While you don't state your destination (FCO?), there are 4 non-stop flights per day from DTW to AMS. They depart roughly every 2 hours starting at about 4PM. Not quite hourly, but still pretty high frequency for a TATL destination. Generally, as long as your flight is not too late, you will be able to take one of the later DTW-AMS flights and connect to your destination via KLM in AMS. I really wouldn't worry too much.