Illinois Department of Insurance signs off on Centene-WellCare merger Dec 6, 2019 | Insurance, Medicaid/Medicare, Top Stories The Illinois Department of Insurance has signed off on a plan to allow Centene Corporation and WellCare Health Plans to merge, the companies announced Thursday.To access this content, you must purchase 1 Year Health News Illinois Subscription or 1 Year Group Subscription - Up to 5 Users, or log in if you are a member.