Number of persons employed by the Entity

No definition available.

Name:	dei_EntityNumberOfEmployees
Namespace Prefix:	dei_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Commitment Capacity Available

+ References

No definition available.

+ Details

Name:	ual_CommitmentCapacityAvailable
Namespace Prefix:	ual_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	ual_CommitmentsAndContingenciesLineItems
Namespace Prefix:	ual_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument maturity year

+ References

No definition available.

+ Details

Name:	ual_DebtInstrumentMaturityYear
Namespace Prefix:	ual_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Remaining Terms

+ References

No definition available.

+ Details

Name:	ual_DebtInstrumentRemainingTerms
Namespace Prefix:	ual_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Estimated construction cost

+ References

No definition available.

+ Details

Name:	ual_EstimatedConstructionCost
Namespace Prefix:	ual_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Expected Delivery Date

+ References

No definition available.

+ Details

Name:	ual_ExpectedDeliveryDate
Namespace Prefix:	ual_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of Aircraft Committed to Purchase

+ References

No definition available.

+ Details

Name:	ual_NumberOfAircraftCommittedToPurchase
Namespace Prefix:	ual_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of Aircraft Expected to Be Delivered

+ References

No definition available.

+ Details

Name:	ual_NumberOfAircraftExpectedToBeDelivered
Namespace Prefix:	ual_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of Aircraft under Financing Arrangement Expected to be Delivered

+ References

No definition available.

+ Details

Name:	ual_NumberOfAircraftUnderFinancingArrangementExpectedToBeDelivered
Namespace Prefix:	ual_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of new aircraft under purchase rights and options.

+ References

No definition available.

+ Details

Name:	ual_NumberOfNewAircraftUnderPurchaseRightsAndOptions
Namespace Prefix:	ual_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of employees represented by labor organizations

+ References

No definition available.

+ Details

Name:	ual_PercentageOfEmployeesRepresentedByLaborOrganizations
Namespace Prefix:	ual_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of lease rates of orders allocated to each subsidiary.

+ References

No definition available.

+ Details

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

- Definition

Project demand period maximum

+ References

No definition available.

+ Details

Name:	ual_ProjectDemandPeriodMaximum
Namespace Prefix:	ual_
Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	duration

- Definition

Project demand period minimum

+ References

No definition available.

+ Details

Name:	ual_ProjectDemandPeriodMinimum
Namespace Prefix:	ual_
Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	duration

- Definition

Scheduled Delivery, Month and Year

+ References

No definition available.

+ Details

Name:	ual_ScheduledDeliveryMonthAndYear
Namespace Prefix:	ual_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	instant

- Definition

Scheduled Delivery Year

+ References

No definition available.

+ Details

Name:	ual_ScheduledDeliveryYear
Namespace Prefix:	ual_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	instant

- Definition

Special Facilities Revenue Bonds

+ References

No definition available.

+ Details

Name:	ual_SpecialFacilitiesRevenueBonds
Namespace Prefix:	ual_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Terminal improvement project amount

+ References

No definition available.

+ Details

Name:	ual_TerminalImprovementProjectAmount
Namespace Prefix:	ual_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 7

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6455398&loc=d3e45280-112737

+ Details

Name:	us-gaap_CapitalLeaseObligations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Cash deposited in a special reserve account for the exclusive benefit of customers pursuant to SEC Regulations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-BRD

-Paragraph 80

-Subparagraph Exhibit 4-8, 3

-IssueDate 2006-05-01

-Chapter 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_CashReserveDepositRequiredAndMade
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date before deducting unamortized discount or premiums (if any). May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number APB14-1

-Paragraph 31

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 4: 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)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Value of revenue deferred or cost to provide future services associated with points or miles outstanding and awards that expect to be redeemed through customer loyalty programs and the value of transportation services sold but as yet used by the passenger. Used to reflect the current portion of the liability (within one year or within the normal operating cycle if longer).

+ 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 210.5-02.20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-AIR

-Paragraph 19

-IssueDate 2003-05-01

-Chapter 3

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_DeferredAirTrafficRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 45

-Paragraph 13

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

+ Details

Name:	us-gaap_GuaranteeObligationsMaximumExposure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 16

-Subparagraph b(i)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 122

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 55

-Paragraph 40

-Subparagraph (Note 3)

-URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717

+ Details

Name:	us-gaap_OperatingLeasesFutureMinimumPaymentsDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended	9 Months Ended	1 Months Ended		9 Months Ended
	Aug. 31, 2012	Sep. 30, 2012 Employee	Nov. 30, 2011 United Continental Holdings Inc Year	May 31, 2011 United Continental Holdings Inc	Sep. 30, 2012 United Continental Holdings Inc	Sep. 30, 2012 United Continental Holdings Inc Capital Addition Purchase Commitments Boeing 737 AirCraft	Sep. 30, 2012 United Continental Holdings Inc Floating Rate Debt	Sep. 30, 2012 United Continental Holdings Inc Fixed Rate Debt	Sep. 30, 2012 United Continental Holdings Inc Loans And Leases From Non U S Entities	Sep. 30, 2012 United Air Lines Inc	Sep. 30, 2012 United Air Lines Inc Capital Addition Purchase Commitments AirCraft	Sep. 30, 2012 United Air Lines Inc Capital Addition Purchase Commitments Boeing 737 AirCraft	Sep. 30, 2012 United Air Lines Inc Capital Addition Purchase Commitments Other Boeing AirCraft	Sep. 30, 2012 United Air Lines Inc Capital Addition Purchase Commitments Airbus AirCraft	Sep. 30, 2012 United Air Lines Inc Floating Rate Debt	Sep. 30, 2012 United Air Lines Inc Fixed Rate Debt	Sep. 30, 2012 United Air Lines Inc Loans And Leases From Non U S Entities	Sep. 30, 2012 Continental Airlines Inc	Sep. 30, 2012 Continental Airlines Inc Capital Addition Purchase Commitments AirCraft	Sep. 30, 2012 Continental Airlines Inc Capital Addition Purchase Commitments Boeing 737 AirCraft	Sep. 30, 2012 Continental Airlines Inc Capital Addition Purchase Commitments Other Boeing AirCraft	Sep. 30, 2012 Continental Airlines Inc Floating Rate Debt	Sep. 30, 2012 Continental Airlines Inc Fixed Rate Debt	Sep. 30, 2012 Continental Airlines Inc Loans And Leases From Non U S Entities	Sep. 30, 2012 United Air Lines Inc and Continental Airline Inc	Sep. 30, 2012 Minimum United Continental Holdings Inc Capital Addition Purchase Commitments Boeing 737	Sep. 30, 2012 Minimum United Air Lines Inc Capital Addition Purchase Commitments	Sep. 30, 2012 Minimum Continental Airlines Inc Capital Addition Purchase Commitments	Sep. 30, 2012 Minimum Bonds United Air Lines Inc and Continental Airline Inc	Sep. 30, 2012 Maximum United Continental Holdings Inc Year	Sep. 30, 2012 Maximum United Continental Holdings Inc Capital Addition Purchase Commitments Boeing 737	Sep. 30, 2012 Maximum United Air Lines Inc Capital Addition Purchase Commitments	Sep. 30, 2012 Maximum Continental Airlines Inc Capital Addition Purchase Commitments	Sep. 30, 2012 Maximum Bonds United Air Lines Inc and Continental Airline Inc
Commitments and Contingencies [Line Items]
Number of new aircraft committed to purchase						100					100								68	44	24
Number of new aircraft under purchase rights and options						100					164								83
New aircraft, scheduled delivery date																										2018	2013				2022	2019	2016
Number of aircraft expected to be delivered												50	25	25						6	4
New aircraft, scheduled delivery date																												Oct. 01, 2012					Dec. 31, 2012
Number of aircraft under financing arrangement expected to be delivered																				20	6
New aircraft, scheduled delivery date																																	2013-07
Percentage of lease rates of orders allocated to each subsidiary											50.00%								50.00%
Reserve required under combined credit card processing agreement																									$ 25,000,000
Expected advanced ticket sales																		0
Guarantor obligations, maximum exposure										270,000,000								1,600,000,000
Operating leases obligations					1,700,000,000					270,000,000								1,400,000,000
Capital leases obligations																		190,000,000
Debt instrument, maturity year																													2015					2033
Debt instrument principal amount							2,600,000,000	357,000,000	2,900,000,000						1,900,000,000	191,000,000	2,100,000,000					676,000,000	166,000,000	762,000,000
Debt instrument, remaining terms (years)																														9
Terminal improvement project amount				1,000,000,000
Special facilities revenue bonds	101,000,000		113,000,000
Estimated construction cost			100,000,000
Project demand period that determines construction of the remaining phases, minimum years			7
Project demand period that determines construction of the remaining phases, maximum years			10
Commitment capacity available					$ 500,000,000
Number of employees		88,000
Percentage of employees represented by various U.S. labor organizations		80.00%