From their website, artificial sweeteners bolded by me (sorry for the caps, but I am not retyping this):
CARBONATED WATER, HIGH FRUCTOSE CORN SYRUP, CARAMEL COLOR, PHOSPHORIC ACID, ASPARTAME, SODIUM BENZOATE, CAFFEINE, NATURAL AND ARTIFICIAL FLAVORS, ACESULFAME POTASSIUM, SODIUM PHOSPHATE
So it's HFCS and not one but two artificial sweeteners.