Does the answer of oguz in https://community.ifs.com/assets-enterprise-service-and-assets-management-44/how-can-i-get-user-login-history-details-4059 help?

FND_SESSION_RUNTIME is a view against the instance dynamic performance view GV$SESSION. That doesn't show history.

Would history logging on FND_CLIENT_LOGON_TAB be a terrible idea?

After enabling history logging on FND_CLIENT_LOGON_TAB, this looks like it might get me what I need. Unfortunately, since we didn’t previously have history logging, it’s only forward-looking.

I only set up this history logging in a development environment so far. Does anyone know of any potential side effects to this solution?

   SELECT logons.username,
          logons.time_stamp  AS logon_date,
          logoffs.time_stamp AS logoff_date
     FROM history_log_tab logons
LEFT JOIN history_log_tab logoffs
       ON logoffs.keys         = logons.keys
      AND logoffs.table_name   = logons.table_name
      AND logoffs.lu_name      = logons.lu_name
      AND logoffs.history_type = '3'
    WHERE logons.table_name   = 'FND_CLIENT_LOGON_TAB'
      AND logons.lu_name      = 'FndClientLogon'
      AND logons.history_type = '1'
 ORDER BY logons.time_stamp DESC;