Difference between "Debt Held by the Public" and "Total Public Debt Outstanding"? On https://www.treasurydirect.gov/NP/debt/rss, we have three numbers:

Debt Held by the Public: $14,387,199,090,397.24
Intragovernmental Holdings: $5,552,709,700,473.24
Total Public Debt Outstanding: $19,939,908,790,870.48


It seems the latter number is often considered the U.S. national debt. What is the difference between the Debt Held by the Public and the Total Public Debt Outstanding?
The difference are the intragovernmental holdings, which consist of  treasuries that are owned by government agencies and are thus not counted as government debt - it's a debt that the government owes to itself.

From Wikipedia (https://en.wikipedia.org/wiki/Intragovernmental_holdings):


  In the United States, intragovernmental holdings are primarily
  composed of the Medicare Trust Fund, the Social Security Trust Fund,
  and Federal Financing Bank securities. A small amount of marketable
  securities are held by government accounts.