DE.DESCENDANTSCOUNT
Returns the recursive number of children of a specified consolidated element. 
    Syntax
DE.DESCENDANTSCOUNT(Dimension,
          Element)
      
Dimension is the name of the dimension
        which contains the consolidated element. Element is the
        element of which you want to determine the number of children, grandchildren,
        great-grandchildren, and so on.
Example
This example returns 16 (12 months + 4 quarters):
DE.DESCENDANTSCOUNT('Period', '2006')
      
The Year element contains four
        quarters, each containing three months. The quarters and months are all descendants of the
          Year element.
If there are multiple hierarchies, elements with the same name are counted only once.