You, most likely, answered something wrong in the interview and it's being treated as a distribution, rather than a conversion. Review form 8606. A distribution will be on line 15c; a conversion on line 18.
After entering the 1099-R, the interview will ask what you did with the money. Convert to Roth IRA is an option. If you did not check converted the full amount, you'll be asked to enter an amount.
