Derivative instruments (Details 3) (Foreign currency contracts [Member], Interest and other income, net [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
Foreign currency contracts [Member] | Interest and other income, net [Member]
Location in the Condensed Consolidated Statements of Income and the amount of gain (loss) recognized in earnings for our derivative instruments not designated as hedging instruments
Amount of gain (loss) recognized in interest and other income, net	$ 11	$ 20	$ (5)	$ 10