AA 3977 then BR 643 at O'Hare
Detroit → Chicago → Anchorage
Timetable, Chicago time
14:05AA 3977 from Detroit at the gate
11:55BR 643 to Anchorage leaves the gate
21 h 50 apart on the timetable, overnight
BR 643 leaves 21 h 50 after AA 3977 arrives on the timetable: more than half a day, so not a connection we count.