It should be called "mininum yearly payment" as my credit card co. so acurately puts it. Or "existing debt payment schedule - 2013".
Here's what it really is:
The debt limit is the total amount of money that the United States government is authorized to borrow to meet its existing legal obligations, including Social Security and Medicare benefits, military salaries, interest on the national debt, tax refunds, and other payments. The debt limit does not authorize new spending commitments. It simply allows the government to finance existing legal obligations that Congresses and presidents of both parties have made in the past.
quote from Treasury.