It's regional accreditation that matters. The national accreditation by DETC for undergraduate degrees doesn't mean anything in this context; it's a solid baseline for online institutions, but it's the regional accreditation that matters.
A four-year degree from a regionally accredited institution is generally required for new officer accession programs by all of the military services. Most government agencies and employers that look at accreditation on undergraduate degrees are looking for regional accreditation. It might seem that national accreditation is "better" than regional, but for undergraduate degrees, regional accreditation is the benchmark. There are six regional accreditors that have historically performed this role, and that's still how it stands today. For graduate and professional degrees, there are speciality nationwide accreditors, and there are national accreditors for some undergraduate professional paths, too. But again, it's the regional accreditation that matters.
And if that isn't enough information for you, I finished my undergraduate degree with American Military University, and am currently finishing a graduate program through AMU as well. I just was just selected in September for a direct commission as an Information Warfare Officer. So the Navy definitely has no problem with AMU, nor with degrees from online institutions as long as the degree is regionally accredited.
