Never worked at Apple, but from what I've heard from friends there ID is a much more powerful role than at most hardware companies. They are the ones who define

Never worked at Apple, but from what I've heard from friends there ID is a much more powerful role than at most hardware companies. They are the ones who define what the product should be and how the user interacts with it and tend to get the final say on such matters. At other companies this would be in an MRD/PRD defined by product managers or another group.