Does your Form 1099-R have code G?
If yes then you should see these follow-up questions after you enter your Form 1099-R:
TurboTax will know this was a rollover because of the code G.
Please be aware that the whole distribution will show as income in TurboTax on the summary screen which shows gross income, not taxable income. To verify that the entry is correct please look at form 1040 line 5b (taxable amount), it should show $0 and state ROLLOVER next to it.
To preview Form 1040 in TurboTax Online: