XML 35 R61.htm IDEA: XBRL DOCUMENT v2.4.1.9
Fair Value Measurements - Measured on Recurring Basis (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount $ 0us-gaap_FairValueAssetsLevel1ToLevel2TransfersAmount $ 0us-gaap_FairValueAssetsLevel1ToLevel2TransfersAmount
Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount 0us-gaap_FairValueLiabilitiesLevel1ToLevel2TransfersAmount 0us-gaap_FairValueLiabilitiesLevel1ToLevel2TransfersAmount
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount 0us-gaap_FairValueAssetsLevel2ToLevel1TransfersAmount 0us-gaap_FairValueAssetsLevel2ToLevel1TransfersAmount
Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount 0us-gaap_FairValueLiabilitiesLevel2ToLevel1TransfersAmount 0us-gaap_FairValueLiabilitiesLevel2ToLevel1TransfersAmount
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net 0us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersNet 0us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersNet
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net 0us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityTransfersNet 0us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityTransfersNet
Fuel derivatives:    
Derivative Asset, Fair Value, Gross Asset 1,360us-gaap_DerivativeFairValueOfDerivativeAsset [1] 503us-gaap_DerivativeFairValueOfDerivativeAsset [1]
Fuel derivatives:    
Derivative Liability, Fair Value, Gross Liability (2,409)us-gaap_DerivativeFairValueOfDerivativeLiability [1] (380)us-gaap_DerivativeFairValueOfDerivativeLiability [1]
Fair Value, Measurements, Recurring | Period end date    
Assets    
Treasury bills 1,450us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
1,570us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Interest rate derivatives (see Note 10) 13us-gaap_InterestRateDerivativeAssetsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
20us-gaap_InterestRateDerivativeAssetsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Fuel derivatives:    
Other available for sale securities 68us-gaap_OtherAssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
63us-gaap_OtherAssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Total assets 4,443us-gaap_AssetsFairValueDisclosureRecurring
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
3,757us-gaap_AssetsFairValueDisclosureRecurring
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Fuel derivatives:    
Interest rate derivatives (see Note 10) (61)us-gaap_InterestRateDerivativeLiabilitiesAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
(77)us-gaap_InterestRateDerivativeLiabilitiesAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Deferred Compensation (168)us-gaap_OtherLiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
(158)us-gaap_OtherLiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Total Liabilities (2,409)us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
(380)us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)    
Assets    
Treasury bills 1,450us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
1,570us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Interest rate derivatives (see Note 10) 0us-gaap_InterestRateDerivativeAssetsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
0us-gaap_InterestRateDerivativeAssetsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Fuel derivatives:    
Other available for sale securities 63us-gaap_OtherAssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
58us-gaap_OtherAssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Total assets 2,623us-gaap_AssetsFairValueDisclosureRecurring
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
2,620us-gaap_AssetsFairValueDisclosureRecurring
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Fuel derivatives:    
Interest rate derivatives (see Note 10) 0us-gaap_InterestRateDerivativeLiabilitiesAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
0us-gaap_InterestRateDerivativeLiabilitiesAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Deferred Compensation (168)us-gaap_OtherLiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
(158)us-gaap_OtherLiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)    
Assets    
Treasury bills 0us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
0us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Interest rate derivatives (see Note 10) 13us-gaap_InterestRateDerivativeAssetsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
20us-gaap_InterestRateDerivativeAssetsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Fuel derivatives:    
Other available for sale securities 0us-gaap_OtherAssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
0us-gaap_OtherAssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Total assets 896us-gaap_AssetsFairValueDisclosureRecurring
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
626us-gaap_AssetsFairValueDisclosureRecurring
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Fuel derivatives:    
Interest rate derivatives (see Note 10) (61)us-gaap_InterestRateDerivativeLiabilitiesAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
(77)us-gaap_InterestRateDerivativeLiabilitiesAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Deferred Compensation 0us-gaap_OtherLiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
0us-gaap_OtherLiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Total Liabilities (426)us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
(85)us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)    
Assets    
Treasury bills 0us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
0us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Interest rate derivatives (see Note 10) 0us-gaap_InterestRateDerivativeAssetsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
0us-gaap_InterestRateDerivativeAssetsAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Fuel derivatives:    
Other available for sale securities 5us-gaap_OtherAssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
5us-gaap_OtherAssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Total assets 924us-gaap_AssetsFairValueDisclosureRecurring
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
511us-gaap_AssetsFairValueDisclosureRecurring
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Fuel derivatives:    
Interest rate derivatives (see Note 10) 0us-gaap_InterestRateDerivativeLiabilitiesAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
0us-gaap_InterestRateDerivativeLiabilitiesAtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Deferred Compensation 0us-gaap_OtherLiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
0us-gaap_OtherLiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Total Liabilities (1,983)us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
(295)us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Cash Equivalents | Fair Value, Measurements, Recurring | Period end date    
Assets    
Cash equivalents 1,110us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CashEquivalentsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
[2] 992us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CashEquivalentsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
[2]
Cash Equivalents | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)    
Assets    
Cash equivalents 1,110us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CashEquivalentsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
[2] 992us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CashEquivalentsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
[2]
Cash Equivalents | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)    
Assets    
Cash equivalents 0us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CashEquivalentsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
[2] 0us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CashEquivalentsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
[2]
Cash Equivalents | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)    
Assets    
Cash equivalents 0us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CashEquivalentsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
[2] 0us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CashEquivalentsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
[2]
Commercial paper | Fair Value, Measurements, Recurring | Period end date    
Assets    
Cash equivalents 70us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CommercialPaperMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
280us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CommercialPaperMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Commercial paper | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)    
Assets    
Cash equivalents 0us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CommercialPaperMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
0us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CommercialPaperMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Commercial paper | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)    
Assets    
Cash equivalents 70us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CommercialPaperMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
280us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CommercialPaperMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Commercial paper | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)    
Assets    
Cash equivalents 0us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CommercialPaperMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
0us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CommercialPaperMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Certificates of deposit | Fair Value, Measurements, Recurring | Period end date    
Assets    
Cash equivalents 4us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CertificatesOfDepositMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
23us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CertificatesOfDepositMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Certificates of deposit | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)    
Assets    
Cash equivalents 0us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CertificatesOfDepositMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
0us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CertificatesOfDepositMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Certificates of deposit | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)    
Assets    
Cash equivalents 4us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CertificatesOfDepositMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
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Certificates of deposit | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)    
Assets    
Cash equivalents 0us-gaap_CashAndCashEquivalentsFairValueDisclosure
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Eurodollar Time Deposits | Fair Value, Measurements, Recurring | Period end date    
Assets    
Cash equivalents 98us-gaap_CashAndCashEquivalentsFairValueDisclosure
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Eurodollar Time Deposits | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)    
Assets    
Cash equivalents 0us-gaap_CashAndCashEquivalentsFairValueDisclosure
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Eurodollar Time Deposits | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)    
Assets    
Cash equivalents 98us-gaap_CashAndCashEquivalentsFairValueDisclosure
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Eurodollar Time Deposits | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)    
Assets    
Cash equivalents 0us-gaap_CashAndCashEquivalentsFairValueDisclosure
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Certificates of deposit | Fair Value, Measurements, Recurring | Period end date    
Assets    
Investments 256us-gaap_InvestmentsFairValueDisclosure
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Certificates of deposit | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)    
Assets    
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Certificates of deposit | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)    
Assets    
Investments 256us-gaap_InvestmentsFairValueDisclosure
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Certificates of deposit | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)    
Assets    
Investments 0us-gaap_InvestmentsFairValueDisclosure
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Auction rate securities | Fair Value, Measurements, Recurring | Period end date    
Assets    
Investments 27us-gaap_InvestmentsFairValueDisclosure
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Auction rate securities | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)    
Assets    
Investments 0us-gaap_InvestmentsFairValueDisclosure
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Auction rate securities | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)    
Assets    
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Auction rate securities | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)    
Assets    
Investments 27us-gaap_InvestmentsFairValueDisclosure
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[3]
Swap | Fair Value, Measurements, Recurring | Period end date    
Fuel derivatives:    
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[5]
Fuel derivatives:    
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[4]
Swap | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)    
Fuel derivatives:    
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Fuel derivatives:    
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[4]
Swap | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)    
Fuel derivatives:    
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[5]
Fuel derivatives:    
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[5]
Swap | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)    
Fuel derivatives:    
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Fuel derivatives:    
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[4]
Options Held | Fair Value, Measurements, Recurring | Period end date    
Fuel derivatives:    
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Fuel derivatives:    
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[4]  
Options Held | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)    
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[4]  
Options Held | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)    
Fuel derivatives:    
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[4]  
Options Held | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)    
Fuel derivatives:    
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[4] 9us-gaap_DerivativeLiabilityFairValueGrossAsset
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= us-gaap_OptionMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
[4]
Fuel derivatives:    
Derivative Asset, Fair Value, Gross Liability   (274)us-gaap_DerivativeAssetFairValueGrossLiability
/ us-gaap_DerivativeByNatureAxis
= us-gaap_OptionMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
[5]
Derivative Liability, Fair Value, Gross Liability $ (1,983)us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeByNatureAxis
= us-gaap_OptionMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
[4]  
[1] Represents the position of each trade before consideration of offsetting positions with each counterparty and does not include the impact of cash collateral deposits provided to or received from counterparties. See discussion of credit risk and collateral following in this Note.
[2] Cash equivalents are primarily composed of money market investments.
[3] Noncurrent investments are included in Other assets in the Consolidated Balance Sheet.
[4] In the Consolidated Balance Sheet amounts are presented as a net liability. See Note 10.
[5] In the Consolidated Balance Sheet amounts are presented as a net asset. See Note 10.