Billionaire Walter Scott, the past top executive of Peter Kiewit Sons Inc. construction firm who helped oversee Warren Buffett’s conglomerate and donated to various causes, particularly construction projects around Omaha, has died. He was 90.

The Suzanne and Walter Scott Foundation that Scott founded said Scott died Saturday. The foundation did not mention a cause of death.

Scott served as a board member of Buffett’s Berkshire Hathaway conglomerate from 1988 until his death, and even invested alongside Berkshire in the company’s utility and energy unit.

Scott held about 8% of Berkshire Hathaway Energy’s stock and 105 Class A Berkshire shares with Buffett’s Berkshire holding nearly all the rest.

Scott, who grew up during the Great Depression after being born in Omaha in 1931, spent his entire career working for the Peter Kiewit Sons’ Inc. — the Omaha-based construction company, which builds major projects all over the world. He worked his way up from overseeing construction projects in California and New York to become the company’s executive vice president in 1965.

“You cannot find a better model for a citizen than Walter Scott,” Buffett, a longtime friend, told the Omaha World-Herald on Saturday. “He was basically a builder, whether he was building Kiewit and physical things or building his vision of Omaha or Nebraska. He was nonstop.”

When Peter Kiewit died in 1979, Scott succeeded him as Chairman and CEO and led the company until 1998. He also went on to serve as chairman of a Kiewit spin-off, Level 3 Communications until that firm was bought in 2014.

The wealth Scott accumulated allowed him to become a philanthropist. Scott and his late wife Suzanne gave large sums to the University of Nebraska at Omaha, the University of Nebraska Medical Center and Colorado State University. One of the main buildings at UNMC’s new Fred and Pamela Buffett Cancer Center is called the Suzanne and Walter Scott Cancer Research Tower because of their donations.

Sections of the Joslyn Art Museum and Holland Performing Arts Center in Omaha are also named in honor of the Scotts’ giving. Scott was also a longtime supporter of the renowned Omaha zoo, where the large aquarium is named in honor of him and his wife. Scott had told The Omaha World-Herald that he intended for nearly all of his personal assets to be donated to his personal foundation, which supports projects in Omaha.

“My children were taken care of long ago — what they make of their lives is now their own responsibility,” Scott said to the World-Herald. “Ultimately, nearly everything will go to the foundation, with the hopes it will benefit my hometown for many generations to come.”

Walter has been a director of numerous charitable and educational organizations and served as chairman of the boards of the Omaha Zoological Society, Omaha Zoo Foundation, Joslyn Art Museum, Horatio Alger Association, Heritage Services and the Board of Policy Advisors for the Peter Kiewit Institute.