General Motors Co. says it's expanding and renovating its downtown Detroit headquarters.

The automaker announced Friday that upgrades to the Renaissance Center will include a multi-storey addition and a large, LED video screen that wraps over the People Mover station in front of the building. It's also adding a GM retail store and other interactive displays.

Construction is expected to start this summer and finish in 2018.

GM completed a major renovation and expansion about a decade ago that focused on the side of the center facing the Detroit River.

The complex, which includes a hotel and Detroit's tallest building at 73 stories, opened in 1977. GM bought it in 1996 and moved from its historic headquarters in the city's New Center area.