I am a proponent of interdisciplinary training, but I am not a proponent of ad hoc degrees. You're better off getting a degree in a well-established major and taking electives in other programs. Employers have at least an approximate baseline reference of what to expect from a candidate with a masters in a well-established major. But what would they expect from a candidate with a masters in interdisciplinary engineering? Would hiring managers skimming through a stack of resumes take the time to find out? More to the point, in many organizations, initial filtering of resumes is done by HR, often via software searching for a match for specific degrees or work experience. "Interdisciplinary engineering" would not likely pass through the filter (perhaps if the filter is set broadly for "engineering", rather than more narrowly, for, e.g., "electrical engineering", "mechanical engineering", or "aerospace engineering").