interest expense, net	$ (1)	$ (1)	$ (1)