Idim vs Phraseological Unit

Hi.
I have a question.. who can explain me the difference between Phraseological Unit and Idiom.. is it the same or not.. may be, you have some theory on it.. or what different linguist say about it..
Beause I think, I have mixed everything

[Noego]

Phraseology (n.):
" The way in which words and phrases are used in speech or writing; style."

From Wikpedia:

"In linguistics, phraseology describes the context in which a word is used. This often includes typical usages/sequences, such as idioms, phrasal verbs, and multi-word units. Phraseological units are (according to Prof. Kunin A.V.) stable word-groups with partially or fully transferred meanings (e.g., "to kick the bucket")."

I don't have any more time just now, but I'm sure one of our experts in linguistics can lend you a hand.