XML 112 R82.htm IDEA: XBRL DOCUMENT v3.6.0.2

Fair Value Measurements - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016
EETC
Fair Value [Line Items]
Available-for-sale securities remaining maturities	2019
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	30 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	5 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	1 year
U.S. Government and Other Securities | Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	3 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

Available for Sale Investment Maturity Year

+ References

No definition available.

+ Details

Name:	ual_AvailableForSaleInvestmentMaturityYear
Namespace Prefix:	ual_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

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:	us-gaap_LongtermDebtTypeAxis=us-gaap_EnhancedEquipmentTrustCertificateMember
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:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RangeAxis=us-gaap_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: