0000100517 2020-02-24 2020-02-24 0000100517 ual:UnitedAirLinesIncMember 2020-02-24 2020-02-24 false 0000100517 0000319687 8-K 2020-02-24 UNITED AIRLINES HOLDINGS, INC. UNITED AIRLINES, INC DE 001-06033 36-2675207 DE 001-10323 74-2099724 233 S. Wacker Drive, Chicago, IL 60606 233 S. Wacker Drive, Chicago, IL 60606 872 825-4000 872 825-4000 false false false false Common Stock, $0.01 par value UAL NASDAQ false