How does a goodwill impairment affect the three statements?

Say the company records a $100M goodwill impairment. On the income statement, it is a non-cash charge that reduces pre-tax income by $100M. In most cases goodwill impairment is not deductible for tax purposes, so there is no tax saving and net income falls by $100M.

On the cash flow statement, net income is down $100M, but we add back the $100M impairment because it is non-cash, so cash from operations and total cash are unchanged. On the balance sheet, goodwill falls by $100M on the asset side, and retained earnings fall by $100M on the equity side, so it balances.

If the interviewer tells me to assume the impairment is tax-deductible at a 25% rate, pre-tax income falls by $100M and net income by $75M. The cash flow statement starts with net income down $75M, adds back $100M, so cash is up $25M from lower taxes. On the balance sheet, cash is up $25M and goodwill is down $100M, so assets are down $75M, and retained earnings are down $75M. It balances.