DE.WEIGHT
When you define a consolidated element, you can assign a weight to each of its
      components. 
    DE.WEIGHT returns the weight of a specified
      component of an element.Syntax
DE.WEIGHT(Dimension, Parent, Child)
      
Example
The Germany element in the REGION dimension is weighted by 1 when consolidated into Europe. This example returns 1:
DE.WEIGHT('REGION', 'Europe',
          'Germany')