These 10 companies have no trouble pulling in the Benjamins. Image source: Emergency Dentists USA.  

It isn't hard to search the Internet and find out who the "most profitable" American companies are. Unfortunately, it paints a very incomplete picture.

There's one big problem with the word "profit": it doesn't reflect how much money a company is able to keep in its pockets at the end of each year. That's because a whole slew of accounting gimmicks can go into figuring out "profit" -- things like amortization or depreciation -- that have no immediate effect on cash.

A far better -- though admittedly not perfect -- measure would be free cash flow. This represents the amount of cash a company is able to generate from continuing operations (its core business), minus any capital expenditures.  

You'll see many familiar names in the Top 10 free cash flow generators, but what's astounding is that the number one company has almost twice the cash coming in than its closest competitor.