What would happen if China decided to cash in their U.S debt securities?

China produces more than it consumes and ships the excess to the US. What dose this do to China's economy? Do we send them back other goods or services? Or, do we just incur more US debt? The Chinese economy continues to grow significantly and they continue to keep on producing.
Do you think that something has gone terribly wrong? Again, what do you think would happen if China decided to cash in their U.S debts securities which is currently around 1,160.00 BILLION. In addition, lets also look at other U.S debts securities the US owes: Russia,UK,Hong Kong,Thailand, ect.