AA 6486 then UA 543 at O'Hare
Detroit → Chicago → San Francisco
Timetable, Chicago time
17:29AA 6486 from Detroit at the gate
10:25UA 543 to San Francisco leaves the gate
16 h 56 apart on the timetable, overnight
UA 543 leaves 16 h 56 after AA 6486 arrives on the timetable: more than half a day, so not a connection we count.