XML 61 R47.htm IDEA: XBRL DOCUMENT v3.19.2

Financial Instruments and Fair Value Measurements - Narrative (Details)	6 Months Ended
	Jun. 30, 2019
Azul
Fair Value [Line Items]
Equity stake	2.00%
Azul | Preferred Stock
Fair Value [Line Items]
Equity stake	8.00%
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 | Minimum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	1 year
Corporate Debt | Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	3 years
CDARS | Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	1 year
U.S. Government and Other Securities | Minimum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	3 years
Other Fixed-Income Securities | Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	2 years

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

- 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:

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: