I don't think we have to worry about saddling our children with $20 trillion of debt.
Most of the bailout money will be repaid initially by the people who borrowed it.
Then, once the economy recovers its health and starts running at a surplus (which will occur during Obama's first term), a lot more of the bailout money will be repaid. During Obama's second term, most of the balance will be repaid.
Any debt balance still remaining at the end of Obama's second term will be fully repaid by the time Joe Biden finishes his second term as president.