XML 38 R44.htm IDEA: XBRL DOCUMENT
v3.20.1

Financial Instruments and Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2020 | Mar. 31, 2019
Fair Value [Line Items] |  |
Carrying value of investment | $ 92 |
Unrealized gain (loss) on derivative asset | $ (24) | $ 3
Asset-Backed Securities | Minimum |  |
Fair Value [Line Items] |  |
Available-for-sale securities remaining maturities | 1 year |
Asset-Backed Securities | Maximum |  |
Fair Value [Line Items] |  |
Available-for-sale securities remaining maturities | 15 years |
Corporate Debt | Maximum |  |
Fair Value [Line Items] |  |
Available-for-sale securities remaining maturities | 3 years |
CDARS |  |
Fair Value [Line Items] |  |
Available-for-sale securities remaining maturities | 1 year |
U.S. Government and Agency Notes |  |
Fair Value [Line Items] |  |
Available-for-sale securities remaining maturities | 3 years |
Other Fixed-Income Securities |  |
Fair Value [Line Items] |  |
Available-for-sale securities remaining maturities | 2 years |
Azul |  |
Fair Value [Line Items] |  |
Equity stake in Azul | 2.00% |
Gain (loss) on equity securities | $ (293) | $ 14
Carrying value of investment | $ 92 |
Azul | Preferred Stock |  |
Fair Value [Line Items] |  |
Equity stake in Azul | 8.00% |

X
- Definition Available for Sale Investment Maturity Term + References No definition available. + Details
Name: | ual_AvailableForSaleInvestmentMaturityTerm
Namespace Prefix: | ual_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Equity Securities, Ownership Percentage + References No definition available. + Details
Name: | ual_EquitySecuritiesOwnershipPercentage
Namespace Prefix: | ual_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair Value [Line Items] + References No definition available. + Details
Name: | ual_FairValueLineItems
Namespace Prefix: | ual_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740 + Details
Name: | us-gaap_EquitySecuritiesFvNi
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=116654751&loc=SL75117546-209714 + Details
Name: | us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585 + Details
Name: | us-gaap_UnrealizedGainLossOnDerivatives
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_CertificatesOfDepositMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=ual_UsGovernmentAgenciesDebtSecuritiesAndOtherFixedIncomeSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_FixedIncomeSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ual_AzulMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_PreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |