Statista has the answer with their post Defense Expenditures Of NATO Countries by Niall McCarthy (7/11/18). They created the infographic copied here.
The following infographic shows how much money NATO members spend on defense as well as its estimated share of GDP. While Germany spent over $45 billion on its military equating to 1.2 percent of GDP in 2017, the U.S. spend $686 billion – 3.6 percent of GDP.
The U.S. spends more than twice as much on defense as all other NATO countries combined. As a percent of GDP, the U.S. spends twice as much or more than all other countries other than the U.K. The link in the quote goes directly to a pdf file from NATO with data on defense spending by country from 2010 to 2017.