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No authoritative reference available. false 4 Passenger - Regional Affiliates 2 uaua_PassengerRevenueRegional uaua false credit duration A transportation carrier's regional affiliates' fare revenue recognized in the period from carrying passengers between... false false false false false false false false false false false terselabel false 1 false true false false 1076000000 1076 false false false 2 false true false false 844000000 844 false false false 3 false true false false 2937000000 2937 false false false 4 false true false false 2252000000 2252 false false false xbrli:monetaryItemType monetary A transportation carrier's regional affiliates' fare revenue recognized in the period from carrying passengers between destinations. No authoritative reference available. false 5 Cargo 2 us-gaap_CargoAndFreightRevenue us-gaap true credit duration No definition available. false false false false false false false false false false false false 1 false true false false 175000000 175 false false false 2 false true false false 125000000 125 false false false 3 false true false false 522000000 522 false false false 4 false true false false 370000000 370 false false false xbrli:monetaryItemType monetary Revenue from transporting cargo and freight between locations. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-AIR -Chapter 3 -Paragraph 4 -IssueDate 2003-05-01 false 6 Other operating revenues 2 us-gaap_OtherSalesRevenueNet us-gaap true credit duration No definition available. false false false false false false false false false false false false 1 false true false false 230000000 230 false false false 2 false true false false 197000000 197 false false false 3 false true false false 686000000 686 false false false 4 false true false false 611000000 611 false false false xbrli:monetaryItemType monetary Revenues from the sale of other goods or rendering of other services, not elsewhere specified in the taxonomy; net of (reduced by) sales adjustments, returns, allowances, and discounts. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 false 7 Total revenues 2 us-gaap_Revenues us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 5394000000 5394 false false false 2 false true false false 4433000000 4433 false false false 3 false true false false 14796000000 14796 false false false 4 false true false false 12142000000 12142 false false false xbrli:monetaryItemType monetary Aggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 true 8 Operating expenses: 2 us-gaap_CostsAndExpensesAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 9 Aircraft fuel 2 us-gaap_FuelCosts us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 1242000000 1242 false false false 2 false true false false 1064000000 1064 false false false 3 false true false false 3398000000 3398 false false false 4 false true false false 2528000000 2528 false false false xbrli:monetaryItemType monetary Fuel costs incurred that are directly related to goods produced and sold and services rendered during the reporting period. No authoritative reference available. false 10 Salaries and related costs 2 us-gaap_LaborAndRelatedExpense us-gaap true debit duration No definition available. false false false false false false false false false false false label false 1 false true false false 1085000000 1085 false false false 2 false true false false 954000000 954 false false false 3 false true false false 3053000000 3053 false false false 4 false true false false 2838000000 2838 false false false xbrli:monetaryItemType monetary The aggregate amount of expenditures for salaries, wages, profit sharing and incentive compensation, and other employee benefits, including share-based compensation, and pension and other postretirement benefit expense. No authoritative reference available. false 11 Regional Affiliates 2 uaua_AirlineCapacityPurchaseArrangements uaua false debit duration Costs incurred related to air services provided by third-party transportation providers, including regional affiliates. false false false false false false false false false false false terselabel false 1 false true false false 914000000 914 false false false 2 false true false false 775000000 775 false false false 3 false true false false 2640000000 2640 false false false 4 false true false false 2154000000 2154 false false false xbrli:monetaryItemType monetary Costs incurred related to air services provided by third-party transportation providers, including regional affiliates. No authoritative reference available. false 12 Purchased services 2 us-gaap_OtherCostOfServices us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 278000000 278 false false false 2 false true false false 279000000 279 false false false 3 false true false false 821000000 821 false false false 4 false true false false 852000000 852 false false false xbrli:monetaryItemType monetary Other costs incurred and are directly related to services rendered by an entity during the reporting period. No authoritative reference available. false 13 Aircraft maintenance materials and outside repairs 2 uaua_AircraftMaintenanceMaterialsAndRepairs uaua false debit duration Maintenance costs incurred and directly related to services rendered by an entity during the reporting period. Includes the... false false false false false false false false false false false terselabel false 1 false true false false 262000000 262 false false false 2 false true false false 253000000 253 false false false 3 false true false false 729000000 729 false false false 4 false true false false 718000000 718 false false false xbrli:monetaryItemType monetary Maintenance costs incurred and directly related to services rendered by an entity during the reporting period. Includes the cost of inspections and repairs, materials and routine maintenance costs for all aircraft and engines. No authoritative reference available. false 14 Landing fees and other rent 2 uaua_LandingFeesAndOtherRentals uaua false debit duration Direct costs incurred at airports in which the Company conducts flight operations. The costs primarily consist of fees paid... false false false false false false false false false false false terselabel false 1 false true false false 240000000 240 false false false 2 false true false false 226000000 226 false false false 3 false true false false 709000000 709 false false false 4 false true false false 676000000 676 false false false xbrli:monetaryItemType monetary Direct costs incurred at airports in which the Company conducts flight operations. The costs primarily consist of fees paid to the airport authority for takeoff and landing, gate space and facilities, allocations of common space and other terminal costs, and fuel storage facilities. No authoritative reference available. false 15 Depreciation and amortization 2 us-gaap_DepreciationAndAmortization us-gaap true debit duration No definition available. false false false false false false false false false false false label false 1 false true false false 224000000 224 false false false 2 false true false false 220000000 220 false false false 3 false true false false 652000000 652 false false false 4 false true false false 675000000 675 false false false xbrli:monetaryItemType monetary The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 false 16 Distribution expenses 2 us-gaap_SellingExpense us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 161000000 161 false false false 2 false true false false 145000000 145 false false false 3 false true false false 452000000 452 false false false 4 false true false false 402000000 402 false false false xbrli:monetaryItemType monetary Expenses recognized in the period that are directly related to the selling and distribution of products or services. No authoritative reference available. false 17 Aircraft rent 2 uaua_AircraftRental uaua false debit duration Expenses incurred related to the lease of aircraft from outside third parties that are used in the Company's business... false false false false false false false false false false false terselabel false 1 false true false false 82000000 82 false false false 2 false true false false 88000000 88 false false false 3 false true false false 244000000 244 false false false 4 false true false false 265000000 265 false false false xbrli:monetaryItemType monetary Expenses incurred related to the lease of aircraft from outside third parties that are used in the Company's business operations No authoritative reference available. false 18 Cost of third party sales 2 uaua_CostOfThirdPartySales uaua false debit duration Operating costs related to ancillary revenues such as maintenance services. false false false false false false false false false false false label false 1 false true false false 64000000 64 false false false 2 false true false false 59000000 59 false false false 3 false true false false 182000000 182 false false false 4 false true false false 172000000 172 false false false xbrli:monetaryItemType monetary Operating costs related to ancillary revenues such as maintenance services. No authoritative reference available. false 19 Impairments, merger-related costs and special items 2 uaua_RestructuringAndOther uaua false debit duration Significant and non-routine operating expenses such as asset impairments and restructuring charges that may not be an... false false false false false false false false false false false verboselabel false 1 false true false false 63000000 63 false false false 2 false true false false 43000000 43 false false false 3 false true false false 187000000 187 false false false 4 false true false false 250000000 250 false false false xbrli:monetaryItemType monetary Significant and non-routine operating expenses such as asset impairments and restructuring charges that may not be an indicator of future cash flows. No authoritative reference available. false 20 Other operating expenses 2 us-gaap_OtherCostAndExpenseOperating us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 244000000 244 false false false 2 false true false false 239000000 239 false false false 3 false true false false 691000000 691 false false false 4 false true false false 699000000 699 false false false xbrli:monetaryItemType monetary The total amount of other operating cost and expense items that are associated with the entity's normal revenue producing operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 3 -Article 5 false 21 Total operating expenses 2 us-gaap_CostsAndExpenses us-gaap true debit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 4859000000 4859 false false false 2 false true false false 4345000000 4345 false false false 3 false true false false 13758000000 13758 false false false 4 false true false false 12229000000 12229 false false false xbrli:monetaryItemType monetary Total costs of sales and operating expenses for the period. No authoritative reference available. true 22 Income (loss) from operations 2 us-gaap_OperatingIncomeLoss us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 535000000 535 false false false 2 false true false false 88000000 88 false false false 3 false true false false 1038000000 1038 false false false 4 false true false false -87000000 -87 false false false xbrli:monetaryItemType monetary The net result for the period of deducting operating expenses from operating revenues. No authoritative reference available. true 23 Other income (expense): 2 us-gaap_NonoperatingIncomeExpenseAbstract us-gaap true na duration No definition available. false false false false false true false false false false false terselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 24 Interest expense 2 us-gaap_InterestExpense us-gaap true debit duration No definition available. false false false false false false false false false false true negated false 1 false true false false -171000000 -171 false false false 2 false true false false -146000000 -146 false false false 3 false true false false -520000000 -520 false false false 4 false true false false -415000000 -415 false false false xbrli:monetaryItemType monetary The cost of borrowed funds accounted for as interest that was charged against earnings during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 34 -Paragraph 21 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher OTS -Name Federal Regulation (FR) -Number Title 12 -Chapter V -Section 563c.102 -Paragraph 9 -Subsection II Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 9 -Article 9 false 25 Interest income 2 us-gaap_InvestmentIncomeInterest us-gaap true credit duration No definition available. false false false false false false false false false false false false 1 false true false false 5000000 5 false false false 2 false true false false 3000000 3 false false false 3 false true false false 8000000 8 false false false 4 false true false false 15000000 15 false false false xbrli:monetaryItemType monetary Income derived from investments in debt securities and on cash and cash equivalents the earnings of which reflect the time value of money or transactions in which the payments are for the use or forbearance of money. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 14 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Article 5 false 26 Interest capitalized 2 us-gaap_InterestCostsCapitalized us-gaap true debit duration No definition available. false false false false false false false false false false true negated false 1 false true false false 2000000 2 false false false 2 false true false false 3000000 3 false false false 3 false true false false 7000000 7 false false false 4 false true false false 8000000 8 false false false xbrli:monetaryItemType monetary The amount of interest that was capitalized during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 34 -Paragraph 21 -Subparagraph b false 27 Miscellaneous, net 2 us-gaap_OtherNonoperatingIncomeExpense us-gaap true credit duration No definition available. false false false false false false false false false false false label false 1 false true false false 15000000 15 false false false 2 false true false false -10000000 -10 false false false 3 false true false false 42000000 42 false false false 4 false true false false 19000000 19 false false false xbrli:monetaryItemType monetary The net amount of other nonoperating income and expense, which does not qualify for separate disclosure on the income statement under materiality guidelines. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 false 28 Total other income (expense) 2 us-gaap_NonoperatingIncomeExpense us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false -149000000 -149 false false false 2 false true false false -150000000 -150 false false false 3 false true false false -463000000 -463 false false false 4 false true false false -373000000 -373 false false false xbrli:monetaryItemType monetary The aggregate amount of income (expense) from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Article 5 true 29 Income (loss) before income taxes and equity in earnings of affiliates 2 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 386000000 386 false false false 2 false true false false -62000000 -62 false false false 3 false true false false 575000000 575 false false false 4 false true false false -460000000 -460 false false false xbrli:monetaryItemType monetary Sum of operating profit and nonoperating income (expense) before income (loss) from equity method investments, income taxes, extraordinary items, cumulative effects of changes in accounting principles, and noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Subparagraph 1(i) -Article 4 true 30 Income taxes 2 us-gaap_IncomeTaxExpenseBenefit us-gaap true debit duration No definition available. false false false false false false false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false true false false -4000000 -4 false false false 3 false true false false -1000000 -1 false false false 4 false true false false -46000000 -46 false false false xbrli:monetaryItemType monetary The sum of the current income tax expense (benefit) and the deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Article 4 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 45 -Subparagraph a, b false 31 Income (loss) before equity in earnings of affiliates 2 uaua_LossBeforeEquityInEarningsOfAffiliates uaua false credit duration Loss before equity in earnings of affiliates false false false false false false false false false false false totallabel false 1 false true false false 386000000 386 false false false 2 false true false false -58000000 -58 false false false 3 false true false false 576000000 576 false false false 4 false true false false -414000000 -414 false false false xbrli:monetaryItemType monetary Loss before equity in earnings of affiliates No authoritative reference available. true 32 Equity in earnings of affiliates, net of tax 2 us-gaap_IncomeLossFromEquityMethodInvestments us-gaap true credit duration No definition available. false false false false false false false false false false false false 1 false true false false 1000000 1 false false false 2 false true false false 1000000 1 false false false 3 false true false false 2000000 2 false false false 4 false true false false 3000000 3 false false false xbrli:monetaryItemType monetary This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. Such amount typically reflects adjustments similar to those made in preparing consolidated statements, including adjustments to eliminate intercompany gains and losses, and to amortize, if appropriate, any difference between cost and underlying equity in net assets of the investee at the date of investment. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 19 -Subparagraph c Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 11 -Article 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 6 -Subparagraph b false 33 Net income (loss) 2 us-gaap_NetIncomeLoss us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 387000000 387 false false false 2 false true false false -57000000 -57 false false false 3 false true false false 578000000 578 false false false 4 false true false false -411000000 -411 false false false xbrli:monetaryItemType monetary The portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent. If the entity does not present consolidated financial statements, the amount of profit or loss for the period, net of income taxes. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 19 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph d Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A7 -Appendix A Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 20 -Article 9 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 10, 15 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 87-21 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28, 29, 30 true 34 Earnings (loss) per share, basic 2 us-gaap_EarningsPerShareBasic us-gaap true na duration No definition available. false false false false false false false false false false false label true 1 true true false false 2.30 2.30 false false false 2 true true false false -0.39 -0.39 false false false 3 true true false false 3.44 3.44 false false false 4 true true false false -2.83 -2.83 false false false us-types:perShareItemType decimal The amount of net income or loss for the period per each share of common stock outstanding during the reporting period. 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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 11, 12, 36 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 false 36 United Air Lines Inc [Member] 0 na true na na No definition available. false true false false false false false false false false false http://www.united.com/role/statementincome false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false false 5 USD true false false false United Air Lines Inc [Member] dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi uaua_UnitedAirLinesIncMember dei_LegalEntityAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 6 USD true false false false United Air Lines Inc [Member] dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi uaua_UnitedAirLinesIncMember dei_LegalEntityAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 7 USD true false false false United Air Lines Inc [Member] dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi uaua_UnitedAirLinesIncMember dei_LegalEntityAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 8 USD true false false false United Air Lines Inc [Member] dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi uaua_UnitedAirLinesIncMember dei_LegalEntityAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 37 Operating revenues: 2 us-gaap_SalesRevenueNetAbstract us-gaap true na duration No definition available. false false false false false true false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 38 Passenger - Mainline 2 uaua_PassengerRevenueMainline uaua false credit duration A transportation carrier's mainline fare revenue recognized in the period from carrying passengers between destinations. false false false false false false false false false false false verboselabel false 1 false true false false 3913000000 3913 false false false 2 false true false false 3267000000 3267 false false false 3 false true false false 10651000000 10651 false false false 4 false true false false 8909000000 8909 false false false xbrli:monetaryItemType monetary A transportation carrier's mainline fare revenue recognized in the period from carrying passengers between destinations. No authoritative reference available. false 39 Passenger - Regional Affiliates 2 uaua_PassengerRevenueRegional uaua false credit duration A transportation carrier's regional affiliates' fare revenue recognized in the period from carrying passengers between... false false false false false false false false false false false terselabel false 1 false true false false 1076000000 1076 false false false 2 false true false false 844000000 844 false false false 3 false true false false 2937000000 2937 false false false 4 false true false false 2252000000 2252 false false false xbrli:monetaryItemType monetary A transportation carrier's regional affiliates' fare revenue recognized in the period from carrying passengers between destinations. No authoritative reference available. false 40 Cargo 2 us-gaap_CargoAndFreightRevenue us-gaap true credit duration No definition available. false false false false false false false false false false false false 1 false true false false 175000000 175 false false false 2 false true false false 125000000 125 false false false 3 false true false false 522000000 522 false false false 4 false true false false 370000000 370 false false false xbrli:monetaryItemType monetary Revenue from transporting cargo and freight between locations. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-AIR -Chapter 3 -Paragraph 4 -IssueDate 2003-05-01 false 41 Other operating revenues 2 us-gaap_OtherSalesRevenueNet us-gaap true credit duration No definition available. false false false false false false false false false false false false 1 false true false false 232000000 232 false false false 2 false true false false 199000000 199 false false false 3 false true false false 692000000 692 false false false 4 false true false false 618000000 618 false false false xbrli:monetaryItemType monetary Revenues from the sale of other goods or rendering of other services, not elsewhere specified in the taxonomy; net of (reduced by) sales adjustments, returns, allowances, and discounts. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 false 42 Total revenues 2 us-gaap_Revenues us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 5396000000 5396 false false false 2 false true false false 4435000000 4435 false false false 3 false true false false 14802000000 14802 false false false 4 false true false false 12149000000 12149 false false false xbrli:monetaryItemType monetary Aggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 true 43 Operating expenses: 2 us-gaap_CostsAndExpensesAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 44 Aircraft fuel 2 us-gaap_FuelCosts us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 1242000000 1242 false false false 2 false true false false 1064000000 1064 false false false 3 false true false false 3398000000 3398 false false false 4 false true false false 2528000000 2528 false false false xbrli:monetaryItemType monetary Fuel costs incurred that are directly related to goods produced and sold and services rendered during the reporting period. No authoritative reference available. false 45 Salaries and related costs 2 us-gaap_LaborAndRelatedExpense us-gaap true debit duration No definition available. false false false false false false false false false false false label false 1 false true false false 1085000000 1085 false false false 2 false true false false 954000000 954 false false false 3 false true false false 3053000000 3053 false false false 4 false true false false 2838000000 2838 false false false xbrli:monetaryItemType monetary The aggregate amount of expenditures for salaries, wages, profit sharing and incentive compensation, and other employee benefits, including share-based compensation, and pension and other postretirement benefit expense. No authoritative reference available. false 46 Regional Affiliates 2 uaua_AirlineCapacityPurchaseArrangements uaua false debit duration Costs incurred related to air services provided by third-party transportation providers, including regional affiliates. false false false false false false false false false false false terselabel false 1 false true false false 914000000 914 false false false 2 false true false false 775000000 775 false false false 3 false true false false 2640000000 2640 false false false 4 false true false false 2154000000 2154 false false false xbrli:monetaryItemType monetary Costs incurred related to air services provided by third-party transportation providers, including regional affiliates. No authoritative reference available. false 47 Purchased services 2 us-gaap_OtherCostOfServices us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 278000000 278 false false false 2 false true false false 279000000 279 false false false 3 false true false false 821000000 821 false false false 4 false true false false 852000000 852 false false false xbrli:monetaryItemType monetary Other costs incurred and are directly related to services rendered by an entity during the reporting period. No authoritative reference available. false 48 Aircraft maintenance materials and outside repairs 2 uaua_AircraftMaintenanceMaterialsAndRepairs uaua false debit duration Maintenance costs incurred and directly related to services rendered by an entity during the reporting period. Includes the... false false false false false false false false false false false terselabel false 1 false true false false 262000000 262 false false false 2 false true false false 253000000 253 false false false 3 false true false false 729000000 729 false false false 4 false true false false 718000000 718 false false false xbrli:monetaryItemType monetary Maintenance costs incurred and directly related to services rendered by an entity during the reporting period. Includes the cost of inspections and repairs, materials and routine maintenance costs for all aircraft and engines. No authoritative reference available. false 49 Landing fees and other rent 2 uaua_LandingFeesAndOtherRentals uaua false debit duration Direct costs incurred at airports in which the Company conducts flight operations. The costs primarily consist of fees paid... false false false false false false false false false false false terselabel false 1 false true false false 240000000 240 false false false 2 false true false false 226000000 226 false false false 3 false true false false 709000000 709 false false false 4 false true false false 676000000 676 false false false xbrli:monetaryItemType monetary Direct costs incurred at airports in which the Company conducts flight operations. The costs primarily consist of fees paid to the airport authority for takeoff and landing, gate space and facilities, allocations of common space and other terminal costs, and fuel storage facilities. No authoritative reference available. false 50 Depreciation and amortization 2 us-gaap_DepreciationAndAmortization us-gaap true debit duration No definition available. false false false false false false false false false false false label false 1 false true false false 224000000 224 false false false 2 false true false false 220000000 220 false false false 3 false true false false 652000000 652 false false false 4 false true false false 675000000 675 false false false xbrli:monetaryItemType monetary The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 false 51 Distribution expenses 2 us-gaap_SellingExpense us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 161000000 161 false false false 2 false true false false 145000000 145 false false false 3 false true false false 452000000 452 false false false 4 false true false false 402000000 402 false false false xbrli:monetaryItemType monetary Expenses recognized in the period that are directly related to the selling and distribution of products or services. No authoritative reference available. false 52 Aircraft rent 2 uaua_AircraftRental uaua false debit duration Expenses incurred related to the lease of aircraft from outside third parties that are used in the Company's business... false false false false false false false false false false false terselabel false 1 false true false false 82000000 82 false false false 2 false true false false 88000000 88 false false false 3 false true false false 244000000 244 false false false 4 false true false false 267000000 267 false false false xbrli:monetaryItemType monetary Expenses incurred related to the lease of aircraft from outside third parties that are used in the Company's business operations No authoritative reference available. false 53 Cost of third party sales 2 uaua_CostOfThirdPartySales uaua false debit duration Operating costs related to ancillary revenues such as maintenance services. false false false false false false false false false false false label false 1 false true false false 63000000 63 false false false 2 false true false false 58000000 58 false false false 3 false true false false 181000000 181 false false false 4 false true false false 171000000 171 false false false xbrli:monetaryItemType monetary Operating costs related to ancillary revenues such as maintenance services. No authoritative reference available. false 54 Impairments, merger-related costs and special items 2 uaua_RestructuringAndOther uaua false debit duration Significant and non-routine operating expenses such as asset impairments and restructuring charges that may not be an... false false false false false false false false false false false verboselabel false 1 false true false false 63000000 63 false false false 2 false true false false 43000000 43 false false false 3 false true false false 187000000 187 false false false 4 false true false false 250000000 250 false false false xbrli:monetaryItemType monetary Significant and non-routine operating expenses such as asset impairments and restructuring charges that may not be an indicator of future cash flows. No authoritative reference available. false 55 Other operating expenses 2 us-gaap_OtherCostAndExpenseOperating us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 240000000 240 false false false 2 false true false false 240000000 240 false false false 3 false true false false 686000000 686 false false false 4 false true false false 699000000 699 false false false xbrli:monetaryItemType monetary The total amount of other operating cost and expense items that are associated with the entity's normal revenue producing operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 3 -Article 5 false 56 Total operating expenses 2 us-gaap_CostsAndExpenses us-gaap true debit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 4854000000 4854 false false false 2 false true false false 4345000000 4345 false false false 3 false true false false 13752000000 13752 false false false 4 false true false false 12230000000 12230 false false false xbrli:monetaryItemType monetary Total costs of sales and operating expenses for the period. No authoritative reference available. true 57 Income (loss) from operations 2 us-gaap_OperatingIncomeLoss us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 542000000 542 false false false 2 false true false false 90000000 90 false false false 3 false true false false 1050000000 1050 false false false 4 false true false false -81000000 -81 false false false xbrli:monetaryItemType monetary The net result for the period of deducting operating expenses from operating revenues. No authoritative reference available. true 58 Other income (expense): 2 us-gaap_NonoperatingIncomeExpenseAbstract us-gaap true na duration No definition available. false false false false false true false false false false false terselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 59 Interest expense 2 us-gaap_InterestExpense us-gaap true debit duration No definition available. false false false false false false false false false false true negated false 1 false true false false -165000000 -165 false false false 2 false true false false -145000000 -145 false false false 3 false true false false -504000000 -504 false false false 4 false true false false -414000000 -414 false false false xbrli:monetaryItemType monetary The cost of borrowed funds accounted for as interest that was charged against earnings during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 34 -Paragraph 21 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher OTS -Name Federal Regulation (FR) -Number Title 12 -Chapter V -Section 563c.102 -Paragraph 9 -Subsection II Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 9 -Article 9 false 60 Interest income 2 us-gaap_InvestmentIncomeInterest us-gaap true credit duration No definition available. false false false false false false false false false false false false 1 false true false false 5000000 5 false false false 2 false true false false 3000000 3 false false false 3 false true false false 8000000 8 false false false 4 false true false false 15000000 15 false false false xbrli:monetaryItemType monetary Income derived from investments in debt securities and on cash and cash equivalents the earnings of which reflect the time value of money or transactions in which the payments are for the use or forbearance of money. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 14 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Article 5 false 61 Interest capitalized 2 us-gaap_InterestCostsCapitalized us-gaap true debit duration No definition available. false false false false false false false false false false true negated false 1 false true false false 2000000 2 false false false 2 false true false false 3000000 3 false false false 3 false true false false 7000000 7 false false false 4 false true false false 8000000 8 false false false xbrli:monetaryItemType monetary The amount of interest that was capitalized during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 34 -Paragraph 21 -Subparagraph b false 62 Miscellaneous, net 2 us-gaap_OtherNonoperatingIncomeExpense us-gaap true credit duration No definition available. false false false false false false false false false false false label false 1 false true false false 14000000 14 false false false 2 false true false false -11000000 -11 false false false 3 false true false false 42000000 42 false false false 4 false true false false 18000000 18 false false false xbrli:monetaryItemType monetary The net amount of other nonoperating income and expense, which does not qualify for separate disclosure on the income statement under materiality guidelines. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 false 63 Total other income (expense) 2 us-gaap_NonoperatingIncomeExpense us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false -144000000 -144 false false false 2 false true false false -150000000 -150 false false false 3 false true false false -447000000 -447 false false false 4 false true false false -373000000 -373 false false false xbrli:monetaryItemType monetary The aggregate amount of income (expense) from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Article 5 true 64 Income (loss) before income taxes and equity in earnings of affiliates 2 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 398000000 398 false false false 2 false true false false -60000000 -60 false false false 3 false true false false 603000000 603 false false false 4 false true false false -454000000 -454 false false false xbrli:monetaryItemType monetary Sum of operating profit and nonoperating income (expense) before income (loss) from equity method investments, income taxes, extraordinary items, cumulative effects of changes in accounting principles, and noncontrolling interest. 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Such amount typically reflects adjustments similar to those made in preparing consolidated statements, including adjustments to eliminate intercompany gains and losses, and to amortize, if appropriate, any difference between cost and underlying equity in net assets of the investee at the date of investment. 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If the entity does not present consolidated financial statements, the amount of profit or loss for the period, net of income taxes. 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