In essence this is a beefed up Russian Imperial Stout.  Generally an American Double/Imperial Stout will have more hops and sometimes more sweetness than a Russian Imperial Stout.  One thing that may be de-emphasized compared to it's Russian cousin would be the dark fruit flavors.  Sometimes American Double/Imperial Stouts are aged in whiskey barrels or have coffee/chocolate flavors added.  These beers have a rich roasted maltiness and a full body.  They also have a high alcohol content (7 - 12%).