UPDATE 3-Kenneth Chenault to step down as AmEx CEO after nearly 17 years By: Reuters: Company News October 18, 2017 at 19:00 PM EDT * Move widely expected; shares just down after hours (Adds details from call, background, analyst quote) Read More >> Related Stocks: American Express Berkshire Hathaway Citigroup Costco Wholesale JPMorgan Chase & Co MasterCard