Yes, any distribution must be reported on a 1099-R. You should be able to get a copy form the IRA custodian or it might be on their website if you have an online account.
You probably should answer the IRS letter at the address on the letter and attach an amended 2014 tax return properly reporting the 1099-R to a copy of the letter rather than just explaining it.
See this TurboTax FAQ for help with amending:
https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filedEnter a 1099-R here:
Federal Taxes,
Wages & Income
I’ll choose what I work on (if that screen comes up),
Retirement Plans & Social Security,
IRA, 401(k), Pension Plan Withdrawals (1099-R).
OR Use the "Tools" menu (if online version under My Account) and then "Search Topics" for "1099-R" which will take you to the same place.
Be sure to choose which spouse the 1099-R is for if this is a joint tax return.
Be sure to pick the correct 1099-R type: Standard 1099-R, CSA-1099-R, CSF-1099-R, RRB-1099-R.
One of the follow-up questions will ask about prior year Roth contributions and conversions. Your own contributions will not be taxable. TurboTax will automatically create the 8606 form to show the non-taxable basis that will be part of the amended return. Be sure to attach a copy of the 1009-R.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
