Allocation of Plan Asset (Detail) (United Airlines, Inc.)	12 Months Ended
Dec. 31, 2014
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percent of Total, Minimum	40.00%
Percent of Total, Maximum	54.00%
Expected Long-Term Rate of Return	10.00%
Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Percent of Total, Minimum	26.00%
Percent of Total, Maximum	34.00%
Expected Long-Term Rate of Return	4.00%
Alternatives
Defined Benefit Plan Disclosure [Line Items]
Percent of Total, Minimum	14.00%
Percent of Total, Maximum	20.00%
Expected Long-Term Rate of Return	7.00%
Other Investments
Defined Benefit Plan Disclosure [Line Items]
Percent of Total, Minimum	4.00%
Percent of Total, Maximum	8.00%
Expected Long-Term Rate of Return	6.00%

An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 30

-Glossary Expected Long-Term Rate of Return on Plan Assets

-URI http://asc.fasb.org/extlink&oid=6512013

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (k)(3)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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- Definition

Target allocation maximum percentage of investments of this type to total plan assets presented on a weighted average basis.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(i)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (c)(i)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e2446-114920

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- Definition

Target allocation minimum percentage of investments of this type to total plan assets presented on a weighted average basis.

+ References

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