In Bill Analyst you can delete filters you've created. You cannot delete shared filters someone else created. If you just want to make some changes, you can edit a filter (you don't have to delete it to change it).
To delete a billing data filter:
Click Reports, click Billing Reports, then click Bill Analyst.
Control Center opens Bill Analyst in a separate window.
Click the Setup tab.
In the Tools box, click Filters.
Shared filters can only be deleted by their owner. If you want to modify a shared filter, copy it and then modify as you want.
Select the radio button next to the report filter you'd like to delete, then click Remove Filter.