AT T Posts \$7.1 Billion Loss on Writedown &lt;p&gt;\&lt;/p&gt;&lt;p&gt; WASHINGTON (Reuters) - AT T Corp. on Thursday reported a\\$7.1 billion third-quarter loss due to an \$11.4 billion\writedown of its assets after its retreat from consumer\services and other restructuring charges.&lt;/p&gt;