|**Fair Value Measurements And Financial Instruments (Tables)**                    | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
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|**Fair Value, by Balance Sheet Grouping, Methodology and Assumptions [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
|Summary Of Components Of Available-For-Sale Securities                            | The following table summarizes the components of the balance of the Company’s available-for-sale securities atJune 30, 2012andDecember 31, 2011(in millions):June 30, 2012December 31, 2011Adjusted cost$11$9Gross unrealized gains3230Fair value$43$39                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
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|                                                                                  | June 30, 2012                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
|Adjusted cost                                                                     | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|Gross unrealized gains                                                            | 32                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
|Fair value                                                                        | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|Summary Of Financial Assets Measured At Fair Value On A Recurring Basis           | A summary of financial assets measured at fair value on a recurring basis atJune 30, 2012andDecember 31, 2011is as follows (in millions):Balance SheetClassificationJune 30, 2012Quoted PricesIn ActiveMarkets(Level 1)SignificantOtherObservableInputs(Level 2)SignificantUnobservableInputs(Level 3)AssetsMoney-market securitiesCash and cash equivalents$1,015$1,015$—$—Available-for-sale securitiesOther current assets4343——Trading securitiesOther assets219219——Total assets$1,277$1,277$—$—Balance SheetClassificationDecember 31, 2011Quoted PricesIn ActiveMarkets(Level 1)SignificantOtherObservableInputs(Level 2)SignificantUnobservableInputs(Level 3)AssetsMoney-market securitiesCash and cash equivalents$745$745$—$—Available-for-sale securitiesOther current assets3939——Trading securitiesOther assets205205——Interest rate swapOther assets18—18—Total assets$1,007$989$18$—
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|                                                                                  | Balance SheetClassification                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
|Assets                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
|Money-market securities                                                           | Cash and cash equivalents                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|Available-for-sale securities                                                     | Other current assets                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Trading securities                                                                | Other assets                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|Total assets                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
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|                                                                                  | Balance SheetClassification                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
|Assets                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
|Money-market securities                                                           | Cash and cash equivalents                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|Available-for-sale securities                                                     | Other current assets                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Trading securities                                                                | Other assets                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|Interest rate swap                                                                | Other assets                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|Total assets                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     

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                    duration X- DefinitionTabular disclosure of assets and liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).+ ReferencesReference 1: http://www.xbrl.org/2003/role/presentationRef -Topic 820 -SubTopic 10 -Publisher FASB -Number  -Article  -Subparagraph  -Name Accounting Standards Codification -Paragraph 1 -Section 50 -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19190-110258+ Details**Name:**
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