Mica said the document, referred to as the "$100 Million Memo" was "one of the most embarrassing documents I've ever seen," The Washington Post reported.
Mica directed his comment to Toyota North America President Yoshimi Inaba at a House Committee on Oversight and Government Reform hearing on Toyota's massive recalls.
Inaba said the document, which said negotiations involving a 2007 recall saved Toyota $100 million, was written before he returned to the company after a two-year hiatus.
Earlier Toyota President Akio Toyoda told a congressional panel in Washington he took "full responsibility" for safety problems plaguing the company.
"In the past few months our customers have started to feel uncertain about the safety of Toyota's vehicles and I take full responsibility," he said in a prepared text.
Toyota has recalled more than 8 million cars since October for a variety of issues, including braking in the 2010 Prius and sticking gas pedal problems in eight models that resulted in a suspension of production in factories, a halt of sales and a recall of 2.3 million U.S. vehicles.