There's a bit more to consider to be able to answer your question about the taxable amount. Having the taxable amount unknown is very common for a traditional IRA because the investment company doesn't have information about your tax return and your basis in the plan.
They don't know the amounts you've taken deductions for in the past (decrease basis) or if contributions weren't allowed to be deducted (increase basis). If it's a Roth IRA there's no deduction amount, but nothing is taxable when you take out, unless you haven't met the 5 year investment period.
However, when you enter your form 1099-R, the software will ask you a series of questions. Answer these questions carefully and the software will determine the taxable amounts. When you complete entering all of your form 1099-Rs, be sure to continue through the entirety of the section. If a distribution is taxable, the software will ask you about the exceptions for withdrawing here and will include the exception to withdraw to buy a home.
You can preview your 1040 at any time to see how the software is treating the distributions and deductions by following the steps below: https://ttlc.intuit.com/replies/3302322
