The Dow fell as declines in shares of Coca-Cola and Pfizer, down 1.6 per cent and 1.4 per cent respectively, outweighed gains in shares of Nike and General Electric, up 1.7 per cent and 1.1 per cent respectively.
Fed policy makers agreed to cut the pace of their monthly bond-buying by US$10 billion to US$25 billion a month.
"A range of labour market indicators suggests that there remains significant underutilisation of labour resources," the Federal Open Market Committee said in a statement.
Indeed, a separate ADP report on Wednesday showed companies hired 218,000 workers in July, fewer than expected and down from June.
"Household spending appears to be rising moderately and business fixed investment is advancing, while the recovery in the housing sector remains slow," according to the Fed. "Inflation has moved somewhat closer to the Committee's longer-run objective."
Most took the latest Fed comments as a sign policy makers won't hike interest rates soon.
"The fact that officials still see excess slack in the labour markets as noteworthy suggests a high level of comfort with leaving rates very low," Omer Esiner, chief market strategist at Commonwealth Foreign Exchange in Washington, told Reuters.
On the earnings front, Twitter was a standout. Shares soared 21.6 per cent after the company posted quarterly revenue that exceeded expectations. It had reported after the closing bell on Tuesday in the US.
"We continue to believe we are in the early stages of a very long growth cycle for Twitter as it leverages cultural ubiquity, invests in product and technology, and grows the platform," Goldman Sachs analysts wrote in a report, Reuters reported, adding that Goldman maintained its "buy" rating and raised its price target to US$63 from US$52.
In Europe, the Stoxx 600 Index finished the day with a 0.5 per cent drop from the previous close, as did the UK's FTSE 100 Index. Germany's DAX fell 0.6 per cent, while France's CAC 40 slumped 1.2 per cent