A discounted-cash-flow model isn't meaningful for American Express Company (AXP) — banks and insurers carry deposits and reserves that a FCF-to-firm model wrongly treats as debt, so they're valued on book value (P/B), return on equity (ROE) and P/E. See the metrics page for the sector-appropriate valuation ratios.
An editable DCF model isn't applicable to AXP — banks and insurers are valued on book value (P/B), return on equity (ROE) and P/E, not a FCF-to-firm DCF.