Stockholders' equity (Tables)

12 Months Ended

Dec. 31, 2011

Stockholders' equity [Abstract]

Summary of activity under our stock repurchase program

	2011					2010				2009
	Shares		Dollars			Shares		Dollars		Shares		Dollars
First quarter		—	$	—			29.1	$	1,684		37.5	$	1,997
Second quarter		12.9		732			10.3		616		—		—
Third quarter		45.4		2,421			6.6		364		—		—
Fourth quarter		86.0		5,154	(1)		20.5		1,136		21.7		1,211
Total stock repurchases		144.3	$	8,307			66.5	$	3,800		59.2	$	3,208

⁽¹⁾  Includes the repurchase of 83.3 million shares of our common stock at an average price paid per share of $60.08 including related expenses, for an aggregate cost of $5.0 billion, under a modified Dutch auction tender offer.

Components of Accumulated Other Comprehensive Income

	Foreign currency translation			Cash flow hedges			Available-for-sale securities			Other			AOCI
Balance as of December 31, 2008	$	25		$	50		$	49		$	(7	)	$	117
Foreign currency translation adjustments		25			—			—			—			25
Unrealized (losses) gains		—			(213	)		116			(12	)		(109	)
Reclassification adjustments to income		—			8			(42	)		—			(34	)
Other		—			—			—			5			5
Income taxes		(10	)		73			(28	)		6			41
Balance as of December 31, 2009		40			(82	)		95			(8	)		45
Foreign currency translation adjustments		(29	)		—			—			—			(29	)
Unrealized gains		—			186			155			1			342
Reclassification adjustments to income		—			(46	)		(90	)		—			(136	)
Income taxes		11			(55	)		(25	)		—			(69	)
Balance as of December 31, 2010		22			3			135			(7	)		153
Foreign currency translation adjustments		(6	)		—			—			—			(6	)
Unrealized (losses) gains		—			(51	)		125			2			76
Reclassification adjustments to income		—			112			(154	)		—			(42	)
Other		—			—			—			(8	)		(8	)
Income taxes		5			(21	)		14			—			(2	)
Balance as of December 31, 2011	$	21		$	43		$	120		$	(13	)	$	171