AA 4102 then UA 3907 at O'Hare
Denver → Chicago → Washington
Timetable, Chicago time
12:55AA 4102 from Denver at the gate
12:00UA 3907 to Washington leaves the gate
23 h 05 apart on the timetable, overnight
UA 3907 leaves 23 h 05 after AA 4102 arrives on the timetable: more than half a day, so not a connection we count.