DETROIT -

General Motors expects to save about $2 billion during the next five years by centralizing global advertising for its Chevrolet brand.

The company said Tuesday that San Francisco-based Goodby, Silverstein and Partners will join with New York-based McCann Erickson to form a new company to handle most Chevy ads.

The company is called Commonwealth and will begin work immediately.

Goodby Silverstein now does Chevy advertising in the U.S., including the "Chevy Runs Deep" campaign. McCann handles ads in China, Latin America, Mexico, Canada and other markets.

Before the change, Chevy had 70 agencies worldwide.

GM also has picked Carat as the agency that will buy television time and other media across the globe.

GM hopes to use part of the savings to boost Chevy marketing, but some will go to bottom-line profits.

2011 Chevrolet Cruze front passenger