XML 59 R48.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Fair Value Measurements - Quantative Information about Level 3 Fair Value (Details) - Option Model - Implied Volatility - Fuel derivatives | Jun. 30, 2018
--- | ---
Third quarter 2018 |
Quantitative Information About Level 3 |
Fair Value Measurement Range, Minimum | 15.00%
Fair Value Measurement Range, Maximum | 30.00%
Fourth quarter 2018 |
Quantitative Information About Level 3 |
Fair Value Measurement Range, Minimum | 22.00%
Fair Value Measurement Range, Maximum | 31.00%
2019 |
Quantitative Information About Level 3 |
Fair Value Measurement Range, Minimum | 22.00%
Fair Value Measurement Range, Maximum | 28.00%
2020 |
Quantitative Information About Level 3 |
Fair Value Measurement Range, Minimum | 21.00%
Fair Value Measurement Range, Maximum | 26.00%
2021 |
Quantitative Information About Level 3 |
Fair Value Measurement Range, Minimum | 20.00%
Fair Value Measurement Range, Maximum | 22.00%
2022 |
Quantitative Information About Level 3 |
Fair Value Measurement Range, Minimum | 19.00%
Fair Value Measurement Range, Maximum | 20.00%

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_ThirdQuarterCYMember
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_FourthQuarterCYMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | luv_PeriodAxis=luv_NextYearMember
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: |