Accordian Feature on Short-term Debt

No definition available.

Name:	luv_AccordianFeatureonShorttermDebt
Namespace Prefix:	luv_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Aircraft Subject to Secure Debt Transactions

+ References

No definition available.

+ Details

Name:	luv_AircraftSubjectToSecureDebtTransactions
Namespace Prefix:	luv_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Convertible Debt Conversion Terms Measurement Period Trading Price Threshold Percentage

+ References

No definition available.

+ Details

Name:	luv_ConvertibleDebtConversionTermsMeasurementPeriodTradingPriceThresholdPercentage
Namespace Prefix:	luv_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Convertible Debt Conversion Terms Percentage of Sales Price Exceeding Conversion Price

+ References

No definition available.

+ Details

Name:	luv_ConvertibleDebtConversionTermsPercentageOfSalesPriceExceedingConversionPrice
Namespace Prefix:	luv_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Face Amount, Net of Fees

+ References

No definition available.

+ Details

Name:	luv_DebtInstrumentFaceAmountNetOfFees
Namespace Prefix:	luv_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Instrument Net of fees

+ References

No definition available.

+ Details

Name:	luv_DebtInstrumentNetOfFees
Namespace Prefix:	luv_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Instrument Underwriters Option to Purchase

+ References

No definition available.

+ Details

Name:	luv_DebtInstrumentUnderwritersOptionToPurchase
Namespace Prefix:	luv_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of Mortgages on Secured Aircraft

+ References

No definition available.

+ Details

Name:	luv_NumberofMortgagesonSecuredAircraft
Namespace Prefix:	luv_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Required Minimum Liquidity Level at All Times After March 31, 2021

+ References

No definition available.

+ Details

Name:	luv_RequiredMinimumLiquidityLevelatAllTimesAfterMarch312021
Namespace Prefix:	luv_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Sale Leaseback Cash Proceeds Investing

+ References

No definition available.

+ Details

Name:	luv_SaleLeasebackCashProceedsInvesting
Namespace Prefix:	luv_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Adjustment to additional paid in capital resulting from the recognition of convertible debt instruments as two separate components - a debt component and an equity component. This bifurcation may result in a basis difference associated with the liability component that represents a temporary difference for purposes of applying accounting for income taxes. The initial recognition of deferred taxes for the tax effect of that temporary difference is as an adjustment to additional paid in capital.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 25
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=51819886&loc=SL6014347-161799

+ Details

Name:	us-gaap_AdjustmentsToAdditionalPaidInCapitalEquityComponentOfConvertibleDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28541-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

+ Details

Name:	us-gaap_AmortizationOfDebtDiscountPremium
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of amortization expense attributable to debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(8))
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28555-108399

+ Details

Name:	us-gaap_AmortizationOfFinancingCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

Name:	us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Face amount or stated value per share of common stock.

+ References

+ Details

Name:	us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of short-term and long-term debt and lease obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13,16)
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

+ Details

Name:	us-gaap_DebtAndCapitalLeaseObligations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Discussion of whether the debt instrument is secured or unsecured, and, if secured, a description of the collateral and guarantees required or provided.

+ References

+ Details

Name:	us-gaap_DebtInstrumentCollateral
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870

+ Details

Name:	us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031898-161870

+ Details

Name:	us-gaap_DebtInstrumentConvertibleConversionPrice1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(5))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

Name:	us-gaap_DebtInstrumentConvertibleConversionRatio1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6036836-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

Name:	us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28555-108399

+ Details

Name:	us-gaap_DeferredFinanceCostsGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Present value of lessee's discounted obligation for lease payments from finance lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918701-209980

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977

+ Details

Name:	us-gaap_FinanceLeaseLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value of the amount outstanding under the credit facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611

+ Details

Name:	us-gaap_LineOfCreditFacilityFairValueOfAmountOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt and lease obligation, classified as noncurrent.

+ References

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt and lease obligation, classified as current.

+ References

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Principal amount of long-term debt and capital lease obligation maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalAfterYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Principal amount of long-term debt and capital lease obligation maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalInYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Principal amount of long-term debt and capital lease obligation maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalInYearFour
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Principal amount of long-term debt and capital lease obligation maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalInYearThree
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Principal amount of long-term debt and capital lease obligation maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalInYearTwo
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Principal amount of long-term debt and capital lease obligation maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligationsRepaymentsOfPrincipalInNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The sum of the fair values, as of the date of each statement of financial position presented, of securities that are restricted as collateral for the payment of related debt obligations, primarily secured borrowings and repurchase agreements, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66007379&loc=d3e113888-111728

+ Details

Name:	us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedAsCollateralAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash inflow from the additional capital contribution to the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfCommonStock
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of gain (loss) on sale and leaseback transaction from transfer of asset accounted for as sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 40
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121606570&loc=SL77919786-209982

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 55
-Paragraph 53
-URI http://asc.fasb.org/extlink&oid=121568110&loc=SL77918982-209971

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918686-209980

+ Details

Name:	us-gaap_SaleAndLeasebackTransactionGainLossNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

A description of the transaction and the assets involved in the sale of property to another party and the lease of the property back to the seller.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121606570&loc=SL77919784-209982

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 40
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121606570&loc=SL77919786-209982

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121586228&loc=d3e50796-112755

+ Details

Name:	us-gaap_SaleLeasebackTransactionDescriptionOfAssetS
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

A description of the terms of the lease(s) related to the assets being leased-back in connection with the transaction involving the sale of property to another party and the lease of the property back to the seller.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121586228&loc=d3e50796-112755

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 40
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121606570&loc=SL77919786-209982

+ Details

Name:	us-gaap_SaleLeasebackTransactionLeaseTerms
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_SecuredDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Per share or per unit amount of equity securities issued.

+ References

No definition available.

+ Details

Name:	us-gaap_SharesIssuedPricePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of new stock issued during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

+ Details

Name:	us-gaap_UnamortizedDebtIssuanceExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=luv_LUVCommonStockWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=srt_B737800Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=srt_B737MaxMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_Amended364DayTermLoanCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_A1250ConvertibleSeniorNotesDue2025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_A4750UnsecuredNotesDue2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_A5250UnsecuredNotesDue2025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_A5125UnsecuredNotesDue2027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_SecuredDebtBySixAircraftMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_A364DayTermLoanCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_SecuredDebtByFourAircraftMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_UnsecuredSeniorNotesDue2020Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_UnsecuredSeniorNotesDue2022Domain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_TotalPassThroughCertificatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_UnsecuredSeniorNotesDue2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_TermLoanAgreementDue2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_UnsecuredSeniorNotesDue2027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=luv_TreasuryRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_Debenturesdue2027Domain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_TermLoanAgreementDue2020Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_PassThroughCertificatesSeriesAlphaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_PassThroughCertificatesSeriesBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_NotesPayableAircraftFloatingRateThrough2020Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_SubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_ConvertibleDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_UnsecuredSeniorNotesDue2030Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_A5125NotesDue2027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_A10PayrollSupportProgramLoanDue2030Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_A345UnsecuredSeniorNotesDue2027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_Total5125NotesDue2027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_EnhancedEquipmentTrustCertificateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_NotesPayableToBanksMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_TermLoanAgreementDue2025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_TermLoanAgreementDue2028Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=luv_A165TermLoanAgreementPayableThrough2028Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	luv_DebtDescriptionAxis=luv_Amended364DayTermLoanCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=luv_NewYorkFedBankRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	luv_DebtDescriptionAxis=luv_AccordianFeaturetoAmended364DayTermLoanCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	luv_DebtDescriptionAxis=luv_SecuredDebtBySixAircraftMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	luv_ExistingRevolvingCreditFacilityAxis=luv_ExistingRevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=luv_A364DayTermLoanCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

FINANCING ACTIVITIES (Details) $ / shares in Units, shares in Millions		3 Months Ended	12 Months Ended
	May 01, 2020 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) aircraft Mortgages $ / shares	Dec. 31, 2020 USD ($) aircraft Mortgages $ / shares	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2018 USD ($)	Jul. 31, 2020 USD ($)	Jun. 08, 2020 USD ($)	May 04, 2020 USD ($)	Apr. 24, 2020 USD ($)	Apr. 09, 2020 $ / shares	Apr. 01, 2020 USD ($)	Mar. 30, 2020 USD ($)
Debt Instrument [Line Items]
Required Minimum Liquidity Level at All Times After March 31, 2021		$ 1,500,000,000	$ 1,500,000,000
Shares Issued, Price Per Share \| $ / shares	$ 28.50
Stock Issued During Period, Shares, New Issues \| shares	80.5
Common stock, par value (in dollars per share) \| $ / shares	$ 1.00	$ 1.00	$ 1.00	$ 1.00
Gain on sale-leaseback transactions			$ (222,000,000)	$ 0	$ 0
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt			(392,000,000)
Proceeds from issuance of long-term debt			5,622,000,000	0	0
Issuance of common stock			2,294,000,000	0	0
Proceeds from sale-leaseback transactions			815,000,000	0	$ 0
Amortization of Debt Discount (Premium)			48,000,000
Amortization of Debt Issuance Costs			5,000,000
Total lease obligations		$ 542,000,000	542,000,000	627,000,000
Debt and Lease Obligation		10,381,000,000	10,381,000,000	2,678,000,000
Less current maturities		220,000,000	220,000,000	819,000,000
Less debt discount and issuance costs		50,000,000	50,000,000	13,000,000
Long-term debt less current maturities		10,111,000,000	10,111,000,000	1,846,000,000
Letters of Credit Outstanding, Amount		138,000,000	138,000,000
Net book value of assets pledged as collateral for the Company's secured borrowings, primarily aircraft and engines		2,100,000,000	2,100,000,000
Aggregate annual principal maturities of debt and finance leases (not including amounts associated with interest on finance leases) - 2021		220,000,000	220,000,000
Aggregate annual principal maturities of debt and finance leases (not including amounts associated with interest on finance leases) - 2022		524,000,000	524,000,000
Aggregate annual principal maturities of debt and finance leases (not including amounts associated with interest on finance leases) - 2023		1,400,000,000	1,400,000,000
Aggregate annual principal maturities of debt and finance leases (not including amounts associated with interest on finance leases) - 2024		152,000,000	152,000,000
Aggregate annual principal maturities of debt and finance leases (not including amounts associated with interest on finance leases) - 2025		4,000,000,000.0	4,000,000,000.0
Aggregate annual principal maturities of debt and finance leases (not including amounts associated with interest on finance leases) - Thereafter		$ 4,400,000,000	$ 4,400,000,000
LUV Common Stock Warrants
Debt Instrument [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights \| $ / shares										$ 36.47
B-737-800
Debt Instrument [Line Items]
Sale Leaseback Transaction, Description of Asset(s)			ten
Gain on sale-leaseback transactions			$ 153,000,000
Sale Leaseback Transaction, Lease Terms			ten years
Proceeds from sale-leaseback transactions			$ 405,000,000
B-737-8 Max
Debt Instrument [Line Items]
Sale Leaseback Transaction, Description of Asset(s)			ten
Gain on sale-leaseback transactions			$ 69,000,000
Sale Leaseback Transaction, Lease Terms			13 years
Proceeds from sale-leaseback transactions			$ 410,000,000
Amended 364-Day Term Loan Credit Facility
Debt Instrument [Line Items]
Face amount of debt											$ 2,300,000,000
1.250 Convertible Senior Notes due 2025
Debt Instrument [Line Items]
Debt Instrument, Convertible, Conversion Price \| $ / shares		$ 38.48	$ 38.48
Debt Instrument, Convertible, Conversion Ratio		25.9909
Debt Instrument, Redemption Price, Percentage		100.00%
Convertible Debt Conversion Terms Percentage of Sales Price Exceeding Conversion Price			130.00%
Convertible Debt Conversion Terms Measurement Period Trading Price Threshold Percentage			98.00%
Interest rate stated in the debt agreement (in hundredths)	1.25%
4.750 Unsecured Notes due 2023
Debt Instrument [Line Items]
Face amount of debt		$ 1,250,000,000	$ 1,250,000,000				$ 500,000,000	$ 750,000,000
Interest rate stated in the debt agreement (in hundredths)								4.75%
5.250 Unsecured Notes due 2025
Debt Instrument [Line Items]
Face amount of debt		$ 1,550,000,000	$ 1,550,000,000					$ 1,250,000,000
5.125 Unsecured Notes due 2027 [Member]
Debt Instrument [Line Items]
Face amount of debt							$ 1,300,000,000
Secured Debt by Six Aircraft [Member]
Debt Instrument [Line Items]
Aircraft Subject to Secure Debt Transactions \| aircraft		6	6
Face amount of debt		$ 197,000,000	$ 197,000,000
Debt Instrument, Face Amount, Net of Fees		190,000,000	190,000,000
364-Day Term Loan Credit Facility
Debt Instrument [Line Items]
Face amount of debt		$ 1,000,000,000.0	$ 1,000,000,000.0
Secured Debt by Four Aircraft [Member]
Debt Instrument [Line Items]
Aircraft Subject to Secure Debt Transactions \| aircraft		4	4
Face amount of debt		$ 125,000,000	$ 125,000,000
Debt Instrument Net of fees		$ 121,000,000	$ 121,000,000
Secured Debt by Four Aircraft [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		1.40%	1.40%
2.65% Notes due 2020
Debt Instrument [Line Items]
Face amount of debt		$ 500,000,000	$ 500,000,000
Interest rate stated in the debt agreement (in hundredths)		2.65%	2.65%
Unsecured Senior Notes Due 2022 - 2.75%
Debt Instrument [Line Items]
Face amount of debt		$ 300,000,000	$ 300,000,000
Interest rate stated in the debt agreement (in hundredths)		2.75%	2.75%
Total Pass Through Certificates [Member]
Debt Instrument [Line Items]
Face amount of debt		$ 500,000,000	$ 500,000,000
Number of mortgages on secured aircraft \| Mortgages		16	16
Total Pass Through Certificates [Member] \| Interest rate derivatives \| Cash Flow Hedging
Debt Instrument [Line Items]
Notional amount		$ 20,000,000	$ 20,000,000
Notional amount		20,000,000	20,000,000
Unsecured Senior Notes Due 2026 - 3.00%
Debt Instrument [Line Items]
Face amount of debt		$ 300,000,000	$ 300,000,000
Interest rate stated in the debt agreement (in hundredths)		3.00%	3.00%
Term Loan Agreement payable through 2026 - 1.34%
Debt Instrument [Line Items]
Number of mortgages on secured aircraft \| Mortgages		7	7
Interest rate stated in the debt agreement (in hundredths)		1.34%	1.34%
Term Loan Agreement payable through 2026 - 1.34% \| Maximum
Debt Instrument [Line Items]
Face amount of debt		$ 215,000,000	$ 215,000,000
Term Loan Agreement payable through 2026 - 1.34% \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Spread on variable rate			1.10%
Unsecured Senior Notes Due 2027 - 3.45%
Debt Instrument [Line Items]
Face amount of debt		$ 300,000,000	$ 300,000,000
Interest rate stated in the debt agreement (in hundredths)		3.45%	3.45%
Unsecured Senior Notes Due 2027 - 3.45% \| Treasury Rate
Debt Instrument [Line Items]
Spread on variable rate			20.00%
7.375% Debentures due 2027
Debt Instrument [Line Items]
Face amount of debt		$ 100,000,000	$ 100,000,000
Interest rate stated in the debt agreement (in hundredths)		7.375%	7.375%
Term Loan Agreement payable through May 2020 - 5.223%
Debt Instrument [Line Items]
Secured Debt		$ 0	$ 0	$ 134,000,000
Face amount of debt		$ 600,000,000	$ 600,000,000
Number of mortgages on secured aircraft \| Mortgages		21	21
Interest rate stated in the debt agreement (in hundredths)		5.223%	5.223%	5.223%
Term Loan Agreement payable through May 2020 - 5.223% \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Spread on variable rate			0.95%
Pass Through Certificates Series A
Debt Instrument [Line Items]
Face amount of debt		$ 412,000,000	$ 412,000,000
Interest rate stated in the debt agreement (in hundredths)		6.15%	6.15%
Pass Through Certificates Series B
Debt Instrument [Line Items]
Face amount of debt		$ 88,000,000	$ 88,000,000
Interest rate stated in the debt agreement (in hundredths)		6.65%	6.65%
737 Aircraft Notes payable through 2020 \| AirTran Airways
Debt Instrument [Line Items]
Secured Debt		$ 0	$ 0	$ 20,000,000
1.25% convertible notes (a) \| 1.250 Convertible Senior Notes due 2025
Debt Instrument [Line Items]
Debt Instrument Underwriters Option to Purchase	$ 300,000,000
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt			$ (11,000,000)
Debt Instrument, Interest Rate, Effective Percentage		5.20%	5.20%
Face amount of debt	$ 2,300,000,000	$ 1,900,000,000	$ 1,900,000,000
Debt Instrument, Convertible, Carrying Amount of Equity Component		403,000,000	403,000,000
Unamortized Debt Issuance Expense		62,000,000	62,000,000
Interest rate stated in the debt agreement (in hundredths)	1.25%
Carrying amount of debt		$ 1,945,000,000	$ 1,945,000,000	0
Unsecured Debt \| 2.625% Notes due 2030
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		2.625%	2.625%
Carrying amount of debt		$ 500,000,000	$ 500,000,000	0
Unsecured Debt \| 1.250 Convertible Senior Notes due 2025
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		1.25%	1.25%
Unsecured Debt \| 4.750 Unsecured Notes due 2023
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		4.75%	4.75%
Carrying amount of debt		$ 1,250,000,000	$ 1,250,000,000	0
Unsecured Debt \| 5.250 Unsecured Notes due 2025
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		5.25%	5.25%
Carrying amount of debt		$ 1,550,000,000	$ 1,550,000,000	0		$ 300,000,000
Unsecured Debt \| 5.125 Notes due 2027
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		5.125%	5.125%
Carrying amount of debt		$ 2,000,000,000	$ 2,000,000,000	0		700,000,000
Unsecured Debt \| 2.65% Notes due 2020
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		2.65%	2.65%
Carrying amount of debt		$ 0	$ 0	500,000,000
Unsecured Debt \| Unsecured Senior Notes Due 2022 - 2.75%
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		2.75%	2.75%
Carrying amount of debt		$ 300,000,000	$ 300,000,000	300,000,000
Unsecured Debt \| Unsecured Senior Notes Due 2026 - 3.00%
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		3.00%	3.00%
Carrying amount of debt		$ 300,000,000	$ 300,000,000	300,000,000
Unsecured Debt \| Unsecured Senior Notes Due 2027 - 3.45%
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		3.45%	3.45%
Unsecured Debt \| 7.375% Debentures due 2027
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		7.375%	7.375%
Carrying amount of debt		$ 119,000,000	$ 119,000,000	122,000,000
Unsecured Debt \| 1.0 Payroll Support Program Loan due 2030
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		1.00%	1.00%
Carrying amount of debt		$ 976,000,000	$ 976,000,000	0
Unsecured Debt \| 3.45 Unsecured Senior Notes due 2027 [Member]
Debt Instrument [Line Items]
Carrying amount of debt		$ 300,000,000	$ 300,000,000	300,000,000
Unsecured Debt \| Total 5.125 Notes due 2027 [Member]
Debt Instrument [Line Items]
Carrying amount of debt						$ 2,000,000,000.0
Enhanced Equipment Trust Certificate \| Total Pass Through Certificates [Member]
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		6.24%	6.24%
Carrying amount of debt		$ 137,000,000	$ 137,000,000	197,000,000
Notes Payable to Banks \| Term Loan Agreement Due 2025 [Member]
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		1.65%	1.65%
Carrying amount of debt		$ 119,000,000	$ 119,000,000	0
Notes Payable to Banks \| Term Loan Agreement payable through 2026 - 1.34%
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		1.34%	1.34%
Carrying amount of debt		$ 159,000,000	$ 159,000,000	178,000,000
Notes Payable to Banks \| Term Loan Agreement Due 2028 [Member]
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		1.65%	1.65%
Notes Payable to Banks \| 1.65 Term Loan Agreement Payable through 2028 [Member]
Debt Instrument [Line Items]
Carrying amount of debt		$ 184,000,000	$ 184,000,000	$ 0
Revolving Credit Facility
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 1,500,000,000	$ 1,500,000,000
Amended 364-Day Term Loan Credit Facility
Debt Instrument [Line Items]
Debt Instrument, Collateral			73
Amended 364-Day Term Loan Credit Facility \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		1.00%	1.00%
Amended 364-Day Term Loan Credit Facility \| London Interbank Offered Rate (LIBOR) [Member] \| Minimum
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		1.00%	1.00%
Amended 364-Day Term Loan Credit Facility \| New York Fed Bank Rate [Member]
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		0.50%	0.50%
Amended 364-Day Term Loan Credit Facility \| Base Rate [Member] \| Minimum
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		1.00%	1.00%
Accordian Feature to Amended 364-Day Term Loan Credit Facility [Member] \| Amended 364-Day Term Loan Credit Facility
Debt Instrument [Line Items]
Accordian Feature on Short-term Debt												$ 417,000,000
Face amount of debt									$ 350,000,000
Secured Debt by Six Aircraft [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)		1.40%	1.40%
Existing Revolving Credit Facility [Member] \| Revolving Credit Facility
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity		$ 1,000,000,000.0	$ 1,000,000,000.0
Revolving Credit Facility, Fair Value Amount Outstanding		0	0
Existing Revolving Credit Facility [Member] \| 364-Day Term Loan Credit Facility
Debt Instrument [Line Items]
Face amount of debt		$ 1,000,000,000.0	$ 1,000,000,000.0