How splitting works

Document splitting is rule-driven. When a document is posted, the system works out what kind of business transaction it is, what each line is, and which rule tells it how to split the lines that need splitting. SAP delivers a standard splitting method, 0000000012, that covers most needs. Projects copy it to their own method (for example Z000000012) before changing anything, so the delivered content stays intact.

Business transactions and item categories

Each document type is classified for document splitting, which links it to a business transaction and a variant. Contoso's supplier invoice document type points to the supplier invoice business transaction; the customer invoice type to the customer invoice transaction; payment document types to the payment transaction. The variant can restrict which item categories are allowed, so a document type used for the wrong purpose can be stopped at posting.

Each line gets an item category. Most come from the G/L account: an account classified as an expense account becomes an expense item, a revenue account a revenue item. Reconciliation accounts give customer and supplier items. In the delivered content, for example, supplier lines are item category 03000, customer lines 02000, expense lines 20000 and revenue lines 30000. Getting the G/L account classification right is half the battle.

Active split: from rules

For a document that does not clear anything, such as a supplier invoice, the splitting rule names the items to be split (the payable and the tax line) and the base items (the expense lines). The system splits the payable in the same proportions as the base lines. That is the active split. A customer invoice works the same way with revenue lines as the base.

Passive split: from the referenced document

When a payment clears the Lakeside invoice, there is no expense line in the payment to use as a base. Instead the clearing document inherits the split of the document it clears. The payable lines in the payment take the segments of the invoice's payable lines: 60% Fleet and 40% Aftermarket. The bank line is then split the same way. This is the passive split, and it is why a payment never needs its own profit center entered.

Inheritance and default account assignment

Two settings fill gaps. Inheritance: if a document contains only one value for a characteristic, lines without it inherit it. A G/L posting with one expense line for profit center Fleet passes Fleet to the offsetting line. SAP recommends always activating inheritance. Standard account assignment (a constant): if a value still cannot be found, the system fills a default value such as a dummy profit center. It prevents postings from failing, but it also hides errors, so SAP's own learning material advises testing without the default first.

A worked example makes the order clear. Contoso posts a G/L journal entry that moves USD 2,500 of freight cost from the Fleet cost center to an Aftermarket cost center. The document type for G/L postings points to the general posting business transaction. Both lines are expense items and both carry a profit center derived from their cost center, so nothing needs splitting. Because the two lines sit in different profit centers, zero-balancing then adds clearing lines, which the next lesson explains. Now change one detail: the second line has no cost center. With only one profit center left in the document, inheritance can pass Fleet to the empty line, and the "transfer" silently becomes Fleet to Fleet: balanced, accepted, and meaningless. Same rules, very different outcome, decided only by master data. That is why splitting tests must check the values on each line, not just whether the posting went through.