First, head to your project list and add your Custom Columns.
Then, add in your Custom Columns. I suggest Remaining Balance, Payment Type, Customer name, Billing Status, and Business to make it easy for you to see these results.
Filter your project list by Business and as a best practice, you can include projects that are Archived.
From here, you can see all projects for this company with the remaining balance and if the project is paid with a deposit (Upfront) or on a Net basis.
Note: If you're just wanting to see what is remaining, but not due, you can sort your projects by Billing Status.
Any project with a Remaining Balance, but no Billing Status will mean that balance isn't currently 'due'.
Finally, you can download your project list into an Excel Document for a summary for the Company.