U.S. stocks slipped Tuesday as investors processed the first presidential debate between Hillary Clinton and Donald Trump on Monday. Roughly thirty minutes into the debate, Trump slammed Federal Reserve Chair Janet Yellen, saying the central bank was playing politics. The S&P Case-Shiller National Home Price Index rose 5.1% year-over-year in July, compared to a 5% increase in June. Denver, Portland and Seattle saw the highest annual gains. Volkswagen (VLKAY) fell 2% on reports the U.S. Department of Justice is figuring out the size of the automaker's fine stemming from its emissions scandal, which came to light last year. Caesars Entertainment (CZR) - Get Report rose after landing an agreement with creditors, after years of legal woes. Apollo Global Management and TPG Capital will take smaller stakes in the company, according to the agreement. TheStreet's Scott Gamm reports from Wall Street.