Yep. This will likely mean shipped... But still a massive, massive number in such a short time.
According to VGChartz data...
360 Sales - 10.2 Million http://www.vgchartz.com/games/game.php?id=28848
PS3 Sales - 7.44 Million http://www.vgchartz.com/games/game.php?id=28847
And the PC sales (which aren't tracked here) will bring it to 20 Million. How do i know this? Because of the new advert for the Stimulus map packs.
At 16 seconds in... "Over 20 Million people are doing it".