Derivative instruments (Details 1) (Derivatives in cash flow hedging relationships [Member], USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 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 cash flow hedge contracts
Total	$ (33)	$ 21	$ (41)	$ 15
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 cash flow hedge contracts
The amount of gain (loss) recognized in interest expense, net	0	0	0	0
Foreign currency 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 cash flow hedge contracts
The amount of gain (loss) recognized in product sales	$ (33)	$ 21	$ (41)	$ 15