Upvote:2
The term you're looking for is apocatastasis. I would argue that it has not officially been condemned as a heresy, although Origen, the primary teacher of apocatastasis, was condemned as a heretic at the 5th ecumenical council. See my response to your other question about universalism for more information.
Upvote:6
I believe you are looking for the theology called "Universalism".
I'm not sure that it has been explicitly declared a heresy, but the Catholic, Orthodox many Protestant churches have made formal declarations that are in disagreement with it, so they presumably do consider it a heresy. Look at the 'disagreements' section of the article.