In the land of the free and the home of the brave, bigger almost always means better, especially when it comes to revenue. These 10 American companies top the Fortune 500 list for annual revenue, but that doesn't mean each doesn't face its own challenges. Rising competition, falling prices, and a touch of mismanagement are just some of the problems these companies must address. 
But at the end of the day, these 10 American workhorses drive much of the country's growth, and most show no sings of slowing down. Click through the slideshow below to find out more about America's biggest companies.