XML 100 R79.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Fair Value Measurements - Quantitative Information about Level 3 Fair Value (Details) - Option Model - Implied Volatility - Fuel derivatives | Dec. 31, 2019
--- | ---
2020 |
Quantitative Information About Level 3 [Line Items] |
Fair Value Measurement Range, Minimum | 13.00%
Fair Value Measurement Range, Maximum | 34.00%
2021 |
Quantitative Information About Level 3 [Line Items] |
Fair Value Measurement Range, Minimum | 17.00%
Fair Value Measurement Range, Maximum | 23.00%
2022 |
Quantitative Information About Level 3 [Line Items] |
Fair Value Measurement Range, Minimum | 17.00%
Fair Value Measurement Range, Maximum | 19.00%
Beyond 2022 |
Quantitative Information About Level 3 [Line Items] |
Fair Value Measurement Range, Minimum | 18.00%
Fair Value Measurement Range, Maximum | 19.00%

X
- Definition Maximum range used in level 3 fair value calculation + References No definition available. + Details
Name: | luv_FairValueMeasurementRangeMax
Namespace Prefix: | luv_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Minimum range used in level 3 fair value calculation + References No definition available. + Details
Name: | luv_FairValueMeasurementRangeMin
Namespace Prefix: | luv_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Quantitative information about Level 3 fair value measurements + References No definition available. + Details
Name: | luv_QuantitativeInformationAboutLevel3LineItems
Namespace Prefix: | luv_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | luv_PeriodAxis=luv_NextFiscalYearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | luv_FairValueValuationTechniqueAxis=luv_OptionModelMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | luv_UnobservableInputAxis=luv_ImpliedVolatilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | luv_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationAxis=us-gaap_CommodityContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | luv_PeriodAxis=luv_YearTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | luv_PeriodAxis=luv_YearThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | luv_PeriodAxis=luv_YearFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |