GM and UAW reach tentative contract agreement

General Motors and the autoworkers’ union said Wednesday that they had reached a tentative agreement on a labor contract that could end the monthlong strike that has idled GM plants across the Midwest and the South.

Details were not released, although the union, the United Automobile Workers, said it had “achieved major wins.” After the union’s announcement of the tentative accord, GM put out a two-sentence announcement of confirmation.

Officials of the union’s GM locals will gather Thursday in Detroit, and if they accept the tentative agreement, they could vote to end the strike immediately. They could also continue the walkout until the deal is ratified by a majority of the 49,000 UAW members employed by GM.

“Out of respect for our members, we will refrain from commenting on the details until the UAW GM leaders gather together and receive all details,” Terry Dittes, the union’s chief GM negotiator, said in a statement.

The walkout, the first against a Detroit automaker’s nationwide operations since 2007, has left a mounting economic toll since it began Sept. 16. It has cost the union, its members and GM itself hundreds of millions of dollars in lost dues, wages and revenue, as well as idling truckers and suppliers that serve the automaker.

The tentative agreement, if it becomes final, would solve the most immediate challenge facing CEO Mary Barra, and should provide certainty in calculating labor costs over the next four years. But she must contend with issues on other fronts, including a sales slowdown in the United States and China, and the need for big investments in electric vehicles and self-driving cars. And like other automakers, GM has continued to feel heat from President Trump over decisions on plant closings and foreign production.

The stakes were also high for the union. It faced...