Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2011

Fair Value Measurements [Abstract]

Assets and liabilities measured at fair value on a recurring basis

	Quoted Prices
	in Active		Significant
	Markets for		Other			Significant
	Identical		Observable			Unobservable
	Assets		Inputs			Inputs
(millions)	(Level 1)		(Level 2)			(Level 3)		Total
As of June 30, 2011:
Cash equivalents	$	172	$	25		$	—	$	197
Marketable securities:
Corporate debt securities		—		167			—		167
U.S. government and agency debt securities		—		63			—		63
Asset-backed debt securities		—		18			—		18
Certificates of deposit		—		49			—		49
Municipal debt securities		—		26			—		26
Derivative assets		—		3			—		3
Derivative liabilities		—		(20	)		—		(20	)
As of December 31, 2010:
Cash equivalents	$	357	$	59		$	—	$	416
Marketable securities:
Corporate debt securities		—		123			—		123
U.S. government and agency debt securities		—		58			—		58
Asset-backed debt securities		—		19			—		19
Non-U.S. government debt securities		—		10			—		10
Certificates of deposit		—		41			—		41
Municipal debt securities		—		27			—		27
Derivative assets		—		1			—		1
Derivative liabilities		—		(25	)		—		(25	)