Medicare Advantage, run by private insurance companies, is an alternative to traditional Medicare. Originally conceived as a way to rein in healthcare costs, the federal government now pays Medicare Advantage companies nearly $200 billion a year to cover some 19 million seniors. Yet, according to one government analysis, nearly 10% of the payments to those private insurance companies are "improper." It's suspected many of those improper payments are the result of fraud. Now, several whistleblower lawsuits allege that some of America's biggest insurance companies are systematically bilking the Medicare Advantage program of billions, all part of their business model.