How much does it take to buy happiness? You might think it takes a fortune to keep Warren Buffett happy. The famous investor and CEO of Berkshire Hathaway is worth more than $75 billion, according to Forbes. But the "Oracle of Omaha" says he would be fine with far less. "I'm already happy. I would be happy with, you know — certainly with $100,000 a year, I could be very happy," says Buffett on PBS Newshour. Of course, that's still nearly double the median household income in the U.S., which was $55,775 in 2015, according to the U.S. Census Bureau.

Warren Buffett's Omaha residence is relatively modest Orjan F. Ellingvag | Getty Images

"I can buy anything, basically," says Buffett. "I have been on 400-foot yachts, and I have ... lived the life a little bit with people that have 10 homes and everything. And I live in the same house I bought in 1958. "And if I could spend $100 million on a house that would make me a lot happier, I would do it. But, for me, that's the happiest house In the world. And it's because it's got memories, and people come back, and all that sort of thing." Ninety-nine percent of Buffett's wealth is in Berkshire Hathaway stock and he has promised to give away every share to philanthropy, he says.

"I'm a trustee for that stock. So, it will go to society," says Buffett on PBS Newshour. His billions "have no utility to me" but they "do have utility to others, so I have got this system to essentially try and translate that into vaccines and education and all of that sort of thing." Buffett is the co-founder of the Giving Pledge, an organization he founded with Bill Gates, the co-founder of Microsoft and the richest man in the world, according to Forbes. Billionaires who are part of the Giving Pledge publicly commit to give away over half their wealth to charity.

Warren Buffett Lacy O’ Toole | CNBC

Specifically, Buffett has been giving to the Bill & Melinda Gates Foundation every year since 2006 and has so far given more than $17 billion. In particular, the Bill & Melinda Gates Foundation invests in improving the health of women and girls who are living in poverty and in developing new vaccines to eliminate infectious diseases. "The truth is, I have got a lot of wealth, little pieces of paper [that say] Berkshire Hathaway on it. They are claim checks on all kinds of goods and services in the world. They can buy anything. I can buy 400-foot yachts and have 20 homes and all that. I wouldn't be happier," says Buffett.

Instead, the investor likes knowing that his wealth is going toward organizations and individuals who are really working to make a difference. "Once [the stocks] move into the hands of people who are working like hell on getting something accomplished in areas I want them to — you know, I love the idea of getting them used, and that's what they're doing." Buffett says his entire estate will be given away 10 years after he dies. By giving his wealth to charity, the Oracle of Omaha is not leaving it for his three children. He says that's because he doesn't want them to be lazy.