XML 110 R86.htm IDEA: XBRL DOCUMENT v3.8.0.1

Summary of Collateral Covenants and Cross Default Provisions (Parenthetical) (Detail) $ in Billions	12 Months Ended
	Dec. 31, 2017 USD ($)
Credit Agreement
Debt Instrument [Line Items]
Unrestricted liquidity required for credit agreement	$ 2.0
Minimum ratio of appraised value of collateral for Credit Agreement	160.00%
6.375% Senior Notes due 2018
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.375%
Debt instrument maturity year	2018
6% Senior Notes due 2020
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.00%
Debt instrument maturity year	2020
5% Senior Notes due 2024
Debt Instrument [Line Items]
Debt instrument stated interest rate	5.00%
Debt instrument maturity year	2024
4.25% Senior Notes due 2022
Debt Instrument [Line Items]
Debt instrument stated interest rate	4.25%
Debt instrument maturity year	2022

X

- Definition

Debt Covenant, Required Liquidity

+ References

No definition available.

+ Details

Name:	ual_DebtCovenantRequiredLiquidity
Namespace Prefix:	ual_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Debt Instrument Maturity Date Year

+ References

No definition available.

+ Details

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

X

- Definition

Minimum ratio of appraised value of collateral for Credit Agreement

+ References

No definition available.

+ Details

Name:	ual_MinimumRatioOfAppraisedValueOfCollateralForCreditAgreement
Namespace Prefix:	ual_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ual_CreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ual_SixPointThreeSevenFivePercentSeniorNotesDueTwentyEighteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ual_SeniorNotesSixPercentDueTwentyTwentyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ual_FivePercentSeniorNotesDueTwentyTwentyFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ual_FourPointTwoFivePercentSeniorNotesDueTwentyTwentyTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: