Dec 11 - Fitch Ratings has assigned an 'A' rating to AT&T Inc.'s (AT&T) offering of EUR1 billion 3.55% senior unsecured notes due 2032. Proceeds are expected to be used for general corporate purposes. The Rating Outlook is Negative. The current 'A' rating is supported by AT&T's financial flexibility, the company's diversified revenue mix, its significant size and economies of scale as the largest telecommunications operator in the U.S., and Fitch's expectation that AT&T will benefit from conti