Answer:
asset
Explanation:
This applies to any client that deposits money in a bank, or a savings and loan association, etc.
For example, I deposit $100 in my savings account. The bank's total cash reserves increase by $100 (this is an asset for the bank), but the bank also owes me $100 (this is a liability for the bank).
You can change the individual for a commercial bank, the bank for the Fed, and the $100 for $100 million, but the concept remains.