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Why Buffett only pays 17.4% of his income in federal taxes: "Last year my federal tax bill ... was $6,938,744. That sounds like a lot of money. But what I paid was only 17.4 percent of my taxable income -- and that's actually a lower percentage than was paid by any of the other 20 people in our office. Their tax burdens ranged from 33 percent to 41 percent and averaged 36 percent."
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Unlike most Americans, Buffett and the country's wealthiest taxpayers make much of their income from investments. The capital gains and dividends those investments generate are taxed at a much lower rate than wages. Long-term capital gains and dividends are currently taxed at 15% -- well below the 35% top income tax rate.

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Buffett deficit plan: Tax the rich

How much money could be raised by hiking taxes on the super rich? Without specifics, it's hard to say. But it's possible to get a ballpark idea if one assumes nothing else changes about the current tax structure.

If lawmakers added a new 50% tax rate to taxable income over $1 million, that could raise an additional $34 billion, according to the Tax Policy Center. So adding that new top rate might raise at least an additional ~ $340 billion over 10 years.

In the context of deficit reduction, $450 billion is less than 5% of the new debt the country is on track to accrue over the next decade. But it's a lot of money in terms of potentially valuable government programs that might otherwise need to be slashed absent additional revenue.