"The U.S. Public Debt, commonly called the national debt or the gross federal debt, is the amount of money owed by the United States federal government. This does not include the money owed by states, corporations, or individuals." (Source: Wikipedia, "U.S. Public Debt")

Current debt as of 9 June 2005 is $7,799,659,687,041.37. (Source: Bureau of the Public Debt, "The Debt to the Penny")

Debt to each country is difficult to calculate, but the purchase of Treasury Securities is the main measure. The top five are (current as of March 2005):

Japan
Mainland China
Caribbean Banking Centers
United Kingdom
Taiwan

(Source: Department of the Treasury, "Major Foreign Holders of Foreign Securities")