As indicated, based on data from the Economist, China has the second largest foreign debt as defined in my post, i.e., debt owed to non-residents and payable in foreign currency. There is plenty of foreign investment in the US, in Treaury bonds and in the stock market and businesses. We have the largest capital market and the place where other countries trust to place their investments and which can absorb them. Our stock market capitalization ($13.8 trillion) is larger than the next 20 countries combined.
I have no problem with foreign investment. It helps create jobs and underwrite our economy. Moreover, it gives these others countries a stake in our success and gives us greater leverage in dealing with them.
Countries whose debt is largely domestically owned are countries whom foreigners do not want to invest in because they think that country's currency is worthless and that it's economy is in peril.
If there were an enormous drop in foreign ownership of US Treasuries, that would be a signal of economic weakness, not strength.