Casualty Loss Carryback before or after $100?

Casualty/Theft Loss (personal) on Sch A $100,000 less $100 = $99,900
AGI already below zero ($15,000), so no 10% haircut.
So Casualty/Theft Loss is to be carried back 3 years.
Would one carryback the $100,000 amount or the $99,900 ?

99,900.