He made his money during the wild and wooly greenmail days by copycating others before it was caught on and which caused the 1970's stock market disaster. Since those easy days his investing style has been a disaster. He is not worth billions. More like Donald the Duck Trump and maybe even upside down like the Duck is. Who would own this piece of junk.
IEP must have some hidden assets then but I doubt it. The company has no actual tangible net worth. Companies like this is why the market is more like a casino. Most companies are either over indebted or consist mostly of of blue sky goodwill in order to show accounting earnings. Take a peek at Oracle as a terrific example.