XML 83 R67.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Fuel and oil | $ 3,940 | $ 3,647 | $ 3,616
Interest Expense | 114 | 122 | 121
Balance at end of period | 12 | (323) |
Fuel derivatives |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest | 3 | (499) | (1,666)
Changes in fair value | (50) | 194 |
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax |  | 973 |
Interest rate derivatives |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest | (7) | (18) | (30)
Changes in fair value | 0 | (3) |
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax |  | 15 |
Defined benefit plan items |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest | (9) | (14) | 22
Changes in fair value | 5 | (36) |
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax | 0 | 0 |
Other |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest | 33 | 20 | 6
Changes in fair value | 13 | 14 |
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax | 0 | 0 |
Deferred tax |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest | (8) | 188 | 617
Changes in fair value | 11 | (63) |
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax | (207) | (366) |
Accumulated other comprehensive income (loss) |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest | 12 | (323) | $ (1,051)
Changes in fair value | (21) | 106 |
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax | 356 | $ 622 |
Fuel derivatives | Reclassification out of Accumulated Other Comprehensive Income |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Fuel and oil | 552 |  |
Interest rate derivatives | Reclassification out of Accumulated Other Comprehensive Income |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Interest Expense | $ 11 |  |

X
- Definition Change in accumulated gains and losses from sources other than derivative instruments designated and qualifying as the effective portion of cash flow hedges, net of tax effect. + References No definition available. + Details
Name: | luv_OtherComprehensiveIncomeChangesInFairValueNetOfTax
Namespace Prefix: | luv_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- 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_AccumulatedOtherComprehensiveIncomeLossLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e637-108580 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e681-108580 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580 + Details
Name: | us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fuel costs incurred that are directly related to goods produced and sold and services rendered during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(a),(d)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_FuelCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of the cost of borrowed funds accounted for as interest expense. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.9) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 + Details
Name: | us-gaap_InterestExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount after tax of reclassification adjustments of other comprehensive income (loss). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 55 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=84158357&loc=d3e1436-108581 + Details
Name: | us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 55 -Paragraph 4I -URI http://asc.fasb.org/extlink&oid=84234705&loc=SL4590271-111686 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 16 -URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4568740-111683 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4568447-111683 + Details
Name: | us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=luv_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesInterestRateDerivativeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=luv_OtherComprehensiveIncomeOtherChangesNetOfTaxMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis=us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | luv_AccumulatedOtherComprehensiveIncomeLossNetOfTaxAxis=us-gaap_InterestRateSwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |