USAA does offer major medical through a 3rd party. Google "USAA medical insurance." Also dental and vision, 3rd party. Its focus is primarily auto, property, banking, investing, financial advice, for active duty, Reserve, Guard, veterans and their families (spouse and children), wherever they serve. USAA is not publicly traded; employees don't work on commission. As an Association, it is not an all-comers company. USMMA midshipmen are eligible for all, same as other 4 SAs.
Usual caveat when I say something about them: I work for them, but not licensed. I post on here in a personal capacity.