It depends how big you need a "field" to be. Much of philosophical logic split off to become mathematical logic (split complete by about 1930). That left the philosophers pondering things like entailment, tense logic, modality, epistemic logic, etc. But around 1960, Kripke put that stuff on a solid basis, and these kinds of logics are now an important topic in computer science. Certainly utility theory, decision theory, and subjective probability have only come over from philosophy (to econ, math, and AI) within the past 150 years. And there are still philosophers involved at the forefront of all these fields.