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Schedule of Commitments to Purchase Aircrafts (Detail) - United Airlines, Inc. - Capital Addition Purchase Commitments | Dec. 31, 2017 Aircraft | [1]
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Airbus A350 Aircraft |
Long-term Purchase Commitment [Line Items] |
Number of new aircraft committed to purchase | 45
Boeing 737 MAX Aircraft |
Long-term Purchase Commitment [Line Items] |
Number of new aircraft committed to purchase | 161
Boeing 777-300ER Aircraft |
Long-term Purchase Commitment [Line Items] |
Number of new aircraft committed to purchase | 4
Boeing 787 Aircraft |
Long-term Purchase Commitment [Line Items] |
Number of new aircraft committed to purchase | 18
[1] | United also has options and purchase rights for additional aircraft.

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