""The actual liabilities of the federal government—including Social Security, Medicare, and federal employees' future retirement benefits—already exceed $86.8 trillion, or 550% of GDP. For the year ending Dec. 31, 2011, the annual accrued expense of Medicare and Social Security was $7 trillion"
Depending on who you want to believe...other sources have numbers much worse than yours.
Debt Clock puts unfunded liabilities north of $121 trillion
Laurence Kotlikoff, a former Reagan advisor, put the number around $211 Trillion.
The federal government's net worth at the end of 2011 was a negative $70 trillion..or about $220K per citizen or $660K per tax paying citizen...you and your wife have a spare 1.2 million hanging around.
The numbers at this point are meaningless since default seems to be the only solution at this point. Some feel we could print/inflate our way out of it....but I think default will more likely happen or people will just no longer accept dollars for payment having the dollar crash.