Quarterly report pursuant to Section 13 or 15(d)

Assets And Liabilities Measured At Fair Value (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details)

v2.4.1.9
Assets And Liabilities Measured At Fair Value (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents $ 2,230us-gaap_CashAndCashEquivalentsFairValueDisclosure $ 2,147us-gaap_CashAndCashEquivalentsFairValueDisclosure
Short term marketable securities 860us-gaap_MarketableSecuritiesCurrent 889us-gaap_MarketableSecuritiesCurrent
Available-for-sale securities 1,207us-gaap_AvailableForSaleSecurities 1,220us-gaap_AvailableForSaleSecurities
Available-for-sale Securities, Noncurrent 1,236us-gaap_AvailableForSaleSecuritiesNoncurrent 1,224us-gaap_AvailableForSaleSecuritiesNoncurrent
Debt 2,502us-gaap_DebtInstrumentFairValue 2,574us-gaap_DebtInstrumentFairValue
Fair Value, Inputs (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 2,230us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
2,147us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
Short term marketable securities 254us-gaap_MarketableSecuritiesCurrent
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
277us-gaap_MarketableSecuritiesCurrent
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
Available-for-sale securities 1,186us-gaap_AvailableForSaleSecurities
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
1,203us-gaap_AvailableForSaleSecurities
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Short term marketable securities 606us-gaap_MarketableSecuritiesCurrent
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
612us-gaap_MarketableSecuritiesCurrent
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
Available-for-sale securities 21us-gaap_AvailableForSaleSecurities
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
17us-gaap_AvailableForSaleSecurities
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
Debt $ 2,502us-gaap_DebtInstrumentFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
$ 2,574us-gaap_DebtInstrumentFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member