Quick googling shows:
The US has a GDP of $17T and debt of $17.8T
The EU has a GDP of $17T and debt of $13.9T
Strange... I was able to pull up 18 Trillion. See the following links.
and
http://www.brillig.com/debt_clock/
and
http://www.theblaze.com/stories/2014/12/01/u-s-national-debt-soars-to-18-trillion-under-obama/
and
It's worse than that. Add to that state and local government debt.