Macro to show pivot table details..Any ideas?

Greg, without seeing the PT etc it's hard to comment... if we assume

a) Grand Total always appear in Column A
b) Field in question always appears in Column C

Then perhaps along the lines of:

Public Sub ShowPTDetail()
Dim wsPT As Worksheet
On Error GoTo Handler:
Set wsPT = Sheets("Sheet1") 'sheet containing PT
wsPT.Cells(Application.Match("Grand Total", wsPT.Columns(1), 0), "C").ShowDetail = True
ExitPoint:
Set wsPT = Nothing
Exit Sub

Handler:
MsgBox "Error Has Occurred etc...",vbCritical,"Routine Terminated"
Resume ExitPoint
End Sub