One way you could do this--though admittedly is a bit of hack could be the following.
1. Create a calculated field similar to the following:
if [Today]=[DT_RECEIPT_DATE] then 'Today' end
2. Place sum(Total) next to the running_sum of Total on the Rows shelf. Right click and create a dual axis.
3. On the marks card, change the Sum(Total) to a bar and place the above calculation on the color shelf (be sure to remove anything else from this marks card).
4. On the color legend, right click on null and select 'Hide.'
Hope this helps! I've attached your workbook here with the example (the calculation is a little more complex since [DT_RECEIPT_DATE] did not have today's date).
Dual Axis Ref Line.twbx 36.8 KB