It depends how you define “billionaire”. They may not actually make a billion dollars in income annually. With that said:
Even if you drill down to the top 400 wealthiest taxpayers — data that was publicly available on an annual basis until President Donald Trump killed the report — they paid an effective tax rate of 23.1 percent in 2014. These taxpayers — with $127 billion of income — that year paid $29.4 billion in income taxes, or more than 2 percent of all income taxes, the IRS said.