A General Motors Co. Cadillac DTS sedan makes its way down the assembly line at the General Motors Co. (GM) Detroit-Hamtramck plant in Detroit, Michigan, U.S., on Monday, Dec. 7, 2009. General Motors Co. said it will spend $336 million to prepare this Detroit factory to build the Chevrolet Volt plug-in hybrid car, slated to begin sales in November 2010. Photographer: Jeff Kowalsky/Bloomberg via Getty Images