I understand the purpose of a fair value hedging instrument (preserve the fair value of an asset, liability, etc) and a speculation derivative (default classification if the derivative isn't documented as hedge accounting derivative). Please correct me if I'm wrong.
What I don't understand is the difference at the accounting level. As far as I understand, they both are valued at fair value (mtm) and the differences of mtm between financial statements are reported in the company results. So, If they have the same accounting effects, Why would I bother to do all the documentation and effectiveness tests?
I'm quite new to this topic, and I'm learning it in Spanish, please let me know if I'm using wrong words.