This is a blog post (click here) about it, but, the law itself is very different from "The Federal Records Act."
Presidential documents (click here) are historical resources that capture each incumbent’s conduct in presidential office. Pursuant to the Presidential Records Act ((PRA) 44 U.S.C. §§2201-2207), the National Archives and Records Administration (NARA) collects most records of Presidents and Vice Presidents at the end of each Administration. They are then disclosed to the public—unless the Archivist of the United States, the incumbent President, or the appropriate former President requests the records be kept private....
The records of the cabinet offices will intersect with the PRA (Presidential Records Act). The law that protects the President's records would override any other legal statute of the government.
The PRA is very clear in it's definition, his cabinet is part of the Executive Branch that advises the President among it's other duties. I am fairly certain the PRA comes to bear with any cabinet Secretary communications.
Not to say the cabinet doesn't keep their own records to function, but, as to emails that is part of the Executive Branch and not the Legislative Branch. President Obama amended the law, too.
Additionally, I think it is questionable as to whether the Legislative Branch can constitutionally order the handling of documents of the Executive Branch, hence the SEPARATE laws.
The actual law of the PRA is clear. (click here)
As used in this chapter--
(1) The term "documentary material" means all books, correspondence, memoranda, documents, papers, pamphlets, works of art, models, pictures, photographs, plats, maps, films, and motion pictures, including, but not limited to, audio and visual records, or other electronic or mechanical recordations, whether in analog, digital, or any other form.
(2) The term "Presidential records" means documentary materials, or any reasonably segregable portion thereof, created or received by the President, the President’s immediate staff, or a unit or individual of the Executive Office of the President whose function is to advise or assist the President, in the course of conducting activities which relate to or have an effect upon the carrying out of the constitutional, statutory, or other official or ceremonial duties of the President. Such term--...
