I am becoming very much aware of the heterodoxy in the Protestant community, which is why I wrote "Reformed" but maybe should have been more specific, i.e. Calvinist or TULIP.
So do all Protestants consider themselves "Reformed?"
The language can be confusing. Reformed has come to mean Calvinist. The majority of Protestants do not consider themselves "Reformed."
As to the teaching of original sin, it is in the Roman Catholic catechism. The U.S. Catholic Bishops have a website that has an explanation of their teaching on the subject here. After reading through the page, I would say the Catholic teaching is what the majority of non-Reformed Protestants believe.