This deserves some discussion.
So, there are types of billionaires, including
a) those that have $1 billion or more, and
b) those that have $1 billion or more more than they owe
Trump is likely to face several powerful groups, not the last of which is Deutsche Bank, coming for the money Trump promised them with contracts that not even Trump can get out of...until he declares personal bankruptcy and basically loses everything. In other words, he's likely the first type. We have a rough idea how much his assets are worth, but he's pretty quiet about how much he owes -- and to whom. He fought for four years for that, the world's largest security risk, to be hidden from Congress. If he really had that much money, I can't imagine he'd need to hide it. Also, if he had that much money, I can't imagine banks would be reluctant to give him loans. Someone with money can be forced to pay. Someone without money cannot.