Jon Huntsman Sr., a billionaire philanthropist and businessman whose son Jon Jr. is ambassador to Russia, has died at age 80, Huntsman's assistant confirmed on Friday afternoon.

A cause of death was not immediately released.

Huntsman was the founder and longtime executive chairman of Huntsman Corp., a $13 billion company that refines raw materials that go into thousands of products. He also served in the Nixon administration as staff secretary to President Richard Nixon.

“There was obviously a dark side to Nixon. History has proven that. I didn’t see it. His behavior didn’t suggest it. I was treated extremely well by the president,” Huntsman once said, according to The Salt Lake Tribune. “Nixon was my hero.”

The businessman also founded the Huntsman Cancer Institute in Salt Lake City, an organization aimed at finding a cure through human genetics.

Sen. Orrin Hatch, R-Utah, labeled Huntsman a "committed public servant, a visionary businessman, and perhaps the greatest philanthropist our state has ever known."

Hatch: "Utah has lost a lion today."

"I know Jon will rightfully be remembered as a giant in the state of Utah, across the country and around the world," Utah Rep. Mia Love tweeted. "His story exemplifies the American dream: He came from humble beginnings, and founded one of the most successful businesses in the nation, now known as the Huntsman Corporation. He was generous and compassionate with his success, investing personally in efforts to eradicate cancer and establishing the Huntsman Cancer Foundation. Thousands of lives have been blessed by that investment. I send my heartfelt thoughts and prayers to his family at this difficult time."

Huntsman had nine children, including Jon Huntsman Jr.

The younger Huntsman served as ambassador to China in the Obama administration and is the current U.S. ambassador to Russia. A former Utah governor, Jon Huntsman Jr. ran for the GOP presidential nomination in 2012 but lost to eventual nominee Mitt Romney. His daughter, Abby, is a Fox News anchor and "Fox & Friends" co-anchor.

"Jon and I have been friends for decades; our families have been friends for generations," Romney, who is expected to run for Hatch's seat, said in a statement posted to Facebook. "He generously gave to the Salt Lake Olympics and provided me with essential counsel. He was the first to volunteer financial support for my campaign for president of the United States. Ann and I will profoundly miss our good friend’s broad smile, his hearty handshake and his example of faith, honor, and integrity."

In a 2015 autobiography, Huntsman Sr. pondered the idea of hearing one's own eulogy.

“It would be a fascinating experience to hear in advance what will be said at our eulogies. Would it match what we see in ourselves?” he wrote.

“Truth be known, few farewell lines at funerals are devoted to one’s academic achievements, professional careers or wealth," he wrote. "Mostly, a eulogy is about what one did for others — as a parent, a volunteer, a teacher, a civic activist, a philanthropist, or one who set good examples. Since we don’t get to see the advanced text of our eulogies, we might think about living each day as if our actions on that day will establish the record on which we’ll be judged.”

The Associated Press contributed to this report.