code: public Double getTotalDetailEstimate(WorkitemFilter filter, boolean includeChildProjects) {
          filter = (filter != null) ? filter : new WorkitemFilter();
  
          return getRollup("Workitems", "DetailEstimate", filter,
                           includeChildProjects);
      }
docs: Count the total detail estimate for all workitems in this project
  optionally filtered.
  
  @param filter               Criteria to filter workitems on.
  @param includeChildProjects If true, include open sub projects, otherwise
  only include this project.
  @return total detail estimate for all workitems in this project
  optionally filtered.