The biggest hidden treasure in this balance sheet is not simply (asset - liability) but the interest profit margin (asset interest income rate - liability interest owed). Wamu interest margin on its loans was 2.9% as of the last 2007 10k that it filed. This 2.9% interest margin wont show up on the balance sheet in 2008 when the WMB was seized. So the bankruptcy remote (safe harbored) piggy bank not only contains the net asset on balance sheet in 2008 but also the 2.9% annual interest it has been collecting for 10 years on the entire asset (not just the net asset).
Thats why Dr. A's $86 B estimate is not only feasible but a conservative estimate. IMO, $100B is possible.