Defense Primer: Intelligence Support to Military Operations [Updated December 30, 2020] [open pdf - 481KB]
From the Document: "The bulk of the 'Intelligence Community' (IC), eight of 17 total elements, resides within the Department of Defense (DOD). This includes the National Security Agency (NSA), Defense Intelligence Agency (DIA), National Geospatial-Intelligence Agency (NGA), and the intelligence components of the Navy, Army, Marines, and Air Force. Non-DOD IC elements, however, also provide support to the military. Integrated IC support of the military includes strategic, operational, and tactical intelligence activities, products and services that are necessary for military strategy, planning, and operations."
CRS In Focus, IF10574
Congressional Research Service: https://crsreports.congress.gov/