My record is 13 hours stuck in traffic after an ice storm knocked down trees and power lines all the way home, about 20 degrees outside.
I idled the whole time to keep the heat on.
I started with about 3/4 tank and finally got home with about 1/8 tank.
Based on your experience, perhaps 24 hours of run-time is not out of the question if the engine was run a while, and turned off for a while. A car is not usually thermally insulated well so it would get uncomfortable real quick in extreme cold with no engine generated heat.
I suppose people that routinely drive in snow or cold weather always carry an emergency kit with blankets, food, water, and chemical hand warmers for just such an occasion.