The chances of being detained if you were to travel to Pyongyang, North Korea probably are pretty great and may depend on what country you are travelling from. As an American, if I were you, I would not go. I would find another way. What could possibly be so important that you have to travel there? It’s simply just too dangerous.
Many Americans have been accused of political crimes, put on trials which are ridiculously staged where they are forced to make confessions and then they are given very harsh sentences to be served in labor camps where the water is unclean and the food barely edible.