I know Jeff Bezos is considered the richest known person but there is a lot of hidden wealth in the world.
I've heard the following people may actually be trillionaires:
Putin
Oil Saudis
Rothschild family
Saudi's family is family who control the kingdom and the oil reserve. They are biggest oil exporter in the world and i think they are rich family. But from what i am read, rothscild family controlling most central bank in the world and they have share in The Fed and Bank of England