5 hours ago, mistermack said:

Yes, I'm also imagining the rate of inflation in America if that happened. And I'm imagining America going bust, if China stopped buying their debt. 

Does China hold a lot  of American debt?How much?

40 minutes ago, geordief said:

Are the main holders private financial institutions?

The treasury has regular statements breaking the numbers down. Quite a bit is in mutual funds, but also state and local governments, but also foreign investors. The data should be in here somewhere, if you are interested: https://www.fiscal.treasury.gov/reports-statements/treasury-bulletin/current.html