What's the combined wealth of the US banks? How much is the amount of money of the US banks?

In terms of:


assets
their own money (the banks make profits and they can keep the profits for further investments)


The question is only about the banks. No retirement funds, no venture capitals, no other kind of financial institutions.
The total assets of all US commercial banks are about \$17.2 trillion.

You'll have to be clearer about what you mean by "their own money". The total equity capital of US commercial banks is about \$1.9 trillion.