Susie Buffett says her billionaire dad Warren Buffett is a normal guy who "does not care about money"

Warren Buffett is a simple man, with just one caveat — his nearly $74 billion fortune.

The current second richest man in the world — just a cool $11 billion under pal Bill Gates — is the subject of a new HBO documentary, titled Becoming Warren Buffett, that explores his lesser-known personal life. But his daughter Susie Buffett warns not to expect anything extravagant from the successful Berkshire Hathaway investor.

“He’s pretty boring — it’s just not what people expect,” Susie tells PEOPLE of the most surprising thing about her dad. “I think it’s also probably surprising to people that the money doesn’t matter to him. He made the money sort of by accident because he was really good at doing what he loved, and when you do that particular thing really well, you end up with a whole bunch of money. But it’s really true that he does not care about having a bunch of money.”

Buffett, 86, echoed his oldest child’s sentiments at the film’s premiere in N.Y.C., telling PEOPLE that it’s not that he’s frugal, he just doesn’t think spending money will make him happier than enjoying the simple things in life.

“I buy everything I want in life,” Buffett said. “Would 10 homes make me more happy? Possessions possess you at a point. I don’t like a $100 meal as well as a hamburger from McDonald’s. That’s the way I’m put together, I don’t equate the amount I spend with the enjoyment I’m going to get from something.”

EPSON scanner image
Credit: Courtesy HBO

Buffett and wife Susan in 1960

His simplicity extends into his family life.

“When we were kids, he wasn’t as successful,” Susie says. “He was certainly slowly turning into that, but he wasn’t rich or famous when we were kids. I’d call it a very normal household, a very normal upbringing. We lived in a nice house but certainly not the biggest house in town. We went to public schools. We didn’t get cars when we turned 16. We got an allowance and we had jobs we had to do around the house. It was pretty normal.”

Buffett married his first wife Susan in 1952 and they were married until her death in 2004. Susie says her parents’ marriage is the reason for her father’s success. “I don’t think there would be any Berkshire Hathaway if he hadn’t married my mother,” Susie says. “If he had married someone else, it wouldn’t have been the same at all. [The documentary tells] the whole story of his relationship with my mother and how important she was in his life and in his personal development as a human being and as a business person.”

She adds that her parents never fought and were always supportive, saying that “it sounds like a fairy tale life, but we did grow up with this wonderful role model of a relationship with our parents.”

Credit: Courtesy HBO

Buffett and Susie in 1954

In the trailer for the film, Buffett once again echoes his daughter’s revelations, saying that there are two turning points in his life: “once when I came out of the womb and once when I met [Susan]. I was a lopsided person, she put me together.”

But Buffett’s marriage to Susan wasn’t exactly conventional. In 1977, Susan moved from the family’s home in Omaha to San Francisco to pursue a singing career. Although the couple remained married during this time, this was also when Buffett’s current wife Astrid came into their lives.

“I understood why my mother wanted to leave and it didn’t have anything to do with her not completely loving my dad or not wanting to stay in the marriage — it wasn’t anything like that,” Susie says of her mother wanting to leave Omaha and move to California. “I knew Astrid before my parents did and then my mother got to know her because she was singing at one of the restaurants down at the market where Astrid worked. When she moved, she asked multiple people to sort of check in on my dad and Astrid was one of them.”

Shortly after Susan left for San Francisco, Astrid moved in with Buffett and the two continue to live together now. They got married in 2006 — two years after Susan’s death.

“Astrid’s been part of the family for a long time, so it just sort of evolved into something that for us was kind of normal,” explains Susie, who was already 24 and living in California when Astrid moved in with her father. “I don’t know that it would work for many people, but it worked for my parents and her. Nobody was being hurt and everybody was happy. So for us, it was normal. But I realize it’s not normal.”

“He’s not somebody that any of us thought would make it too well on his own so it kinda worked out perfectly,” she adds. “That’s why we’re all glad Astrid moved in.”

Now in his mid-80s, the billionaire remains a simple family man who still takes all his grandchildren and great-grandchildren to Dairy Queen for lunch once a month.

“I don’t think people realize, he’s got a bunch of great-grandchildren and he could tell you everything about what they’re all doing. He knows every one of those kids and he knows about their lives,” she says. “This documentary is the definitive piece that will be able to be passed down to the generations that didn’t get to know him. They really got it — they got my dad warts and all.”

The HBO documentary Becoming Warren Buffett premieres Jan. 30.

  • With reporting by MABEL MARTINEZ