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Financial Derivative Instruments - Fair Values of Fuel Derivatives Amounts Posted as Collateral (Details) (Fuel derivatives, USD $)
In Millions, unless otherwise specified
Mar. 31, 2015
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Derivative Liability, Fair Value, Amount Not Offset Against Collateral $ (1,066)us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral
Cash collateral held by CP (283)us-gaap_CollateralAlreadyPostedAggregateFairValue
Aircraft collateral pledged to CP (302)luv_AircraftCollateralPledgedAggregateFairValue
Letters of credit (LC) (75)luv_LettersofCreditCollateralPledgedAggregateFairValue
Counterparty A  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Derivative Liability, Fair Value, Amount Not Offset Against Collateral (424)us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Cash collateral held by CP (150)us-gaap_CollateralAlreadyPostedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Aircraft collateral pledged to CP (188)luv_AircraftCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Letters of credit (LC) 0luv_LettersofCreditCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Counterparty B  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Derivative Liability, Fair Value, Amount Not Offset Against Collateral (142)us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Cash collateral held by CP (50)us-gaap_CollateralAlreadyPostedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Aircraft collateral pledged to CP (43)luv_AircraftCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Letters of credit (LC) 0luv_LettersofCreditCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Counterparty C  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Derivative Liability, Fair Value, Amount Not Offset Against Collateral (127)us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral
/ luv_CounterpartyAxis
= luv_CounterpartyCMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Cash collateral held by CP (57)us-gaap_CollateralAlreadyPostedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyCMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Aircraft collateral pledged to CP 0luv_AircraftCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyCMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Letters of credit (LC) 0luv_LettersofCreditCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyCMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Counterparty D  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Derivative Liability, Fair Value, Amount Not Offset Against Collateral (211)us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Cash collateral held by CP 0us-gaap_CollateralAlreadyPostedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Aircraft collateral pledged to CP (71)luv_AircraftCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Letters of credit (LC) (75)luv_LettersofCreditCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Counterparty E  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Derivative Liability, Fair Value, Amount Not Offset Against Collateral (65)us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral
/ luv_CounterpartyAxis
= luv_CounterpartyEMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Cash collateral held by CP (1)us-gaap_CollateralAlreadyPostedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyEMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Aircraft collateral pledged to CP 0luv_AircraftCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyEMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Letters of credit (LC) 0luv_LettersofCreditCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyEMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Counterparty F  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Derivative Liability, Fair Value, Amount Not Offset Against Collateral (68)us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral
/ luv_CounterpartyAxis
= luv_CounterpartyFMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Cash collateral held by CP (25)us-gaap_CollateralAlreadyPostedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyFMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Aircraft collateral pledged to CP 0luv_AircraftCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyFMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Letters of credit (LC) 0luv_LettersofCreditCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyFMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
Counterparty Other  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Derivative Liability, Fair Value, Amount Not Offset Against Collateral (29)us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral
/ luv_CounterpartyAxis
= luv_CounterpartyOtherMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember		 [1]
Cash collateral held by CP 0us-gaap_CollateralAlreadyPostedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyOtherMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember		 [1]
Aircraft collateral pledged to CP 0luv_AircraftCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyOtherMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember		 [1]
Letters of credit (LC) 0luv_LettersofCreditCollateralPledgedAggregateFairValue
/ luv_CounterpartyAxis
= luv_CounterpartyOtherMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember		 [1]
Minimum | Counterparty A  
If credit rating is investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 (50)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative levels at which cash is provided to CP Threshold 2 (600)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichCashIsProvidedThreshold2
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative level at which cash is received from CP 50luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsReceived
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP (200)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichAircraftOrCashCollateralIsPledged
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember		 [2]
If credit rating is non-investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 0luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative levels at which cash is provided to CP Threshold 2 (600)luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsProvidedThreshold2
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative level at which cash is received from CP    [3]
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP (200)luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelsatWhichAircraftOrCashcollateralIsPledged
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Minimum | Counterparty B  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Option to substitute LC for aircraft (100)luv_FairValueOfFuelDerivativeLevelsInWhichLettersOfCreditMayBeSubstitutedForAircraft
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember		 [4]
Option to substitute LC for cash Threshold 1 (500)luv_FairValueOfFuelDerivativeLevelsInWhichLettersOfCreditMayBeSubstitutedForCashThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
If credit rating is investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 (50)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative levels at which cash is provided to CP Threshold 2 (500)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichCashIsProvidedThreshold2
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative level at which cash is received from CP 150luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsReceived
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP (100)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichAircraftOrCashCollateralIsPledged
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
If credit rating is non-investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 0luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative levels at which cash is provided to CP Threshold 2 (500)luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsProvidedThreshold2
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative level at which cash is received from CP    [3]
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP (100)luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelsatWhichAircraftOrCashcollateralIsPledged
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Minimum | Counterparty C  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Option to substitute LC for cash Threshold 1 (100)luv_FairValueOfFuelDerivativeLevelsInWhichLettersOfCreditMayBeSubstitutedForCashThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyCMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember		 [5]
If credit rating is investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 (75)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyCMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative level at which cash is received from CP 175luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsReceived
/ luv_CounterpartyAxis
= luv_CounterpartyCMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember		 [6]
If credit rating is non-investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1    [3]
Fair value of fuel derivative level at which cash is received from CP    [3]
Minimum | Counterparty D  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Option to substitute LC for aircraft (150)luv_FairValueOfFuelDerivativeLevelsInWhichLettersOfCreditMayBeSubstitutedForAircraft
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember		 [4]
Option to substitute LC for cash Threshold 1 (75)luv_FairValueOfFuelDerivativeLevelsInWhichLettersOfCreditMayBeSubstitutedForCashThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember		 [4]
Option to substitute LC for cash Threshold 2 (550)luv_FairValueOfFuelDerivativeLevelsInWhichLettersOfCreditMayBeSubstitutedForCashThreshold2
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember		 [4]
If credit rating is investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 (75)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative levels at which cash is provided to CP Threshold 2 (550)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichCashIsProvidedThreshold2
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative level at which cash is received from CP 200luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsReceived
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP (150)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichAircraftOrCashCollateralIsPledged
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember		 [4]
If credit rating is non-investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 0luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative levels at which cash is provided to CP Threshold 2 (550)luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsProvidedThreshold2
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative level at which cash is received from CP    [3]
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP (150)luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelsatWhichAircraftOrCashcollateralIsPledged
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Minimum | Counterparty E  
If credit rating is investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 (65)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyEMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative level at which cash is received from CP 30luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsReceived
/ luv_CounterpartyAxis
= luv_CounterpartyEMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
If credit rating is non-investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1    [3]
Fair value of fuel derivative level at which cash is received from CP    [3]
Minimum | Counterparty F  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Option to substitute LC for cash Threshold 1    [7]
If credit rating is investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 (50)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyFMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Fair value of fuel derivative level at which cash is received from CP 50luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsReceived
/ luv_CounterpartyAxis
= luv_CounterpartyFMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
If credit rating is non-investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1    [3]
Fair value of fuel derivative level at which cash is received from CP    [3]
Maximum | Counterparty A  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Option to substitute LC for aircraft (400)luv_FairValueOfFuelDerivativeLevelsInWhichLettersOfCreditMayBeSubstitutedForAircraft
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		 [8]
If credit rating is investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 (200)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP (600)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichAircraftOrCashCollateralIsPledged
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		 [2]
If credit rating is non-investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 (200)luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP (600)luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelsatWhichAircraftOrCashcollateralIsPledged
/ luv_CounterpartyAxis
= luv_CounterpartyAlphaMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Maximum | Counterparty B  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Option to substitute LC for aircraft (500)luv_FairValueOfFuelDerivativeLevelsInWhichLettersOfCreditMayBeSubstitutedForAircraft
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		 [4]
If credit rating is investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 (100)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP (500)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichAircraftOrCashCollateralIsPledged
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		 [4]
If credit rating is non-investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 (100)luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP (500)luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelsatWhichAircraftOrCashcollateralIsPledged
/ luv_CounterpartyAxis
= luv_CounterpartyBMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Maximum | Counterparty C  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Option to substitute LC for cash Threshold 1 (150)luv_FairValueOfFuelDerivativeLevelsInWhichLettersOfCreditMayBeSubstitutedForCashThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyCMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		 [5]
Maximum | Counterparty D  
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]  
Option to substitute LC for aircraft (550)luv_FairValueOfFuelDerivativeLevelsInWhichLettersOfCreditMayBeSubstitutedForAircraft
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		 [4]
Option to substitute LC for cash Threshold 1 (150)luv_FairValueOfFuelDerivativeLevelsInWhichLettersOfCreditMayBeSubstitutedForCashThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		 [4]
If credit rating is investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 (150)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP (550)luv_InvestmentGradeRatingFairValueOfFuelDerivativeLevelsInWhichAircraftOrCashCollateralIsPledged
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		 [4]
If credit rating is non-investment grade, fair value of fuel derivative level at which:  
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1 (150)luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelInWhichCashIsProvidedThreshold1
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP $ (550)luv_NonInvestmentGradeRatingFairValueOfFuelDerivativeLevelsatWhichAircraftOrCashcollateralIsPledged
/ luv_CounterpartyAxis
= luv_CounterpartyDMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
[1] Individual counterparties with fair value of fuel derivatives <$20 million.
[2] The Company has the option of providing cash or pledging aircraft as collateral.
[3] Cash collateral is provided at 100 percent of fair value of fuel derivative contracts.
[4] The Company has the option of providing cash, letters of credit, or pledging aircraft as collateral.
[5] The Company has the option of providing cash or letters of credit as collateral.
[6] Thresholds may vary based on changes in credit ratings within investment grade.
[7] The Company has the option to substitute letters of credit for 100 percent of cash collateral requirement.
[8] The Company has the option of providing letters of credit in addition to aircraft collateral if the appraised value of the aircraft does not meet the collateral requirements.