How to show negative values in a pie chart?

I have a list of accounts and want to show the balances in a pie chart. That's pretty straightforward as long as all of the accounts have a positive balance.

When some of the accounts have negative balances (such as a loan or an overdraft checking account) is there some clever way to still present that data as a pie chart?

The best idea I've been able to come up with is to turn the pie chart into two semicircles, one which shows the assets on top of one which shows the liabilities, with the radius of each semicircle proportional to the total of assets/liabilities.