detail vs expatiate

detail is a noun but expatiate is not a noun.

Word	Noun	Adjective	Verb	Adverb
detail	Yes	No	Yes	No
expatiate	No	No	Yes	No

As verbs, expatiate is a hypernym of detail; that is, expatiate is a word with a broader meaning than detail:

detail: provide details for
expatiate: add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing

Other hypernyms of detail include dilate, elaborate, enlarge, expand, exposit, expound, flesh out, lucubrate.

detail (noun)	expatiate (noun)
an isolated fact that is considered separately from the whole
extended treatment of particulars
a temporary military unit
a crew of workers selected for a particular task
a small part that can be considered separately from the whole

detail (verb)	expatiate (verb)
assign to a specific task	add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing
provide details for