Tennessee Gov. Bill Haslam (AP Photo/Erik Schelzig, File)

Tennessee Gov. Bill Haslam (R) is now the richest politician in the country, worth an estimated $2 billion, according to Forbes.

Haslam is the son of the founder of the company now known as Pilot Flying J, which operates more than 500 truck stops, and his net worth has more than doubled thanks to cheaper gas prices, Forbes found. Pilot Flying J’s operating income grew from $1.1 billion to $1.4 billion since August, and Haslam owns 15 percent of the company. He was president from 1995 to 1999.

Haslam served as mayor of Knoxville, Tenn., before running for governor in 2010. He was named 2015 Republican Governors Association chairman in November.