UPDATE: here is a simpler way to make running totals in Power Query
https://youtu.be/hxJ_HrSG5qM
This video is a wild one! To make running totals in native Excel is pretty easy. However, in this video, you will see the adventure for making Running Totals in Power Query (Get and Transform).
You will see some M Coding in Power Query, Lists, List.Range, List.Sum, custom columns, and putting an entire table inside a single column.
In Excel we can work at the cell level and that's what makes running totals easy. But, in Power Query, we have to work on entire rows or columns. So, there are a lot of steps to force Power Query to give us what we want.
#RunningTotals
#PowerQueryRunningTotals
#PowerQuery
For an intro to Get & Transform (Power Query) try my Lynda.com course:
https://www.lynda.com/Excel-tutorials/Excel-2016-Get-Transform/608994-2.html
Website: http://ozdusoleil.com
My book: Guerrilla Data Analysis 2nd Edition
http://www.amazon.com/Guerrilla-Analysis-Using-Microsoft-Excel/dp/1615470336
My old blog: http://datascopic.net/blog-2-2