Retirement tax questions

Repayments of Social Security follows a slightly different rule than other repayments, *IF* this pertains to you:

If you properly receive Social Security payments for the current year, the repayment is subtracted from what you receive.  So if you received $8000 of Social Security but need to repay $4000, then $4000 is reported on the tax return, and you don't need to deal with the credit or deduction (enter the entire SSA-1099 form, and TurboTax should do that part).
<a rel="nofollow" target="_blank" href="https://www.irs.gov/publications/p915#en_US_2016_publink100097877">https://www.irs.gov/publications/...>

If the repayments are more than the amount you receive, then the 'extra' amount of repayment is subject to the 'usual' rules that Hal_Al mentioned.