You don't need $250B for "safety". Apple needs maybe $50B tops. If it has a bad year it's going to slash spending. It's got professional management that know pretty much how much it will make in a quarter and how much it can spend. It also has access to further financing, both debt and equity.

Repatriate the $250M, payoff the $78M in debt, and pay out at least $100M to shareholders. Apple will have over $100M in cash again by the end of the year.