Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] UAL and United UAL And United [Member] UAL And United [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] 2019 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 2020 Long-term Debt, Maturities, Repayments of Principal in Year Two 2021 Long-term Debt, Maturities, Repayments of Principal in Year Three 2022 Long-term Debt, Maturities, Repayments of Principal in Year Four 2023 Long-term Debt, Maturities, Repayments of Principal in Year Five After 2023 Long-term Debt, Maturities, Repayments of Principal after Year Five Long-term debt Long-term Debt Fair Value Disclosures [Abstract] Financial Assets and Liabilities Measured at Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Carrying Values and Estimated Fair Values of Financial Instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Income Tax Disclosure [Abstract] Deferred Income Tax Assets And Liabilities [Table] Deferred Income Tax Assets And Liabilities [Table] Deferred Income Tax Assets And Liabilities [Table] United Airlines, Inc. United Air Lines Inc [Member] United Airlines, Inc. [Member] Deferred Income Tax Assets And Liabilities [Line Items] Deferred Income Tax Assets And Liabilities [Line Items] Deferred Income Tax Assets And Liabilities [Line Items] Deferred income tax asset (liability): Deferred Tax Assets, Net, Classification [Abstract] Federal and state net operating loss (NOL) carryforwards Deferred Tax Assets, Operating Loss Carryforwards Deferred revenue Deferred Tax Assets, Deferred Income Employee benefits, including pension, postretirement and medical Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits Other Deferred Tax Assets, Other Less: Valuation allowance Deferred Tax Assets, Valuation Allowance Total deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Depreciation Deferred Tax Liabilities, Property, Plant and Equipment Intangibles Deferred Tax Liabilities, Intangible Assets Total deferred tax liabilities Deferred Tax Liabilities, Gross Net deferred tax liability Deferred Tax Liabilities, Net Accounting Policies [Abstract] Significant Accounting Policies Significant Accounting Policies [Text Block] Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Statement [Line Items] Statement [Line Items] Receivables, allowance for doubtful accounts Allowance for Doubtful Accounts Receivable, Current Aircraft fuel, spare parts and supplies, obsolescence allowance Airline Related Inventory, Valuation Reserves Intangibles, accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common shares, authorized (in shares) Common Stock, Shares Authorized Common shares, issued (in shares) Common Stock, Shares, Issued Common shares, outstanding (in shares) Common Stock, Shares, Outstanding Other Income and Expenses [Abstract] Operating: Operating Expenses [Abstract] Impairment of assets Asset Impairment Charges Termination of an engine maintenance service agreement Loss on Contract Termination Severance and benefit costs Postemployment Benefits, Period Expense Cleveland airport lease restructuring Restructuring Charges Labor agreement costs Labor Agreement Costs Bonus payments made to employees in conjunction with the ratification of employment contracts. (Gains) losses on sale of assets and other special charges Gain (Loss) On Sale Of Other Assets And Other Miscellaneous Charges Amount of gain (loss) on sale of other assets and other miscellaneous charges. Total operating special charges Restructuring, Settlement and Impairment Provisions Nonoperating income (expense): Nonoperating Income (Expense) [Abstract] Postretirement curtailment gain Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment Gains on extinguishment of debt and other Gain (Loss) on Extinguishment of Debt Total operating and nonoperating special charges before income taxes Special Items Before Income Taxes Special items before income taxes. Nonoperating mark-to-market (MTM) losses on financial instruments Gain (Loss) On Financial Instruments, Nonoperating Gain (Loss) On Financial Instruments, Nonoperating Total special charges and MTM (gains) losses on financial instruments Special Charges And Losses On Financial Instruments, Nonoperating, Before Tax Special Charges And Losses On Financial Instruments, Nonoperating, Before Tax Income tax benefit Income Tax Expense (Benefit) Special Charges Income tax expense (benefit) special charges. Income tax adjustments Income Tax Adjustments Income tax adjustments that include items such as deferred income tax expense in AOCI and valuation allowance adjustments. Total operating special charges, net of income taxes and income tax adjustments Special Items Net of Income Tax Benefit(s) Total special items in the period. Statement of Stockholders' Equity [Abstract] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Additional Capital Invested Additional Paid-in Capital [Member] Treasury Stock Treasury Stock [Member] Retained Earnings (Accumulated Deficit) Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Receivable from Related Parties, Net Receivables from Stockholder [Member] Balance (in shares) Balance Stockholders' Equity Attributable to Parent Net income Net Income (Loss) Attributable to Parent Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Stock-settled share-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Dividend to UAL Capital Contributions To Parent Capital Contributions To Parent Proceeds from exercise of stock options / net treasury stock issued for share-based awards (in shares) Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Proceeds from exercise of stock options Stock Issued During Period, Value, Stock Options Exercised Repurchases of common stock (in shares) Treasury Stock, Shares, Acquired Repurchases of common stock Treasury Stock, Value, Acquired, Cost Method Treasury stock retired Treasury Stock, Retired, Cost Method, Amount Net treasury stock issued for share-based awards Stock Issued During Period, Value, Treasury Stock Reissued UAL contribution related to stock plans Capital Contributions From Parent Capital contributions from parent Reclassification of stranded tax effects Tax Cuts And Jobs Act Of 2017, Reclassification From AOCI To Retained Earnings, Tax Effect Tax Cuts and Jobs Act of 2017, Reclassification from AOCI to Retained Earnings, Tax Effect Adoption of accounting standard Cumulative Effect of New Accounting Principle in Period of Adoption Other Stockholders' Equity, Other Balance (in shares) Balance Document And Entity Information [Abstract] Document and Entity Information [Abstract] Document Information [Table] Document Information [Table] Document Information [Line Items] Document Information [Line Items] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Public Float Entity Public Float ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Short-term investments Short-term Investments Receivables, less allowance for doubtful accounts (2018—$8; 2017—$7) Receivables, Net, Current Aircraft fuel, spare parts and supplies, less obsolescence allowance (2018—$412; 2017—$354) Airline Related Inventory, Net Prepaid expenses and other Prepaid Expense and Other Assets, Current Total current assets Assets, Current Operating property and equipment: Property, Plant and Equipment, Net [Abstract] Owned— Property, Plant, and Equipment, Owned, Net [Abstract] Flight equipment Flight Equipment, Gross Other property and equipment Property, Plant and Equipment, Other, Gross Total owned property and equipment Property, Plant, and Equipment, Owned, Gross Less—Accumulated depreciation and amortization Property, Plant, and Equipment, Owned, Accumulated Depreciation Total owned property and equipment, net Property, Plant, and Equipment, Owned, Net Purchase deposits for flight equipment Deposits on Flight Equipment Capital leases— Capital Leases, Lessee Balance Sheet [Abstract] Flight equipment Capital Leases, Lessee Balance Sheet, Assets by Major Class, Flight Equipment, Gross Other property and equipment Capital Leases, Lessee Balance Sheet, Assets by Major Class, Other Property, Plant, and Equipment, Gross Total capital leases Capital Leased Assets, Gross Less—Accumulated amortization Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation Total capital leases, net Capital Leases, Balance Sheet, Assets by Major Class, Net Total operating property and equipment, net Property, Plant and Equipment, Net Other assets: Other Assets, Noncurrent [Abstract] Goodwill Goodwill Intangibles, less accumulated amortization (2018—$1,380; 2017—$1,313) Intangible Assets, Net (Excluding Goodwill) Restricted cash Restricted Cash and Cash Equivalents, Noncurrent Notes receivable, net Notes, Loans and Financing Receivable, Net, Noncurrent Investments in affiliates and other, net Investments and Other Noncurrent Assets Total other assets Other Assets, Noncurrent Total assets Assets LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Advance ticket sales Air Traffic Liability, Current Frequent flyer deferred revenue Frequent Flier Liability, Current Accounts payable Accounts Payable, Current Accrued salaries and benefits Employee-related Liabilities, Current Current maturities of long-term debt Long-term Debt, Current Maturities Current maturities of capital leases Capital Lease Obligations, Current Other Accounts Payable and Other Accrued Liabilities, Current Total current liabilities Liabilities, Current Long-term debt Long-term Debt, Excluding Current Maturities Long-term obligations under capital leases Capital Lease Obligations, Noncurrent Other liabilities and deferred credits: Deferred Credits and Other Liabilities [Abstract] Frequent flyer deferred revenue Frequent Flier Liability, Noncurrent Postretirement benefit liability Liability, Other Postretirement Defined Benefit Plan, Noncurrent Pension liability Liability, Defined Benefit Pension Plan, Noncurrent Deferred income taxes Deferred Income Tax Liabilities, Net Other Other Sundry Liabilities, Noncurrent Total other liabilities and deferred credits Other Liabilities, Noncurrent Commitments and contingencies Commitments and Contingencies Stockholders' equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock Preferred Stock, Value, Issued Common stock Common Stock, Value, Issued Additional capital invested Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Stock held in treasury, at cost Treasury Stock, Value Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Receivable from related parties Receivable from Shareholders or Affiliates for Issuance of Capital Stock Total stockholders' equity Total liabilities and stockholders' equity Liabilities and Equity Fair Value [Table] Fair Value [Table] Fair Value [Table] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Synergy Synergy Aerospace Corporation [Member] Synergy [Member] Kingsland Kingsland Holdings Limited [Member] Kingsland Holdings Limited [Member] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Azul Azul [Member] Azul [Member] Republic Republic Airways Holdings, Inc. [Member] Republic Airways Holdings, Inc. [Member] ManaAir ManaAir, LLC [Member] ManaAir, LLC [Member] ExpressJet Airlines, Inc. ExpressJet Airlines, Inc. [Member] ExpressJet Airlines, Inc. [Member] Champlain Champlain Enterprises LLC [Member] Champlain Enterprises LLC [Member] Fulcrum Fulcrum BioEnergy, Inc. [Member] Fulcrum BioEnergy, Inc. [Member] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Preferred Stock Preferred Stock [Member] Asset Class Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Asset-backed Securities Asset-backed Securities [Member] Corporate Debt Corporate Debt Securities [Member] CDARS Certificates of Deposit [Member] U.S. Government and Other Securities Us Government Agencies Debt Securities and Other Fixed Income Securities [Member] Us Government Agencies Debt Securities and Other Fixed Income Securities [Member] Long-term Debt, Type Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] EETC Enhanced Equipment Trust Certificate [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Fair Value [Line Items] Fair Value [Line Items] Fair Value [Line Items] Available-for-sale securities remaining maturities Available for Sale Investment Maturity Term Available for Sale Investment Maturity Term Available-for-sale securities remaining maturities Available for Sale Investment Maturity Year Available for Sale Investment Maturity Year Investment in equity securities Payments to Acquire Investments Equity stake Equity Securities, Ownership Percentage Equity Securities, Ownership Percentage Loan amount Loans Receivable, Principal Amount Loans Receivable, Principal Amount Number of shares that may be put to United (in shares) Loans Receivable, Agreement, Put Options Loans Receivable, Agreement, Put Options Number of ADRs that may be put to United (in shares) Loans Receivable, Agreement, Put Option, Deposit Receipts Loans Receivable, Agreement, Put Option, Deposit Receipts Percentage of installment that may be paid in shares (up to) Loans Receivable, Percentage Of Installment That May Be Paid In Shares Loans Receivable, Percentage Of Installment That May Be Paid In Shares Annual interest rate Loan Receivable, Stated Interest Rate Loan Receivable, Stated Interest Rate Number of shares that may be purchased at United's option (up to) (in shares) Loans Receivable, Number Of Options To Acquire Shares Loans Receivable, Number Of Options To Acquire Shares Shares subject to increase in value agreement (in shares) Loans Receivable, Shares Subject To Increase In Value Agreement Loans Receivable, Shares Subject To Increase In Value Agreement Market price of common stock at fifth anniversary (in dollars per share) Loans Receivable, Guarantee And Payout Share Price At Fifth Anniversary Loans Receivable, Guarantee And Payout Share Price At Fifth Anniversary Aggregate maximum possible combined put payment and guarantee amount Loans Receivable, Aggregate Maximum Payment And Guarantee Amount Loans Receivable, Aggregate Maximum Payment And Guarantee Amount Investments in securities accounted for under the equity method Equity Method Investments Ownership stake Equity Method Investment, Ownership Percentage Equity Securities Without Readily Determinable Fair Value, Ownership Interest Equity Securities Without Readily Determinable Fair Value, Ownership Interest Equity Securities Without Readily Determinable Fair Value, Ownership Interest Carrying value of other investment Equity Securities Without Readily Determinable Fair Value, Amount Equity Securities Without Readily Determinable Fair Value, Amount Retirement Benefits [Abstract] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plan, Asset Categories [Axis] Defined Benefit Plan, Asset Categories [Axis] Plan Asset Categories [Domain] Plan Asset Categories [Domain] Equity securities Equity Securities [Member] Fixed-income securities Fixed Income Funds [Member] Alternatives Alternative [Member] Alternative [Member] Other Other Investments [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Percent of total Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Expected long-term rate of return Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets Leases [Abstract] Leases and Capacity Purchase Agreements Leases of Lessee Disclosure [Text Block] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Pension Benefits Pension Plan [Member] Other Postretirement Benefits Other Postretirement Benefits Plan [Member] Accumulated benefit obligation Defined Benefit Plan, Accumulated Benefit Obligation Change in projected benefit obligation: Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Projected benefit obligation at beginning of year Defined Benefit Plan, Benefit Obligation Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Plan participants' contributions Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant Actuarial (gain) loss Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Gross benefits paid and settlements Defined Benefit Plan, Benefit Obligation, Benefits Paid And Payments For Settlement Defined Benefit Plan Benefits Paid And Settlements Benefits paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Other Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Other Change Projected benefit obligation at end of year Change in plan assets: Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Fair value of plan assets at beginning of year Defined Benefit Plan, Fair Value of Plan Assets Actual (loss) return on plan assets Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Employer contributions Defined Benefit Plan, Plan Assets, Contributions by Employer Plan participants' contributions Defined Benefit Plan, Plan Assets, Contributions by Plan Participant Gross benefits paid and settlements Defined Benefit Plan, Plan Assets, Benefits Paid And Payments For Settlement Defined Benefit Plan, Plan Assets, Benefits Paid And Payments For Settlement Benefits paid Defined Benefit Plan, Plan Assets, Benefits Paid Other Defined Benefit Plan Other Changes Plan Assets Defined benefit plan other changes plan assets Fair value of plan assets at end of year Funded status—Net amount recognized Defined Benefit Plan, Funded (Unfunded) Status of Plan Amounts recognized in the consolidated balance sheets consist of: Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract] Noncurrent asset Assets for Plan Benefits, Defined Benefit Plan Current liability Liability, Defined Benefit Plan, Current Noncurrent liability Liability, Defined Benefit Plan, Noncurrent Total liability Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position Amounts recognized in accumulated other comprehensive loss consist of: Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract] Net actuarial loss Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax Prior service cost Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax Total accumulated other comprehensive loss Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax Statement of Cash Flows [Abstract] Operating Activities: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Adjustments to reconcile net income to net cash provided by operating activities - Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Deferred income taxes Deferred Income Tax Expense (Benefit) Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Special charges, non-cash portion Restructuring Costs and Asset Impairment Charges Other operating activities Other Operating Activities, Cash Flow Statement Changes in operating assets and liabilities - Increase (Decrease) in Other Operating Assets and Liabilities, Net [Abstract] Increase in receivables Increase (Decrease) in Receivables Increase in intercompany receivables Increase (Decrease) Due from Affiliates (Increase) decrease in other assets Increase (Decrease) in Other Operating Assets Increase (decrease) in advance ticket sales Increase (Decrease) in Air Traffic Liability Increase (decrease) in frequent flyer deferred revenue Increase (Decrease) in Frequent Flyer Deferred Revenue Increase (decrease) in frequent flyer deferred revenue. Increase in accounts payable Increase (Decrease) in Accounts Payable Decrease in advanced purchase of miles Increase Decrease in Advanced Purchase of Miles Increase (decrease) in advanced purchase of miles. Decrease in other liabilities Increase (Decrease) in Other Operating Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations Investing Activities: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Capital expenditures Payments to Acquire Productive Assets Purchases of short-term and other investments Proceeds from sale of short-term and other investments Payments to Acquire Short-term Investments Proceeds from sale of short-term and other investments Payments for (Proceeds from) Investments Loans made to others Payments to Acquire Loans Receivable Investment in affiliates Payments to Acquire Interest in Subsidiaries and Affiliates Other, net Payments for (Proceeds from) Other Investing Activities Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations Financing Activities: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Proceeds from issuance of long-term debt and airport construction financing Proceeds from Issuance of Long-term Debt Payments of long-term debt Repayments of Long-term Debt Dividend to UAL Payments Of Dividends To Parent Company Payments of dividends to parent company. Repurchases of common stock Payments for Repurchase of Common Stock Principal payments under capital leases Repayments of Long-term Capital Lease Obligations Capitalized financing costs Payments of Debt Issuance Costs Other, net Proceeds from (Payments for) Other Financing Activities Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net increase (decrease) in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash, cash equivalents and restricted cash at beginning of year Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of year Investing and Financing Activities Not Affecting Cash: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Property and equipment acquired through the issuance of debt and capital leases Noncash or Part Noncash Acquisition, Fixed Assets Acquired Debt associated with termination of a maintenance service agreement Termination Of Maintenance Service Agreement, Noncash Termination Of Maintenance Service Agreement, Noncash Investment in Republic Airways Holdings, Inc. received from bankruptcy claims Equity Interest Received In Consideration For Bankruptcy Claims Equity interest received in consideration for bankruptcy claims. Airport construction financing Non Cash Obligation For Property Plant And Equipment Non cash obligation for property plant and equipment. Noncash is defined as information about all investing and financing activities of an enterprise during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. Operating lease conversions to capital lease Capital Lease Conversion From Operating Lease Recorded Property Plant And Equipment Capital Lease Conversion From Operating Lease Recorded Property Plant And Equipment Cash Paid During the Period for: Cash Paid Refunded During Period For [Abstract] Cash Paid Refunded During Period For [Abstract] Interest Interest Paid, Net Income taxes Income Taxes Paid, Net Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type Award Type [Axis] Equity Award [Domain] Equity Award [Domain] RSUs Restricted Stock Units (RSUs) [Member] Time-Vested RSUs Time Vested Restricted Stock Units RSUs [Member] Time vested restricted stock units RSUs. Performance-Based RSUs Performance Based Restricted Stock Units R S Us [Member] Performance based restricted stock units RSUs. Stock Options Employee Stock Option [Member] Exercise Price Range [Axis] Exercise Price Range [Axis] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] Exercise Prices at a 25% Premium of the Grant Date Fair Value Exercise Prices at Twenty Five Percent Premium of Grant Date Fair Market Value [Member] Exercise Prices at Twenty Five Percent Premium of Grant Date Fair Market Value [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Awards granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Number of days used to compute performance period average closing price of restricted stock units Determination Period Average Closing Price The time period over which the stock closing prices are averaged to arrive at a per-share valuation for equity based awards such as Restricted Stock Units, Performance Share and other equity based awards. Liabilities related to share based payments Deferred Compensation Share-based Arrangements, Liability, Current and Noncurrent Payment related to share-based liabilities Employee Service Share-based Compensation, Cash Flow Effect, Cash Used to Settle Awards Fair value of RSUs and restricted stock vested in period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Stock options granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Weighted-average grant date exercise price of stock options granted (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Weighted-average grant date fair value of stock options granted Stock Issued During Period, Value, Share-based Compensation, Gross Percentage of premium of the grant date fair market value Percentage of Premium on Grant Date Fair Market Value Percentage of Premium on Grant Date Fair Market Value Stock option awards outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Stock option awards exercisable (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Weighted-average exercise price of stock options outstanding (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Weighted-average exercise price of stock options exercisable (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Intrinsic value of stock options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Intrinsic value of stock options exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Weighted average remaining contractual lives of stock options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Weighted average remaining contractual lives of stock options exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Equity [Abstract] Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Investments and Fair Value Measurements Fair Value Disclosures [Text Block] Defined Contribution Plan [Table] Defined Contribution Plan [Table] Equity securities funds Alternatives Deposit administration fund Deposit Administration Fund [Member] Deposit Administration Fund [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Assets Measured at NAV Fair Value Measured At Net Asset Value Per Share [Member] Fair Value Measured At Net Asset Value Per Share [Member] Defined Contribution Plan Disclosure [Line Items] Defined Contribution Plan Disclosure [Line Items] Fair value of plan assets Income Taxes [Table] Income Taxes [Table] Income Taxes [Table] AOCI Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Energy [Axis] Energy [Axis] Energy [Domain] Energy [Domain] Fuel Fuel [Member] Regulatory Liability [Axis] Regulatory Liability [Axis] Regulatory Liability [Domain] Regulatory Liability [Domain] Pension and Other Postretirement Liabilities Pension and Other Postretirement Plans Costs [Member] Income Taxes [Line Items] Income Taxes [Line Items] Income Taxes [Line Items] Income tax provision at statutory rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount State income taxes, net of federal income tax benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Foreign tax rate differential Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount Global intangible low-taxed income Effective Income Tax Rate Reconciliation, Global Intangible Low-Taxed Income, Amount Effective Income Tax Rate Reconciliation, Global Intangible Low-Taxed Income Foreign income taxes Effective Income Tax Rate Reconciliation, Foreign Income Taxes Effective Income Tax Rate Reconciliation, Foreign Income Taxes Nondeductible employee meals Effective Income Tax Rate Reconciliation, Nondeductible Expense, Meals and Entertainment, Amount Impact of Tax Act Income Tax Rate Reconciliation, Impact of Tax Cuts and Jobs Act Amount Income tax rate reconciliation, impact of tax cuts and jobs act amount. Income tax adjustment from AOCI Income Tax Adjustments From Accumulated Other Comprehensive Income Income tax adjustments from accumulated other comprehensive income. State rate change Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Valuation allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount Other, net Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Income tax expense (benefit) Income Tax Expense (Benefit) Current Current Income Tax Expense (Benefit) Deferred Valuation allowance recorded Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] ASC 606 Accounting Standards Update 2014-09 [Member] ASU 2017-07 Accounting Standards Update 2017-07 [Member] Accounting standards update two thousand seventeen zero seven. Operating Revenue by Principal Geographic Region Disaggregation of Revenue [Table Text Block] Roll Forward of Frequent Flyer Deferred Revenue Deferred Revenue, by Arrangement, Disclosure [Table Text Block] Impact of the Adoption of the New Revenue Standard and the New Retirement Standard and the Expected Impact of the Adoption of the New Lease Standard Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block] Reconciliation of Cash, Cash Equivalents and Restricted Cash Schedule of Cash and Cash Equivalents [Table Text Block] Reconciliation of Cash, Cash Equivalents and Restricted Cash Restrictions on Cash and Cash Equivalents [Table Text Block] Estimated Useful Lives of Property and Equipment Property, Plant and Equipment [Table Text Block] Projected benefit obligation Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation Accumulated benefit obligation Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation Fair value of plan assets Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Fair Value of Plan Assets Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies [Table] Commitments and Contingencies [Table] Commitments And Contingencies [Table] Aircraft Type [Axis] Aircraft Type [Axis] Aircraft [Domain] Aircraft [Domain] Embraer E175 Embraer E175 [Member] Embraer E175 [Member] Boeing 737 MAX Boeing 737 MAX Aircraft [Member] Boeing 737 MAX aircraft. Boeing 787 Boeing 787 Aircraft [Member] Boeing 787 aircraft. Boeing 777-300ER Boeing 777-300ER Aircraft [Member] [Member] Boeing 777-300ER Aircraft [Member] [Member] Airbus A319s Airbus A319s [Member] Airbus A319s [Member] Embraer ERJ 145 Embraer ERJ 145 [Member] Embraer ERJ 145 [Member] Debt Instrument Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Tax-Exempt Special Facilities Revenue Bonds Tax Exempt Bonds [Member] Tax Exempt Bonds [Member] Floating Rate Debt Floating Rate Debt [Member] Floating Rate Debt [Member] Fixed Rate Debt Fixed Rate Debt [Member] Fixed Rate Debt [Member] Loans And Leases From Non U S Entities Loans And Leases From Non U S Entities [Member] Loans And Leases From Non U.S Entities [Member] Aircraft Mortgage Debt Aircraft Mortgage Debt [Member] Aircraft Mortgage Debt [Member] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Indirect Guarantee of Indebtedness Indirect Guarantee of Indebtedness [Member] Commitments and Contingencies [Line Items] Commitments and Contingencies [Line Items] Commitments And Contingencies [Line Items] Number of aircrafts expects to take delivery Number of Aircrafts Expected to Take Delivery Number of aircrafts expected to take delivery. Number of aircraft expected to be delivered Number of Aircraft Expected to Be Delivered Number of Aircraft Expected to Be Delivered Number of firm commitments Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required Number of aircraft under lease Capital Leased Assets, Number Of Aircraft Capital Leased Assets, Number Of Aircraft Debt instrument principal amount Debt Instrument, Face Amount Guarantor obligations, maximum exposure Guarantor Obligations, Maximum Exposure, Undiscounted Operating leases obligations Operating Leases, Future Minimum Payments Due Capital leases obligations Capital Lease Obligations Maturity date Debt Instrument Maturity Year Debt instrument maturity year Debt instrument, remaining terms Debt Instrument Remaining Terms Years remaining on debt instruments. Aggregate balance Contractual Obligation Contingent liabilities based on participation Guarantor Obligations, Current Carrying Value Number of call options to purchase regional jet aircraft Number of Call Options To Purchase Regional Jet Aircraft Number of Call Options To Purchase Regional Jet Aircraft Number of employees Entity Number of Employees Percentage of employees represented by various U.S. labor organizations Percentage Of Employees Represented By Labor Organizations Percentage of employees represented by labor organizations Income Tax Provision (Benefit) Differed from Amounts Computed at the Statutory Federal Income Tax Rate and Significant Components Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Temporary Differences and Carryforwards Giving Rise to Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Information about Goodwill and Other Intangible Assets Schedule of Intangible Assets and Goodwill [Table Text Block] Schedule of Cash and Cash Equivalents [Table] Schedule of Cash and Cash Equivalents [Table] Balance Sheet Location Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Prepaid Expenses and Other Prepaid Expenses and Other Current Assets [Member] Cash and Cash Equivalents [Line Items] Cash and Cash Equivalents [Line Items] Restricted cash Restricted Cash and Cash Equivalents, Current Total cash, cash equivalents and restricted cash shown in the statement of consolidated cash flows Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Airline Destinations [Axis] Airline Destinations [Axis] Airline Destination [Domain] Airline Destination [Domain] Domestic (U.S. and Canada) Domestic Destination [Member] Atlantic Atlantic Destination [Member] Pacific Pacific Destination [Member] Latin America Latin America Destination [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenue Revenue from Contract with Customer, Excluding Assessed Tax Reconciliation of the Change in Benefit Obligation and Plan Assets and Funded Status Schedule of Net Funded Status [Table Text Block] Amounts Recognized in Consolidated Balance Sheet and Accumulated Other Comprehensive Income (Loss) Schedule of Amounts Recognized in Balance Sheet [Table Text Block] Accumulated Benefit Obligation and Projected Benefit Obligation in Excess of Plan Assets Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block] Components Of Net Periodic Benefit Cost Schedule of Net Benefit Costs [Table Text Block] Assumptions Used for Benefit Plans Schedule of Assumptions Used [Table Text Block] Allocation of Plan Assets Schedule of Allocation of Plan Assets [Table Text Block] Pension and Other Postretirement Plan Assets Schedule of Defined Benefit Plans Disclosures [Table Text Block] Defined Benefit Plan Assets Measured at Fair Value Using Unobservable Inputs Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets [Table Text Block] Estimated Future Benefit Payments Schedule of Expected Benefit Payments [Table Text Block] Participation in the IAM National Pension Plan Schedule of Multiemployer Plans [Table Text Block] Quarterly Financial Information Disclosure [Abstract] Summary of Selected Quarterly Financial Data Quarterly Financial Information [Table Text Block] Impact of Significant Items on Quarterly Results Schedule Of Quarterly Reporting [Table Text Block] Schedule Of Quarterly Reporting Table. Business Combinations [Abstract] Components of Special Charges Restructuring and Related Costs [Table Text Block] Activity Related to the Accruals for Severance and Medical Costs and Future Lease Payments Schedule of Restructuring Reserve by Type of Cost [Table Text Block] Restricted stock Restricted Stock [Member] Stock options Compensation cost Allocated Share-based Compensation Expense Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring Fair Value, Measurements, Recurring [Member] Schedule of Fair Value of Separate Accounts by Major Category of Investment Investment Type [Axis] Investments [Domain] Investments [Domain] U.S. Government and Agency Notes US Government Agencies Debt Securities [Member] Other Fixed Income Securities Fixed Income Securities [Member] Other Investments Measured At NAV Other Investments Measured At Net Asset Value [Member] Other Investments Measured At Net Asset Value [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Short-term investments Investments, Fair Value Disclosure Restricted cash Restricted Cash, Fair Value Disclosure Restricted Cash Fair Value Disclosure Equity securities Equity Securities, Fair Value Equity securities, fair value Enhanced equipment trust certificates (EETC) Available-for-sale Securities Avianca Holdings S.A. (AVH) Derivative Assets Derivative Asset Earnings Per Share [Abstract] Earnings available to common stockholders Net Income (Loss) Available to Common Stockholders, Basic Basic weighted-average shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Effect of employee stock awards (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Diluted weighted-average shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Earnings per share, basic (in dollars per share) Earnings Per Share, Basic Earnings per share, diluted (in dollars per share) Earnings Per Share, Diluted Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Measurement Basis Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Carrying Amount Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Long-term debt, carrying amount Long-term debt, fair value Long-term Debt, Fair Value Synergy Term Loan, carrying amount Loans Receivable, Net Synergy Term Loan, fair value Loans Receivable, Fair Value Disclosure Special Charges [Table] Special Charges [Table] Special Charges [Table] Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Severance/ Benefit Costs Severance Or Benefit Cost [Member] Severance or Medical Cost [Member] Permanently Grounded Aircraft Permanently Grounded Aircraft [Member] Permanently Grounded Aircraft [Member] Schedule Of Accrual Activity [Line Items] Schedule Of Accrual Activity [Line Items] Schedule of Accrual Activity [Line Items] Balance Restructuring Reserve Accrual and related adjustments Restructuring Reserve, Accrual Adjustment Payments Payments for Restructuring Balance SPECIAL CHARGES Business Acquisition, Integration, Restructuring and Other Related Costs [Text Block] Summary of Long-Term Debt Schedule of Long-term Debt Instruments [Table Text Block] Contractual Principal Payments under Outstanding Long-Term Debt Agreements Schedule of Maturities of Long-term Debt [Table Text Block] Details of Pass Through Trusts Schedule of Debt Instruments Pass Through Trusts [Table Text Block] Schedule of Debt Instruments Pass Through Trusts Summary of Collateral Covenants and Cross Default Provisions Schedule of Financial Covenants [Table Text Block] Schedule of Financial Covenants Computation of Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Valuation and Qualifying Accounts [Abstract] Valuation and Qualifying Accounts Disclosure [Table] Valuation and Qualifying Accounts Disclosure [Table] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves [Domain] Valuation Allowances and Reserves [Domain] Allowance for doubtful accounts Allowance for Doubtful Accounts [Member] Obsolescence allowance-spare parts Inventory Valuation Reserve [Member] Valuation allowance for deferred tax assets Valuation Allowance of Deferred Tax Assets [Member] Valuation and Qualifying Accounts Disclosure [Line Items] Valuation and Qualifying Accounts Disclosure [Line Items] Balance at Beginning of Period Valuation Allowances and Reserves, Balance Additions Charged to Costs and Expenses Valuation Allowances and Reserves, Additions for Charges to Cost and Expense Deductions Valuation Allowances and Reserves, Deductions Other Valuation Allowances and Reserves, Additions for Charges to Other Accounts Balance at End of Period Organization, Consolidation and Presentation of Financial Statements [Abstract] Variable Interest Entities Variable Interest Entity Disclosure [Text Block] Schedule II - Valuation and Qualifying Accounts Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Hong Kong Routes Airline Routes - Hong Kong [Member] Airline Routes [Member] Brazil Routes Airline Routes - Brazil [Member] Airline Routes - Brazil [Member] Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Management Management [Member] International Brotherhood of Teamsters International Brotherhood Of Teamsters [Member] International Brotherhood of Teamsters. Int'l Association of Machinists International Association Of Machinists [Member] International Association Of Machinists [Member] Voluntary Early Out Program Voluntary Early Out Program [Member] Voluntary Early Out Program [Member] Obsolete Spare Parts Inventory Obsolete Spare Parts Inventory [Member] Obsolete spare parts inventory. Maintenance Service Agreement Maintenance Service Agreement [Member] Maintenance service agreement. Management Reorganization Initiative Management Reorganization Initiative [Member] Management reorganization initiative. Newark Liberty International Airport Newark Liberty International Airport [Member] Newark Liberty International Airport [Member] Postretirement Medical Plan Post Retirement Medical Plan [Member] Post Retirement Medical Plan [Member] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Flight Attendant Postretirement Medical Plan Flight Attendant Postretirement Medical Plan [Member] Flight Attendant Postretirement Medical Plan [Member] Special Charges [Line Items] Special Charges [Line Items] Special Charges [Line Items] Intangible assets impairment charge Impairment of Intangible Assets (Excluding Goodwill) Intangible assets impairment charge, net of tax Impairment Of Intangible Assets (Excluding Goodwill), Net Of Tax Impairment Of Intangible Assets (Excluding Goodwill), Net Of Tax Fair value adjustments related to aircraft purchased off lease, write-off of unexercised aircraft purchase options and other impairments Special Charges, Fair Value Adjustment, Write-Offs, And Impairments Of Aircraft Special Charges, Fair Value Adjustment, Write-Offs, And Impairments Of Aircraft Fair value adjustments related to aircraft purchased off lease, write-off of unexercised aircraft purchase options and other impairments, net of tax Special Charges, Fair Value Adjustment, Write-Offs, And Impairments Of Aircraft, Net Of Tax Special Charges, Fair Value Adjustment, Write-Offs, And Impairments Of Aircraft, Net Of Tax Termination of an engine maintenance service agreement, net of tax Loss On Contract Termination, Net Of Tax Loss On Contract Termination, Net Of Tax Severance and benefits costs, net of tax Postemployment Benefits, Period Expense, Net Of Tax Period expense related to postemployment benefits, net of tax. Gain on change in market value of equity investments Equity Securities, Fv-Ni, Gain (Loss) Equity Securities, FV-NI, Gain (Loss) Gain on change in market value of equity investments, net of tax Equity Securities, FV-NI, Gain (Loss), Net Of Tax Equity Securities, FV-NI, Gain (Loss), Net Of Tax Losses due to the change in fair value of derivatives Derivative, Loss on Derivative Losses due to the change in fair value of derivatives, net of tax Derivative, Loss On Derivative, Net Of Tax Derivative, Loss On Derivative, Net Of Tax Severance payment per participant Restructuring and Related Cost, Expected Cost Impairment of assets, net of tax Asset Impairment Charges, Net Of Tax Asset Impairment Charges, Net Of Tax Impairment of indefinite-lived intangible assets Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) Impairment of indefinite-lived intangible assets, net of tax benefits Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill), Net of Tax Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill), Net of Tax Cleveland airport lease restructuring, net of taxes Restructuring charges, Net of Tax Amount of expenses associated with exit or disposal activities pursuant to an authorized plan, net of tax. Excludes expenses related to a discontinued operation or an asset retirement obligation. Number of new contracts extended Number of Contracts Extended Number of Contracts Extended Service contract extended year New Contracts Extended, Maturity Year New Contracts Extended, Maturity Year Labor agreement costs, net of tax Labor Agreement Costs Net Of Tax Bonus payments made to employees in conjunction with the ratification of employment contracts, net of tax. Curtailment gain recognition of prior service credit Curtailment gain recognition of prior service credit, net of tax Defined Benefit Plan Recognized Net Gain Loss Due To Curtailments Net Of Tax Defined Benefit Plan Recognized Net Gain Loss Due To Curtailments Net Of Tax Summary Of Significant Accounting Policies [Table] Summary Of Significant Accounting Policies [Table] Summary Of Significant Accounting Policies [Table] Deferred Revenue Arrangement Type [Axis] Deferred Revenue Arrangement Type [Axis] Deferred Revenue [Domain] Deferred Revenue [Domain] Transportation Advance Ticket Arrangement Transportation Advance Ticket Arrangement [Member] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Passenger Revenue Passenger [Member] Passenger [Member] Other Operating Revenue Product And Service, Other [Member] Product And Service, Other [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Passenger Revenue Passenger Revenue [Member] Passenger revenue. Type of Arrangement and Non-arrangement Transactions [Axis] Type of Arrangement and Non-arrangement Transactions [Axis] Arrangements and Non-arrangement Transactions [Domain] Arrangements and Non-arrangement Transactions [Domain] Chase and Other Partner Agreements Chase And Other Partner Agreements [Member] Chase and other partner agreements. Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Aircraft Seats Aircraft Seats [Member] Aircraft Seats [Member] Aircraft and Aircraft Spare Parts Aircraft and Aircraft Spare Parts [Member] Aircraft and Aircraft Spare Parts [Member] Computer Software Software and Software Development Costs [Member] ASU 2016-01 Accounting Standards Update 2016-01 [Member] Summary Of Significant Accounting Policies [Line Items] Summary Of Significant Accounting Policies [Line Items] Summary Of Significant Accounting Policies [Line Items] Ancillary fees Ancillary Fees Ancillary fees. Frequent flier program expiration period Frequent Flyer Mileage Program Expiration Period Frequent flyer mileage program expiration period. Period of member account inactivity at which miles expire Frequent Flyer Mileage Program Expiration Period After Member Account Inactivity Frequent flyer mileage program expiration period after member account inactivity. Estimated useful life Property, Plant and Equipment, Useful Life Carrying value of computer software Capitalized Computer Software, Gross Residual value Property, Plant and Equipment, Salvage Value, Percentage Depreciation expense Depreciation Advertising expense Advertising Expense Reclassification to retained earnings upon adoption of accounting standard Operating revenue Operating income Operating Income (Loss) Share-Based Compensation Plans Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward] Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward] Actual return (loss) on plan assets: Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) [Abstract] Sold during the year Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Actual Return (Loss) on Plan Assets Sold Held at year end Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Actual Return (Loss) on Plan Assets Still Held Purchases, sales, issuances and settlements (net) Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Purchases, Sales, and Settlements Selected Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Schedule of Multiemployer Plans [Table] Schedule of Multiemployer Plans [Table] Multiemployer Plan Name [Axis] Multiemployer Plan Name [Axis] Multiemployer Plan Name [Domain] Multiemployer Plan Name [Domain] IAM National Pension Plan International Association Of Machinists National Pension Plan [Member] International Association of Machinists National Pension Plan [Member] Multiemployer Plan Type [Axis] Multiemployer Plan Type [Axis] Multiemployer Plans Type [Domain] Multiemployer Plans Type [Domain] Multi-Employer Pension Plans Multiemployer Plans, Pension [Member] Multiemployer Plans [Line Items] Multiemployer Plans [Line Items] EIN Entity Tax Identification Number Pension Plan Number Multiemployer Plan Number Pension Protection Act Zone Status Multiemployer Plans, Certified Zone Status FIP/RP Status Pending/Implemented Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan United's Contributions Multiemployer Plan, Contributions by Employer Surcharge Imposed Multiemployer Plans, Surcharge Pension and Other Postretirement Plans Pension and Other Postretirement Benefits Disclosure [Text Block] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] ASU 2014-09 Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] As Previously Reported Scenario, Previously Reported [Member] Adjustment Restatement Adjustment [Member] Passenger revenue Cargo Cargo And Freight [Member] Cargo And Freight [Member] Other operating revenue Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Domain] Initial Application Period Cumulative Effect Transition [Domain] As Previously Reported Calculated under Revenue Guidance in Effect before Topic 606 [Member] New Revenue Standard Adjustments Difference between Revenue Guidance in Effect before and after Topic 606 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Statements of Consolidated Operations Income Statement [Abstract] Operating revenue: Revenue, Net [Abstract] Operating expenses Costs and Expenses Total nonoperating expense, net Nonoperating Income (Expense) Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax expense Consolidated Balance Sheets Current assets: Current liabilities: Other liabilities and deferred credits: Other Liabilities [Abstract] Stockholders' equity: Credit Agreement Credit Agreement [Member] Credit Agreement [Member] 6.375% Senior Notes due 2018 Six Point Three Seven Five Percent Senior Notes Due Twenty Eighteen [Member] Six Point Three Seven Five Percent Senior Notes Due Twenty Eighteen [Member] 6% Senior Notes due 2020 Senior Notes Six Percent Due Twenty Twenty [Member] Senior Notes Six Percent Due Twenty Twenty [Member] 5% Senior Notes due 2024 Five Percent Senior Notes Due Twenty Twenty Four [Member] Four point two five percent senior notes due twenty twenty two. 4.25% Senior Notes due 2022 Four Point Two Five Percent Senior Notes Due Twenty Twenty Two[Member] Four point two five percent senior notes due twenty twenty two. Unrestricted liquidity required for credit agreement Debt Covenant, Required Liquidity Debt Covenant, Required Liquidity Minimum ratio of appraised value of collateral for Credit Agreement Minimum ratio of appraised value of collateral for Credit Agreement Minimum ratio of appraised value of collateral for Credit Agreement Fixed interest rate Debt Instrument, Interest Rate, Stated Percentage Debt instrument maturity year Debt Instrument Maturity Date Year Debt Instrument Maturity Date Year Amortization expense Amortization of Intangible Assets Projected amortization expense: Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract] Projected amortization expense in 2019 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Projected amortization expense in 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Two Projected amortization expense in 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Three Projected amortization expense in 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Four Projected amortization expense in 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Five Earnings Per Share Earnings Per Share [Text Block] Income Taxes Income Tax Disclosure [Text Block] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Assumptions used to determine benefit obligations Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract] Discount rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Rate of compensation increase Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Assumptions used to determine net expense Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Discount rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Expected return on plan assets Rate of compensation increase Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Health care cost trend rate assumed for next year Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year Rate to which the cost trend rate is assumed to decline (ultimate trend rate in 2023) Defined Benefit Plan, Ultimate Health Care Cost Trend Rate Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Pension and Other Postretirement Liabilities Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Fuel Derivatives Contracts Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] Investments and Other Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Balance, before tax AOCI before Tax, Attributable to Parent Balance, deferred taxes AOCI Tax, Attributable to Parent Other comprehensive income (loss) before reclassifications, before tax Other Comprehensive Income (Loss), before Reclassifications, before Tax Other comprehensive income (loss) before reclassifications, deferred taxes Other Comprehensive Income (Loss) before Reclassifications, Tax Other comprehensive income (loss) before reclassifications, net of tax Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Amounts reclassified from accumulated other comprehensive income, before tax Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Amounts reclassified from accumulated other comprehensive income, deferred taxes Reclassification from AOCI, Current Period, Tax Amounts reclassified from accumulated other comprehensive income, net of tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Reclassification of stranded tax effects, tax Tax Cuts And Jobs Act Of 2017 Reclassification From Aoci, Tax Tax Cuts And Jobs Act Of 2017 Reclassification From Aoci, Tax Reclassification of stranded tax effects Amounts reclassified to retained earnings, before tax Reclassification From Accumulated Other Comprehensive Income, To Retained Earnings Current Period, before Tax Reclassification From Accumulated Other Comprehensive Income, To Retained Earnings Current Period, before Tax Amounts reclassified to retained earnings, deferred taxes Reclassification From Accumulated Other Comprehensive Income To Retained Earnings. Current Period, Tax Reclassification From Accumulated Other Comprehensive Income To Retained Earnings. Current Period, Tax Amounts reclassified to retained earnings, net of taxes Reclassification From Accumulated Other Comprehensive Income, To Retained Earnings Current Period, Net Of Tax Reclassification from accumulated other comprehensive income, to retained earnings current period, net of tax. Balance, before tax Balance, deferred taxes Decrease (increase) in prior service credits Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), after Tax Decrease (increase) in actuarial losses Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax Summary of Commitments to Purchase Aircraft Long-term Purchase Commitment [Table Text Block] Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Fuel derivative contracts Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] Pension and Postretirement liabilities and other Investments and other Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Amount Reclassified from AOCI to Income Reclassification out of Accumulated Other Comprehensive Income [Member] Aircraft fuel Fuel Costs Miscellaneous, net Other Nonoperating Income (Expense) Debt Long-term Debt [Text Block] Deposit Administration Fund Percent of plan assets invested Effect on post retirement benefit obligation, 1% Decrease Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation Effect on total service and interest cost, 1% Decrease Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components Expected employer contributions to pension and postretirement plans Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year Employer contribution percentage Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Expense for defined contribution plans Defined Contribution Plan, Employer Discretionary Contribution Amount Multi-employer plan contributions Multiemployer Plans, Plan Contributions Percent of company's contribution to plan Multiemployer Pension Employer Percentage Multiemployer Pension Employer Percentage Percentage of pre-tax earnings paid for profit sharing plan Profit Sharing Plan Percentage Of Pre Tax Earnings Paid Profit Sharing Plan, Percentage of Pre-Tax Earnings Paid Profit sharing and payroll tax expense Defined Benefit Plan Profit Sharing And Payroll Tax Expense Defined Benefit Plan Profit Sharing And Payroll Tax Expense Statement of Comprehensive Income [Abstract] Other comprehensive income (loss), net change related to: Other Comprehensive Income (Loss), Net of Tax [Abstract] Employee benefit plans, net of taxes Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Fuel derivative financial instruments, net of taxes Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Investments and other, net of taxes Other Comprehensive Income, Investments and Other, Net of Tax Other Comprehensive Income, Investments and Other, Net of Tax Total other comprehensive income (loss), net Total comprehensive income, net Comprehensive Income (Loss), Net of Tax, Attributable to Parent Components of AOCI Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Pension and Other Postretirement Defined Benefit Plan, Expected Future Benefit Payment [Abstract] 2019 Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months 2020 Defined Benefit Plan, Expected Future Benefit Payment, Year Two 2021 Defined Benefit Plan, Expected Future Benefit Payment, Year Three 2022 Defined Benefit Plan, Expected Future Benefit Payment, Year Four 2023 Defined Benefit Plan, Expected Future Benefit Payment, Year Five Years 2024-2028 Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter Other Postretirement— subsidy receipts Defined Benefit Plan, Expected Future Prescription Drug Subsidy Receipt [Abstract] 2019 Defined Benefit Plan, Expected Future Prescription Drug Subsidy Receipt, Next Twelve Months 2020 Defined Benefit Plan, Expected Future Prescription Drug Subsidy Receipt, Year Two 2021 Defined Benefit Plan, Expected Future Prescription Drug Subsidy Receipt, Year Three 2022 Defined Benefit Plan, Expected Future Prescription Drug Subsidy Receipt, Year Four 2023 Defined Benefit Plan, Expected Future Prescription Drug Subsidy Receipt, Year Five Years 2024-2028 Defined Benefit Plan, Expected Future Prescription Drug Subsidy Receipt, after Year Five 2019 Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months 2020 Unrecorded Unconditional Purchase Obligation, Due within Two Years 2021 Unrecorded Unconditional Purchase Obligation, Due within Three Years 2022 Unrecorded Unconditional Purchase Obligation, Due within Four Years 2023 Unrecorded Unconditional Purchase Obligation, Due within Five Years After 2023 Unrecorded Unconditional Purchase Obligation, Due after Five Years Total Unrecorded Unconditional Purchase Obligation Movement in Deferred Revenue [Roll Forward] Movement in Deferred Revenue [Roll Forward] Total Frequent flyer deferred revenue - beginning balance Contract with Customer, Liability Total miles awarded Frequent Flyer Mileage Miles Awarded in Period Frequent flyer mileage miles awarded in period. Travel miles redeemed (Passenger revenue) Travel Miles Redemption, Frequent Flyer Deferred Revenue Travel miles redemption, frequent flyer deferred revenue. Non-travel miles redeemed (Other operating revenue) Non-travel Miles Redemption, Frequent Flyer Deferred Revenue Non-travel miles redemption, frequent flyer deferred revenue. Total Frequent flyer deferred revenue - ending balance Schedule Of Capital Leased Assets [Table] Schedule Of Capital Leased Assets [Table] Schedule Of Capital Leased Assets [Table] Chicago O'Hare Chicago O Hare International Airport [Member] Chicago O Hare International Airport. CRJ 200 CRJ-200 [Member] Mainline Mainline [Member] Regional Carrier Regional Carrier [Member] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Domain] Lease Arrangement, Type [Domain] Airline Use and Lease Agreement - Chicago O'Hare March 2018 Facility And Other Operating Leases [Member] March 2018 Facility and other operating leases. Hangars, Ground Equipment Maintenance Building and Employee Parking Lease May 2018 Facility And Other Operating Leases [Member] May 2018 Facility And Other Operating Leases [Member] Aircraft Operating Leases Aircraft Operating Leases [Member] Aircraft Operating Leases Major Property Class [Axis] Major Property Class [Axis] Major Property Class [Domain] Major Property Class [Domain] Regional Aircraft Regional Aircraft [Member] Regional Aircraft [Member] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Not Primary Beneficiary Variable Interest Entity, Not Primary Beneficiary [Member] Fresh-Start Adjustments [Axis] Fresh-Start Adjustments [Axis] Type of Fresh-Start Adjustment [Domain] Type of Fresh-Start Adjustment [Domain] Revaluation of Liabilities Revaluation of Liabilities [Member] Recorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Recorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Capacity Purchase Agreements Capacity Purchase Agreements [Member] Capacity Purchase Agreements Forecast Scenario, Forecast [Member] Capital Leased Assets [Line Items] Capital Leased Assets [Line Items] Operating lease term Lessee, Operating Lease, Term of Contract Number of assets subject to lease Number Of Assets Subject to Lease Number Of Assets Subject to Lease Imputed interest rate Capital Lease Imputed Interest Rate Capital Lease Imputed Interest Rate Operating lease expiration date Operating Lease Expiration Year Operating Lease Expiration Year Nonaircraft rent expense Nonaircraft Rent Expense Nonaircraft Rent Expense Regional capacity purchase expense Airline, Capacity Purchase Arrangements Remaining lease term Lease Remaining Term Lease Remaining Term Net accretion amounts Net Accretion Amounts of Noncurrent Deferred Finance Costs Liability Net Accretion Amounts of Noncurrent Deferred Finance Costs Liability Number of regional aircraft Number of Aircraft Operated Airline capacity purchase arrangements, expiration year Airline, Capacity Purchase Arrangements Expiration Year Airline, Capacity Purchase Arrangements Expiration Year Number of aircraft to operate Number of Aircraft To Operate Number of aircraft to operate. Number of aircrafts under the extended term of contract Number Of Aircrafts Under Extension Of Existing Contract Terms The approximate number of aircraft whose term was extended under an existing contract. Capacity purchase agreement contract expiration date after extension Capacity Purchase Agreement Contract Expiration Date After Extension Capacity Purchase Agreement Contract Expiration Date After Extension Expenses Accounts receivable from regional carriers Accounts Receivable, Net, Current Scheduled block hours increase (decrease) percentage Scheduled Block Hours Increase (Decrease) Percentage Scheduled Block Hours Increase (Decrease) Percentage Change in cash obligation Increase (Decrease) in Cash Obligation Increase (Decrease) in Cash Obligation Goodwill Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Frequent flyer database Frequent Flyer Database [Member] Frequent Flyer Database [Member] Hubs Hubs [Member] Hubs [Member] Contracts Contracts [Member] Contracts [Member] Patents and tradenames Patents And Trade Names [Member] Patents And Tradenames [Member] Airport slots and gates Airport Slots and Gates [Member] Airport Slots and Gates [Member] Other Other Intangible Assets [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Gross carrying amount Finite-Lived Intangible Assets, Gross Accumulated amortization Schedule of Indefinite-Lived Intangible Assets [Table] Schedule of Indefinite-Lived Intangible Assets [Table] Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Route authorities Route Authorities [Member] Route Authorities [Member] Airport slots and gates Airport Slots And Gates Indefinite Lived [Member] Airport Slots And Gates [Member] Tradenames and logos Tradenames And Logos [Member] Tradenames And Logos [Member] Alliances Alliances [Member] Alliances [Member] Indefinite-lived Intangible Assets [Line Items] Indefinite-lived Intangible Assets [Line Items] Gross carrying amount Indefinite-Lived Intangible Assets (Excluding Goodwill) Future Minimum Lease Payments for Capital and Operating Leases Schedule Of Future Minimum Lease Payments For Capital And Operating Leases [Table Text Block] Schedule Of Future Minimum Lease Payments For Capital And Operating Leases. Future Lease Payment Under Terms of Capacity Purchase Agreement Future Lease Payment Terms For Capacity Purchase Agreement [Table Text Block] Future Lease Payment Terms For Capacity Purchase Agreement Long-term Purchase Commitment [Table] Long-term Purchase Commitment [Table] Airbus A350 Airbus [Member] Airbus [Member] Boeing 737 MAX Boeing 737 Max [Member] Boeing 737 Max Boeing 777-300ER B-777-300 [Member] Boeing 787 Boeing 787 [Member] Boeing 787. Long-term Purchase Commitment [Line Items] Long-term Purchase Commitment [Line Items] Number aircraft under purchase agreements Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Federal Domestic Tax Authority [Member] State State and Local Jurisdiction [Member] Net Operating Loss Carryforward, By Expiration [Axis] Net Operating Loss Carryforward, By Expiration [Axis] Net Operating Loss Carryforward, By Expiration [Axis] Net Operating Loss Carryforward, By Expiration [Domain] Net Operating Loss Carryforward, By Expiration [Domain] [Domain] for Net Operating Loss Carryforward, By Expiration [Axis] 2030 Net Operating Loss Carry Forward Expiration Year 2030 [Member] Net Operating Loss Carry Forward Expiration Year 2030 [Member] Thereafter Net Operating Loss Carry Forward Expiration Period Thereafter [Member] Net Operating Loss Carry Forward Expiration Period Thereafter [Member] Federal statutory income tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Income tax benefit for the one-time transition tax Effective Income Tax Rate Reconciliation, Tax Cuts And Jobs Act Of 2017, Transition Tax On Accumulated Foreign Earnings, Amount Effective Income Tax Rate Reconciliation, Tax Cuts And Jobs Act Of 2017, Transition Tax On Accumulated Foreign Earnings, Amount NOL carry forwards Operating Loss Carryforwards NOL carry forwards, valuation allowance Operating Loss Carryforwards, Valuation Allowance Unrecognized tax benefits Unrecognized Tax Benefits Unrecognized tax benefits that would impact effective tax rate if recognized Unrecognized Tax Benefits that Would Impact Effective Tax Rate Nonoperating mark-to-market (MTM) (gains) losses on financial instruments Income taxes: Income Taxes [Abstract] Income Taxes [Abstract] Income tax benefit related to special charges Income tax adjustments 2019 Contractual Obligation, Due in Next Fiscal Year 2020 Contractual Obligation, Due in Second Year 2021 Contractual Obligation, Due in Third Year 2022 Contractual Obligation, Due in Fourth Year 2023 Contractual Obligation, Due in Fifth Year 2024 Contractual Obligation, Due after Fifth Year Total Equity Awards - RSUs Restricted Stock Units (RSUs) - Equity Awards [Member] Restricted Stock Units (RSUs) - Equity Awards [Member] Liability Awards - RSUs Restricted Stock Units (RSUs) - Liability Awards [Member] Restricted Stock Units (RSUs) - Liability Awards [Member] Restricted Stock Awards Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (in shares) Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Outstanding (in shares) Weighted- Average Grant Price Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Outstanding (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Outstanding (in dollars per share) Unearned compensation Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Weighted average remaining period Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition ASU 2016-02 Accounting Standards Update 2016-02 [Member] New Lease Standard Adjustments Flight Equipment Flight Equipment [Member] Other Property and Equipment Property, Plant and Equipment, Other Types [Member] Less-Accumulated depreciation and amortization (owned) Flight equipment (Finance leases) Finance Leases, Lessee, Balance Sheet Assets By Major Class, Flight Equipment, Gross Finance Leases, Lessee, Balance Sheet Assets By Major Class, Flight Equipment, Gross Less-Accumulated amortization Less-Accumulated amortization Finance Leases, Lessee, Balance Sheet Assets By Major Class, Accumulated Depreciation Finance Leases, Lessee, Balance Sheet Assets By Major Class, Accumulated Depreciation Operating lease assets Operating Lease, Right-of-Use Asset Current maturities of finance leases Finance Lease, Liability, Current Current maturities of operating leases Operating Lease, Liability, Current Long-term obligations under finance leases Finance Lease, Liability, Noncurrent Long-term obligations under operating leases Operating Lease, Liability, Noncurrent Operating expense: Costs and Expenses [Abstract] Regional capacity purchase Landing fees and other rent Landing Fees and Other Rentals Depreciation and amortization Interest expense Interest Expense Interest capitalized Interest Costs Capitalized Adjustment Income tax expense Number of shares repurchased (in shares) Repurchases of common stock Share repurchase program additional amount authorized Stock Repurchase Program, Authorized Amount Amount remaining under repurchase programs Stock Repurchase Program, Remaining Authorized Repurchase Amount Common stock reserved for future issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Junior preferred stock outstanding (in shares) Preferred Stock, Shares Outstanding Junior preferred stock par value per share (in dollars per share) Preferred Stock, Par or Stated Value Per Share Preferred stock authorized to issue (in shares) Preferred Stock, Shares Authorized Information Related to Share-Based Compensation Plan Cost Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Summary of Unearned Compensation and Weighted-Average Remaining Period to Recognize Costs Schedule of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block] Summary of RSU and Restricted Stock Activity Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Aircraft and related rotable parts Aircraft And Related Rotable Parts [Member] Aircraft And Related Rotable Parts [Member] Aircraft seats Buildings Building [Member] Other property and equipment Other Capitalized Property Plant and Equipment [Member] Computer software Building improvements Building Improvements [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Use of Estimates Use of Estimates, Policy [Policy Text Block] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Frequent Flyer Accounting Frequent Flier Program, Policy [Policy Text Block] Cash and Cash Equivalents and Restricted Cash Cash and Cash Equivalents, Policy [Policy Text Block] Short-term Investments Short Term Investments [Policy Text Block] Short-term Investments Accounts Receivable Receivables, Policy [Policy Text Block] Aircraft Fuel, Spare Parts and Supplies Aircraft Fuel Spare Parts And Supplies [Policy Text Block] Aircraft Fuel Spare Parts And Supplies Property and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Maintenance and Repairs Maintenance Cost, Policy [Policy Text Block] Lease Fair Value Adjustments Lease Fair Value Adjustments [Policy Text Block] Lease Fair Value Adjustments Regional Capacity Purchase Regional Capacity Purchase [Policy Text Block] Regional Capacity Purchase Advertising Advertising Costs, Policy [Policy Text Block] Intangibles Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block] Long-Lived Asset Impairments Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Share-Based Compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Ticket Taxes Ticket Taxes [Policy Text Block] Ticket Taxes Retirement of Leased Aircraft Retirement of Leased Aircraft [Policy Text Block] Retirement Of Leased Aircraft Uncertain Income Tax Positions Income Tax Uncertainties, Policy [Policy Text Block] Labor Costs Labor Costs [Policy Text Block] Labor Costs Policy Third-Party Business Third Party Business [Policy Text Block] Third Party Business Policy Recently Issued Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Mainline Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Aircraft under operating lease, fixed purchase options Number of Aircraft under Operating Lease Agreements with Fixed Price Purchase Options Number of Aircraft under Operating Lease Agreements with Fixed Price Purchase Options Aircraft under operating lease Number Of Aircraft Under Operating Lease Agreements With Purchase Options At Prices Potentially Below Fair Value Number of aircraft under operating lease agreements with purchase options at prices potentially below fair value. Operating revenue: Revenues [Abstract] Salaries and related costs Labor and Related Expense Aircraft fuel Aircraft maintenance materials and outside repairs Aircraft Maintenance, Materials, and Repairs Distribution expenses Selling Expense Aircraft rent Aircraft Rental Special charges Other operating expenses Other Cost and Expense, Operating Total operating expense Operating income Interest expense Interest income Investment Income, Interest Miscellaneous, net Total nonoperating expense, net Income before income taxes Net income AA Class A A Pass Through Certificates [Member] Class A A Pass Through Certificates [Member] A Class A Pass Through Certificates [Member] Class A Pass Through Certificates [Member] B Class B Pass Through Certificates [Member] Class B Pass Through Certificates [Member] Period [Axis] Period [Axis] Period [Axis] Period [Domain] Period [Domain] Period [Domain] February 2019 February 2019 [Member] February 2019 [Member] May 2018 May Twenty Eighteen [Member] May Twenty Eighteen [Member] February 2018 February Twenty Eighteen [Member] February 2018. Principal Stated interest rate Total debt recorded Long-term Debt, Gross Proceeds received from issuance of debt Remaining proceeds from issuance of debt to be received in future periods Remaining Proceeds From Borrowings Amount of borrowing capacity currently available under the debt instrument (initial borrowing capacity less the amount of proceeds received). Secured Debt Secured Debt [Member] Unsecured Debt Unsecured Debt [Member] Notes payable, fixed interest rates of 0.0% to 9.52% (weighted average rate of 4.18% as of December 31, 2018), payable through 2030 Notes Payable Fixed Interest Rate Of Two Point Eight Eight Percent To Nine Point Five Two Percent Payable Through Two Thousand Twenty Eight [Member] Notes Payable Fixed Interest Rate Of Two Point Eight Eight Percent To Nine Point Five Two Percent Payable Through Two Thousand Twenty Eight [Member] Notes payable, floating interest rates of the London interbank offered rate (LIBOR) plus 1.05% to 1.75%, payable through 2030 Notes Payable Floating Interest Rates Of Libor Plus Zero Point Two Percent To Two Point Two Five Percent Payable Through Two Thousand Twenty Eight [Member] Notes Payable Floating Interest Rates Of Libor Plus Zero Point Two Percent To Two Point Two Five Percent Payable Through Two Thousand Twenty Eight [Member] Term loan, LIBOR plus 1.75%, or alternative rate based on certain market rates plus 0.75%, due 2024 Term Loan Facility Due Twenty Twenty Four [Member] Term loan facility due twenty twenty four. Other Other Debt [Member] Other Debt [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Alternative Rate Based on Certain Market Interest Rates Certain Market Interest Rates [Member] Certain Market Interest Rates [Member] Long term debt Less: unamortized debt discount, premiums and debt issuance costs Debt Instrument Unamortized Discount Premium and Debt Issuance Costs Debt Instrument Unamortized Discount Premium and Debt Issuance Costs Less: current portion of long-term debt Long-term debt, net Weighted average rate Long-term Debt, Weighted Average Interest Rate, at Point in Time Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Curtailment gain Amortization of unrecognized actuarial (gain) loss Defined Benefit Plan, Amortization of Gain (Loss) Amortization of prior service credits Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Other Defined Benefit Plan, Other Cost (Credit) Net periodic benefit cost (credit) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Term Loan due April 1, 2024 Term Loan Facility Due April One Two Thousand Twenty Four[Member] Term loan facility due April one two thousand twenty four. Revolving Credit Facility Available for Drawing until April 1, 2022 Revolving Credit Facility Available For Drawing Until April One Two Thousand Twenty Two [Member] Revolving credit facility available for drawing until April one two thousand twenty two. Revolving Credit Facility Revolving Credit Facility [Member] Letters of Credit Letter of Credit [Member] Surety Bond Surety Bond [Member] Term Loan due April 1, 2024 Term Loan Due April One Two Thousand Twenty Four [Member] Term loan due April one two thousand twenty four. Pass-Through Certificates Pass Through Certificates [Member] Pass Through Certificates [Member] Debt Security [Axis] Debt Security [Axis] Major Types of Debt Securities [Domain] Major Types of Debt Securities [Domain] Cash Collateralized Letters of Credit Collateralized Debt Obligations [Member] Aggregate principal amount Debt instrument maturity date Debt Instrument, Maturity Date Credit agreement Line of Credit Facility, Maximum Borrowing Capacity Revolving credit facility available for drawing date Line of Credit Facility, Expiration Date Quarterly principal repayment amount Longterm Debt Maturities Repayments of Principal in Quarterly Installments Percent Longterm Debt Maturities Repayments of Principal in Quarterly Installments Percent Commitment fee percentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Available under revolving credit facility Line of Credit Facility, Remaining Borrowing Capacity Credit facility outstanding amount Long-term Line of Credit Credit facility expiration year Line Of Credit Facility Maturity Year Line Of Credit Facility Maturity Year Notes repurchase price Debt Instrument, Redemption Price, Percentage Common Stockholders' Equity and Preferred Securities Stockholders' Equity Note Disclosure [Text Block] Capital Leases And Operating Leases [Table] Capital Leases And Operating Leases [Table] Capital Leases And Operating Leases [Table] Facility and Other Operating Leases Facility And Other Operating Leases [Member] Facility and Other Operating Leases Airport Construction Projects Airport Construction Projects [Member] Airport construction projects. Capital Leases And Operating Leases [Line Items] Capital Leases And Operating Leases [Line Items] Capital Leases And Operating Leases [Line Items] Capital Leases Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2019 Capital Leases, Future Minimum Payments Due, Next Twelve Months 2020 Capital Leases, Future Minimum Payments Due in Two Years 2021 Capital Leases, Future Minimum Payments Due in Three Years 2022 Capital Leases, Future Minimum Payments Due in Four Years 2023 Capital Leases, Future Minimum Payments Due in Five Years After 2023 Capital Leases, Future Minimum Payments Due Thereafter Minimum lease payments Capital Leases, Future Minimum Payments, Net Minimum Payments Imputed interest Capital Leases, Future Minimum Payments, Interest Included in Payments Present value of minimum lease payments Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments Current portion Long-term obligations under capital leases Operating Leases Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2019 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2020 Operating Leases, Future Minimum Payments, Due in Two Years 2021 Operating Leases, Future Minimum Payments, Due in Three Years 2022 Operating Leases, Future Minimum Payments, Due in Four Years 2023 Operating Leases, Future Minimum Payments, Due in Five Years After 2023 Operating Leases, Future Minimum Payments, Due Thereafter Minimum lease payments Operating property and equipment under capital leases Property, Plant and Equipment, Other, Net Obligations under capital leases