What health insurance do Tenet hospitals provide?

What health insurance do Tenet hospitals provide? I'm considering a position with them and the benefits handout that HR gave me does not list a specific company, which worries me. I can call HR, but thought someone here may know tonight. Thanks!
Tenet includes numerous facilities in 7 or more states ... the specific benefit providers are going to vary from facility to facility based on licensed insurance providers in each state, etc.