Jerome Powell has responded to sharp criticism from the Trump administration about renovations to the Fed’s offices, answering questions about changes to the project as well as reaffirming the central bank’s commitment to “transparency for our decisions and to be accountable to the public.”

For a moment on Wednesday, it looked like President Donald Trump would finally attempt the improbable and fire Federal Reserve Chair Jerome Powell.

As frequently happens with government building projects, the project has blown past its planned budget, with the cost skyrocketing from an initially large $1.9 billion to an eye-popping $2.5 billion....