This would be great, and you are not the only one that would like it! There’s a long discussion on it here:
It is currently possible to either download a PDF statement to see the running balance, or you can download a CSV of all your transactions from the beginning of time and use a spreadsheet to add a running balance column. Neither are as convenient as being able to just look at the transaction detail as you’ve suggested, which would be useful when trying to do quick checks/reconciliations.
Hugo did say that this information would be provided in the transaction detail, but I’ve not heard anything since. Hopefully it’s still planned at some point? 