"I like numbers," Warren Buffett says in an upcoming HBO documentary about his life. "It started before I could remember. It just felt good, working with numbers."

File photo: Warren Buffett, chairman and CEO of Berkshire Hathaway, speaks at the Fortune's Most Powerful Women's Summit in Washington, DC, U.S. on October 13, 2015.

Success with numbers has helped the billionaire become one of the world's most admired investors and top philanthropists, despite spending most of his 86 years far from Wall Street in Omaha, Nebraska, where he has run Berkshire Hathaway Inc since 1965.

That life is now the subject of "Becoming Warren Buffett," which is being previewed for journalists this week ahead of its Jan. 30 airing on Time Warner Inc's HBO.

Directed by Peter Kunhardt, whose film subjects have included U.S. President Richard Nixon and media mogul Oprah Winfrey, the documentary was largely narrated by Buffett and contains interviews with people close to him, including his sisters, three children, Berkshire Vice Chairman Charlie Munger, and philanthropists Bill and Melinda Gates.

It also provides a fresh overview of the "Oracle of Omaha," the subject of a best-selling 2008 biography for which he also extensively cooperated but reportedly had mixed feelings.

Longtime fans will not learn much new. And Buffett remained reticent on some matters, including his last conversation with his father, and his first wife Susan's decision in 1977 to move out.

But he fondly recalled lesser-known stories, including overcoming his fear of public speaking by attending a Dale Carnegie course, and picking up a high school date in a hearse he owned half of. "Not the smoothest thing," he recalled.

The Buffetts remained married but lived separately until Susan Buffett died in 2004. "There's no finer human being than who he is," she recalled in an interview just before her death.

Buffett's second wife Astrid, who he married on his 76th birthday, was not interviewed for the film.

The film shows Buffett's preference for a buy-and-hold style of investing in "wonderful companies at fair prices," not fair companies at wonderful prices.

"I do know what I call my circle of competence," he said.

It also shows Buffett's ability to connect with ordinary people, including his driving himself to work from his normal-sized house, his distaste for vegetables, and his plain talk about markets and the world.

That includes his 1991 Congressional testimony about a Treasury auction bidding scandal at Salomon Brothers, where he was interim chairman, and vowed to be "ruthless" toward people who harm their employer's reputation.

"Warren is not interested in making money by cheating people," Munger said.

Source: Reuters