UA 925 then DL 8841 at Dulles
London → Washington → Toronto Pearson
Timetable, Washington time
20:15UA 925 from London at the gate
16:00DL 8841 to Toronto Pearson leaves the gate
19 h 45 apart on the timetable, overnight
DL 8841 leaves 19 h 45 after UA 925 arrives on the timetable: more than half a day, so not a connection we count.