CEO Mary Barra on how GM is revving up electric vehicles

Correspondent Kris Van Cleave talks with Mary Barra, General Motors’ second-longest-serving CEO, about the company’s expanding electric vehicle lineup. He also takes a “high-speed” tour of GM’s Milford Proving Ground in Michigan, which has been a hub for automotive innovation for a century, and gets behind the wheel of GM’s soon-to-be-released electric Cadillac Escalade IQ.