it is actually a either and neither, it just means cleaner and there isn't any strong chemicals inside of the detergent which makes it a neutral.
honestly it depends on which type of laundry detergent, if you use let's say oxiclean it is consider an alkaline because the not so strong chemicals in there dull out the acidity in the detergent which makes it alkaline or neutral.
so what i'm trying to say is, laundry detergent can be either and neither. it is all depends on which type of laundry detergent you get (like bleach, bleach can be used on laundry if you have stains)
hope this : )
have a great day