The relationship between an idiomatic phrase and a literal phrase is best described by the statement: an idiomatic phrase presents non-literal language that influences the connotation of the literal phrase.
In this context, idiomatic phrases often carry meanings that are not directly derived from the individual words, whereas literal phrases convey straightforward, direct meanings. The idiomatic phrases can enrich or alter the emotional or contextual understanding of the literal phrases, impacting their connotation.