It depends: if your state is one that allows you to Itemize on the State return even if you claim the Standard Deduction on your federal return (such as New York) it will automatically consider both options and then choose the one that provides the largest benefit for you.
If your state requires that you take the Standard Deduction if you also take the Standard Deduction on the Federal Return, then TurboTax will automatically do so in order to be compliant with your state's laws.
