Cost of disengaged employees: $256 to $363 billion.
Cost of spam: $22 billion.
Cost of product counterfeiting and copyright piracy: $600 billion.
Cost of movie pirating: $3 billion.
Cost of delays at U.S.-Canada border: $4.1 billion.
Cost of power disruptions: $100 billion.
These figures aren't destined for any reputable economics textbook. To begin with, it's hard to believe that workplace interruptions really do nearly eight times the damage of rising oil prices, which are said to cost the economy $75 billion. Then consider the double-dipping. No doubt some work "negativity" involves all those annoying co-workers. And when the power goes out, disengaged employees don't even notice. Consider in addition that each of these costs has a corresponding economic payoff. Anti-spam efforts keep well-paid software engineers employed. Annoying co-workers have spawned a healthy market in noise-canceling headphones. There's no standard method for smoothing out all the overlap and contradiction.
Often, though not invariably, "costs to the U.S. economy" are self-serving sums concocted by lobbyists, companies, and advocacy and trade groups in order to grab attention. Basex, for example, is a consulting company that—you guessed it—would love to help you cut down on all those pesky interruptions, for a fee.
That's not to say there's nothing at all to the hype, though. If I'd closed my office door and muted my phone, I'd have finished writing this 25 minutes ago. Which would have given me time to send a copy of the Natalie Portman rap to my buddy Andrew. Ah, I can annoy him with that tomorrow.