$UAL
United Airlines Holdings, Inc. Stock $ual

$ual Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-K Financial Statement

#000010051721000016 Filed on March 01, 2021

Income Statement

Concept	2020 Q4	2020 Q2	2020 Q1
Revenue	$3.412B	$1.475B	$7.979B
YoY Change	-68.66%	-87.06%	-16.79%
Cost Of Revenue	$1.993B	$1.214B	$3.570B
YoY Change	-52.16%	-71.46%	-5.76%
Gross Profit	$1.419B	$261.0M	$4.409B
YoY Change	-78.89%	-96.35%	-24.0%
Gross Profit Margin	41.59%	17.69%	55.26%
Selling, General & Admin	$2.248B	$2.201B	$3.250B
YoY Change	-35.68%	-37.1%	0.53%
% of Gross Profit	158.42%	843.3%	73.71%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$629.0M	$618.0M	$615.0M
YoY Change	3.8%	10.36%	12.43%
% of Gross Profit	44.33%	236.78%	13.95%
Operating Expenses	$3.703B	$3.347B	$5.318B
YoY Change	-35.39%	-40.29%	0.57%
Operating Profit	-$2.135B	-$1.637B	-$972.0M
YoY Change	-347.97%	-211.21%	-296.36%
Interest Expense	-$228.0M	-$159.0M	-$443.0M
YoY Change	-642.86%	-183.25%	-335.64%
% of Operating Profit
Other Income/Expense, Net	-$10.00M	-$366.0M	-$1.142B
YoY Change	-83.05%	210.17%	792.19%
Pretax Income	-$2.373B	-$2.003B	-$2.114B
YoY Change	-381.16%	-247.93%	-676.02%
Income Tax	-$476.0M	-$376.0M	-$410.0M
% Of Pretax Income
Net Earnings	-$1.897B	-$1.627B	-$1.704B
YoY Change	-395.94%	-254.66%	-683.56%
Net Earnings / Revenue	-55.6%	-110.31%	-21.36%
Basic Earnings Per Share	-$6.39	-$5.79	-$6.86
Diluted Earnings Per Share	-$6.387M	-$5.79	-$6.843M
COMMON SHARES
Basic Shares Outstanding	291.0M shares	280.7M shares	248.5M shares
Diluted Shares Outstanding		280.7M shares	248.5M shares

Balance Sheet

Concept	2020 Q4	2020 Q2	2020 Q1
SHORT-TERM ASSETS
Cash & Short-Term Investments	$11.68B	$7.463B	$5.221B
YoY Change	136.31%	37.09%	28.37%
Cash & Equivalents	$11.27B	$6.505B	$3.442B
Short-Term Investments	$414.0M	$958.0M	$1.779B
Other Short-Term Assets	$890.0M	$766.0M	$822.0M
YoY Change	9.34%	8.19%	5.38%
Inventory	$932.0M	$955.0M	$1.070B
Prepaid Expenses
Receivables	$1.295B	$857.0M	$792.0M
Other Receivables	$0.00	$0.00	$0.00
Total Short-Term Assets	$14.80B	$10.04B	$7.905B
YoY Change	80.62%	12.69%	3.9%
LONG-TERM ASSETS
Property, Plant & Equipment	$36.00B	$36.47B	$36.66B
YoY Change	19.33%	26.13%	28.26%
Goodwill	$4.527B	$4.523B	$4.523B
YoY Change	0.09%	0.0%	0.0%
Intangibles	$2.838B	$2.852B	$2.945B
YoY Change	-5.68%	-8.85%	-6.33%
Long-Term Investments	$139.0M	$798.0M	$763.0M
YoY Change	10.32%	-29.94%	-30.51%
Other Assets	$8.745B	$8.387B	$8.486B
YoY Change	-7.84%	-10.91%	-9.53%
Total Long-Term Assets	$44.75B	$44.86B	$45.15B
YoY Change	0.75%	3.75%	4.92%
TOTAL ASSETS
Total Short-Term Assets	$14.80B	$10.04B	$7.905B
Total Long-Term Assets	$44.75B	$44.86B	$45.15B
Total Assets	$59.55B	$54.90B	$53.06B
YoY Change	13.19%	5.28%	4.77%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$1.595B	$1.725B	$2.436B
YoY Change	-40.99%	-43.13%	-10.01%
Accrued Expenses	$2.572B	$3.775B	$2.335B
YoY Change	-13.02%	50.52%	1.57%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$1.911B	$4.454B	$4.055B
YoY Change	35.82%	254.9%	237.64%
Total Short-Term Liabilities	$12.73B	$16.40B	$16.09B
YoY Change	-14.81%	1.97%	4.9%
LONG-TERM LIABILITIES
Long-Term Debt	$24.84B	$14.32B	$13.20B
YoY Change	88.94%	10.67%	3.64%
Other Long-Term Liabilities	$1.156B	$1.430B	$1.179B
YoY Change	12.89%	45.92%	-84.04%
Total Long-Term Liabilities	$25.99B	$15.75B	$14.38B
YoY Change	83.44%	13.15%	-28.55%
TOTAL LIABILITIES
Total Short-Term Liabilities	$12.73B	$16.40B	$16.09B
Total Long-Term Liabilities	$25.99B	$15.75B	$14.38B
Total Liabilities	$38.72B	$32.14B	$30.46B
YoY Change	33.02%	7.16%	-14.08%
SHAREHOLDERS EQUITY
Retained Earnings	$2.626B	$6.365B	$7.991B
YoY Change	-72.97%	-20.93%	14.17%
Common Stock	$8.370B	$7.310B	$6.099B
YoY Change	36.5%	19.86%	0.26%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$3.897B	$3.899B	$3.901B
YoY Change	8.28%	29.02%	56.86%
Treasury Stock Shares
Shareholders Equity	$5.960B	$8.517B	$9.418B
YoY Change
Total Liabilities & Shareholders Equity	$59.55B	$54.90B	$53.06B
YoY Change	13.19%	5.28%	4.77%

Cashflow Statement

Concept	2020 Q4	2020 Q2	2020 Q1
OPERATING ACTIVITIES
Net Income	-$1.897B	-$1.627B	-$1.704B
YoY Change	-395.94%	-254.66%	-683.56%
Depreciation, Depletion And Amortization	$629.0M	$618.0M	$615.0M
YoY Change	3.8%	10.36%	12.43%
Cash From Operating Activities	-$2.177B	-$130.0M	$63.00M
YoY Change	-284.34%	-104.8%	-96.71%
INVESTING ACTIVITIES
Capital Expenditures	-$97.00M	-$39.00M	-$1.959B
YoY Change	-91.86%	-95.45%	21.75%
Acquisitions
YoY Change
Other Investing Activities	$137.0M	$851.0M	-$1.000M
YoY Change	-200.0%	42450.0%	-106.67%
Cash From Investing Activities	$40.00M	$812.0M	-$1.572B
YoY Change	-103.01%	-194.86%	-0.51%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net		$1.100B	$353.0M
YoY Change			-31.19%
Debt Paid & Issued, Net			$253.0M
YoY Change			1.2%
Cash From Financing Activities	481.0M	2.382B	$2.189B
YoY Change	-1123.4%	-597.29%	-1296.17%
NET CHANGE
Cash From Operating Activities	-2.177B	-130.0M	$63.00M
Cash From Investing Activities	40.00M	812.0M	-$1.572B
Cash From Financing Activities	481.0M	2.382B	$2.189B
Net Change In Cash	-1.656B	3.064B	$680.0M
YoY Change	749.23%	122.84%	347.37%
FREE CASH FLOW
Cash From Operating Activities	-$2.177B	-$130.0M	$63.00M
Capital Expenditures	-$97.00M	-$39.00M	-$1.959B
Free Cash Flow	-$2.080B	-$91.00M	$2.022B
YoY Change	-187.65%	-102.55%	-42.62%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
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CY2020	dei	Entity Registrant Name EntityRegistrantName	United Airlines Holdings, Inc.
CY2020	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
CY2020	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	36-2675207
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CY2020Q4	us-gaap	Assets Assets	59548000000	USD
CY2019Q4	us-gaap	Assets Assets	52611000000	USD
CY2020Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	1595000000	USD
CY2019Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	2703000000	USD
CY2020Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	1960000000	USD
CY2019Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	2271000000	USD
CY2020Q4	ual	Contract With Customer Liability Current Advance Ticket Sales ContractWithCustomerLiabilityCurrentAdvanceTicketSales	4833000000	USD
CY2019Q4	ual	Contract With Customer Liability Current Advance Ticket Sales ContractWithCustomerLiabilityCurrentAdvanceTicketSales	4819000000	USD
CY2020Q4	ual	Contract With Customer Liability Current Frequent Flyer ContractWithCustomerLiabilityCurrentFrequentFlyer	908000000	USD
CY2019Q4	ual	Contract With Customer Liability Current Frequent Flyer ContractWithCustomerLiabilityCurrentFrequentFlyer	2440000000	USD
CY2020Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	1911000000	USD
CY2019Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	1407000000	USD
CY2020Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	612000000	USD
CY2019Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	686000000	USD
CY2020Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	182000000	USD
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	4986000000	USD
CY2020Q4	ual	Contract With Customer Liability Noncurrent Frequent Flyer ContractWithCustomerLiabilityNoncurrentFrequentFlyer	5067000000	USD
CY2020Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	724000000	USD
CY2019Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	566000000	USD
CY2020Q4	us-gaap	Liabilities Current LiabilitiesCurrent	12725000000	USD
CY2019Q4	us-gaap	Liabilities Current LiabilitiesCurrent	14938000000	USD
CY2020Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	24836000000	USD
CY2019Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	13145000000	USD
CY2019Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	4946000000	USD
CY2020Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	224000000	USD
CY2019Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	220000000	USD
CY2019Q4	ual	Contract With Customer Liability Noncurrent Frequent Flyer ContractWithCustomerLiabilityNoncurrentFrequentFlyer	2836000000	USD
CY2020Q4	us-gaap	Defined Benefit Pension Plan Liabilities Noncurrent DefinedBenefitPensionPlanLiabilitiesNoncurrent	2460000000	USD
CY2019Q4	us-gaap	Defined Benefit Pension Plan Liabilities Noncurrent DefinedBenefitPensionPlanLiabilitiesNoncurrent	1446000000	USD
CY2020Q4	us-gaap	Other Postretirement Defined Benefit Plan Liabilities Noncurrent OtherPostretirementDefinedBenefitPlanLiabilitiesNoncurrent	994000000	USD
CY2019Q4	us-gaap	Other Postretirement Defined Benefit Plan Liabilities Noncurrent OtherPostretirementDefinedBenefitPlanLiabilitiesNoncurrent	789000000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	0	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	1736000000	USD
CY2020Q4	ual	Financial Liabilities Sale Leaseback Transactions Noncurrent FinancialLiabilitiesSaleLeasebackTransactionsNoncurrent	1140000000	USD
CY2019Q4	ual	Financial Liabilities Sale Leaseback Transactions Noncurrent FinancialLiabilitiesSaleLeasebackTransactionsNoncurrent	0	USD
CY2020Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	1156000000	USD
CY2019Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	1024000000	USD
CY2020Q4	ual	Other Liabilities And Deferred Credits Noncurrent OtherLiabilitiesAndDeferredCreditsNoncurrent	10817000000	USD
CY2019Q4	ual	Other Liabilities And Deferred Credits Noncurrent OtherLiabilitiesAndDeferredCreditsNoncurrent	7831000000	USD
CY2020Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2019Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2020Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2019Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2019Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2020Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2020Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	1000000000	shares
CY2019Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	1000000000	shares
CY2020Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	311845232	shares
CY2019Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	251216381	shares
CY2020Q4	us-gaap	Common Stock Value CommonStockValue	4000000	USD
CY2019Q4	us-gaap	Common Stock Value CommonStockValue	3000000	USD
CY2020Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	8366000000	USD
CY2019Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	6129000000	USD
CY2020Q4	us-gaap	Treasury Stock Value TreasuryStockValue	3897000000	USD
CY2019Q4	us-gaap	Treasury Stock Value TreasuryStockValue	3599000000	USD
CY2020Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	2626000000	USD
CY2019Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	9716000000	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-1139000000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-718000000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	5960000000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	11531000000	USD
CY2020Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	59548000000	USD
CY2019Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	52611000000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	-7069000000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	3009000000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	2122000000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1741000000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	882000000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	512000000	USD
CY2020	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	2488000000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	2288000000	USD
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	2165000000	USD
CY2020	us-gaap	Restructuring Costs And Asset Impairment Charges RestructuringCostsAndAssetImpairmentCharges	1448000000	USD
CY2019	us-gaap	Restructuring Costs And Asset Impairment Charges RestructuringCostsAndAssetImpairmentCharges	175000000	USD
CY2018	us-gaap	Restructuring Costs And Asset Impairment Charges RestructuringCostsAndAssetImpairmentCharges	416000000	USD
CY2020	us-gaap	Unrealized Gain Loss On Investments UnrealizedGainLossOnInvestments	-194000000	USD
CY2019	us-gaap	Unrealized Gain Loss On Investments UnrealizedGainLossOnInvestments	153000000	USD
CY2018	us-gaap	Unrealized Gain Loss On Investments UnrealizedGainLossOnInvestments	-5000000	USD
CY2020	us-gaap	Other Operating Activities Cash Flow Statement OtherOperatingActivitiesCashFlowStatement	320000000	USD
CY2019	us-gaap	Other Operating Activities Cash Flow Statement OtherOperatingActivitiesCashFlowStatement	185000000	USD
CY2018	us-gaap	Other Operating Activities Cash Flow Statement OtherOperatingActivitiesCashFlowStatement	161000000	USD
CY2020	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	-135000000	USD
CY2019	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	-44000000	USD
CY2018	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	-17000000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-484000000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	252000000	USD
CY2018	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-265000000	USD
CY2020	ual	Increase Decrease In Contract With Customer Liability Advance Ticket Sales IncreaseDecreaseInContractWithCustomerLiabilityAdvanceTicketSales	14000000	USD
CY2019	ual	Increase Decrease In Contract With Customer Liability Advance Ticket Sales IncreaseDecreaseInContractWithCustomerLiabilityAdvanceTicketSales	438000000	USD
CY2018	ual	Increase Decrease In Contract With Customer Liability Advance Ticket Sales IncreaseDecreaseInContractWithCustomerLiabilityAdvanceTicketSales	441000000	USD
CY2020	ual	Increase Decreasein Contractwith Customer Liability Frequent Flyer IncreaseDecreaseinContractwithCustomerLiabilityFrequentFlyer	699000000	USD
CY2019	ual	Increase Decreasein Contractwith Customer Liability Frequent Flyer IncreaseDecreaseinContractwithCustomerLiabilityFrequentFlyer	271000000	USD
CY2018	ual	Increase Decreasein Contractwith Customer Liability Frequent Flyer IncreaseDecreaseinContractwithCustomerLiabilityFrequentFlyer	222000000	USD
CY2020	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-1079000000	USD
CY2019	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	324000000	USD
CY2018	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	130000000	USD
CY2019	us-gaap	Payments To Acquire Loans Receivable PaymentsToAcquireLoansReceivable	174000000	USD
CY2018	us-gaap	Payments To Acquire Loans Receivable PaymentsToAcquireLoansReceivable	466000000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-26000000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-302000000	USD
CY2018	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-292000000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-4133000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	6909000000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	6164000000	USD
CY2020	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	1727000000	USD
CY2019	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	4528000000	USD
CY2018	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	4070000000	USD
CY2020	us-gaap	Payments To Acquire Short Term Investments PaymentsToAcquireShortTermInvestments	552000000	USD
CY2019	us-gaap	Payments To Acquire Short Term Investments PaymentsToAcquireShortTermInvestments	2897000000	USD
CY2018	us-gaap	Payments To Acquire Short Term Investments PaymentsToAcquireShortTermInvestments	2552000000	USD
CY2020	us-gaap	Proceeds From Sale Maturity And Collections Of Investments ProceedsFromSaleMaturityAndCollectionsOfInvestments	2319000000	USD
CY2019	us-gaap	Proceeds From Sale Maturity And Collections Of Investments ProceedsFromSaleMaturityAndCollectionsOfInvestments	2996000000	USD
CY2018	us-gaap	Proceeds From Sale Maturity And Collections Of Investments ProceedsFromSaleMaturityAndCollectionsOfInvestments	2616000000	USD
CY2020	us-gaap	Payments To Acquire Loans Receivable PaymentsToAcquireLoansReceivable	0	USD
CY2020	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	0	USD
CY2019	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	36000000	USD
CY2018	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	139000000	USD
CY2020	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-10000000	USD
CY2019	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-79000000	USD
CY2018	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-156000000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	50000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-4560000000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-4455000000	USD
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	353000000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1645000000	USD
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1235000000	USD
CY2020	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	16044000000	USD
CY2019	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	1847000000	USD
CY2018	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	1594000000	USD
CY2020	us-gaap	Proceeds From Issuance Or Sale Of Equity ProceedsFromIssuanceOrSaleOfEquity	2103000000	USD
CY2019	us-gaap	Proceeds From Issuance Or Sale Of Equity ProceedsFromIssuanceOrSaleOfEquity	0	USD
CY2018	us-gaap	Proceeds From Issuance Or Sale Of Equity ProceedsFromIssuanceOrSaleOfEquity	0	USD
CY2020	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	4383000000	USD
CY2019	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	1240000000	USD
CY2018	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	1727000000	USD
CY2020	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	66000000	USD
CY2019	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	151000000	USD
CY2018	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	79000000	USD
CY2020	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	368000000	USD
CY2019	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	61000000	USD
CY2018	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	37000000	USD
CY2020	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-20000000	USD
CY2019	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-30000000	USD
CY2018	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-17000000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	12957000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-1280000000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	1799000000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-1501000000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	8874000000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	1069000000	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	208000000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	2868000000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	1799000000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	1591000000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	11742000000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	2868000000	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	1968000000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	515000000	USD
CY2018	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	160000000	USD
CY2020	ual	Lease Conversions From Operating Lease Recorded Property Plant And Equipment LeaseConversionsFromOperatingLeaseRecordedPropertyPlantAndEquipment	527000000	USD
CY2019	ual	Lease Conversions From Operating Lease Recorded Property Plant And Equipment LeaseConversionsFromOperatingLeaseRecordedPropertyPlantAndEquipment	-2000000	USD
CY2018	ual	Lease Conversions From Operating Lease Recorded Property Plant And Equipment LeaseConversionsFromOperatingLeaseRecordedPropertyPlantAndEquipment	52000000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	2122000000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	198000000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	498000000	USD
CY2018	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	663000000	USD
CY2020	ual	Noncash Investing And Financing Items Debt Associated With Capacity Purchase Agreement NoncashInvestingAndFinancingItemsDebtAssociatedWithCapacityPurchaseAgreement	33000000	USD
CY2019	ual	Noncash Investing And Financing Items Debt Associated With Capacity Purchase Agreement NoncashInvestingAndFinancingItemsDebtAssociatedWithCapacityPurchaseAgreement	0	USD
CY2018	ual	Noncash Investing And Financing Items Debt Associated With Capacity Purchase Agreement NoncashInvestingAndFinancingItemsDebtAssociatedWithCapacityPurchaseAgreement	0	USD
CY2020	ual	Noncash Investing And Financing Items Debt Associated With Termination Of Maintenance Service Agreement NoncashInvestingAndFinancingItemsDebtAssociatedWithTerminationOfMaintenanceServiceAgreement	0	USD
CY2019	ual	Noncash Investing And Financing Items Debt Associated With Termination Of Maintenance Service Agreement NoncashInvestingAndFinancingItemsDebtAssociatedWithTerminationOfMaintenanceServiceAgreement	0	USD
CY2018	ual	Noncash Investing And Financing Items Debt Associated With Termination Of Maintenance Service Agreement NoncashInvestingAndFinancingItemsDebtAssociatedWithTerminationOfMaintenanceServiceAgreement	163000000	USD
CY2020	us-gaap	Interest Paid Net InterestPaidNet	874000000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	648000000	USD
CY2018	us-gaap	Interest Paid Net InterestPaidNet	651000000	USD
CY2020	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	-29000000	USD
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	29000000	USD
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	19000000	USD
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	8788000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	338000000	USD
CY2018	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	60000000	USD
CY2018	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	1250000000	USD
CY2018	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-16000000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	10042000000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	3009000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	85000000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	66000000	USD
CY2019	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	1641000000	USD
CY2019	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-30000000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	11531000000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	-7069000000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-421000000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	97000000	USD
CY2020	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	2103000000	USD
CY2020	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	342000000	USD
CY2020	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-19000000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Warrant Issued AdjustmentsToAdditionalPaidInCapitalWarrantIssued	97000000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	5960000000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	-7100000000	USD
CY2020	ual	Unusual Or Infrequent Items Percent Of Capacity Cut UnusualOrInfrequentItemsPercentOfCapacityCut	0.57
CY2020	ual	Unusual Or Infrequent Items Rolling Flight Cancellation Period UnusualOrInfrequentItemsRollingFlightCancellationPeriod	P60D
CY2020	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	2100000000	USD
CY2020	ual	Unusual Or Infrequent Event Payroll Taxes Deferred Under Cares Act UnusualOrInfrequentEventPayrollTaxesDeferredUnderCARESAct	199000000	USD
CY2020Q3	ual	Number Of Employees Notified Of Plans For Workforce Reduction NumberOfEmployeesNotifiedOfPlansForWorkforceReduction	36000	employee
CY2020Q4	ual	Number Of Employees Furloughed NumberOfEmployeesFurloughed	13000	employee
CY2020Q4	ual	Number Of Employees Subject To Voluntary Options NumberOfEmployeesSubjectToVoluntaryOptions	9000	employee
CY2020Q2	ual	Payroll Support Program Funding Provided PayrollSupportProgramFundingProvided	5100000000	USD
CY2020Q2	ual	Payroll Support Program Funding Provided Amounts Received Through Direct Grants PayrollSupportProgramFundingProvidedAmountsReceivedThroughDirectGrants	3600000000	USD
CY2020Q2	ual	Payroll Support Program Funding Provided PayrollSupportProgramFundingProvided	5100000000	USD
CY2020Q2	ual	Payroll Support Program Funding Provided Amounts Received Through Loans PayrollSupportProgramFundingProvidedAmountsReceivedThroughLoans	1500000000	USD
CY2020	us-gaap	Use Of Estimates UseOfEstimates	<span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%;padding-left:24.91pt">Use of Estimates—</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("GAAP") requires management to make estimates and assumptions that affect the amounts reported in these financial statements and accompanying notes. Actual results could differ from those estimates.</span>
CY2020	ual	Refundable Tickets Expiration Period RefundableTicketsExpirationPeriod	P1Y
CY2020	ual	Refundable Tickets Temporary Expiration Period RefundableTicketsTemporaryExpirationPeriod	P24M
CY2020Q4	ual	Electronic Travel Certificates And Future Flight Credits Percent Of Credits With Expiration Dates Beyond12 Months ElectronicTravelCertificatesAndFutureFlightCreditsPercentOfCreditsWithExpirationDatesBeyond12Months	0.74
CY2020	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1	segment
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	15355000000	USD
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	43259000000	USD
CY2018	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	41303000000	USD
CY2020Q4	ual	Excise Tax Refunds Receivable ExciseTaxRefundsReceivable	150000000	USD
CY2020	us-gaap	Revenue Performance Obligation Description Of Timing RevenuePerformanceObligationDescriptionOfTiming	two years
CY2020Q4	us-gaap	Cash Collateral For Borrowed Securities CashCollateralForBorrowedSecurities	217000000	USD
CY2020Q4	ual	Restricted Cash Amounts To Be Used For Borrowing Fees Principal And Interest RestrictedCashAmountsToBeUsedForBorrowingFeesPrincipalAndInterest	6800000000	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	11269000000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	2762000000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	1694000000	USD
CY2020Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	255000000	USD
CY2019Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	0	USD
CY2018Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	0	USD
CY2020Q4	us-gaap	Restricted Cash And Cash Equivalents Noncurrent RestrictedCashAndCashEquivalentsNoncurrent	218000000	USD
CY2019Q4	us-gaap	Restricted Cash And Cash Equivalents Noncurrent RestrictedCashAndCashEquivalentsNoncurrent	106000000	USD
CY2018Q4	us-gaap	Restricted Cash And Cash Equivalents Noncurrent RestrictedCashAndCashEquivalentsNoncurrent	105000000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	11742000000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	2868000000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	1799000000	USD
CY2020Q4	us-gaap	Capitalized Computer Software Gross CapitalizedComputerSoftwareGross	548000000	USD
CY2019Q4	us-gaap	Capitalized Computer Software Gross CapitalizedComputerSoftwareGross	422000000	USD
CY2020Q4	us-gaap	Common Stock Capital Shares Reserved For Future Issuance CommonStockCapitalSharesReservedForFutureIssuance	6000000	shares
CY2020Q4	us-gaap	Goodwill Goodwill	4527000000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	4523000000	USD
CY2020Q4	us-gaap	Indefinite Lived Intangible Assets Excluding Goodwill IndefiniteLivedIntangibleAssetsExcludingGoodwill	2577000000	USD
CY2019Q4	us-gaap	Indefinite Lived Intangible Assets Excluding Goodwill IndefiniteLivedIntangibleAssetsExcludingGoodwill	2693000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	1756000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	1495000000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	1756000000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	1440000000	USD
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	55000000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	60000000	USD
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	67000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	50000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	40000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	37000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	32000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	28000000	USD
CY2020Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	2	shares
CY2020	us-gaap	Advertising Expense AdvertisingExpense	87000000	USD
CY2019	us-gaap	Advertising Expense AdvertisingExpense	212000000	USD
CY2018	us-gaap	Advertising Expense AdvertisingExpense	211000000	USD
CY2020	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	4000000	shares
CY2020	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	300000000	USD
CY2020Q2	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	1100000000	USD
CY2020Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2020Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	250000000	shares
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-7069000000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	3009000000	USD
CY2018	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	2122000000	USD
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	279400000	shares
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	258800000	shares
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	275500000	shares
CY2020	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	0	shares
CY2019	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1100000	shares
CY2018	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1200000	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	279400000	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	259900000	shares
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	276700000	shares
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-25.30
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	11.63
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	7.70
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-25.30
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	11.58
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	7.67
CY2020	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	108000000	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	100000000	USD
CY2018	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	101000000	USD
CY2020Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	88000000	USD
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Total Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue	87000000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Total Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue	99000000	USD
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Total Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue	70000000	USD
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	700000	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	300000	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	82.12
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	58.25
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P6Y3M18D
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P3Y6M
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	0	USD
CY2020Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	0	USD
CY2017Q4	us-gaap	Aoci Tax Attributable To Parent AociTaxAttributableToParent	39000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Before Reclassifications Tax OtherComprehensiveIncomeLossBeforeReclassificationsTax	83000000	USD
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CY2018	us-gaap	Reclassification From Aoci Current Period Net Of Tax Attributable To Parent ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent	-49000000	USD
CY2018	ual	Reclassification From Accumulated Other Comprehensive Income To Retained Earnings.Current Period Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeToRetainedEarnings.CurrentPeriodTax	-1000000	USD
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CY2018Q4	us-gaap	Aoci Tax Attributable To Parent AociTaxAttributableToParent	136000000	USD
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CY2019	us-gaap	Oci Before Reclassifications Net Of Tax Attributable To Parent OciBeforeReclassificationsNetOfTaxAttributableToParent	88000000	USD
CY2019	us-gaap	Reclassification From Aoci Current Period Tax ReclassificationFromAociCurrentPeriodTax	0	USD
CY2019	us-gaap	Reclassification From Aoci Current Period Net Of Tax Attributable To Parent ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent	3000000	USD
CY2019Q4	us-gaap	Aoci Tax Attributable To Parent AociTaxAttributableToParent	160000000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Before Reclassifications Tax OtherComprehensiveIncomeLossBeforeReclassificationsTax	-221000000	USD
CY2020	us-gaap	Oci Before Reclassifications Net Of Tax Attributable To Parent OciBeforeReclassificationsNetOfTaxAttributableToParent	-772000000	USD
CY2020	us-gaap	Reclassification From Aoci Current Period Tax ReclassificationFromAociCurrentPeriodTax	-100000000	USD
CY2020	us-gaap	Reclassification From Aoci Current Period Net Of Tax Attributable To Parent ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent	-351000000	USD
CY2020Q4	us-gaap	Aoci Tax Attributable To Parent AociTaxAttributableToParent	39000000	USD
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-1852000000	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	822000000	USD
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	556000000	USD
CY2020	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	-110000000	USD
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	50000000	USD
CY2018	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	29000000	USD
CY2020	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	0	USD
CY2019	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-90000000	USD
CY2018	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-84000000	USD
CY2020	ual	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Amount EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeAmount	0	USD
CY2019	ual	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Amount EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeAmount	90000000	USD
CY2018	ual	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Amount EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeAmount	4000000	USD
CY2020	ual	Effective Income Tax Rate Reconciliation Foreign Income Taxes EffectiveIncomeTaxRateReconciliationForeignIncomeTaxes	1000000	USD
CY2019	ual	Effective Income Tax Rate Reconciliation Foreign Income Taxes EffectiveIncomeTaxRateReconciliationForeignIncomeTaxes	1000000	USD
CY2018	ual	Effective Income Tax Rate Reconciliation Foreign Income Taxes EffectiveIncomeTaxRateReconciliationForeignIncomeTaxes	2000000	USD
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense Meals And Entertainment IncomeTaxReconciliationNondeductibleExpenseMealsAndEntertainment	5000000	USD
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Meals And Entertainment IncomeTaxReconciliationNondeductibleExpenseMealsAndEntertainment	12000000	USD
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense Meals And Entertainment IncomeTaxReconciliationNondeductibleExpenseMealsAndEntertainment	12000000	USD
CY2020	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-2000000	USD
CY2019	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	0	USD
CY2018	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	3000000	USD
CY2020	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	197000000	USD
CY2019	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	-4000000	USD
CY2018	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	-3000000	USD
CY2020	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	8000000	USD
CY2019	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	24000000	USD
CY2018	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	7000000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-1753000000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	905000000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	526000000	USD
CY2020	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	197000000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	526000000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-12000000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	23000000	USD
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	14000000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1741000000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	882000000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	512000000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-1753000000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	905000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	2476000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	695000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Deferred Income DeferredTaxAssetsDeferredIncome	1409000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Deferred Income DeferredTaxAssetsDeferredIncome	1287000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	6610000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	1103000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	715000000	USD
CY2020Q4	ual	Deferred Tax Asset Leasing Arrangements DeferredTaxAssetLeasingArrangements	1247000000	USD
CY2019Q4	ual	Deferred Tax Asset Leasing Arrangements DeferredTaxAssetLeasingArrangements	1256000000	USD
CY2020Q4	ual	Deferred Tax Assets Sale Leaseback Liability DeferredTaxAssetsSaleLeasebackLiability	260000000	USD
CY2019Q4	ual	Deferred Tax Assets Sale Leaseback Liability DeferredTaxAssetsSaleLeasebackLiability	0	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	362000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	165000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	247000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	58000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	4060000000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	4789000000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	4011000000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	1028000000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	1061000000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	662000000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	724000000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	6479000000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	5796000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	131000000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	1736000000	USD
CY2020Q4	ual	Capital Loss Carryforwards Valuation Allowance CapitalLossCarryforwardsValuationAllowance	185000000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	57000000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	53000000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	39000000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	57000000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Amounts Recognized In Balance Sheet DefinedBenefitPlanAmountsRecognizedInBalanceSheet	-2456000000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Amounts Recognized In Balance Sheet DefinedBenefitPlanAmountsRecognizedInBalanceSheet	-1434000000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets Aggregate Projected Benefit Obligation DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation	6250000000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets Aggregate Projected Benefit Obligation DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation	6161000000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets Aggregate Accumulated Benefit Obligation DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation	5163000000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets Aggregate Accumulated Benefit Obligation DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation	5137000000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets Aggregate Fair Value Of Plan Assets DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets	3786000000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets Aggregate Fair Value Of Plan Assets DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets	4714000000	USD
CY2020	ual	Defined Benefit Plan Profit Sharing And Payroll Tax Expense DefinedBenefitPlanProfitSharingAndPayrollTaxExpense	0	USD
CY2019	ual	Defined Benefit Plan Profit Sharing And Payroll Tax Expense DefinedBenefitPlanProfitSharingAndPayrollTaxExpense	491000000	USD
CY2018	ual	Defined Benefit Plan Profit Sharing And Payroll Tax Expense DefinedBenefitPlanProfitSharingAndPayrollTaxExpense	334000000	USD
CY2020	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	-24000000	USD
CY2019	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	13000000	USD
CY2020Q4	us-gaap	Equity Method Investments EquityMethodInvestments	139000000	USD
CY2020Q4	us-gaap	Debt Instrument Carrying Amount DebtInstrumentCarryingAmount	27301000000	USD
CY2019Q4	us-gaap	Debt Instrument Carrying Amount DebtInstrumentCarryingAmount	14733000000	USD
CY2020Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	-554000000	USD
CY2019Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	-181000000	USD
CY2020Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	1911000000	USD
CY2019Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	1407000000	USD
CY2020Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	24836000000	USD
CY2019Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	13145000000	USD
CY2020Q2	ual	Payroll Support Program Funding Provided PayrollSupportProgramFundingProvided	5100000000	USD
CY2020Q2	ual	Payroll Support Program Funding Provided Amounts Received Through Loans PayrollSupportProgramFundingProvidedAmountsReceivedThroughLoans	1500000000	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	933000000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	1038000000	USD
CY2018	us-gaap	Operating Lease Cost OperatingLeaseCost	1213000000	USD
CY2020	ual	Variable And Short Term Lease Cost VariableAndShortTermLeaseCost	1968000000	USD
CY2019	ual	Variable And Short Term Lease Cost VariableAndShortTermLeaseCost	2548000000	USD
CY2018	ual	Variable And Short Term Lease Cost VariableAndShortTermLeaseCost	2569000000	USD
CY2020	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	88000000	USD
CY2019	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	68000000	USD
CY2018	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	75000000	USD
CY2020	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	16000000	USD
CY2019	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	85000000	USD
CY2018	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	44000000	USD
CY2020	us-gaap	Sublease Income SubleaseIncome	23000000	USD
CY2019	us-gaap	Sublease Income SubleaseIncome	32000000	USD
CY2018	us-gaap	Sublease Income SubleaseIncome	38000000	USD
CY2020	us-gaap	Lease Cost LeaseCost	2982000000	USD
CY2019	us-gaap	Lease Cost LeaseCost	3707000000	USD
CY2018	us-gaap	Lease Cost LeaseCost	3863000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	847000000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Next Twelve Months FinanceLeaseLiabilityPaymentsDueNextTwelveMonths	198000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	693000000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	59000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	723000000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	51000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	704000000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	47000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	585000000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Five FinanceLeaseLiabilityPaymentsDueYearFive	35000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	3979000000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due After Year Five FinanceLeaseLiabilityPaymentsDueAfterYearFive	64000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	7531000000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	454000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	1933000000	USD
CY2020Q4	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	48000000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	5598000000	USD
CY2020Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	406000000	USD
CY2020Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	612000000	USD
CY2020Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	182000000	USD
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	4986000000	USD
CY2020Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	224000000	USD
CY2020Q4	ual	Lessee Operating And Finance Lease Not Yet Commenced Amount LesseeOperatingAndFinanceLeaseNotYetCommencedAmount	740000000	USD
CY2020	ual	Lessee Operating And Finance Lease Not Yet Commenced Term Of Contract LesseeOperatingAndFinanceLeaseNotYetCommencedTermOfContract	P12Y
CY2020Q4	ual	Number Of Aircraft In Sale Leaseback Transaction Included In Flight Equipment NumberOfAircraftInSaleLeasebackTransactionIncludedInFlightEquipment	11	aircraft
CY2020Q4	ual	Number Of Aircraft In Sale Leaseback Transaction Included In Operating Lease Amounts NumberOfAircraftInSaleLeasebackTransactionIncludedInOperatingLeaseAmounts	4	aircraft
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P11Y
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P11Y
CY2020Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P4Y
CY2019Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P6Y
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.051
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.052
CY2020Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.044
CY2019Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.057
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	788000000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	902000000	USD
CY2018	us-gaap	Operating Lease Payments OperatingLeasePayments	1078000000	USD
CY2020	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	20000000	USD
CY2019	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	70000000	USD
CY2018	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	53000000	USD
CY2020	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	66000000	USD
CY2019	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	151000000	USD
CY2018	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	79000000	USD
CY2020Q4	us-gaap	Contractual Obligation Due In Next Twelve Months ContractualObligationDueInNextTwelveMonths	1800000000	USD
CY2020Q4	us-gaap	Contractual Obligation Due In Second Year ContractualObligationDueInSecondYear	1800000000	USD
CY2020Q4	us-gaap	Contractual Obligation Due In Third Year ContractualObligationDueInThirdYear	1700000000	USD
CY2020Q4	us-gaap	Contractual Obligation Due In Fourth Year ContractualObligationDueInFourthYear	1500000000	USD
CY2020Q4	us-gaap	Contractual Obligation Due In Fifth Year ContractualObligationDueInFifthYear	1200000000	USD
CY2020Q4	us-gaap	Contractual Obligation Due After Fifth Year ContractualObligationDueAfterFifthYear	3100000000	USD
CY2020Q4	us-gaap	Contractual Obligation ContractualObligation	11100000000	USD
CY2020Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Balance On First Anniversary UnrecordedUnconditionalPurchaseObligationBalanceOnFirstAnniversary	4900000000	USD
CY2020Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Balance On Second Anniversary UnrecordedUnconditionalPurchaseObligationBalanceOnSecondAnniversary	2900000000	USD
CY2020Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Balance On Third Anniversary UnrecordedUnconditionalPurchaseObligationBalanceOnThirdAnniversary	2800000000	USD
CY2020Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Balance On Fourth Anniversary UnrecordedUnconditionalPurchaseObligationBalanceOnFourthAnniversary	1600000000	USD
CY2020Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Balance On Fifth Anniversary UnrecordedUnconditionalPurchaseObligationBalanceOnFifthAnniversary	2000000000.0	USD
CY2020Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Due After Five Years UnrecordedUnconditionalPurchaseObligationDueAfterFiveYears	10100000000	USD
CY2020Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Balance Sheet Amount UnrecordedUnconditionalPurchaseObligationBalanceSheetAmount	24300000000	USD
CY2020	ual	Number Of Call Options To Purchase Regional Jet Aircraft NumberOfCallOptionsToPurchaseRegionalJetAircraft	303	option
CY2020	us-gaap	Unusual Or Infrequent Item Gain Gross UnusualOrInfrequentItemGainGross	3536000000	USD
CY2019	us-gaap	Unusual Or Infrequent Item Gain Gross UnusualOrInfrequentItemGainGross	0	USD
CY2018	us-gaap	Unusual Or Infrequent Item Gain Gross UnusualOrInfrequentItemGainGross	0	USD
CY2020	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	575000000	USD
CY2019	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	16000000	USD
CY2018	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	41000000	USD
CY2020	us-gaap	Asset Impairment Charges AssetImpairmentCharges	318000000	USD
CY2019	us-gaap	Asset Impairment Charges AssetImpairmentCharges	171000000	USD
CY2018	us-gaap	Asset Impairment Charges AssetImpairmentCharges	377000000	USD
CY2020	us-gaap	Loss On Contract Termination LossOnContractTermination	0	USD
CY2019	us-gaap	Loss On Contract Termination LossOnContractTermination	0	USD
CY2018	us-gaap	Loss On Contract Termination LossOnContractTermination	64000000	USD
CY2020	ual	Gain Loss On Sale Of Other Assets And Other Miscellaneous Charges GainLossOnSaleOfOtherAssetsAndOtherMiscellaneousCharges	-27000000	USD
CY2019	ual	Gain Loss On Sale Of Other Assets And Other Miscellaneous Charges GainLossOnSaleOfOtherAssetsAndOtherMiscellaneousCharges	-59000000	USD
CY2018	ual	Gain Loss On Sale Of Other Assets And Other Miscellaneous Charges GainLossOnSaleOfOtherAssetsAndOtherMiscellaneousCharges	-5000000	USD
CY2020	us-gaap	Restructuring Settlement And Impairment Provisions RestructuringSettlementAndImpairmentProvisions	-2616000000	USD
CY2019	us-gaap	Restructuring Settlement And Impairment Provisions RestructuringSettlementAndImpairmentProvisions	246000000	USD
CY2018	us-gaap	Restructuring Settlement And Impairment Provisions RestructuringSettlementAndImpairmentProvisions	487000000	USD
CY2020	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	697000000	USD
CY2019	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	0	USD
CY2018	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	0	USD
CY2020	ual	Defined Benefit Plan Net Periodic Benefit Cost Credit Gain Loss Due To Settlement Restructuring And Special And Contractual Termination Benefits DefinedBenefitPlanNetPeriodicBenefitCostCreditGainLossDueToSettlementRestructuringAndSpecialAndContractualTerminationBenefits	-687000000	USD
CY2019	ual	Defined Benefit Plan Net Periodic Benefit Cost Credit Gain Loss Due To Settlement Restructuring And Special And Contractual Termination Benefits DefinedBenefitPlanNetPeriodicBenefitCostCreditGainLossDueToSettlementRestructuringAndSpecialAndContractualTerminationBenefits	0	USD
CY2018	ual	Defined Benefit Plan Net Periodic Benefit Cost Credit Gain Loss Due To Settlement Restructuring And Special And Contractual Termination Benefits DefinedBenefitPlanNetPeriodicBenefitCostCreditGainLossDueToSettlementRestructuringAndSpecialAndContractualTerminationBenefits	0	USD
CY2020	ual	Gain Loss On Financial Instruments Non Operating GainLossOnFinancialInstrumentsNonOperating	-194000000	USD
CY2019	ual	Gain Loss On Financial Instruments Non Operating GainLossOnFinancialInstrumentsNonOperating	153000000	USD
CY2018	ual	Gain Loss On Financial Instruments Non Operating GainLossOnFinancialInstrumentsNonOperating	-5000000	USD
CY2020	ual	Special Charges And Losses On Financial Instruments Non Operating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsNonOperatingBeforeTax	1578000000	USD
CY2019	ual	Special Charges And Losses On Financial Instruments Non Operating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsNonOperatingBeforeTax	-153000000	USD
CY2018	ual	Special Charges And Losses On Financial Instruments Non Operating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsNonOperatingBeforeTax	5000000	USD
CY2020	ual	Special Charges And Losses On Financial Instruments Operating And Nonoperating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsOperatingAndNonoperatingBeforeTax	-1038000000	USD
CY2019	ual	Special Charges And Losses On Financial Instruments Operating And Nonoperating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsOperatingAndNonoperatingBeforeTax	93000000	USD
CY2020Q4	ual	Number Of Employees Subject To Voluntary Options NumberOfEmployeesSubjectToVoluntaryOptions	9000	employee
CY2018	ual	Special Charges And Losses On Financial Instruments Operating And Nonoperating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsOperatingAndNonoperatingBeforeTax	492000000	USD
CY2020	ual	Income Tax Expense Benefit Special Charges IncomeTaxExpenseBenefitSpecialCharges	404000000	USD
CY2019	ual	Income Tax Expense Benefit Special Charges IncomeTaxExpenseBenefitSpecialCharges	-21000000	USD
CY2018	ual	Income Tax Expense Benefit Special Charges IncomeTaxExpenseBenefitSpecialCharges	-110000000	USD
CY2020	ual	Income Tax Adjustments IncomeTaxAdjustments	0	USD
CY2020	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	575000000	USD
CY2019	ual	Income Tax Adjustments IncomeTaxAdjustments	0	USD
CY2018	ual	Income Tax Adjustments IncomeTaxAdjustments	-5000000	USD
CY2020	ual	Special Items Net Of Income Tax Benefits SpecialItemsNetOfIncomeTaxBenefits	-634000000	USD
CY2019	ual	Special Items Net Of Income Tax Benefits SpecialItemsNetOfIncomeTaxBenefits	72000000	USD
CY2018	ual	Special Items Net Of Income Tax Benefits SpecialItemsNetOfIncomeTaxBenefits	377000000	USD
CY2020	ual	Proceeds From Government Assistance ProceedsFromGovernmentAssistance	5100000000	USD
CY2020	ual	Proceeds From Government Assistance Grants ProceedsFromGovernmentAssistanceGrants	3600000000	USD
CY2020	us-gaap	Proceeds From Issuance Of Unsecured Debt ProceedsFromIssuanceOfUnsecuredDebt	1500000000	USD
CY2020	us-gaap	Proceeds From Issuance Of Warrants ProceedsFromIssuanceOfWarrants	66000000	USD
CY2020Q3	ual	Number Of Employees Notified Of Plans For Workforce Reduction NumberOfEmployeesNotifiedOfPlansForWorkforceReduction	36000	employee
CY2020Q4	ual	Number Of Employees Furloughed NumberOfEmployeesFurloughed	13000	employee
CY2020	us-gaap	Impairment Of Leasehold ImpairmentOfLeasehold	38000000	USD
CY2020	us-gaap	Impairment Of Ongoing Project ImpairmentOfOngoingProject	56000000	USD
CY2020	ual	Defined Benefit Plan Net Periodic Benefit Cost Credit Gain Loss Due To Settlement Restructuring And Special And Contractual Termination Benefits DefinedBenefitPlanNetPeriodicBenefitCostCreditGainLossDueToSettlementRestructuringAndSpecialAndContractualTerminationBenefits	-687000000	USD
CY2020	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	-24000000	USD
CY2020	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	697000000	USD
CY2019	ual	Special Charges Adjustment Write Off Unexercise And Impairments Of Aircraft SpecialChargesAdjustmentWriteOffUnexerciseAndImpairmentsOfAircraft	18000000	USD
CY2019	us-gaap	Other Asset Impairment Charges OtherAssetImpairmentCharges	20000000	USD
CY2019	us-gaap	Gain Loss On Contract Termination GainLossOnContractTermination	-25000000	USD
CY2019	us-gaap	Gain Loss Related To Litigation Settlement GainLossRelatedToLitigationSettlement	-18000000	USD
CY2019	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	-14000000	USD
CY2019	us-gaap	Other Restructuring Costs OtherRestructuringCosts	2000000	USD
CY2019	us-gaap	Derivative Gain On Derivative DerivativeGainOnDerivative	13000000	USD
CY2018	ual	Special Charges Fair Value Adjustment Write Offs And Impairments Of Aircraft SpecialChargesFairValueAdjustmentWriteOffsAndImpairmentsOfAircraft	66000000	USD
CY2018	us-gaap	Loss On Contract Termination LossOnContractTermination	64000000	USD
CY2018	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	28000000	USD
CY2018	us-gaap	Derivative Loss On Derivative DerivativeLossOnDerivative	33000000	USD
CY2020Q1	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	7979000000	USD
CY2020Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1475000000	USD
CY2020Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2489000000	USD
CY2020Q4	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3412000000	USD
CY2020Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	-972000000	USD
CY2020Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	-1637000000	USD
CY2020Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	-1615000000	USD
CY2020Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	-2135000000	USD
CY2020Q1	us-gaap	Net Income Loss NetIncomeLoss	-1704000000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	-1627000000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	-1841000000	USD
CY2020Q4	us-gaap	Net Income Loss NetIncomeLoss	-1897000000	USD
CY2020Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-6.86
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-5.79
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-6.33
CY2020Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-6.39
CY2019Q1	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	9589000000	USD
CY2019Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	11402000000	USD
CY2019Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	11380000000	USD
CY2019Q4	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	10888000000	USD
CY2019Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	495000000	USD
CY2019Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	1472000000	USD
CY2019Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	1473000000	USD
CY2019Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	861000000	USD
CY2019Q1	us-gaap	Net Income Loss NetIncomeLoss	292000000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	1052000000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	1024000000	USD
CY2019Q4	us-gaap	Net Income Loss NetIncomeLoss	641000000	USD
CY2019Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.09
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.03
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.01
CY2019Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.54
CY2019Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.09
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.02
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.99
CY2019Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.53
CY2020Q1	us-gaap	Unusual Or Infrequent Item Gain Gross UnusualOrInfrequentItemGainGross	0	USD
CY2020Q2	us-gaap	Unusual Or Infrequent Item Gain Gross UnusualOrInfrequentItemGainGross	1589000000	USD
CY2020Q3	us-gaap	Unusual Or Infrequent Item Gain Gross UnusualOrInfrequentItemGainGross	1494000000	USD
CY2020Q4	us-gaap	Unusual Or Infrequent Item Gain Gross UnusualOrInfrequentItemGainGross	453000000	USD
CY2020Q1	us-gaap	Asset Impairment Charges AssetImpairmentCharges	50000000	USD
CY2020Q2	us-gaap	Asset Impairment Charges AssetImpairmentCharges	80000000	USD
CY2020Q3	us-gaap	Asset Impairment Charges AssetImpairmentCharges	51000000	USD
CY2020Q4	us-gaap	Asset Impairment Charges AssetImpairmentCharges	137000000	USD
CY2020Q1	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	0	USD
CY2020Q2	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	63000000	USD
CY2020Q3	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	350000000	USD
CY2020Q4	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	162000000	USD
CY2020Q1	ual	Gain Loss On Sale Of Other Assets And Other Miscellaneous Charges GainLossOnSaleOfOtherAssetsAndOtherMiscellaneousCharges	-13000000	USD
CY2020Q4	ual	Defined Benefit Plan Net Periodic Benefit Cost Credit Gain Loss Due To Settlement Restructuring And Special And Contractual Termination Benefits DefinedBenefitPlanNetPeriodicBenefitCostCreditGainLossDueToSettlementRestructuringAndSpecialAndContractualTerminationBenefits	-41000000	USD
CY2020Q2	ual	Gain Loss On Sale Of Other Assets And Other Miscellaneous Charges GainLossOnSaleOfOtherAssetsAndOtherMiscellaneousCharges	3000000	USD
CY2020Q3	ual	Gain Loss On Sale Of Other Assets And Other Miscellaneous Charges GainLossOnSaleOfOtherAssetsAndOtherMiscellaneousCharges	-12000000	USD
CY2020Q4	ual	Gain Loss On Sale Of Other Assets And Other Miscellaneous Charges GainLossOnSaleOfOtherAssetsAndOtherMiscellaneousCharges	-5000000	USD
CY2020Q1	us-gaap	Restructuring Settlement And Impairment Provisions RestructuringSettlementAndImpairmentProvisions	63000000	USD
CY2020Q2	us-gaap	Restructuring Settlement And Impairment Provisions RestructuringSettlementAndImpairmentProvisions	-1449000000	USD
CY2020Q3	us-gaap	Restructuring Settlement And Impairment Provisions RestructuringSettlementAndImpairmentProvisions	-1081000000	USD
CY2020Q4	us-gaap	Restructuring Settlement And Impairment Provisions RestructuringSettlementAndImpairmentProvisions	-149000000	USD
CY2020Q1	ual	Defined Benefit Plan Net Periodic Benefit Cost Credit Gain Loss Due To Settlement Restructuring And Special And Contractual Termination Benefits DefinedBenefitPlanNetPeriodicBenefitCostCreditGainLossDueToSettlementRestructuringAndSpecialAndContractualTerminationBenefits	0	USD
CY2020Q2	ual	Defined Benefit Plan Net Periodic Benefit Cost Credit Gain Loss Due To Settlement Restructuring And Special And Contractual Termination Benefits DefinedBenefitPlanNetPeriodicBenefitCostCreditGainLossDueToSettlementRestructuringAndSpecialAndContractualTerminationBenefits	-231000000	USD
CY2020Q3	ual	Defined Benefit Plan Net Periodic Benefit Cost Credit Gain Loss Due To Settlement Restructuring And Special And Contractual Termination Benefits DefinedBenefitPlanNetPeriodicBenefitCostCreditGainLossDueToSettlementRestructuringAndSpecialAndContractualTerminationBenefits	-415000000	USD
CY2020Q1	ual	Gain Loss On Financial Instruments Non Operating GainLossOnFinancialInstrumentsNonOperating	-319000000	USD
CY2020Q2	ual	Gain Loss On Financial Instruments Non Operating GainLossOnFinancialInstrumentsNonOperating	9000000	USD
CY2020Q3	ual	Gain Loss On Financial Instruments Non Operating GainLossOnFinancialInstrumentsNonOperating	15000000	USD
CY2020Q4	ual	Gain Loss On Financial Instruments Non Operating GainLossOnFinancialInstrumentsNonOperating	101000000	USD
CY2020Q1	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	697000000	USD
CY2020Q2	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	0	USD
CY2020Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	0	USD
CY2020Q4	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	0	USD
CY2020Q1	ual	Special Charges And Losses On Financial Instruments Non Operating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsNonOperatingBeforeTax	1016000000	USD
CY2020Q2	ual	Special Charges And Losses On Financial Instruments Non Operating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsNonOperatingBeforeTax	222000000	USD
CY2020Q3	ual	Special Charges And Losses On Financial Instruments Non Operating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsNonOperatingBeforeTax	400000000	USD
CY2020Q4	ual	Special Charges And Losses On Financial Instruments Non Operating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsNonOperatingBeforeTax	-60000000	USD
CY2020Q1	ual	Special Charges And Losses On Financial Instruments Operating And Nonoperating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsOperatingAndNonoperatingBeforeTax	1079000000	USD
CY2020Q2	ual	Special Charges And Losses On Financial Instruments Operating And Nonoperating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsOperatingAndNonoperatingBeforeTax	-1227000000	USD
CY2020Q3	ual	Special Charges And Losses On Financial Instruments Operating And Nonoperating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsOperatingAndNonoperatingBeforeTax	-681000000	USD
CY2020Q4	ual	Special Charges And Losses On Financial Instruments Operating And Nonoperating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsOperatingAndNonoperatingBeforeTax	-209000000	USD
CY2020Q1	ual	Income Tax Expense Benefit Special Charges IncomeTaxExpenseBenefitSpecialCharges	-14000000	USD
CY2020Q2	ual	Income Tax Expense Benefit Special Charges IncomeTaxExpenseBenefitSpecialCharges	241000000	USD
CY2020Q3	ual	Income Tax Expense Benefit Special Charges IncomeTaxExpenseBenefitSpecialCharges	148000000	USD
CY2020Q4	ual	Income Tax Expense Benefit Special Charges IncomeTaxExpenseBenefitSpecialCharges	29000000	USD
CY2020Q1	ual	Special Items Net Of Income Tax Benefits SpecialItemsNetOfIncomeTaxBenefits	1065000000	USD
CY2019Q2	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	6000000	USD
CY2019Q3	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	2000000	USD
CY2019Q4	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	2000000	USD
CY2019Q2	ual	Special Items Net Of Income Tax Benefits SpecialItemsNetOfIncomeTaxBenefits	29000000	USD
CY2019Q3	ual	Special Items Net Of Income Tax Benefits SpecialItemsNetOfIncomeTaxBenefits	4000000	USD
CY2020Q2	ual	Special Items Net Of Income Tax Benefits SpecialItemsNetOfIncomeTaxBenefits	-986000000	USD
CY2020Q3	ual	Special Items Net Of Income Tax Benefits SpecialItemsNetOfIncomeTaxBenefits	-533000000	USD
CY2020Q4	ual	Special Items Net Of Income Tax Benefits SpecialItemsNetOfIncomeTaxBenefits	-180000000	USD
CY2019Q1	us-gaap	Asset Impairment Charges AssetImpairmentCharges	8000000	USD
CY2019Q2	us-gaap	Asset Impairment Charges AssetImpairmentCharges	61000000	USD
CY2019Q3	us-gaap	Asset Impairment Charges AssetImpairmentCharges	0	USD
CY2019Q4	us-gaap	Asset Impairment Charges AssetImpairmentCharges	102000000	USD
CY2019Q1	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	6000000	USD
CY2019Q1	ual	Gain Loss On Sale Of Other Assets And Other Miscellaneous Charges GainLossOnSaleOfOtherAssetsAndOtherMiscellaneousCharges	-4000000	USD
CY2019Q2	ual	Gain Loss On Sale Of Other Assets And Other Miscellaneous Charges GainLossOnSaleOfOtherAssetsAndOtherMiscellaneousCharges	-4000000	USD
CY2019Q3	ual	Gain Loss On Sale Of Other Assets And Other Miscellaneous Charges GainLossOnSaleOfOtherAssetsAndOtherMiscellaneousCharges	-25000000	USD
CY2019Q4	ual	Gain Loss On Sale Of Other Assets And Other Miscellaneous Charges GainLossOnSaleOfOtherAssetsAndOtherMiscellaneousCharges	-26000000	USD
CY2019Q1	us-gaap	Restructuring Settlement And Impairment Provisions RestructuringSettlementAndImpairmentProvisions	18000000	USD
CY2019Q2	us-gaap	Restructuring Settlement And Impairment Provisions RestructuringSettlementAndImpairmentProvisions	71000000	USD
CY2019Q3	us-gaap	Restructuring Settlement And Impairment Provisions RestructuringSettlementAndImpairmentProvisions	27000000	USD
CY2019Q4	us-gaap	Restructuring Settlement And Impairment Provisions RestructuringSettlementAndImpairmentProvisions	130000000	USD
CY2019Q1	ual	Gain Loss On Financial Instruments Non Operating GainLossOnFinancialInstrumentsNonOperating	17000000	USD
CY2019Q2	ual	Gain Loss On Financial Instruments Non Operating GainLossOnFinancialInstrumentsNonOperating	34000000	USD
CY2019Q3	ual	Gain Loss On Financial Instruments Non Operating GainLossOnFinancialInstrumentsNonOperating	21000000	USD
CY2019Q4	ual	Gain Loss On Financial Instruments Non Operating GainLossOnFinancialInstrumentsNonOperating	81000000	USD
CY2019Q1	ual	Special Charges And Losses On Financial Instruments Non Operating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsNonOperatingBeforeTax	1000000	USD
CY2019Q2	ual	Special Charges And Losses On Financial Instruments Non Operating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsNonOperatingBeforeTax	37000000	USD
CY2019Q3	ual	Special Charges And Losses On Financial Instruments Non Operating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsNonOperatingBeforeTax	6000000	USD
CY2019Q4	ual	Special Charges And Losses On Financial Instruments Non Operating Before Tax SpecialChargesAndLossesOnFinancialInstrumentsNonOperatingBeforeTax	49000000	USD
CY2019Q1	ual	Income Tax Expense Benefit Special Charges IncomeTaxExpenseBenefitSpecialCharges	0	USD
CY2019Q2	ual	Income Tax Expense Benefit Special Charges IncomeTaxExpenseBenefitSpecialCharges	-8000000	USD
CY2019Q3	ual	Income Tax Expense Benefit Special Charges IncomeTaxExpenseBenefitSpecialCharges	-2000000	USD
CY2019Q4	ual	Income Tax Expense Benefit Special Charges IncomeTaxExpenseBenefitSpecialCharges	-11000000	USD
CY2019Q1	ual	Special Items Net Of Income Tax Benefits SpecialItemsNetOfIncomeTaxBenefits	1000000	USD
CY2019Q4	ual	Special Items Net Of Income Tax Benefits SpecialItemsNetOfIncomeTaxBenefits	38000000	USD

Files In Submission

Name	View Source	Status
0000100517-21-000016-index-headers.html	Edgar Link	pending
0000100517-21-000016-index.html	Edgar Link	pending
0000100517-21-000016.txt	Edgar Link	pending
0000100517-21-000016-xbrl.zip	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
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report.css	Edgar Link	pending
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ual-20201231.htm	Edgar Link	pending
ual-20201231.xsd	Edgar Link	pending
ual-20201231_cal.xml	Edgar Link	unprocessable
ual-20201231_def.xml	Edgar Link	unprocessable
ual-20201231_g1.jpg	Edgar Link	pending
ual-20201231_g2.jpg	Edgar Link	pending
ual-20201231_htm.xml	Edgar Link	completed
ual-20201231_lab.xml	Edgar Link	unprocessable
ual-20201231_pre.xml	Edgar Link	unprocessable
ual_12312010kex1022.htm	Edgar Link	pending
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ual_12312010kex418.htm	Edgar Link	pending

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$UAL
United Airlines Holdings, Inc. Stock $ual

2020 Q4 Form 10-K Financial Statement

#000010051721000016 Filed on March 01, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$UAL United Airlines Holdings, Inc. Stock $ual

2020 Q4 Form 10-K Financial Statement

#000010051721000016 Filed on March 01, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$UAL
United Airlines Holdings, Inc. Stock $ual