Sergio Marchionne, longtime CEO and chief for Fiat Chrysler Automobiles, stepped down Saturday due to serious complications after surgery, the company announced. Mike Manley, head of Jeep and Ram brands, replaced him. John Elkann, grandson of Gianni Agnelli and chairman of the company that controls FCA, said his family was shocked by Marchionne's failing health. "I am profoundly saddened to learn of Sergio’s state of health. It is a situation that was unthinkable until a few hours ago, and one that leaves us all with a real sense of injustice," Elkann said in a statement. Elkann will fill Marchionne's chairman...