Non-Christians can be saved?

Saw a video by bishop Barron where he talks about the fullness of truth in the Catholic church. He mentions how according to Vatican II, people of other faiths and even atheists with a good conscience can be saved.

This is what I've leaned to as well for years but coming from Orthodoxy we were taught that fullness of truth simply meant "we are right everyone else is wrong" so I guess this is kind of unexpected.

Can anyone just expand on the statement please?