Its 20 oz when Hot as Venti means 20 in Italian. Although for cold beverages its 24 oz. Same is for Trenta cup, as Trenta means 30 in Italian. Trenta cup is reserved for cold beverages in Starbucks. Trenta cup = 30 oz cold beverage.
A utility bill would be a bill for your water, electric, gas, etc.
How energy bills are calculated. When calculating the price of your bill, energy providers monitor how many kilowatt hours of gas or electricity you have used over a certain period of time, and then multiply this by the price per unit set in your tariff.