An equality definition is a definition of equality between any two values in a typed-dimension domain definition. A typed-dimension domain definition is the element in an XML Schema that defines the content model for a typed dimension and that is identified as such by an @xbrldt:typedDomainRef attribute on the XML Schema element declaring a typed dimension. An equality-definition relationship, which is the relationship between a typed-dimension domain definition and an equality definition, is displayed as reverse relation between the equality definition and the corresponding typed dimension.
An equality-definition relationship can be established by dragging a typed dimension from the Global Elements entry helper onto an equality definition component. Note that neither the equality definition nor the typed dimension may be involved in an existing equality-definition relationship yet.