DL 420 then UA 752 at O'Hare
Savannah → Chicago → Washington National
Timetable, Chicago time
13:13DL 420 from Savannah at the gate
12:29UA 752 to Washington National leaves the gate
23 h 16 apart on the timetable, overnight
UA 752 leaves 23 h 16 after DL 420 arrives on the timetable: more than half a day, so not a connection we count.