I suggest that you refer to the following answers, which were posted by TT for 2017.
https://ttlc.intuit.com/questions/4332060-help-with-2017-ssdi-lump-sum-award-and-repayment-back-to-p...
https://ttlc.intuit.com/questions/4321469-2017-ssdi-lump-sum-repayments-to-ltd-long-term-disability-...
These are answers to questions very similar to yours. If the above links do not work, look at your question and see the Similar Questions listed below yours.
Note however, that because of the change in Tax Laws effective in 2018, that the itemized deduction may not be attractive for your situation. Of course, that will depend on the specifics of your income and SSDI amount repaid. Be certain to check both the deduction and credit alternatives and choose the one which results in the lowest taxes to be paid.
Also note that the above links are targeted toward the 2017 TurboTax software. I am assuming that the 2018 TT process for Lump Sums has not significantly changed.
