CHICAGO--(BUSINESS WIRE)--Fitch Ratings has assigned a 'BB' rating to Frontier Communications Corporation's (Frontier) (NYSE:FTR) $6.6 billion offering of senior unsecured notes. The notes consist of three tranches: $1 billion of 8.875% senior unsecured notes due 2020, $2 billion of 10.5% senior unsecured notes due 2022 and $3.6 billion of 11% senior unsecured notes due 2025. The issue ratings of the $6.6 billion offering are also on Rating Watch Negative. Frontier's Issuer Default Rating (IDR)