Detroit Diesel Corporation (DDC) is an American diesel engine manufacturer headquartered in Detroit, Michigan, USA and a subsidiary of Daimler Trucks North America, itself a wholly owned subsidiary of the German Daimler AG. The company manufactures heavy-duty engines and chassis components for the on-highway and vocational commercial truck markets. Detroit Diesel has built more than 5 million engines since 1938, more than 1 million of which are still in operation worldwide.