You can set the default label mode to ID or Description in Data Layout. This setting impacts only those dimensions set to display the Default label mode in Dimension Browser.
The Description label comes from the alias table setting, saved per database connection and per active user as a database user preference.
You can set the default label mode before querying using Data Layout options or the last step in the wizard, and after querying using the data object shortcut menu. You can specify which description label to use in dimensions, using Dimension Browser and the data object shortcut menu.