Stanley Kubrick's later films were shot specifically so they would look good either on a television screen or on a wider theater screen. Unfortunately, the degree of damage done when a widescreen movie is cropped to fit a television screen is usually greater, and, I would argue, significant even in these cases. Do everything you can to support letterboxing. Buy letterboxed video tapes or DVDs. First do a search on the movie in question.
Some movies are even wider and suffer even more.