The NuTeV experiment at Fermilab has obtained a unique high-statistics sample of neutrino and antineutrino interactions using its high-energy sign-selected beam. We present a measurement of the differential cross section for charged-current neutrino and antineutrino scattering from iron. We determine the relative (nu) over bar to nu cross section, r=sigma((nu) over bar)/sigma(nu), at high energy with errors a factor of 2 smaller than the previous world average. Structure functions, F-2(x,Q(2)) and xF(3)(x,Q(2)), are determined by fitting the inelasticity, y, dependence of the cross sections. This measurement has significantly improved systematic precision as a consequence of more precise understanding of hadron and muon energy scales.