UA 2865 then BR 643 at O'Hare
Denver → Chicago → Anchorage
Timetable, Chicago time
14:55UA 2865 from Denver at the gate
11:55BR 643 to Anchorage leaves the gate
21 h apart on the timetable, overnight
BR 643 leaves 21 h after UA 2865 arrives on the timetable: more than half a day, so not a connection we count.