AA 359 then UA 3876 at O'Hare
Washington National → Chicago → Miami
Timetable, Chicago time
16:08AA 359 from Washington National at the gate
07:00UA 3876 to Miami leaves the gate
14 h 52 apart on the timetable, overnight
UA 3876 leaves 14 h 52 after AA 359 arrives on the timetable: more than half a day, so not a connection we count.