UnitedHealth Group Inc. has been dealt a blow in a bid to secure a multibillion-dollar military benefits contract after a lengthy fight with Humana. After awarding the contract to UnitedHealth in June 2009, the U.S. Department of Defense reversed course last week and gave it to Humana, the government's current vendor. The contract, which provides healthcare benefits to soldiers and family members in 10 southern states, is worth an estimated $23.5 billion over five years. About 93% of that goes to hospitals, clinics and doctors who provide the care. The insurer collects fees for processing claims, managing provider networks and providing customer service. Minnetonka, MN-based UnitedHealth said the contract fight isn't over.