It looks to me like long term the USD is pegged to the Yen, also the Canadian even the AUD and the NZD. The GBP and the EUR and CHS all go opposite.

The Dollar I believe has been pegged to the Chines Yuan (allowed to fluctuate very little) I assume to protect the US companies that off shored there.

https://finviz.com/futures_charts?t=CURRENCIES&p=m