I'm not a financial expert, so someone who is please step in and correct anything that I say is wrong. I need to learn too.

It's because the government's debt is also a surplus. Government debt isn't like personal debt because the government debt is mostly through selling bonds that the government issues. Most of that debt is owned by American citizens, in one way or another, who buy those bonds. Most of that $34 trillion is money the government owes it's people, or at least the Americans who hold those bonds.

It's not really money you owe but it's money that is owed to you. Well actually the billionaire class who can actually afford to buy these bonds but hey, that's Capitalism baby.