Nooo! JPMC got the $258.5 billion assets because they also assumed exactly the same amount ($258.5B) in liabilites.
I don't know how much escrows will get. It depends on many factors. But the FDIC subtracted these $40.2B asset related equity adjustments that contain the $13.x billion WMB bonds which is a liability. I don't want to repeat everything over and over again...