AA 6486 then UA 4572 at O'Hare
Detroit → Chicago → Sioux Falls
Timetable, Chicago time
17:29AA 6486 from Detroit at the gate
12:29UA 4572 to Sioux Falls leaves the gate
19 h apart on the timetable, overnight
UA 4572 leaves 19 h after AA 6486 arrives on the timetable: more than half a day, so not a connection we count.