Johns Hopkins Medicine, Health Systems & Hospital. * Chairman, Johns Hopkins Medicine, Health Systems and Hospital --July 2005 to present. * Chairman, Comcast Corporation -- 2002 to 2004. * Chairman and Chief Executive Officer, AT&T Corp. -- 1997 to 2002. * Chairman and Chief Executive Officer, Hughes Electronic Corporation -- 1992 to 1997. * International Business Machines Corporation -- 1961 to 1992. Member, IBM Management Committee. Chairman, IBM World Trade Corporation. * Director of Citigroup (or predecessor) since 1989. * Other Directorships: IHS Inc. (Lead Independent Director), and The Parsons Corporation. * Other Activities: Johns Hopkins University (Vice Chairman), President's Export Council (Chairman, Retired), Council on Foreign Relations (member), MIT Sloan School of Management (Visiting Professor), Telluride Foundation (Director), and Miami University, Corporate Campaign (Chairman).