With the U.S. Federal Debt topping $14 trillion, it's worth taking a look at who actually lends the U.S. all this money.

The biggest creditor is the U.S. itself.

Of the total debt, 42% is held by the U.S. government and the Federal Reserve, according to March statistics from the U.S. Treasury.

Of that, the biggest chunk – $2.6 trillion – is held by the Social Security Agency, the U.S. government's program for retirees. Big lenders after that include the Federal Reserve and the trust funds that administer U.S. federal employee benefits.

The next chunk, 32%, is in foreign hands. That's why so many other nations have a stake in this debt standoff.

China is the largest lender, buying up $1.3 trillion in U.S. Treasuries, followed by Japan and the United Kingdom. To find out how much U.S. debt your country holds, take a look here.

The rest of the debt – 26% – is in private hands. That includes vehicles like mutual, bond and pension funds, savings bonds and institutional investors.

Lots of national governments and private investors have long chosen U.S. Treasuries because they were considered a safe haven. In times of uncertainty and crisis, the U.S. government was one of the most reliable places to park your cash. It may not be much longer.