XML 101 R71.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Allocation of Plan Assets (Detail) - United Airlines, Inc. | 12 Months Ended
--- | ---
Dec. 31, 2016
Equity Securities |
Defined Benefit Plan Disclosure [Line Items] |
Percent of Total, Minimum | 30.00%
Percent of Total, Maximum | 40.00%
Expected Long-Term Rate of Return | 9.50%
Fixed-Income Securities |
Defined Benefit Plan Disclosure [Line Items] |
Percent of Total, Minimum | 34.00%
Percent of Total, Maximum | 44.00%
Expected Long-Term Rate of Return | 5.00%
Alternatives |
Defined Benefit Plan Disclosure [Line Items] |
Percent of Total, Minimum | 14.00%
Percent of Total, Maximum | 27.00%
Expected Long-Term Rate of Return | 7.30%
Other Investments |
Defined Benefit Plan Disclosure [Line Items] |
Percent of Total, Minimum | 0.00%
Percent of Total, Maximum | 10.00%
Expected Long-Term Rate of Return | 7.00%

X
- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Expected Long-Term Rate of Return on Plan Assets -URI http://asc.fasb.org/extlink&oid=6512046 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=65897934&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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 5 -Subparagraph (c)(i) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2446-114920 Reference 2: 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=65897934&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanTargetPlanAssetAllocationsRangeMaximum
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Target allocation minimum 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=65897934&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=65897934&loc=d3e2446-114920 + Details
Name: | us-gaap_DefinedBenefitPlanTargetPlanAssetAllocationsRangeMinimum
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=ual_UnitedAirLinesIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_FixedIncomeFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=ual_AlternativeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=ual_OtherEquityInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |