Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2012

Fair Value Disclosures [Abstract]

Cash and cash equivalents or short-term or long-term marketable securities

	September 30, 2012
	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Cash and Cash Equivalents		Short-Term Marketable Securities		Long-Term Marketable Securities
							(in millions)
Cash	$	206	$	—	$	—	$	206	$	206	$	—	$	—
Level 1:
Bank and time deposits	386		—		—		386		385		1		—
Money market funds	286		—		—		286		286		—		—
U.S. treasury and agency obligations	893		1		—		894		38		240		616
Corporate bonds	10		—		—		10		—		10		—
Subtotal	1,575		1		—		1,576		709		251		616
Level 2:
Commercial paper	597		—		—		597		496		101		—
Corporate bonds	746		2		—		748		5		360		383
Asset-backed securities and other	63		—		—		63		—		23		40
Subtotal	1,406		2		—		1,408		501		484		423
Level 3:
None	—		—		—		—		—		—		—
Total	$	3,187	$	3	$	—	$	3,190	$	1,416	$	735	$	1,039

	December 31, 2011
	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Cash and Cash Equivalents		Short-Term Marketable Securities		Long-Term Marketable Securities
								(in millions)
Cash	$	154	$	—	$	—		$	154	$	154	$	—	$	—
Level 1:
Bank and time deposits	2,717		—		—			2,717		2,716		—		1
Money market funds	914		—		—			914		914		—		—
U.S. treasury and agency obligations	469		—		—			469		—		90		379
Corporate bonds	7		—		—			7		—		7		—
Subtotal	4,107		—		—			4,107		3,630		97		380
Level 2:
Commercial paper	381		—		—			381		311		70		—
Corporate bonds	543		1		(2		)	542		51		211		280
Asset-backed securities and other	21		—		—			21		—		5		16
Subtotal	945		1		(2		)	944		362		286		296
Level 3:
None	—		—		—			—		—		—		—
Total	$	5,206	$	1	$	(2	)	$	5,205	$	4,146	$	383	$	676