In general, idiomatic usages are more frequent, but for some expressions the literal meaning may be more common (Li and Sporleder, 2010a).
there are two fundamental tasks in NLP idiom processing: idiom type classification is the task of identifying expressions that have possible idiomatic interpretations and idiom token classification is the task of distinguishing between idiomatic and literal usages of potentially idiomatic phrases (Fazly et al., 2009).