For other currencies, sell stocks, get USD, sell USD to buy currencies appreciating over the USD.
It's already happening, past 6 months USD has been losing value against EUR, CHF, GBP, even BRL and almost flat against the JPY which was losing a ton of value the past years.
based on my understanding of what all the financial pros are saying: they'll never let that happen. they'll inflate away to the moon before they allow for a deflationary bust. that's why everyone's in equities in the first place. it's almost insured, at this point.