Is there a way to automatically import ALL the data I entered last year for my 2017 federal taxes into Turbo Tax 2018 so I can see if I'm really getting a tax cut?

You didn't indicate what TurboTax product you are using. If you are using the CD/Download TurboTax software, select Tax History on the Tools menu for a quick graphical comparison. For a more detailed comparison, switch to forms mode and look for the Two-Year Comparison in the forms list on the left side, near the end of the federal return.

I don't know if the Two-Year Comparison is available in TurboTax Online. If it is, it would be in the PDF when you print your return and select the option to include all worksheets.

And if you used Turbo Tax for 2017.  Or did you use something else?  If you used Turbo Tax it should have automatically Transferred from 2017.  

I want to run my 2017 Turbo Tax Deluxe data through 2018 Turbo Tax Deluxe to see what my 2017 tax would have been using the new 2018 tax code rules.  This will tell me if the new tax code gives me a tax cut or tax increase. Unfortunately I'm guessing increase.

If you are using the Desktop CD/Download program you can start a new return and manually enter your 2017 info like it was 2018.  Be sure to name it something you can tell what it is, like 2017 TEST.  

For Online you could set up a new account and enter it in.  You wouldn't have to pay unless you wanted to print or save it.  

You still haven't told us what TurboTax product you are using. There's no way to literally run the 2017 data through the 2018 program. But if you are using the CD/Download software, you can probably accomplish what you want quickly and simply by using the What-If Worksheet in the *2017* software. Go to forms mode and open the What-If Worksheet. Column 1 is your 2017 data. Check the box at the top to copy column 1 to column 2, and check the box at the top of column 2 to use 2018 tax rates.