Catholics and Protestants bbzzzzt WRONG
Coptics, Chaldean, and there are several other ancient denominations that in the Middle East and Africa.
But the big 4 divisions are:
Catholic - including Roman Catholic, Anglican Communion, and a few others
Orthodox - Eastern/Greek, Russian, Serbian, and others
Protestant - Grab Bag ranging from almost Catholics like some Lutheran (Catholic in liturgical and Apostolic Succession recognition) to Baptist and many non-denominational fundamentals
Proto (my word) - Ancient churches springing from early Christendom missions by Apostles and Disciples, etc, Like Coptic Christians, Chaldeans, these churches may pre-date the Roman Church
And the kinda Christians, like LDS, Jehovahs Witnesses, which really don't fit in the other categories.
So shoot or flame me, that's my take.