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Pension, Postretirement And Other Employee Benefit Plans - Participation in the IAM National Pension Plan (Details) - IAM National Pension Plan - Pension Benefits - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Jan. 01, 2021
Multiemployer Plans [Line Items] |  |  |  |
Plan length | 10 years |  |  |
Additional contribution as a percentage of the hourly contribution rate | 2.50% |  |  |
Surcharge imposed | No |  |  |
United Airlines, Inc. |  |  |  |
Multiemployer Plans [Line Items] |  |  |  |
Funded percentage |  |  |  | 87.10%
Contributions | $ 87 | $ 75 | $ 58 |

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- Definition Multiemployer Plan, Rehabilitation Plan Term + References No definition available. + Details
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