The calculation hierarchy for the Statement of Cash Flows is the most challenging of the face statements. Here is a quick and reliable procedure for doing it correctly.
XBRL Calculation Logic
Recall the basic XBRL calculation logic:
Calculation relationship contributor items that are of the same balance type (credit or debit) as the calculation relationship total item should have a positive calculation weight.
Calculation relationship contributor items that are of the opposite balance type have a negative calculation weight.
A value displayed in Wdesk sometimes needs its sign reversed when translated to an XBRL fact. This is done so that the value is properly reported and that fact may then comply with the calculation weights.
It is common that a value displayed in Wdesk shows the opposite sign of the XBRL fact version to support the presentation of the simple sum.
Regarding the Statement of Cashflows, the calculation relationship that you want to define calculates how the company’s cash balance increased or decreased from operating activities. Cash always increases with a debit and decreases with a credit, and therefore debits must have a positive weight and credits must have a negative weight.
There is an exception for net income (NI) because NI is not closed to cash but rather closed to retained earnings. By itself, NI or net loss does not directly show the effect on a company’s cash balance. This is why the operating cash flows make appropriate adjustments to reflect the actual cash effect.
Handling Debits and Credits
When the calculation relationship contributors and calculation relationship total have predefined balance types, Wdesk automatically sets the calculation weight to positive or negative, as appropriate for the balance type relationship between each calculation relationship contributor and the calculation relationship total.
The following image shows these the calculation weights already set:
Manually Assigning Weights
Some US GAAP taxonomy concepts are not defined with a balance type. In this case you need to manually define the calculation weight in the relationship formula. This can happen, for example, in the operating activities section of the Cash Flows Statement.
In the image, the Net Cash Provided by (Used in) Operating Activities tag does not have a balance type. Therefore, you need to manually assign the calculation weight on all line items in this section. You set the weight according to basic calculation rules, with one exception: Net Income receives a positive weight. Treat the operating cashflow as a natural debit balance (the same as the investing and financing cashflow).
NOTE: Items of the balance type opposite of the calculation relationship target (the subtotal) will receive a negative calculation weight. These same items should also have their source value reversed in the XBRL fact properties and have their label role set to negated.