This Wikipedia list puts the Greek Orthodox church's net worth at 700B Euros in 2011 (about 974B USD), above any branch of the Catholic church or other religion. Its source is France 24, but I am not sure whether the 700B estimate is trustworthy. Other miscellaneous sources differ; e.g. Orthodox Church Quotes quotes the net worth at simply over 1B.
Is Wikipedia's claim true? The claim has two parts:
Is the net worth of the Greek Orthodox church around 700B Euros?
Is the Greek Orthodox church the single wealthiest religious organization in the world?