Best there is: "Reverse Input Protection to –60V". In the meanwhile, ISO 7637-2-2011 talks about -220V spikes...
BUT(2)!
Such bidirectional TVS on input makes me think the thing can actually do -220V as well, as long as the TVS diode can handle the energy left after spike has been clamped:
I already?...

It's a low energy pulse! It's not plugging into the wall, a TVS is fine!
Sort of like this ? I think 47k resistance should be fine for Q3. V_z = 20V as Q3 will likely have Vgs_max at that point.
Uh, check the drain current before you wire that up...
Also, you've already got a 6.8V zener in there, why not like...
...Or you didn't understand the choice of that, before, either, but, why not ask instead of, I guess copy-pasting something else--?
Perhaps, I've overestimated your level; these examples seem roughly reasonable, but then your understanding of them seems quite lacking. Should this [subthread] actually be in the beginner section, say?
Not to belittle you, mind -- well, admittedly, maybe a little bit, in as much as giving a bite for this apparent discrepancy

-- but still not much, after all, fake it long enough, you will eventually make it!

-- but just from the point of: if you have a particular, immediate need, then please lay out those requirements, and let someone solve it for you, don't worry about understanding it; or if you have a general need for which understanding and knowledge is required, then show us where to start from and we can build upon that.
And these are not exclusive options [practical vs. theoretical], the one can motivate the other; but make it clear what your aim is, and be open to examples alongside, but different from, your particular need, as a means of illustrating how the outputs (component choice, values, topologies) can vary with the inputs (requirements).
Or more generally still: learning how to learn. Use your existing knowledge to guide the acquisition of new knowledge. This circuit could be discussed top-down (it has to do X, Y and Z, using T, U and V components in the process; which in turn operate as....), or bottom-up (we're inevitably going to need diodes, transistors, etc., and they operate in this and that way....), or anything inbetween. Figure out what works for you and guide the conversation as best suits you.

Cheers!
Tim