XML 61 R46.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Commitments and Contingencies - Airport Projects (Details) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2010 | Dec. 31, 2017
Airport Project [Line Items] |  |  |  |  |
Reimbursement for airport construction |  | $ 139 | $ 49 |  |
Assets constructed for others |  | 1,607 |  |  | $ 1,543
Assets constructed for others, net |  | 1,504 |  |  | 1,448
Construction obligation |  | 1,563 |  |  | 1,390
Fort Lauderdale-Hollywood International Airport |  |  |  |  |
Airport Project [Line Items] |  |  |  |  |
Total Expected Cost Of Airport Project |  | 333 |  |  |
Assets constructed for others | [1] | 282 |  |  | 258
Assets constructed for others, net | [1],[2] | 279 |  |  | 256
Construction obligation | [1],[3] | 281 |  |  | 258
Los Angeles World Airport Terminal 1 |  |  |  |  |
Airport Project [Line Items] |  |  |  |  |
Total Expected Cost Of Airport Project |  | 526 |  |  |
Total Expected Cost Of Airport Project Nonproprietary |  | 510 |  |  |
Remaining guaranteed obligation |  | 143 |  |  |
Assets constructed for others | [1] | 450 |  |  | 433
Assets constructed for others, net | [1],[2] | 432 |  |  | 417
Construction obligation | [1],[3] | 447 |  |  | 433
Los Angeles World Airport Terminal 1.5 |  |  |  |  |
Airport Project [Line Items] |  |  |  |  |
Total Expected Cost Of Airport Project |  | 479 |  |  |
Remaining guaranteed obligation |  | 46 |  |  |
Assets constructed for others | [1] | 42 |  |  | 31
Assets constructed for others, net | [1],[2] | 42 |  |  | 31
Construction obligation | [1],[3] | 42 |  |  | 31
Dallas Love Field Terminal |  |  |  |  |
Airport Project [Line Items] |  |  |  |  |
Assets constructed for others |  | 543 |  |  | 543
Assets constructed for others, net | [2] | 470 |  |  | 474
Construction obligation | [3] | 513 |  |  | 516
Municipal bonds issued |  |  |  | $ 456 |
Municipal bonds principal remaining |  | 424 |  |  |
Dallas Love Field Parking Garage |  |  |  |  |
Airport Project [Line Items] |  |  |  |  |
Assets constructed for others | [1] | 164 |  |  | 152
Assets constructed for others, net | [1],[2] | 164 |  |  | 152
Construction obligation | [1],[3] | 164 |  |  | 152
Houston Hobby Airport |  |  |  |  |
Airport Project [Line Items] |  |  |  |  |
Total Cost of Airport Project |  | 150 |  |  |
Reimbursement for airport construction |  | 116 |  |  |
Assets constructed for others |  | 126 |  |  | 126
Assets constructed for others, net | [2] | 117 |  |  | 118
Construction obligation | [3] | $ 116 |  |  | $ 0
[1] | Projects still in progress.
[2] | Net of accumulated depreciation.
[3] | Construction obligation will be reduced through future facility rent payments. These future payments are not fixed per the lease agreement, but are variable and fluctuate based on various market and other factors outside the control of the Company.

X
- Definition [Line Items] for Airport Project [Table] + References No definition available. + Details
Name: | luv_AirportProjectLineItems
Namespace Prefix: | luv_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The aggregate costs related to airport construction projects recorded as an asset. + References No definition available. + Details
Name: | luv_AssetsConstructedForOthers
Namespace Prefix: | luv_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Assets Constructed For Others Net + References No definition available. + Details
Name: | luv_AssetsConstructedForOthersNet
Namespace Prefix: | luv_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Construction Obligation, Noncurrent + References No definition available. + Details
Name: | luv_ConstructionObligationNoncurrent
Namespace Prefix: | luv_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Long-term debt securities issued by state, city or local governments or the agencies operated by state, city or local governments. + References No definition available. + Details
Name: | luv_MunicipalBondsIssued
Namespace Prefix: | luv_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Municipal Bonds Principal Remaining + References No definition available. + Details
Name: | luv_MunicipalBondsPrincipalRemaining
Namespace Prefix: | luv_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Cash inflow related to the reimbursement for airport construction. + References No definition available. + Details
Name: | luv_Reimbursementforairportconstruction
Namespace Prefix: | luv_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Remaining guaranteed obligation + References No definition available. + Details
Name: | luv_Remainingguaranteedobligation
Namespace Prefix: | luv_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Tota lCos tof Airport Project + References No definition available. + Details
Name: | luv_TotalCostofAirportProject
Namespace Prefix: | luv_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The total expected cost of the airport modernization project for the city. + References No definition available. + Details
Name: | luv_TotalExpectedCostOfAirportProject
Namespace Prefix: | luv_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Total Expected Cost Of Airport Project Nonproprietary + References No definition available. + Details
Name: | luv_TotalExpectedCostOfAirportProjectNonproprietary
Namespace Prefix: | luv_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | luv_AirportProjectAxis=luv_FortLauderdaleHollywoodInternationalAirportMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | luv_AirportProjectAxis=luv_LosAngelesWorldAirportMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | luv_AirportProjectAxis=luv_LosAngelesWorldAirportTerminal1.5Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | luv_AirportProjectAxis=luv_DALMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | luv_AirportProjectAxis=luv_DALGarageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | luv_AirportProjectAxis=luv_HOUMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |