Chances are your benefits may stay the same as you know them. FedEx Express and FedEx Freight, do not have the same benefits, I'm guessing that you will have a different benefit package than the other FedEx divisions. From what I can tell, FedEx Express (The original FedEx) has the best. FedEx Freight's benefits are ok, not great.
With Freight being self-insured, they pay the bills, and usually not the whole bill. There is a broker(Cigna Healthcare for example) who helps with doctor/dentist access. FedEx usues their name and contacts, to ensure a greater pool of medical providers. It all depends on the state and where in the state you live.