AT&T Inc is preparing to spin off its media business and merge it with Discovery Inc in a tax-friendly deal, people with knowledge of the matter said, a surprise reversal for a company that spent US$85 billion to acquire the assets less than three years ago. A deal could be announced as soon as this week, said the people, who asked not to be identified because the information is private. The transaction would be structured as a so-called Reverse Morris Trust, or a merger with another company that is structured to be tax-free, one of the people said. The idea is to