Something like 25% of the headcount is going to be outsourced. This is across fabs, products, and support groups. Some support groups will be fully outsourced, with massive badge flipping elsewhere.
Production is about half of the total headcount, and at least 2 or 3 fabs will be sold to another foundry. That will be another 10%-15% of total headcount.
Non-EUV fabs won't ever be retrofitted and are quite busy making 10nm and 7nm, so at peak valuation and that makes this the right time to sell them, then buy back the wafers from the acquiring foundry.
Non-core or non-performing products will be in either sold or shut down, and that is somewhere in the range of 5% of total headcount.
This adds up to at least 40% of the current headcount, over the next few years.
So in reality this is just the start of the savings, with many billions to be saved per year yet to come.
Bumping this from @az+1jzsy3kjy for info.