You can read President Trump's full proclamation regarding conditions of travel between the US and Schengen zone here. Nowhere in this proclamation is a mention of a quarantine.
However, several major news outlets seem to be reporting different (and contradictory) things.
Under President Donald Trump, the federal government has banned non-citizens from coronavirus-hit regions entry, but US citizens are allowed back into the country after a two-week quarantine.
Yet, CNN says
Returning travelers will be screened prior to entering the US and asked to self-quarantine for 14 days.
My question is, which is it? Will people exempt by the restriction face a mandated quarantine at the airport, or be told to self-quarantine? Nowhere in the official proclamation do I see mention of screening (which I am all for). If one of these people who is exempt from the restriction passes the screening (negative for the virus), are they free to go?