"The two countries signed a series of agreements," Adel al-Jubeir told reporters at a joint press conference with US Secretary of State Rex Tillerson.
He said the "total value of investments... (is) in excess of $380 billion", including by Saudi Arabia in American infrastructure, and US investment in developing the kingdom's defence industry.
"We expect that these investments over the next 10 years or so will provide hundreds of thousands of jobs in both the United States and in Saudi Arabia," Jubeir said.
Tillerson clarified that almost a third of the total figure is military-related.
Separately, Saudi Arabia's state oil company Saudi Aramco said in a statement that it had signed joint venture and MOU agreements with American companies estimated to be worth about $50 billion.