I fully agree with @KateGregory 's answer which covers your question quite thoroughly - I just want to provide another perspective to this toxic workplace situation in case it doesn't get resolved to your liking and you consider leaving:
IANAL, but depending on the country and your local laws (you might want to add a country/location tag for clarification), swearing and calling someone names (especially in front of other people/public) can be seen as 'honorable insult' in front of a court. In AUT for example we have a pragraph for that (§ 115 StGB). Such laws exist in most european countries.
Here's a rough translation of § 115 StGB
(1) Anyone who publicly or in front of several people abused, ridiculed, maltreated or threatened with physical abuse in public or in front of several people is, if he is not threatened with another provision of more severe punishment, imprisonment up to three months or fine up to 180 To punish daily rates.
(2) An act is committed in front of several people if it is committed in the presence of more than two perpetrators and attacked by different people and they can be perceived.
(3) Anyone who gets carried away by indignation at someone else's behavior, insulting, taunting, maltreating or maltreating him in a way that is excusable, is excused if his indignation, especially in regard to his time elapsed, is generally comprehensible.
This should be definitly the last resort - but since your manager is insulting and verbally abusing you ("..I was immediately snapped at and called an idiot") you might have a strong case here in front of a judge..
