Are you preparing your 2016 return? If not, I don't understand why this is coming up now.
Any payment in excess of cost basis is taxable capital gains. If you didn't fill out the casualty loss section, the income is still considered a taxable gain that would have to be reported on schedule D.
For personal property, your basis is what you originally paid. There's no adjustments, but the more you can do to accurately prove a higher cost for your personal items, the smaller the gain.
For your home, there are two provisions that will help you.
First, if you were using the home as your main home for at least 2 of the past 5 years, you can exclude the first $250,000 of gain if you are single, or $500,000 of gain if you are married filing jointly, the same as if you sold the house. (There are some limitations and adjustments if you used part of the house for business or a rental in the past.) Gain over the exclusion amount is taxable.
Second, you can reduce your gain by carefully documenting your adjusted cost basis. Your adjusted cost basis is the original purchase price, plus certain closing costs, plus the cost of any permanent improvements you made to the home, such as a new roof, addition, remodeling and so on. Basis adjustments are described on page 8 here. https://www.irs.gov/pub/irs-pdf/p523.pdf
If the program asks for the purchase price of the home, enter the adjusted basis instead. That may reduce your taxable gain.
If you were not claiming a casualty loss, you would report this under "Sale of my home" and use the insurance proceeds as the selling price, and the date of the fire as the date of sale. The program will give you the 250/500 exclusion if you qualify.
I'm not sure how the casualty loss section will interact with the home sale interview. Someone else might have additional advice. Or you could seek a professional to review your situation.
@dmertz @macuser_22
