I am trying to determine if will I be able to deduct my mortgage interest in 2018 and beyond if I do not itemize deductions?
No, you will still have to itemize to deduct mortgage interest. Most other itemized deductions are disappearing, however, so it may be that, with the higher standard deductions, your mortgage interest may not be enough to make all your itemized deductions larger then the new standard deductions. In that case, you will use the standard and lose your mortgage interest.
So far they have not. Mortgage interest is still deductible-=but the deduction is much harder to get because of the higher standard deductions.
Your itemized deductions have to be more than your standard deduction before you will see a change in your tax owed or tax refund. The deductions you enter do not necessarily count “dollar for dollar;” many of them are subject to meeting tough thresholds—medical expenses, for example, must meet a threshold that is pretty hard to reach. The software program uses all the IRS rules that apply to the expenses you enter, and it tells you if you have enough to use your itemized deductions or if using the standard deduction is more advantageous for you. Under the new tax laws, some deductions have been capped—there is a $10,000 limit to the itemized deductions for state, local, property and sales taxes.
Your standard deduction lowers your taxable income. It is not a refund
2018 Standard Deductions:
Single $12,000 (+ $1600 65 or older)
Married Filing Separately $12,000 (+ $1300 65 or older)
Married Filing Jointly $24,000 (+ $1300 each spouse 65 or older)
Head of Household $18,000 (+ $1600 65 or older
Look at line 8 of your Form 1040 to see your standard or itemized deductions.