As far as I know WMI's debt is 8B. Most of it very lng term debt (up to 2049). Only 1-1.5 was due in 2009. You are right about the prefs....this is about 3.5-3.7B (interest included)
Again, as far as I know - an maybe I missed something - the rest is WMB debt, and the WMB's debt holders are just trying to be a party in the Bk court to protect their interests ... just in case the outcome put their interest at risk.