Financial Institution Living Will Improvement Act of 2018 This bill amends the Dodd-Frank Wall Street Reform and Consumer Protection Act to establish the frequency with which certain nonbank financial companies and bank holding companies shall be required to submit a "living will" (i.e., the company's plan for rapid and orderly resolution in the event of financial distress or failure) to the Federal Reserve Board (FRB), the Financial Stability Oversight Council, and the Federal Deposit Insurance Corporation (FDIC). Specifically, such companies shall be required to do so once every two years. (Current regulations generally require annual submission of plans.) The FRB and the FDIC must provide feedback to a company regarding such a plan within six months.