From Wikipedia:
Blue Cross and/or Blue Shield insurance companies are franchisees, independent of the association (and traditionally each other), offering insurance plans within defined regions under one or both of the association's brands. Blue Cross Blue Shield insurers offer some form of health insurance coverage in every US state. They also act as administrators of Medicare in many states or regions of the U.S., and regularly can be found providing group coverage to state government employees, as well as the U.S. Federal government under a nationwide option of the Federal Employees Health Benefit Plan (FEHBP) established by the association on their behalf. Thus a strong bond exists between the Blue Cross Blue Shield system and health insurance policy-making bodies at the highest levels of government in the United States.

For Blue Cross Insurance.