Only 43B in USA. That is total of just 10% of float if they spent every penny of it. Only 10 bucks per year in EPS coming in. that would buy back 1/46th of the stock if they spent every penny of that cash flow which is about 2%. So your 12% per year does not work.
Overseas cash would lose 1/3 of the 90B reducing it to 60B and they will NEVER bring it back to USA and take that hit.