In the Iliad, he is found among the first rank of the Greek generals, leading his troops and engaging the enemy head-on, and escaping serious injury. Like most of the other leaders of the Greeks he is alive and well as the story comes to a close.
After the war, his ship hit a horrible storm. Idomeneus promised Poseidon that he would sacrifice the first living thing he saw when he returned home if Poseidon would save his ship and crew. The first living thing was his son, whom Idomeneus duly sacrificed. The gods were angry at his murder of his own son and they sent him into exile in Calabria, Italy. (Virgil III, 400)
Idomeneo, a 1780 opera seria by Mozart is based on the story of Idomeneus.