From the Document: "The Department of the Navy (DON) is a single military department that includes two military services--the Navy and the Marine Corps. As such, DON has a single civilian leader, the Secretary of the Navy, and two four-star military service chiefs--an admiral whose title is the Chief of Naval Operations (CNO), and a general whose title is the Commandant of the Marine Corps. Although the title 'Secretary of the Navy' includes only the term 'Navy,' the secretary serves as the civilian leader for both the Navy and Marine Corps. The CNO and the Commandant of the Marine Corps are members of the Joint Chiefs of Staff (JCS). [...] Although the term 'naval' is often used to refer specifically to the Navy, it more properly refers to both the Navy and Marine Corps, because both the Navy and Marine Corps are naval services. [...] DON's proposed FY2022 budget requests $211.7 billion, of which, DON states, $163.9 billion (77.4%) is for the Navy and $47.9 billion (22.6%) is for the Marine Corps. In terms of appropriation groups, about 26.7% is for military personnel, about 33.6% is for operations and maintenance, about 27.5% is for procurement, about 10.7% is for research and development, about 1.4% is for infrastructure, and about 0.1% is for revolving and management funds."
CRS In Focus, IF10484
Congressional Research Service: https://crsreports.congress.gov/