Various ecumenical movements have attempted cooperation or reorganization of the various divided Protestant denominations, according to various models of union, but divisions continue to outpace unions, as there is no overarching authority to which any of the churches owe allegiance, which can authoritatively define the faith. Most denominations share common beliefs in the major aspects of the Christian faith while differing in many secondary doctrines, although what is major and what is secondary is a matter of idiosyncratic belief.
Is there an answer to this question (If it cannot be answered, say "unanswerable"): Which is larger, divisions or unions of Protestantism?
divisions