UA 4500 then UA 950 at Dulles
Detroit → Washington → Brussels
Timetable, Washington time
21:17UA 4500 from Detroit at the gate
17:45UA 950 to Brussels leaves the gate
20 h 28 apart on the timetable, overnight
UA 950 leaves 20 h 28 after UA 4500 arrives on the timetable: more than half a day, so not a connection we count.