AA 6486 then UA 2857 at O'Hare
Detroit → Chicago → Denver
Timetable, Chicago time
17:29AA 6486 from Detroit at the gate
10:55UA 2857 to Denver leaves the gate
17 h 26 apart on the timetable, overnight
UA 2857 leaves 17 h 26 after AA 6486 arrives on the timetable: more than half a day, so not a connection we count.