The answer is...sort of. If you don't major in engineering, you will essentially minor in engineering because of the requirement to take engineering courses. However, it is not called a minor. I haven't looked at my transcripts but I don't think they reflect it as a minor. Back in the day, it used to be more of "minor" because it was a 5-course engineering track. It's now a 3-course track, IIRC. Perhaps a cadet can verify.
You can, however, double major. Majoring in engineering pretty much guarantees that you won't have space for anything else. Many top
engineering schools take 5 years to teach you what USMA must teach you in 4 years. We always pitied the engineering majors.