This idea has been merged into another idea. To comment or vote on this idea, please visit A-I-12829 Automation - set field to the Same as the Idea Created by user.
As of now we can utilize created by field of features to copy it to another field by using automation rules BUT we cannot copy similarly of an idea by using automation rules!
Some ideas portals are used for internal purpose where we need to identify creator and copy it to feature when its gets promoted and send to Jira via integration if needed.
It should work same as features created by field.