Records of the Legislature are exempt. G.L. c. 66, § 18; Westinghouse Broadcasting Co. v. Sergeant-At-Arms of Gen. Court of Mass., 375 Mass. 179, 184, 375 N.E.2d 1205 (1978) (telephone billing records of Legislature not “public records” subject to disclosure, because Legislature is not “agency, executive office, department, board, commission, bureau, division or authority of Commonwealth).