Warren Buffett is giving away $140 billion to charities. But what happens to the taxes?

Warren Buffett, who started giving away his wealth two decades ago, has pledged to completely dispose of his roughly $140 billion stake in Berkshire Hathaway Inc. by 2034.

His latest donation, comprising 12 million Class B shares, is instead going to four foundations led by his children, Susie, Howard and Peter. Noting that his children were getting older and were ready to distribute his wealth, Buffett said in interview excerpts on CNBC, “I tell the three children that it is theirs, and it’s their responsibility to get it done well."

While some applauded his decision to direct wealth to charitable causes, others questioned whether foundations were the best vehicle for supporting vulnerable Americans. And some accused Buffett of using philanthropy to avoid paying estate and capital gains taxes.

Warren Buffett pays less tax than his secretary

Buffett has often said he doesn't mind paying taxes and takes pride in the billions Berkshire Hathaway has sent to Washington.

He has repeatedly argued that he has benefited enormously from American society and therefore believes he should contribute more to it. In fact, Buffett has said he is “under-taxed” relative to what society has provided him.

He also noted that his secretary pays a higher tax rate than he does when payroll taxes are taken into account, and because capital gains are taxed at a lower rate than ordinary income.

That led President Barack Obama to propose a “Buffett rule” that would have imposed a 30% minimum tax on Americans earnings more than $1 million a year. It was rejected by the Senate in 2012.

Even though he’s proud to pay taxes, Buffett joked in 1998, “I don’t send along any voluntary payments to the I.R.S, I want you to understand.”

Buffett ends ties with Gates Foundation

Meanwhile, Buffett decided to sever ties with the Gates Foundation as its co-founder, Bill Gates, faces increased congressional scrutiny over his ties to late sex offender Jeffrey Epstein.

The 95-year-old chairman of Berkshire Hathaway Inc. met with Gates in Omaha, Nebraska, weeks ago and discussed the decision, he said in an interview with CNBC earlier this month. Buffett said he’d been following the public scrutiny of Gates’ ties with Epstein, including the tech billionaire’s sworn testimony to Congress.

“I found nothing in there that was beyond what I could picture myself doing,” Buffett said, adding that Gates eventually severed ties with Epstein.

The billionaire investor said that while he views the findings of the Congressional review as “distasteful,” he stopped short of disavowing the Microsoft Corp. co-founder.

“While he made mistakes, I made mistakes in hiring all kinds of people or choosing friends and then finding out later that, one way or another, they weren’t what I thought they were,” Buffett said of Gates.