I live in America, so I can assure you we call the literature written in English "English Literature" and make no distinction of whether it is written by an American, Brit, Australian, Canadian, New Zealander, etc. We note who wrote it and which country they call or called home, but we call it all "English Literature." One can certainly take an "American English Literature" class in college, just as one can take "Middle English Literature" class or "French Literature" or whatever. However, our degrees in "English Literature" contain a required mix of literature written in English from all over the world throughout the history of the English language. To say English literature in England should only contain works by British authors seems rather arrogant to me, but then I'm just a child of the colonies.