Okay, maybe I'm not making the question clear. Let me try an example.
I work for a major university. You've heard of it, I promise you. The university has a total of 12 schools; (University name) Law School; (University name) Med School; (University Name) Business School, etc. Each school has their own HR division that handles their own hiring, (most) employee relations, leave administration, etc. However, there is an overall HR department that handles things that are common to all the schools - benefits being among them. HR policies are another that are centrally administered. No school gets to decide their own benefits or their own policies. With a company as large are you are talking about, I promise you that you've got the same thing. Even if every division has their own HR unit, there is SOMEWHERE a central HR structure that all divisions report to.
Are you at the same location as that central HR structure?