  We show that in clean chaotic cavities the power of shot noise takes a
universal form. Our predictions go beyond previous results from random-matrix
theory, in covering the experimentally relevant case of few channels. Following
a semiclassical approach we evaluate the contributions of quadruplets of
classical trajectories to shot noise. Our approach can be extended to a variety
of transport phenomena as illustrated for the crossover between symmetry
classes in the presence of a weak magnetic field.
