IMO, if you're including both credits and fees in the same document, it is no longer an invoice.
a bill; a commercial document issued by a seller to a buyer indicating the products, quantities and agreed prices for products or services that the seller has already provided the buyer with. An invoice indicates that, unless paid in advance, payment is due by the buyer to the seller, according to the agreed terms.
A more fitting term would be something along the lines of statement (sense 3) or account statement. You could also get away with calling it a billing statement.
Based on the OP's comments below, rather than a word representing a document containing credits and fees, what is being sought is one representing the items in a list of credits and fees which is, in turn, embedded in a document. Such items are usually called transactions (sense 4) or simply entries (sense 6).