13. (248) Marian Ilitch, $6.64 billion
Ilitch, 85, is the she second-richest self-made woman in the U.S. and, perhaps, the most visible U.S. female billionaire. She is the co-founder, with her late husband Mike Ilitch, of Little Caesers Pizza, the third-largest pizza chain in the U.S. Her success with the pizza company springboarded her to success in other industries, including ownership of the Detroit Tigers baseball team and Detroit Red Wings hockey team, which has won four Stanley Cup championships under her ownership. She has also become a player in the casino industry and was one of the original owners of MotorCity Casino in Detroit.