This article provides tips for determining the correct sign of an XBRL fact value and the steps for how to change the sign.
When determining the correct sign of an XBRL fact, consider the XBRL fact value itself and how the fact appears within the document. In some cases, these two might have opposite signs.
Fact Values and Presentations Signs
To determine the correct sign for an XBRL value, always keep in mind that the true sign of an XBRL fact:
Is most often a positive value.
Can be different than the sign it shows when it appears in the financial report.
Should be determined only by considering both the meaning of the fact and the meaning of the value in the report.
For example, on an income statement, income (loss) is reported as (134,375). A reader will understand that the parentheses indicate a loss or negative number. In an attached disclosure note, the text reads, "We had a loss of $134,375." Here the wording describing the loss displays the same value as a positive number.
In this example, both values mean the same thing; therefore, they are correctly captured as a single XBRL fact. However, this XBRL fact cannot be both positive and negative. It is the financial reporting context in which it appears that changes. That specific reporting context dictates which sign conveys the fact’s proper meaning. The sign on the fact value representing the loss of $134,375 should be reversed to show a negative fact value.
The underlying XBRL fact value remains the same. The fact value’s true sign is independent of each visual representation.
Determining the Correct Sign
To determine the sign of an XBRL fact, you need to know the meaning of the concept used to tag it and what you want to say with the fact in context.
Be mindful of the conventions followed in the US GAAP taxonomy:
Most XBRL concepts are designed to represent absolute values, regardless of the balance and on which side they might fall in an accounting equation. For example, the concept us-gaap_AllowanceForDoubtfulAccountsReceivable is intended to represent a positive number in most cases, regardless of how it is presented. Rarely would you report a negative allowance for doubtful accounts when disclosing the net accounts receivable.
Specific two-way XBRL concept names indicate that they can be both positive and negative:
In these cases, the concepts have a name that identifies two different conclusions. The first corresponds to a positive value; the second to a negative value.
Setting the XBRL Fact Value Sign
Once you determine the correct XBRL fact value, you can set it in the XBRL Fact Properties tab.
In the document (with XBRL enabled), select the value for which you want to change the fact value’s sign. TIP: You can multiple-select values to change the fact value sign for all of them at once.
Below the document editing area, click the XBRL Fact Properties icon to open the fact properties in the bottom panel.
In the Numeric Attributes section, for Reverse Source Value Sign, select Yes.
When you reverse the sign, notice that this affects only the XBRL Fact Value. It does not change the sign for the Source Link Value. Reversing the sign here changes the interpretation of the source link value for the XBRL fact value.
A. The selected cell, here in a Property, plant, and equipment note.
B. Reversing the sign affects the XBRL fact value, as well as the outline label role. Review the outline label role for accuracy.