I don't understand the "Less: Arizona Subtractions" line on the sheet "Your Arizona Bottom Line". It states $2,734,090. What is this and how can it be so much?

"Less: Arizona Subtractions" refers to items that are taxed on the federal return but which are not taxable in Arizona. That is, they are reductions to Arizona income.

A number of the screens prior to this point can affect your Arizona subtractions, although many of them are done automatically by TurboTax (such as removing taxable Social Security income).

Go back to the screen labeled "Any Other Subtraction Adjustments?" and click "yes". Do you see an adjustment there that doesn't make sense?

Note that you can deduct certain items in Arizona like all medical expenses (not just that which is in excess of 7.5% of your AGI like on the federal return).

Alternatively, if you can't locate the culprit, you might try deleting the state return and re-adding it to force a fresh start.