Not sure about the structure of your data or how you build your Viz, however, I will try to recreate something similar with Sample-Superstore data set, I only have data for 2015 and 2016, after I create a simple line graph to see/ compare profit per month, I will create 3 calculated fields to get the difference per month
Get the profit just for 2015 & 2016 years with an IF THEN END Statement
Now the difference between 2016 profit - 2015 profit
After you have the difference per month, then the cumulative difference is a Table Calculation Running Total (Table across ) [or RUNNING_SUM]
Then create the view
Attached .twbx file for reference (using Ver 10.2)
Let me know if this helps!
NOTE: I notice that you are using a Spanish version of Tableau, I speak Spanish too!
Book1.twbx 1.1 MB
It works just fine.