XML 64 R49.htm IDEA: XBRL DOCUMENT v3.8.0.1

Fair Value Measurements - Quantative Information about Level 3 Fair Value (Details) - Option Model - Implied Volatility - Fuel derivatives	Mar. 31, 2018
Second quarter 2018
Quantitative Information About Level 3
Fair Value Measurement Range, Minimum	14.00%
Fair Value Measurement Range, Maximum	31.00%
Third quarter 2018
Quantitative Information About Level 3
Fair Value Measurement Range, Minimum	21.00%
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	29.00%
2019
Quantitative Information About Level 3
Fair Value Measurement Range, Minimum	21.00%
Fair Value Measurement Range, Maximum	26.00%
2020
Quantitative Information About Level 3
Fair Value Measurement Range, Minimum	20.00%
Fair Value Measurement Range, Maximum	23.00%
2021
Quantitative Information About Level 3
Fair Value Measurement Range, Minimum	19.00%
Fair Value Measurement Range, Maximum	20.00%
2022
Quantitative Information About Level 3
Fair Value Measurement Range, Minimum	19.00%
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_SecondQuarterCYMember
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_ThirdQuarterCYMember
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: