The National Center for Education Statistics releases all IPEDS data through the Peer Analysis System (PAS).
The IPEDS PAS is located at http://nces.ed.gov/IPEDS/find_data/?frm=4.
The University of Illinois campuses are:
University of Illinois University Administration - Institution ID 149587
University of Illinois at Chicago - Institution ID 145600
University of Illinois at Springfield - Institution ID 148654
University of Illinois at Urbana-Champaign - Institution ID 145637