Matrix Total Calculation

jamiefisher OK, so are 1 Budget, 2 Comm, 3 Actual are those measures or are those values in a column?

I mean, in general you should be able to create a measure like the following:

Measure = 
  VAR __1 = SUMX( FILTER( 'Table'[Column] = "1 Budget" ), [Value] )
  VAR __2 = SUMX( FILTER( 'Table'[Column] = "1 Budget" ), [Value] )
  VAR __3 = SUMX( FILTER( 'Table'[Column] = "1 Budget" ), [Value] )
  VAR __Result = __1 - __2 - __3
RETURN
  __Result

Note, I am making assumptions about your data model because I don't know what it actually looks like.