Fair Value Measurements (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	$ 323
Fair Value, Measurements, Recurring [Member]
Assets and liabilities measured at fair value on a recurring basis
Cash equivalents	197	416
Derivative Assets	3	1
Derivative liabilities	(20)	(25)
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Assets and liabilities measured at fair value on a recurring basis
Cash equivalents	172	357
Derivative Assets	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member] | Corporate debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member] | U.S. government and agency debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member] | Asset-backed debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member] | Non-U.S. government debt securities
Assets and liabilities measured at fair value on a recurring basis
Marketable securities		0
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member] | Certificates of deposit [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member] | Municipal debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets and liabilities measured at fair value on a recurring basis
Cash equivalents	25	59
Derivative Assets	3	1
Derivative liabilities	(20)	(25)
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	167	123
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. government and agency debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	63	58
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Asset-backed debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	18	19
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Non-U.S. government debt securities
Assets and liabilities measured at fair value on a recurring basis
Marketable securities		10
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Certificates of deposit [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	49	41
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Municipal debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	26	27
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets and liabilities measured at fair value on a recurring basis
Cash equivalents	0	0
Derivative Assets	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Corporate debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. government and agency debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Asset-backed debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Non-U.S. government debt securities
Assets and liabilities measured at fair value on a recurring basis
Marketable securities		0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Certificates of deposit [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Municipal debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	167	123
Fair Value, Measurements, Recurring [Member] | U.S. government and agency debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	63	58
Fair Value, Measurements, Recurring [Member] | Asset-backed debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	18	19
Fair Value, Measurements, Recurring [Member] | Non-U.S. government debt securities
Assets and liabilities measured at fair value on a recurring basis
Marketable securities		10
Fair Value, Measurements, Recurring [Member] | Certificates of deposit [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	49	41
Fair Value, Measurements, Recurring [Member] | Municipal debt securities [Member]
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	$ 26	$ 27