Summary of Commitments to Purchase Aircraft Long-term Purchase Commitment [Table Text Block] Awards granted (in shares) Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Intangibles Deferred Tax Liabilities, Intangible Assets Percent of total Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Intrinsic value of stock options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Extended expiration period for refundable tickets Refundable Tickets, Temporary Expiration Period Refundable Tickets, Temporary Expiration Period Change in projected benefit obligation: Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Expected employer contributions to pension and postretirement plans Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Bridge Loan Bridge Loan [Member] Total miles awarded Frequent Flyer Mileage Miles Awarded in Period Frequent flyer mileage miles awarded in period. Change in plan assets: Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Recorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Recorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Aircraft Fuel, Spare Parts and Supplies Aircraft Fuel Spare Parts And Supplies [Policy Text Block] Aircraft Fuel Spare Parts And Supplies Percent of capacity cut Unusual Or Infrequent Items, Percent Of Capacity Cut Unusual Or Infrequent Items, Percent Of Capacity Cut Third-Party Business Third Party Business [Policy Text Block] Third Party Business Policy State rate change Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Frequent flyer deferred revenue Contract With Customer, Liability, Current, Frequent Flyer Contract With Customer, Liability, Current, Frequent Flyer Number of employee furloughs Number Of Employees Furloughed Number Of Employees Furloughed Statistical Measurement [Domain] Statistical Measurement [Domain] LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity [Abstract] Net Operating Loss Carryforward, By Expiration [Axis] Net Operating Loss Carryforward, By Expiration [Axis] Net Operating Loss Carryforward, By Expiration [Axis] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Landing fees and other rent Landing Fees and Other Rentals Amortization of finance lease assets Finance Lease, Right-of-Use Asset, Amortization Investment in affiliates Payments to Acquire Interest in Subsidiaries and Affiliates Salaries and related costs Labor and Related Expense Kingsland Kingsland Holdings Limited [Member] Kingsland Holdings Limited [Member] Preferred Stock Preferred Stock [Member] Security Exchange Name Security Exchange Name Debt Instrument, Interest Rate Period [Axis] Debt Instrument, Interest Rate Period [Axis] Debt Instrument, Interest Rate Period [Axis] Fair value of plan assets at beginning of year Fair value of plan assets at end of year Fair value of plan assets Defined Benefit Plan, Plan Assets, Amount Variable rate floor Debt Instrument, Variable Rate Floor Debt Instrument, Variable Rate Floor Proceeds from issuance of debt Proceeds received from issuance of debt Proceeds from Issuance of Long-term Debt Number of warrants issuable under agreement (up to) Class of Warrant or Right, Number Of Securities Called by Warrants Or Rights Issuable Under Agreement Class of Warrant or Right, Number Of Securities Called by Warrants Or Rights Issuable Under Agreement Total current liabilities Liabilities, Current Curtailment Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment Number of employees notified of plans for workforce reduction Number Of Employees Notified Of Plans For Workforce Reduction Number Of Employees Notified Of Plans For Workforce Reduction Prepaid expenses and other Prepaid Expense and Other Assets, Current Outstanding (in dollars per share) 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 Variable Rate [Domain] Variable Rate [Domain] 2025 Defined Benefit Plan, Expected Future Benefit Payment, Year Five Minimum lease payments Finance Lease, Liability, Payment, Due ASSETS Assets [Abstract] Investment, Name [Axis] Investment, Name [Axis] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Accounting Policies [Abstract] Accounting Policies [Abstract] Net treasury stock issued for share-based awards Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture Operating cash flows for operating leases Operating Lease, Payments 2023 Long-Term Debt, Maturity, Year Three Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] One-time payment Revenue from Contract with Customer, One-Time Payment Recognized Revenue from Contract with Customer, One-Time Payment Recognized Cash Paid (Refunded) During the Period for: Cash Paid Refunded During Period For [Abstract] Cash Paid Refunded During Period For [Abstract] Boeing 737 MAX Boeing 737 Max [Member] Boeing 737 Max Property and equipment acquired through the issuance of debt, finance leases and other Noncash or Part Noncash Acquisition, Fixed Assets Acquired 2021 Lessee, Operating Lease, Liability, to be Paid, Year One Repurchases of common stock (in shares) Number of shares repurchased (in shares) Treasury Stock, Shares, Acquired Balance, deferred taxes Balance, deferred taxes AOCI Tax, Attributable to Parent Stock option awards outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number 2024 Lessee, Operating Lease, Liability, to be Paid, Year Four 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] Balance, before tax Balance, before tax AOCI before Tax, Attributable to Parent Unearned compensation Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Underlying debt and interest Guarantor obligations, maximum exposure Guarantor Obligations, Maximum Exposure, Undiscounted Tax credits Tax Credit Carryforward, Amount Preferred stock Preferred Stock, Value, Issued 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] Class A EETC - Issued September 2019 Class A Pass-Through Certificates Issued September 2019 [Member] Class A Pass-Through Certificates Issued September 2019 [Member] Tangible asset impairment charges Tangible Asset Impairment Charges Buildings Building [Member] Other comprehensive income (loss), net of tax: Other Comprehensive Income (Loss), Net of Tax [Abstract] Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share 2023 Defined Benefit Plan, Expected Future Benefit Payment, Year Three Number of employees subject to voluntary options Number Of Employees Subject To Voluntary Options Number Of Employees Subject To Voluntary Options Other Other Liabilities, Noncurrent Deferred income taxes Deferred Income Tax Assets, Net Principal payments under finance leases Financing cash flows for finance leases Finance Lease, Principal Payments Document Information [Table] Document Information [Table] Valuation allowance for deferred tax assets SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member] Payments for defined benefit plan settlements Defined Benefit Plan, Benefit Obligation, Payment for Settlement Measurement Frequency [Domain] Measurement Frequency [Domain] Schedule of Multiemployer Plans [Table] Multiemployer Plan [Table] 2026 Net Operating Loss Carry Forward Expiration Year 2026 [Member] Net Operating Loss Carry Forward Expiration Year 2026 [Member] Fair value of plan assets Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] Statement [Line Items] Statement [Line Items] Voluntary pay reduction Executive And Director Compensation, Voluntary Decrease In Salary, Percent Executive And Director Compensation, Voluntary Decrease In Salary, Percent Class of Stock [Domain] Class of Stock [Domain] Notes Receivables Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Term of debt Debt Instrument, Term Write-off of unexercised aircraft purchase Special Charges Adjustment Write Off Unexercise And Impairments Of Aircraft Special Charges Adjustment Write Off Unexercise And Impairments Of Aircraft Statement [Table] Statement [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Employee benefits, including pension, postretirement and medical Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits Type of Restructuring [Domain] Type of Restructuring [Domain] Interest cost Defined Benefit Plan, Interest Cost Statistical Measurement [Axis] Statistical Measurement [Axis] Scheduled aircraft deliveries in 2022 Number Of Aircrafts Expected To Take Delivery, Year Two Number Of Aircrafts Expected To Take Delivery, Year Two Unusual or Infrequent Items, or Both [Abstract] Strike price (in dollars per share) Class of Warrant or Right, Exercise Price of Warrants or Rights Airline Destinations [Axis] Airline Destinations [Axis] Entity Small Business Entity Small Business Total Unrecorded Unconditional Purchase Obligation DIP Loan Debtor-In-Possession Loan (DIP Loan) [Member] Debtor-In-Possession Loan (DIP Loan) Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Scheduled aircraft deliveries for 2023 from new firm orders Number Of Aircrafts Expected To Take Delivery, New Purchases, Year Three Number Of Aircrafts Expected To Take Delivery, New Purchases, Year Three Increase in postretirement benefit liability if there was a 50 basis point decrease in the weighted average discount rate Defined Benefit Plan, Effect Of 50 Basis Point Decrease In Discount Rate On Accumulated Postretirement Benefit Obligation Defined Benefit Plan Effect Of 50 Basis Point Decrease In Discount Rate On Accumulated Postretirement Benefit Obligation Amendment Flag Amendment Flag Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Amounts reclassified to earnings Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent (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. Measurement Frequency [Axis] Measurement Frequency [Axis] 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] Notes Unsecured Notes [Member] Unsecured Notes Financial Instruments [Domain] Financial Instruments [Domain] Surety Bonds Surety Bond [Member] Frequent flyer database Frequent Flyer Database [Member] Frequent Flyer Database [Member] Carrying Values and Estimated Fair Values of Financial Instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Fair Value Measurement [Domain] Fair Value Measurement [Domain] Standby Letter of Credit Standby Letters of Credit [Member] Net Operating Loss Carryforward, By Expiration [Domain] Net Operating Loss Carryforward, By Expiration [Domain] [Domain] for Net Operating Loss Carryforward, By Expiration [Axis] Scheduled aircraft deliveries for 2022 from rescheduled deliveries Number Of Aircrafts Expected To Take Delivery, Rescheduled Deliveries, Year Two Number Of Aircrafts Expected To Take Delivery, Rescheduled Deliveries, Year Two Debt instrument, remaining terms Debt Instrument Remaining Terms Years remaining on debt instruments. Long-Lived Tangible Asset [Axis] Long-Lived Tangible Asset [Axis] Summary of RSU and Restricted Stock Activity Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block] Balance at Beginning of Period Balance at End of Period SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount Receivables, allowance for doubtful accounts Accounts Receivable, Allowance for Credit Loss, Current 2022 Lessee, Operating Lease, Liability, to be Paid, Year Two Class AA EETC - Issued September 2019 Class AA Pass-Through Certificates Issued September 2019 [Member] Class AA Pass-Through Certificates Issued September 2019 [Member] State State and Local Jurisdiction [Member] Aircraft, spare engines and related rotable parts Aircraft And Related Rotable Parts [Member] Aircraft And Related Rotable Parts [Member] Deferred revenue Deferred Tax Assets, Deferred Income Components of Lease Cost Lease, Cost [Table Text Block] Cash collateral for a standby letter of credit Cash Collateral for Borrowed Securities Aircraft Mortgage Debt Aircraft Mortgage Debt [Member] Aircraft Mortgage Debt [Member] 2023 Lessee, Operating Lease, Liability, to be Paid, Year Three Total other assets Other Assets, Noncurrent Aircraft [Domain] Aircraft [Domain] Airbus A319 Airbus A319s [Member] Airbus A319s [Member] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Total assets Assets ManaAir ManaAir, LLC [Member] ManaAir, LLC [Member] Reconciliation of the Change in Benefit Obligation and Plan Assets and Funded Status Schedule of Net Funded Status [Table Text Block] Outstanding (in shares) Outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Finance Leases Finance Lease, Liability, Payment, Due [Abstract] Amortization of prior service credits Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Pension and Other Postretirement Defined Benefit Plan, Expected Future Benefit Payment [Abstract] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Class of Warrant or Right [Axis] Class of Warrant or Right [Axis] 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 Payroll taxes deferred under the CARES Act Unusual Or Infrequent Event, Payroll Taxes Deferred Under CARES Act Unusual Or Infrequent Event, Payroll Taxes Deferred Under CARES Act Gain (loss) on equity securities Gain (loss) on equity securities Equity Securities, FV-NI, Unrealized Gain (Loss) Other Other Intangible Assets [Member] Amount of warrants issued as a percent of the principal amount of disbursements Class Of Warrant Or Right, Warrants To Be Issued As A Percent Of Principal Amount Class Of Warrant Or Right, Warrants To Be Issued As A Percent Of Principal Amount Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items] Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items] Defined Benefit Plans And Defined Contribution Plans Disclosures Retirement Plan Type [Axis] Retirement Plan Type [Axis] Imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Accumulated benefit obligation Defined Benefit Plan, Accumulated Benefit Obligation Plan participants' contributions Defined Benefit Plan, Plan Assets, Contributions by Plan Participant Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Level 1 Fair Value, Inputs, Level 1 [Member] After 2025 Unrecorded Unconditional Purchase Obligation, to be Paid, after Year Five Public Offering Public Offering [Member] Public Offering [Member] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] 2022 Unrecorded Unconditional Purchase Obligation, to be Paid, Year Two Profit sharing and payroll tax expense Defined Benefit Plan Profit Sharing And Payroll Tax Expense Defined Benefit Plan Profit Sharing And Payroll Tax Expense Voluntary Early Out Program Voluntary Early Out Program [Member] Voluntary Early Out Program [Member] Restricted cash Restricted Cash and Cash Equivalents, Noncurrent Awards Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Additional Capital Invested Additional Paid-in Capital [Member] Capacity Purchase Agreements Capacity Purchase Agreements [Member] Capacity Purchase Agreements Fair Value [Table] Fair Value [Table] Fair Value [Table] Other operating activities Other Operating Activities, Cash Flow Statement Movement in Deferred Revenue [Roll Forward] Movement In Contract With Customer Liability [Roll Forward] Movement In Contract With Customer Liability [Roll Forward] Class A EETC - Issued October 2020 Class A Pass-Through Certificates Issued October 2020 [Member] Class A Pass-Through Certificates Issued October 2020 Asset Class Asset Class [Axis] Interest on finance lease liabilities Finance Lease, Interest Expense Cash and Cash Equivalents [Line Items] Cash and Cash Equivalents [Line Items] Investments in securities accounted for under the equity method Equity Method Investments Common shares, outstanding (in shares) Balance (in shares) Balance (in shares) Common Stock, Shares, Outstanding Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] 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 Revolving Credit Facility Revolving Credit Facility [Member] Variable Interest Entities (VIE) Variable Interest Entity Disclosure [Text Block] Income (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Purchases, sales, issuances and settlements (net) Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Purchase, Sale, and Settlement 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 Common shares, authorized (in shares) Common Stock, Shares Authorized Effect of share-based awards (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements 2022 Defined Benefit Plan, Expected Future Benefit Payment, Year Two Special termination benefit Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Funded status—Net amount recognized Defined Benefit Plan, Funded (Unfunded) Status of Plan SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] Equity stake Equity Securities, Ownership Percentage Equity Securities, Ownership Percentage Income Statement [Abstract] Income Statement [Abstract] 2025 Unrecorded Unconditional Purchase Obligation, to be Paid, Year Five Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Operating lease liabilities Deferred Tax Asset, Leasing Arrangements Deferred Tax Asset, Leasing Arrangements Less: unamortized debt discount, premiums and debt issuance costs Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Use of Estimates Use of Estimates, Policy [Policy Text Block] Income Tax Authority [Domain] Income Tax Authority [Domain] Actual return (loss) on plan assets: Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Purchase, Sale, and Settlement [Abstract] Tax-Exempt Special Facilities Revenue Bonds Tax Exempt Bonds [Member] Tax Exempt Bonds [Member] Severance and benefit costs Severance and benefit expenses Postemployment Benefits, Period Expense Assumptions Used for Benefit Plans Defined Benefit Plan, Assumptions [Table Text Block] Computer software Software and Software Development Costs [Member] Commitments and Contingencies [Table] Commitments and Contingencies [Table] Commitments And Contingencies [Table] Other Defined Benefit Plan Other Changes Plan Assets Defined benefit plan other changes plan assets Lease modifications and lease conversions Lease Conversions From Operating Lease Recorded Property Plant And Equipment Lease Conversions From Operating Lease Recorded Property Plant And Equipment Scenario [Domain] Scenario [Domain] Counterparty Name [Domain] Counterparty Name [Domain] Decrease in expected long-term rate of return on plan assets if there was a 50 basis point decrease in the weighted average discount rate Defined Benefit Plan, Effect Of 50 Basis Point Decrease In Discount Rate On Expected Return On Plan Assets Defined Benefit Plan, Effect Of 50 Basis Point Decrease In Discount Rate On Expected Return On Plan Assets Debt Long-term Debt [Text Block] Expiration period for advance ticket sales Electronic Travel Certificates, Expiration Period Electronic Travel Certificates, Expiration Period 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 Actual return on plan assets Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Common stock reserved for future issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Non-Employee Directors Director [Member] Hong Kong Routes Airline Routes - Hong Kong [Member] Airline Routes [Member] Chase and Other Partner Agreements Chase And Other Partner Agreements [Member] Chase And Other Partner Agreements [Member] Aircraft rent Aircraft Rental Total funding provided under the Payroll Support Program Payroll Support Program, Funding Provided Payroll Support Program, Total Funding Provided Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Years 2026 – 2030 Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years Change in value, deferred tax Other Comprehensive Income (Loss) before Reclassifications, Tax Cargo Cargo and Freight [Member] Equity securities Carrying value of investment Equity Securities, FV-NI Entity [Domain] Entity [Domain] Other investments measured at NAV Other Investments Measured At Net Asset Value [Member] Other Investments Measured At Net Asset Value [Member] Components of Special Charges Restructuring and Related Costs [Table Text Block] Selected Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Fulcrum Fulcrum BioEnergy, Inc. [Member] Fulcrum BioEnergy, Inc. [Member] Number of aircraft subject to finance leases Number Of Aircraft Subject To Finance Leases Number Of Aircraft Subject To Finance Leases Estimated useful life Property, Plant and Equipment, Useful Life Operating property and equipment: Property, Plant and Equipment, Net [Abstract] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Boeing 737-700 Boeing 737-700 [Member] Boeing 737-700 [Member] Obsolescence allowance-spare parts SEC Schedule, 12-09, Reserve, Inventory [Member] Net deferred tax asset Deferred Tax Assets, Net Proceeds from equity issuance Proceeds from Issuance or Sale of Equity Restricted stock Restricted  Stock Restricted Stock [Member] Share-based Payment Arrangement [Abstract] Share-based Payment Arrangement [Abstract] Current maturities of operating leases Less: current maturities of lease obligations Operating Lease, Liability, Current Rate to which the cost trend rate is assumed to decline (ultimate trend rate in 2033) Defined Benefit Plan, Ultimate Health Care Cost Trend Rate Class of Financing Receivable [Domain] Class of Financing Receivable [Domain] 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 Investments and Fair Value Measurements Fair Value Disclosures [Text Block] Alternatives Alternatives Alternative [Member] Alternative [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] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] 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 PSP2 Warrants Payroll Support Program 2 (PSP2) Warrants [Member] Payroll Support Program 2 (PSP2) Warrants Adoption of New Accounting Standard Cumulative Effect, Period of Adoption, Adjustment [Member] Intangibles Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block] Additional capital invested Additional Paid in Capital, Common Stock IAM National Pension Plan International Association Of Machinists National Pension Plan [Member] International Association of Machinists National Pension Plan [Member] Entity Registrant Name Entity Registrant Name Subsequent Event Type [Domain] Subsequent Event Type [Domain] Weighted-average discount rate - operating leases Operating Lease, Weighted Average Discount Rate, Percent Increase in advance ticket sales Increase (Decrease) In Contract With Customer, Liability, Advance Ticket Sales Increase (Decrease) in Contract with Customer, Liability, Advance Ticket Sales Decrease in other liabilities Increase (Decrease) in Other Operating Liabilities Impairment of assets Asset Impairment Charges Proceeds from issuance of warrants Proceeds from Issuance of Warrants Total special charges and unrealized (gains) losses on investments Special Charges And Losses On Financial Instruments, Non-Operating, Before Tax Special Charges And Losses On Financial Instruments, Nonoperating, Before Tax Spare Engines Facility Spare Engines Credit Agreement [Member] Spare Engines Credit Agreement Imputed interest Finance Lease, Liability, Undiscounted Excess Amount Increase in intercompany receivables Increase (Decrease) Due from Affiliates Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Purchase deposits for flight equipment Deposits on Flight Equipment Excise taxes refunded to customers but still outstanding from the U.S. government Excise Tax Refunds Receivable Excise Tax Refunds Receivable Other Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Other Change Share price (in dollars per share) Shares Issued, Price Per Share Reconciliation of Cash, Cash Equivalents and Restricted Cash Schedule of Cash and Cash Equivalents [Table Text Block] Restricted cash Restricted Cash, Noncurrent Tax credit expiration period Tax Credit Carryforward, Expiration Period Tax Credit Carryforward, Expiration Period Sale of Stock [Axis] Sale of Stock [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Number of firm commitments Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required COVID-19 [Member] COVID-19 [Member] COVID-19 Total deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Restructuring Type [Axis] Restructuring Type [Axis] Special Charges [Table] Special Charges [Table] Special Charges [Table] Distribution expenses Selling Expense Additional contribution as a percentage of the hourly contribution rate Multiemployer Plan, Additional Contribution Rate In Excess Of The Hourly Contribution Rate Multiemployer Plan, Additional Contribution Rate In Excess Of The Hourly Contribution Rate Goodwill Goodwill Description of Fair Value of Financial Instruments and Fair Value Methodology Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] CARES Act Credit Agreement CARES Act Credit Agreement [Member] CARES Act Credit Agreement Number of shares that may be put to United (in shares) Loans Receivable, Agreement, Put Options Loans Receivable, Agreement, Put Options Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Amounts reclassified to retained earnings 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. Preferred Stock Purchase Rights Warrant [Member] Federal and state net operating loss ("NOL") carryforwards Deferred Tax Assets, Operating Loss Carryforwards Operating and non-operating special charges, non-cash portion Restructuring Costs and Asset Impairment Charges Aggregate principal amount Principal Debt Instrument, Face Amount Asset Class [Domain] Asset Class [Domain] Equity [Abstract] Equity [Abstract] Aircraft Engines Aircraft Engines [Member] Aircraft Engines [Member] Investing and Financing Activities Not Affecting Cash: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Information about Goodwill and Other Intangible Assets Schedule of Intangible Assets and Goodwill [Table Text Block] SOFR Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Convertible Term Loan Convertible Term Loan [Member] Convertible Term Loan [Member] Contract liabilities Contract with Customer, Liability, Current Accounting Standards Update [Extensible List] Accounting Standards Update [Extensible List] 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 Scheduled aircraft deliveries after 2022 Number Of Aircrafts Expected To Take Delivery, Thereafter Number Of Aircrafts Expected To Take Delivery, Thereafter Diluted weighted-average shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Defined Contribution Plan [Table] Defined Contribution Plan [Table] Number of operating segments Number of Operating Segments Debt Disclosure [Abstract] Debt Disclosure [Abstract] Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period CARES Act Term Loan Facility CARES Act Term Loan Facility [Member] CARES Act Term Loan Facility Unsecured Debt Unsecured Unsecured Debt [Member] Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Payments of long-term debt Repayments of Long-term Debt Warrants issued Adjustments to Additional Paid in Capital, Warrant Issued After 2025 Contractual Obligation, to be Paid, after Year Five Change in cash obligation Increase (Decrease) in Cash Obligation Increase (Decrease) in Cash Obligation Non-Aircraft Non-Aircraft [Member] Non-Aircraft [Member] Unrecognized tax benefits Unrecognized Tax Benefits Counterparty Name [Axis] Counterparty Name [Axis] Common stock Common Stock, Value, Issued 2024 Defined Benefit Plan, Expected Future Benefit Payment, Year Four Liabilities related to share based payments Deferred Compensation Share-based Arrangements, Liability, Current and Noncurrent Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Document Fiscal Year Focus Document Fiscal Year Focus Other assets Other Long-term Investments Mainline Aircraft Mainline [Member] Projected amortization expense in 2022 Finite-Lived Intangible Asset, Expected Amortization, Year Two Airbus A321XLR Airbus A321XLR [Member] Airbus A321XLR [Member] Restricted cash Restricted Cash, Current SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract] SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract] Current maturities of long-term debt Less: current portion of long-term debt Long-term Debt, Current Maturities Projected benefit obligation at beginning of year Projected benefit obligation at end of year Defined Benefit Plan, Benefit Obligation Entity Current Reporting Status Entity Current Reporting Status Severance payment per participant Restructuring and Related Cost, Expected Cost Aircraft fuel, spare parts and supplies, less obsolescence allowance (2020—$478; 2019—$425) Airline Related Inventory, Net Sold during the year Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Actual Return (Loss) on Plan Assets Sold Impact of Significant Items on Quarterly Results Schedule Of Quarterly Reporting [Table Text Block] Schedule Of Quarterly Reporting Table. Common shares, issued (in shares) Common Stock, Shares, Issued Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Equity Distribution Agreement Equity Distribution Agreement [Member] Equity Distribution Agreement [Member] Funding provided through loans under the Payroll Support Program Payroll Support Program, Funding Provided, Amounts Received Through Loans Payroll Support Program, Funding Provided, Amounts Received Through Loans Present value of minimum lease payments Operating Lease, Liability Net deferred tax asset (liability) Deferred Tax Liabilities, Net Long-term debt Long-term debt, net Long-term Debt, Excluding Current Maturities 2024 Contractual Obligation, to be Paid, Year Four Summary Of Significant Accounting Policies [Line Items] Summary Of Significant Accounting Policies [Line Items] Summary Of Significant Accounting Policies [Line Items] Debt Instrument [Line Items] Debt Instrument [Line Items] Total stockholders' equity Balance Balance Stockholders' equity Stockholders' Equity Attributable to Parent Investments and other Other Comprehensive Income, Investments and Other, Net of Tax Other Comprehensive Income, Investments and Other, Net of Tax Fair Value [Line Items] Fair Value [Line Items] Fair Value [Line Items] Foreign tax rate differential Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount 2024 Unrecorded Unconditional Purchase Obligation, to be Paid, Year Four Unrestricted liquidity required for credit agreement Debt Covenant, Required Liquidity Debt Covenant, Required Liquidity Tax effected amount of NOLs Operating Loss Carryforwards, Tax Effected Amount Operating Loss Carryforwards, Tax Effected Amount Total operating and nonoperating special charges (credit) and unrealized (gains) losses on investments Total operating and nonoperating special charges (credit) and unrealized (gains) losses on investments Special Charges And Losses On Financial Instruments, Operating And Nonoperating, Before Tax Special Charges And Losses On Financial Instruments, Operating And Nonoperating, Before Tax Dividend to UAL Payments Of Dividends To Parent Company Payments of dividends to parent company. Entity Address, City or Town Entity Address, City or Town (Receivable from) Payable to Related Parties, Net Receivables from Stockholder [Member] 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. Accrued salaries and benefits Employee-related Liabilities, Current Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] RSUs Restricted Stock Units (RSUs) [Member] Health care cost trend rate assumed for next year Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year Other assets: Other Assets, Noncurrent [Abstract] 2025 Lessee, Operating Lease, Liability, to be Paid, Year Five Borrowings Financing Aircraft Purchases Aircraft Purchase Financing Loans [Member] Aircraft Purchase Financing Loans [Member] Financial Instrument [Axis] Financial Instrument [Axis] Time-Vested RSUs Time-Vested Restricted Stock Units (RSUs) [Member] Time-Vested Restricted Stock Units (RSUs) [Member] Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets [Axis] NOL and tax credit carryforwards, valuation allowance Operating Loss Carryforwards And Tax Credit Carryforwards, Valuation Allowance Operating Loss Carryforwards And Tax Credit Carryforwards, Valuation Allowance Debt associated with termination of a maintenance service agreement Noncash Investing And Financing Items, Debt Associated With Termination Of Maintenance Service Agreement Noncash Investing And Financing Items, Debt Associated With Termination Of Maintenance Service Agreement Operating lease right-of-use asset Deferred Tax Liabilities, Leasing Arrangements Less: Valuation allowance Deferred Tax Assets, Valuation Allowance Frequent flyer deferred revenue Contract With Customer, Liability, Noncurrent, Frequent Flyer Contract With Customer, Liability, Noncurrent, Frequent Flyer Projected amortization expense in 2023 Finite-Lived Intangible Asset, Expected Amortization, Year Three Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Term of warrants Warrants and Rights Outstanding, Term Long-term obligations under finance leases Long-term lease obligations Finance Lease, Liability, Noncurrent Other Other Liabilities, Current Impairment of right-of-use assets Impairment of Leasehold Investment, Name [Domain] Investment, Name [Domain] Total other comprehensive income (loss), net of tax Other comprehensive loss Other Comprehensive Income (Loss), Net of Tax Aircraft Type [Axis] Aircraft Type [Axis] Leases [Abstract] Leases [Abstract] Accounts payable Accounts Payable, Related Parties, Current Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Total current assets Assets, Current Republic Republic Airways Holdings, Inc. [Member] Republic Airways Holdings, Inc. [Member] NOL carryforwards Operating Loss Carryforwards Earnings Per Share [Abstract] Earnings Per Share [Abstract] Frequent Flyer Accounting Frequent Flier Program, Policy [Policy Text Block] Temporary Differences and Carryforwards Giving Rise to Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [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 Assets Measured at NAV Fair Value Measured at Net Asset Value Per Share [Member] Total operating property and equipment Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, before Accumulated Depreciation and Amortization Pension and Other Postretirement Liabilities Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Stockholders' equity: Stockholders' Equity Attributable to Parent [Abstract] Projected amortization expense in 2025 Finite-Lived Intangible Asset, Expected Amortization, Year Five Document Fiscal Period Focus Document Fiscal Period Focus Latin America Latin America Destination [Member] Additional Information Related to Leases Lessee, Operating And Finance Leases, Weighted-Average Assumptions [Table Text Block] Lessee, Operating And Finance Leases, Weighted-Average Assumptions [Table Text Block] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] Certificates of deposit placed through an account registry service Certificates of Deposit [Member] Amounts to be used for the payment of fees, principal and interest Restricted Cash, Amounts To Be Used For Borrowing Fees, Principal, And Interest Restricted Cash, Amounts To Be Used For Borrowing Fees, Principal, And Interest Charges for the settlement of certain legal matters Gain (Loss) Related to Litigation Settlement Pension liability Liability, Defined Benefit Pension Plan, Noncurrent Lease terms of additional leases that have not yet commenced (up to) Lessee, Operating And Finance Lease, Not Yet Commenced, Term Of Contract Lessee, Operating And Finance Lease, Not Yet Commenced, Term Of Contract Employer contributions Defined Benefit Plan, Plan Assets, Contributions by Employer Mortgage Mortgages [Member] Investments in affiliates and other, net Investments and Other Noncurrent Assets Entity Filer Category Entity Filer Category Common Stock Common Stock [Member] Product and Service [Domain] Product and Service [Domain] Cash received under the Payroll Support Program Proceeds From Government Assistance Proceeds From Government Assistance Nondeductible employee meals Effective Income Tax Rate Reconciliation, Nondeductible Expense, Meals and Entertainment, Amount CARES Act grant Portion of grant recognized as a credit to special charges Unusual or Infrequent Item, or Both, Gain, Gross Weighted-average discount rate - 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Increase (Decrease) in Other Operating Assets and Liabilities, Net [Abstract] Operating income (loss) Loss from operations Operating Income (Loss) Capitalized financing costs Payments of Debt Issuance Costs AVH Avianca Holdings S.A. (“AVH”) [Member] Avianca Holdings S.A. 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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] 2021 Finance Lease, Liability, to be Paid, Year One Brazil Routes Airline Routes - Brazil [Member] Airline Routes - Brazil [Member] Regional capacity purchase Airline, Capacity Purchase Arrangements Aircraft fuel, spare parts and supplies, obsolescence allowance Airline Related Inventory, Valuation Reserves Total lease cost Lease, Cost Stock option awards exercisable (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Other, net Payments for (Proceeds from) Other Investing Activities Stock-settled share-based compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition After 2025 Long-Term Debt, Maturity, after Year Five Operating revenue Revenue Revenue from Contract with Customer, Excluding Assessed Tax Number of technicians and related employees electing to voluntarily separate from the Company Number Of Employees Voluntarily Separated Number Of Employees Voluntarily Separated Advertising expense Advertising Expense Settlement losses Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Fixed-income securities Fixed Income Funds [Member] Forecast Forecast [Member] Debt Instrument, Interest Rate Period [Domain] Debt Instrument, Interest Rate Period [Domain] Debt Instrument, Interest Rate Period Unrealized gains (losses) on investments, net Unrealized (gains) losses on investments Unrealized Gain (Loss) on Investments Entity Voluntary Filers Entity Voluntary Filers Scheduled aircraft deliveries in 2021 Number Of Aircrafts Expected To Take Delivery, Year One Number Of Aircrafts Expected To Take Delivery, Year One Flight equipment Flight Equipment, Gross Expenses Costs and Expenses, Related Party Credit Facility [Axis] Credit Facility [Axis] Assumptions used to determine benefit obligations Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract] U.S. government and agency notes US Government Agencies Debt Securities [Member] Restructuring and Related Activities [Abstract] Restructuring and Related Activities [Abstract] Multiemployer Plan Name [Domain] Retirement Plan Name [Domain] Operating Leases Lessee, Operating Lease, Liability, Payment, Due [Abstract] Class B EETC - Issued February 2021 Class A Pass-Through Certificates Issued February 2021 [Member] Class A Pass-Through Certificates Issued February 2021 Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] MileagePlus Senior Secured Notes Mileage Plus Senior Secured Notes 6.50% Senior Secured Notes Due 2027 (Mileage Plus Senior Secured Notes) [Member] 6.50% Senior Secured Notes Due 2027 (Mileage Plus Senior Secured Notes) 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 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 Proceeds from the issuance of common stock Proceeds from Issuance of Common Stock Computation of Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Leases and Capacity Purchase Agreements Lessee, Finance Leases [Text Block] Long-term line of credit Long-term Line of Credit Fair Value Information Fair Value Measurement, Policy [Policy Text Block] Other investments Other Investments [Member] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Axis] Net cash provided by (used in) operating activities Net Cash Provided by (Used in) 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Facility 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 Scheduled aircraft deliveries for 2023 from rescheduled deliveries Number Of Aircrafts Expected To Take Delivery, Rescheduled Deliveries, Year Three Number Of Aircrafts Expected To Take Delivery, Rescheduled Deliveries, Year Three Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding CLEAR CLEAR [Member] CLEAR Indefinite-lived Intangible Assets [Line Items] Indefinite-lived Intangible Assets [Line Items] Accounts Receivable Receivable [Policy Text Block] Amortization expense Amortization of Intangible Assets Sale of common stock Stock Issued During Period, Value, New Issues Receivables, less allowance for credit losses (2020—$78; 2019—$9) Receivables, Net, Current Operating cash flows for finance leases Finance Lease, Interest Payment on Liability Scenario [Axis] Scenario [Axis] Amounts recognized in accumulated other comprehensive loss consist of: Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract] Credit Agreement Warrants Credit Agreement Warrant Agreement [Member] Credit Agreement Warrant Agreement Title of 12(b) Security Title of 12(b) Security Gain (loss) on change in market value of equity investments Equity Securities, FV-NI, Gain (Loss) Plan length Multiemployer Plan, Plan Term Multiemployer Plan, Plan Term Noncurrent asset Assets for Plan Benefits, Defined Benefit Plan Cash Collateralized Letters of Credit Collateralized Debt Obligations [Member] CEO and President Chief Executive Officer [Member] Summary of Scheduled Future Minimum Lease Payments under Finance Leases Finance Lease, Liability, Fiscal Year Maturity [Table Text Block] 2021 Contractual Obligation, to be Paid, Year One Other (b) Stockholders' Equity, Other Depreciation and amortization Depreciation and amortization Depreciation, 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2028 [Member] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Increase (decrease) in accounts payable Increase (Decrease) in Accounts Payable Frequent Flyer Frequent Flyer Program [Member] Frequent Flyer Program [Member] Allowance for credit losses on notes receivable Financing Receivable, Allowance for Credit Loss Unrealized gain (loss) on derivative asset Unrealized loss on derivative assets Unrealized Gain (Loss) on Derivatives Debt Instrument [Axis] Debt Instrument [Axis] Summary of Selected Quarterly Financial Data Quarterly Financial Information [Table Text Block] Rolling cancellation period Unusual Or Infrequent Items, Rolling Flight Cancellation Period Unusual Or Infrequent Items, Rolling Flight Cancellation Period Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Class of Stock [Line Items] Class of Stock [Line Items] Repurchases of common stock Repurchases of common stock Treasury Stock, Value, Acquired, Cost Method Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities - Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Frequent flier program expiration period Frequent Flyer Mileage Program Expiration Period Frequent flyer mileage program expiration period. Other financial liabilities from sale-leasebacks Financial Liabilities, Sale-Leaseback Transactions, Noncurrent Financial Liabilities, Sale-Leaseback Transactions, Noncurrent Increase in principal amount as a percent of treasury disbursements Debt Instrument, Increase In Principal Amount As A Percent Of Treasury Disbursements Debt Instrument, Increase In Principal Amount As A Percent Of Treasury Disbursements State income taxes, net of federal income tax benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Number of shares issuable under Equity Distribution Agreement (up to) (in shares) Sale Of Stock, Number Of Shares Issuable Under Agreement Sale Of Stock, Number Of Shares Issuable Under Agreement Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Projected benefit obligation Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation Other miscellaneous impairments Other Asset Impairment Charges Years One through Five Debt Instrument, Interest Rate Period, Years 1 Through 5 [Member] Debt Instrument, Interest Rate Period, Years 1 Through 5 [Member] 2029 Net Operating Loss Carry Forward Expiration Year 2029 [Member] Net Operating Loss Carry Forward Expiration Year 2029 [Member] Subsequent Event Subsequent Event [Member] Federal Domestic Tax Authority [Member] Airbus A350 Airbus A350 [Member] Airbus A350 [Member] Number of aircraft included in flight equipment Number Of Aircraft In Sale-Leaseback Transaction Included In Flight Equipment Number Of Aircraft In Sale-Leaseback Transaction Included In Flight Equipment Uncertain Income Tax Positions Income Tax Uncertainties, Policy [Policy Text Block] Fair Value Estimate of Fair Value Measurement [Member] Pass-Through Certificates Pass-Through Certificates [Member] Pass-Through Certificates [Member] United Airlines, Inc. United Air Lines Inc [Member] United Airlines, Inc. [Member] Costs related to the transition of fleet types Gain (Loss) on Disposition of Assets Long-term obligations under operating leases Long-term lease obligations Operating Lease, Liability, Noncurrent Projected amortization expense in 2024 Finite-Lived Intangible Asset, Expected Amortization, Year Four Domestic (U.S. and Canada) Domestic Destination [Member] Number of aircraft delivered under sale and leaseback transaction Sale And Leaseback Transaction, Number Of Units Sold Sale And Leaseback Transaction, Number Of Units Sold Employee benefit plans Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Sale leaseback liabilities Deferred Tax Assets, Sale-Leaseback Liability Deferred Tax Assets, Sale-Leaseback Liability Current assets: Assets, Current [Abstract] Interest income Investment Income, Interest Investing Activities: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Short-term investments Investments, Fair Value Disclosure Airline Destination [Domain] Airline Destination [Domain] Total comprehensive income (loss), net Comprehensive Income (Loss), Net of Tax, Attributable to Parent 2023 Finance Lease, Liability, to be Paid, Year Three Junior preferred stock par value per share (in dollars per share) Preferred Stock, Par or Stated Value Per Share Documents Incorporated by Reference Documents Incorporated by Reference [Text Block] 2021 Long-Term Debt, Maturity, Year One 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] Number of shares pledged as collateral (in shares) Financing Receivable, Agreement, Shares Pledged As Collateral Financing Receivable, Agreement, Shares Pledged As Collateral Rate of compensation increase Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Deductions SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction Change in value OCI, before Reclassifications, Net of Tax, Attributable to Parent City Area Code City Area Code Legal Entity [Axis] Legal Entity [Axis] Class B EETC - Issued September 2019 Class B Pass-Through Certificates Issued September 2019 [Member] Class B Pass-Through Certificates Issued September 2019 [Member] Atlantic Atlantic Destination [Member] Income Tax Authority [Axis] Income Tax Authority [Axis] Airport slots and gates Airport Slots And Gates Indefinite Lived [Member] Airport Slots And Gates [Member] Document Period End Date Document Period End Date 2023 Unrecorded Unconditional Purchase Obligation, to be Paid, Year Three PSP2 Note Payroll Support Program 2 (PSP2) Note [Member] Payroll Support Program 2 (PSP2) Note Operating Revenue by Principal Geographic Region Disaggregation of Revenue [Table Text Block] Long-Lived Asset Impairments Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Quarterly Financial Information Disclosure [Abstract] Quarterly Financial Information Disclosure [Abstract] Information Related to Share-Based Compensation Plan Cost Share-based Payment Arrangement, Cost by Plan [Table Text Block] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Capital expenditures, net of flight equipment purchase deposit returns Payments to Acquire Productive Assets Other, net Proceeds from (Payments for) Other Financing Activities Cover [Abstract] Cover [Abstract] Employer contribution percentage Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Term Loan Term Loan Receivable [Member] Term Loan Receivable [Member] Losses due to the change in fair value of derivatives Derivative, Loss on Derivative Champlain Champlain Enterprises LLC [Member] Champlain Enterprises LLC [Member] Pacific Pacific Destination [Member] Other fixed-income securities Fixed Income Securities [Member] Long-term debt, carrying amount Long-term debt Long term debt Long-term Debt Leases and Capacity Purchase Agreements Lessee, Operating Leases [Text Block] Plan participants' contributions Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant Multiemployer Plan Name [Axis] Retirement Plan Name [Axis] Service cost Defined Benefit Plan, Service Cost Cash paid for amounts included in the measurement of lease liabilities: Cash Flow, Leases, Lessee [Abstract] Cash Flow, Leases, Lessee [Abstract] Total operating expense Costs and Expenses Variable and short-term lease cost Variable And Short-Term Lease, Cost Variable And Short-Term Lease, Cost Equity Components [Axis] Equity Components [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Allowance for credit losses - notes receivable SEC Schedule, 12-09, Allowance, Notes Receivable [Member] Receivables [Abstract] Receivables [Abstract] Minimum Minimum [Member] Alliances Alliances [Member] Alliances [Member] Total operating property and equipment, net Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization Income tax adjustments Income Tax Adjustments Income tax adjustments that include items such as deferred income tax expense in AOCI and valuation allowance adjustments. Accumulated benefit obligation Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation Supplemental Cash Flow Information Related to Leases Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Defined Benefit Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Plan Assets, Category [Domain] Equity securities Equity securities funds Defined Benefit Plan, Equity Securities [Member] Aircraft notes Used Aircraft Facility Used Aircraft Facility [Member] Used Aircraft Facility Asset-backed securities Asset-backed Securities Asset-backed Securities [Member] Amortization of unrecognized actuarial (gain) loss Defined Benefit Plan, Amortization of Gain (Loss) Amounts Recognized in Consolidated Balance Sheet and Accumulated Other Comprehensive Income (Loss) Schedule of Amounts Recognized in Balance Sheet [Table Text Block] 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 Entity Interactive Data Current Entity Interactive Data Current Net periodic benefit cost (credit) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Allocation of Plan Assets Schedule of Allocation of Plan Assets [Table Text Block] Reconciliation of Cash, Cash Equivalents and Restricted Cash Restrictions on Cash and Cash Equivalents [Table Text Block] Operating revenue: Revenues [Abstract] Common Stockholders' Equity and Preferred Securities Stockholders' Equity Note Disclosure [Text Block] Loans made to others Payments to Acquire Loans Receivable Share-Based Compensation Share-based Payment Arrangement [Policy Text Block] Unusual or Infrequent Item, or Both [Axis] Unusual or Infrequent Item, or Both [Axis] Total other liabilities and deferred credits Other Liabilities And Deferred Credits, Noncurrent Other Liabilities And Deferred Credits, Noncurrent Class of Warrant or Right [Domain] Class of Warrant or Right [Domain] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] 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] 2021 Defined Benefit Plan, Expected Future Benefit Payment, Year One Total deferred tax liabilities Deferred Tax Liabilities, Gross Advertising Advertising Cost [Policy Text Block] Other operating expenses Other Cost and Expense, Operating Boeing 787 Boeing 787 [Member] Boeing 787. Initial term of operating leases Lessee, Operating And Finance Leases, Term Of Contract Lessee, Operating And Finance Leases, Term Of Contract Retirement Plan Type [Domain] Retirement Plan Type [Domain] Summary of Unearned Compensation and Weighted-Average Remaining Period to Recognize Costs Share-based Payment Arrangement, Nonvested Award, Cost [Table Text Block] Aircraft fuel Fuel Costs Additions Charged to Costs and Expenses SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Cost and Expense United Airlines, Inc. and Kingsland International Group, S.A. United Airlines, Inc. and Kingsland International Group, S.A. [Member] United Airlines, Inc. and Kingsland International Group, S.A. [Member] Embraer E175 Embraer E175 [Member] Embraer E175 [Member] Minimum lease payments Lessee, Operating Lease, Liability, to be Paid 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 Other Deferred Tax Assets, Other Increase in benefits expense if there was a 50 basis point decrease in the weighted average discount rate Defined Benefit Plan, Effect Of 50 Basis Point Decrease In Discount Rate On Net Periodic Benefit Cost Defined Benefit Plan Effect Of 50 Basis Point Decrease In Discount Rate On Net Periodic Benefit Cost Income Taxes [Table] Income Taxes [Table] Income Taxes [Table] Document Transition Report Document Transition Report Title of Individual [Axis] Title of Individual [Axis] Income tax expense (benefit), net of valuation allowance Income tax expense (benefit), net of valuation allowance Income Tax Expense (Benefit) Special Charges Income tax expense (benefit) special charges. 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Document Annual Report Document Annual Report Dividend to UAL Capital Contributions To Parent Capital Contributions To Parent Settlement loss - VSPs Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due To Settlement, Restructuring Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due To Settlement, Restructuring Capacity purchase agreement liability converted to debt Noncash Investing And Financing Items, Debt Associated With Capacity Purchase Agreement Noncash Investing And Financing Items, Debt Associated With Capacity Purchase Agreement Intrinsic value of stock options exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value 2024 Finance Lease, Liability, to be Paid, Year Four Indirect Guarantee of Indebtedness Indirect Guarantee of Indebtedness [Member] Issuance of notes receivable Payments to Acquire Finance Receivables Retirement Benefits [Abstract] Retirement Benefits [Abstract] Available-for-sale securities remaining maturities Available for Sale Investment Maturity Term Available for Sale Investment Maturity Term Nonoperating special termination benefits and settlement losses Settlement losses related to defined benefit pension plans Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due To Settlement, Restructuring And Special And Contractual Termination Benefits Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due To Settlement, Restructuring And Special And Contractual Termination Benefits Net treasury stock issued for share-based awards (in shares) Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] 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 Liability Awards - 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VSPs Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due To Special And Contractual Termination Benefits Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due To Special And Contractual Termination Benefits Long-term debt, fair value Long-term Debt, Fair Value Cash and Cash Equivalents and Restricted Cash Cash and Cash Equivalents, Policy [Policy Text Block] Maintenance and Repairs Maintenance Cost, Policy [Policy Text Block] Income tax expense (benefit) Income tax expense (benefit) Income Tax Expense (Benefit) Cash, cash equivalents and restricted cash at beginning of year Cash, cash equivalents and restricted cash at end of year Total cash, cash equivalents and restricted cash shown in the statement of consolidated cash flows Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Property and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Contractual Principal Payments under Outstanding Long-Term Debt Agreements Schedule of Maturities of Long-term Debt [Table Text Block] Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Title of Individual [Domain] Title of Individual [Domain] 2022 Contractual Obligation, to be Paid, Year Two Current maturities of finance leases Less: current maturities of lease obligations Finance Lease, Liability, Current Long-term Purchase Commitment [Table] Long-term Purchase Commitment [Table] Local Phone Number Local Phone Number Cumulative Effect, Period of Adoption [Domain] Cumulative Effect, Period of Adoption [Domain] 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 Additional leases that have not yet commenced Lessee, Operating And Finance Lease, Not Yet Commenced, Amount Lessee, Operating And Finance Lease, Not Yet Commenced, Amount Labor Costs Labor Costs [Policy Text Block] Labor Costs Policy Long term debt Long term debt Total debt recorded Long-term Debt, Gross Summary of Collateral Covenants and Cross Default Provisions Schedule of Financial Covenants [Table Text Block] Schedule of Financial Covenants Interest rate Financing Receivable, Stated Interest Rate Financing Receivable, Stated Interest Rate Total Frequent flyer deferred revenue - beginning balance Total Frequent flyer deferred revenue - ending balance Contract with Customer, Liability (Increase) decrease in other assets Increase (Decrease) in Other Operating Assets Schedule II - Valuation and Qualifying Accounts SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Unusual or Infrequent Item, or Both [Table] Unusual or Infrequent Item, or Both [Table] Multiemployer Plans [Line Items] Multiemployer Plan [Line Items] Credit agreement Line of Credit Facility, Maximum Borrowing Capacity Assumptions used to determine net expense Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Award Type Award Type [Axis] 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] Discount rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Class of Financing Receivable [Axis] Class of Financing Receivable [Axis] 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 Overview Unusual or Infrequent Items, or Both, Disclosure [Text Block] Retained Earnings Retained Earnings [Member] Junior preferred stock outstanding (in shares) Preferred Stock, Shares Outstanding Measurement Basis Measurement Basis [Axis] Components Of Net Periodic Benefit Cost Schedule of Net Benefit Costs [Table Text Block] Significant Accounting Policies Significant Accounting Policies [Text Block] Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities 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 Term loan Term Loan Due 2024 [Member] Term Loan Due 2024 Travel miles redeemed (Passenger revenue) Travel Miles Redemption, Frequent Flyer Deferred Revenue Travel miles redemption, frequent flyer deferred revenue. Award Type [Domain] Award Type [Domain] Contingent liabilities based on participation Guarantor Obligations, Current Carrying Value Current liability Liability, Defined Benefit Plan, Current BRW BRW Aviation Holding LLC And BRW Aviation LLC (“BRW”) [Member] BRW Aviation Holding LLC and BRW Aviation LLC (“BRW”) [Member] Corporate debt Corporate Debt Corporate Debt Securities [Member] Surcharge imposed Multiemployer Plan, Pension, Significant, Surcharge [Fixed List] 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 Change in value, before tax OCI, before Reclassifications, before Tax, Attributable to Parent Commitment fee percentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Stock held in treasury, at cost Treasury Stock, Value Pension Benefits Pension Plan [Member] Earnings (Loss) Per Share Earnings Per Share [Text Block] Discount rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Other liabilities and deferred credits: Deferred Credits and Other Liabilities [Abstract] Current liabilities: Liabilities, Current [Abstract] Financing Activities: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Recently Issued Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Proceeds from lines of credit Proceeds from Lines of Credit Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Alternative Rate Based on Certain Market Interest Rates Certain Market Interest Rates [Member] Certain Market Interest Rates [Member] Aircraft seats Aircraft Seats [Member] Aircraft Seats [Member] Short-term investments Short-term Investments