40 ILCS 5/22-402

Each such pension fund is hereby declared to be created in the public interest and for the general welfare of the State, and pursuant to the governmental powers of the State, separate and apart from the corporate purposes of the State, and of any county, city, town, municipal corporation or body politic and corporate in the State, and in which such pension fund is empowered to operate by virtue of the terms and provisions of the law creating such pension fund.