Which one is the largest economic cooperation?

The European Union (EU) is a politico-economic union of 28 member states that are located primarily in Europe.[11][12] It covers an area of 4,324,782 km2, with an estimated population of over 508 million. The EU operates through a system of supranational institutions and intergovernmental-negotiated decisions by the member states.[13][14] The institutions are: the European Parliament, the European Council, the Council of the European Union, the European Commission, the Court of Justice of the European Union, the European Central Bank, and the Court of Auditors. The European Parliament is elected every five years by EU citizens.