Thirty-eight main ideas and practices long identified with public utility regulation were identified and grouped into concepts; twelve as propositions, and twelve as doctrines. Each of the items in the groupings was judged to determine which were casualties, survivors, or modifications. A doctrine that became a casualty of deregulation and reregulation is the clear bright line in dual regulatory jurisdiction. Surviving doctrines include public interest theory, fairness and equity, judicial review, rate base regulation, and prudence tests, while doctrines that have been modified include regulatory bargain, incentive regulation, universal service, and proxy for competition. 36 footnotes.