You reported this incorrectly by putting it under miscellaneous income. The payer will send you a Form 1099-R for this by the end of January which you must enter into TurboTax. The taxable amount shown in box 2a must appear on Form 1040 line 16b or Form 1040A line 12b, and the tax withholding shown in box 4 will be combined with your other tax withholding and credited toward your overall tax liability.
If you have already submitted your 2016 tax return, you'll need to wait until either your submission is rejected, in which case you'll be able to make the change before resubmitting, or your submission is accepted and your original tax return is fully processed, in which case you must amend your filed tax return.
To amend:
https://ttlc.intuit.com/replies/3288565
