Capitol Hill was abuzz this week as the first of President-elect Donald Trump's Cabinet nominees went through a gauntlet of confirmation hearings.
Tillerson also faced tough questioning on Exxon's lobbying against Iran sanctions.
"I have never lobbied against sanctions, personally," Tillerson said. "To my knowledge, Exxon never directly lobbied against sanctions. Not to my knowledge."
But committee Chairman Bob Corker said he recalled Tillerson calling him to lobby on the bill, and New Jersey Democrat Bob Menendez brought documents showing millions in Exxon lobbying spending into the hearing.
"There was lobbying here," Menendez told him. "It's a little amazing that you don't know Exxon was lobbying on these issues."