On Monday, May 16, the world’s largest insurance broker, Aon Corp, has designated Kristi Savacool and Baljit Dail as replacement co-chief executive officers to Russ Fradin. Fradin is leaving Aon Hewitt to join SunGard. Savacool comes from the Benefits Administration at Aon where she was the CEO and Dail worked as his counterpart in the consulting division.