Apple Inc was down 0.3 percent, paring earlier declines, after it reported a surprise fall in iPhone sales in its fiscal second quarter on Tuesday. The drop came on the heels of a decline in sales for US automakers for April and a soft first-quarter reading on US growth last week.

Even with the decline in iPhone sales, Apple still managed to top earnings estimates in what has been a strong quarter for US companies. Thomson Reuters data shows first-quarter growth is currently expected to be 14.2 percent, the best quarter since 2011, with 357 of S&P 500 companies having reported.

"Despite some isolated incidents, overall the season has been great," said Randy Frederick, vice president of trading and derivatives for Charles Schwab in Austin, Texas.

"And that's one of the reasons why the indexes are hovering near record levels."

A report by payrolls processor ADP said private employers expanded their payrolls by 177,000 jobs last month, the smallest gain since the 62,000 increase last October as they faced increasing difficulty finding qualified workers.

Other data indicated the pace of growth in the US economy's service sector increased in April, led by a jump in new orders, according to an industry report.

The Dow Jones Industrial Average fell 16.43 points, or 0.08 percent, to 20,933.46, the S&P 500 lost 6 points, or 0.25 percent, to 2,385.17 and the Nasdaq Composite dropped 28.98 points, or 0.48 percent, to 6,066.39.

Europe's STOXX 600 index lost 0.04 percent to retreat from a 20-month high and MSCI's gauge of stocks across the globe shed 0.23 percent.

The US economic data helped push the dollar higher ahead of the Federal Reserve statement.

While the central bank is expected to leave interest rates unchanged later on Wednesday, investors will look for signs it may hike them in June. Traders are currently pricing in a 70.7-percent chance of a hike of at least a quarter-point next month, according to CME's FedWatch tool.

The dollar index rose 0.12 percent, with the euro down 0.12 percent to $1.0914.

Benchmark 10-year notes last fell 1/32 in price to yield 2.2982 percent, from 2.296 percent late on Tuesday.

The US Treasury said it is studying the possibility of issuing ultra long-term bonds.

Oil prices retreated from earlier highs after US government data showed a smaller-than-expected decline in domestic crude inventories and weak demand for gasoline, feeding concerns about a supply glut.

US crude fell 0.06 percent to $47.63 per barrel and Brent was last at $50.59, up 0.26 percent on the day.