As the OP wrote, this is only for 1-3 years, not a job offer.

What usually happens in such big companies is that you might have to work in another country for the same company of a couple of years. Big but is that you go there as an employee of the source country taking with you the respective salary and not that of the destination country. They usually pay for the fixed expenses, eg. accommodation and even might have an allowance for the daily expenses but depends on the company and still it might not be enough to make it with your salary.

Also you don't really have an option to decline, you are up next then for dismiss and in many countries it is not that easy to find a similar job etc. etc.