Several legislators made references on Wednesday to Clinton's possible political future, with Republican Steve Chabot of Ohio drawing a laugh from the secretary when he said: "I wish you the best in your future endeavors. Mostly."

Polls show strong public support for Clinton and her performance as secretary of state, with an ABC News/Washington Post survey released Wednesday showing 67% of respondents had a favorable impression of her.

Clinton was originally scheduled to testify last month but postponed her appearance as she was treated for illness, a concussion and a blood clot near her brain. The country's top diplomat returned to work just over two weeks ago.