| Cover | Jul. 08, 2020 |
| Entity Information [Line Items] | |
| Document Type | 8-K/A |
| Amendment Flag | true |
| Amendment Description | On July 8, 2020, United Airlines Holdings, Inc. and United Airlines, Inc. (together, the "Company") filed a Form 8-K (the "Initial Form 8-K") disclosing, among other items, plans to implement a workforce reduction. On September 2, 2020, the Company filed Amendment No. 1 to the Initial Form 8-K ("Amendment No. 1" and, together with the Initial Form 8-K, the "Original Form 8-K") disclosing additional details regarding the planned workforce reduction. At the respective times of the filing of the Initial Form 8-K and Amendment No. 1, the Company was unable in good faith to make a determination of an estimate or range of estimates required by paragraphs (b), (c) and (d) of Item 2.05 of Form 8-K with respect to such workforce reduction actions. This Amendment No. 2 is being filed by the Company to provide such information. Except as set forth herein, the remainder of the Original Form 8-K is unchanged. |
| Document Period End Date | Jul. 8, 2020 |
| Entity File Number | 001-06033 |
| Entity Registrant Name | UNITED AIRLINES HOLDINGS, INC. |
| Entity Central Index Key | 0000100517 |
| Entity Tax Identification Number | 36-2675207 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 233 S. Wacker Drive |
| Entity Address, City or Town | Chicago |
| Entity Address, State or Province | IL |
| Entity Address, Postal Zip Code | 60606 |
| City Area Code | 872 |
| Local Phone Number | 825-4000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.01 par value |
| Trading Symbol | UAL |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| UNITED AIRLINES, INC. | |
| Entity Information [Line Items] | |
| Entity File Number | 001-10323 |
| Entity Registrant Name | UNITED AIRLINES, INC. |
| Entity Tax Identification Number | 74-2099724 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 233 S. Wacker Drive |
| Entity Address, City or Town | Chicago |
| Entity Address, State or Province | IL |
| Entity Address, Postal Zip Code | 60606 |
| City Area Code | 872 |
| Local Phone Number | 825-4000 |
