Health insurer Humana announced Friday it will retain the Department of Defense's Tricare contract to provide health coverage for military personnel in the south and their dependents.Humana previously held the contract, but lost a bid to renew it two years ago. It was instead awarded to the United Health Group. Humana challenged the decision, saying the two companies were not judged according to the same criteria. The award has been re-evaluated, and Humana will once again have the contract.The Pentagon places the value of the contract at over $23 billion for 5 years.