Source: Board of Governors of the Federal Reserve System (US)  

Release: Z.1 Financial Accounts of the United States  

Units:  Millions of Dollars, Not Seasonally Adjusted

Frequency:  Quarterly, End of Period

The Mortgage Debt Outstanding table is no longer being updated as of March 2020. Many of the series that were published in this table can be found in the Z1 Financial Accounts of the United States release. The Z1 equivalent of this series is found at BOGZ1FL403065035Q.

For further information, please refer to the Board of Governors of the Federal Reserve System's Mortgage Debt Outstanding.