Coleen3
Intuit Alumni

Retirement tax questions

After you enter your 2017 SSA-1099 information, we'll ask if you received a lump-sum Social Security payment. Answer Yes and follow the onscreen instructions. (See the attached screenshot below. Click to enlarge.)
Your SSA-1099 lump-sum section breaks down the payments into what amount was received for each preceding year. You can only enter one year at a time. Start with 2015. (See the attached screenshot below. Click to enlarge.)
On the next screen, Enter your 2015 lump-sum payments received in 2017 (See the attached screenshot below. Click to enlarge.) and Continue
On the next screen, Tell Us About Payments Received in 2015 (probably leave blank) and Continue
On the Tell Us About Your 2015 Income enter your 2015 income as required (See the attached screenshot below. Click to enlarge.) and Continue
When finished with 2015, click Add Another Lump Sum if you need to enter benefits received for a different tax year (2016)
Now simply do the same thing that you just did for 2015, but use the relevant numbers for the next year (e.g.2016).
While your lump sum may include benefit payments for more than one year, you do not have to file an amended tax return for any prior year. You might need to pay taxes on a small portion of your lump-sum payment. However, you might be able to avoid these taxes by apportioning prior year benefits to those previous years’ income (still without filing any amended returns). 
After you enter your lump-sum Social Security payment information, TurboTax will automatically figure what if any taxes you owe due to the lump-sum payment.