Yup, not as good as Bill Belichick's 36-44 with the Browns.
Crennel's winning percentage in Cleveland was .375%, Belichicks was .450%.
Belichick was 1-1 in the playoffs with the Browns, Crennel despite his wildly successful 10-6 campaign did not make the playoffs as the Browns head coach.
Crennel in his second head coaching job with the Chiefs was 4-15, including a stellar 2-14 season, he finished last in the AFC West twice.
Belichick in his second head coaching job with the Patriots is currently 237-83, including 17 AFC East titles, 6-3 in the Super Bowl and 13 appearances in the AFCCG.
He's won more playoff games (31) then Crennel won as a head coach.
Bill O'Brien is 52-44 as the head coach of the Houston Texans, he's won the AFC South four times and is 2-4 in the playoffs.
O'Brien is the most successful coach from the Belichick tree and it's not even close.