Legendary investor Warren Buffett is stepping down as chairman of Berkshire Hathaway, the company said on Friday."Serving as your Chairman has been the privilege of a lifetime, and I have never taken your trust for granted," Buffett, who was named chairman emeritus, said in a letter to shareholders. "Father Time always wins. He has, however, been generous with me. He has given me the opportunity to see Berkshire reach a point where I am more confident than ever about what lies ahead."Buffett's son, Howard Buffett, will become chairman of the board, effective immediately. He has been a Berkshir...