Summaries in the program usually show gross amounts of income, not taxable amounts.  Look at the 1040 to see.  Click on Forms on upper right, then 1040 on the left.

Form 1040 Box 15a shows an amount that is higher than it should be on Line 15a by the difference between Box 1 and Box 2a as I entered into Turbotax.  If I enter the Box 2a amount as the gross distribution, then Line 15a reflects the correct amount. It appears TurboTax is picking up Box 1 as taxable, not Box 2a.

Box 1 is supposed to be the taxable amount if you had no "basis" (i.e., after-tax contributions) in your retirement vehicle. What type of vehicle is this 1099-R for, and did you have any after-tax contributions in it?

What code is in box 7?
Is the IRA/SEP/SIMPLE box checked?
Is the box 2b "not determined" box checked?
Is there a value in box 2a that is less then box 1 or is box 2a blank?

In response to TurboTaxBillMC, the 1099-R is for a non-qualified IRA annuity account.  There were after-tax contributions made to it that were withdrawn and cashed out.  That is the Box 1 amount.  The only thing that should be taxed is the amount shown in Box 2a, which is the interest paid through the year on the money that was in the account.  There is a value in Box 5 that is the difference of box 1 less box 2a.
In response to manuser_22, the IRA/SEP/SIMPLE box is not checked.  Box 2b "taxable amount not determined" is not checked.  There is a value in box 2a that is less than box 1.

What code is in box 7?

There is no such thing as a "non-qualified IRA annuity".   Any IRA is qualified even if there is an annuity held within the IRA.   A Traditional IRA will always have the IRA box checked and the same amount in both box 1 ans 2a and box 2b checked.  It does not sound like this is an IRA.  If held in a Roth IRA then box 7 would be a code J, T or Q.

If box 7 is a code "D" then it is a non-qualified annuity.   The box 1 amount should be on line 16a and box 2a on 16b on the 1040 form (line 12a/b on 1040A).   What is on your 1040?

Thank you macuser_22!  I had inadvertently entered into TurboTax that the IRA/SEP/SIMPLE box was checked when in fact it was not checked on the 1099-R and continued to overlook that I had checked the box.  That little oversight was what was causing the issue.  TurboTax now gives me the same numbers as I have calculated manually.  Thanks to you and all who provided comment to my question!

Solved in comments.