I'd suggest building 2 new fields in a query, to split them out. Assume your field is [Balance].
You'll need these fields in blank columns of the query grid --
Assets:IIF([Balance]>0,[Balance],0)
Liabilities:IIF([Balance]<0,[Balance],0)
Now your reports, summary queries, etc can use these 2 new fields as long as you base them on teh new query.
Denis