The healthcare company has generated some massive returns for investors in recent years.Making a million dollars from a single stock sounds like it could be an unrealistic goal. But if you pick a good growth stock, which also pays a dividend, and hold on to it for the long haul, it's entirely possible to envision.A stock that has been an exceptional investment over the past decade is UnitedHealth Group (UNH -0.40%). In 10 years, the healthcare stock has generated total returns (including dividends) of more ...