To show the Account Debited in the Open Bills report, you must add the column "Split". To do this:
1. Navigate to Reports > Vendors/Payables > Open Bills > Customize.
2. In Edit Columns, expand the Open Bill folder and click on Split.
3. Rename Report and click Save.
Note: Adding this field will only expose the account if a single account is affected. If there are two or more, it will display "-Split-".