The FRED series Total Credit Market Debt Owed is now known as All Sectors; Debt Securities and Loans; Liability, Level.
The replacement for this series is adding https://fred.stlouisfed.org/series/ASTDSL and https://fred.stlouisfed.org/series/ASTLL.
The source series id is FL894104005.Q.
The series previously appeared in Table L.1, but is updated in the underlying data set. For further information see the assistance provided in the guide to the Financial Accounts at http://www.federalreserve.gov/apps/fof/.
Board of Governors of the Federal Reserve System (US), All Sectors; Debt Securities and Loans; Liability, Level [TCMDO], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/TCMDO, April 22, 2019.