Although U.S. stock futures edged higher ahead of the open, Wall Street was flat on Tuesday as CPI data showed consumer goods were unchanged in November, while costs excluding food and energy rose 0.2 percent. The Dow Jones industrial average fell 0 points, or 0.21 percent, to 15,884.36. The S&P 500 Index was down 4.81 points, or 0.27 percent, to 1,781.73. The Nasdaq Composite lost 8.87 points, or 0.22 percent, to 4,020.65.