When Jamie Dimon was wheeled into the operating room for an emergency heart surgery, he didn’t know whether he would make it out—what he did know was he had no big regrets in life. The 69-year-old JPMorgan CEO has become the face of American banking over his decades-long career—and was even at one point, Wall Street’s savior. He is well known for navigating the bank nearly unscathed through the 2008 housing crash and for his deft actions in helping prop up the U.S. financial system. But around five years ...