U.S. Blue Chips Near Flat; Verizon Weighs  NEW YORK (Reuters) - U.S. blue chips were lower on Tuesday,  as a drop in phone company Verizon Communications Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=VZ.N target=/stocks/quickinfo/fullquote"&gt;VZ.N&lt;/A&gt;  overshadowed a brokerage upgrade on Caterpillar Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=CAT.N target=/stocks/quickinfo/fullquote"&gt;CAT.N&lt;/A&gt;  and a three-session drop in oil prices.