  We calculate the massive Wilson coefficients for the heavy flavor
contributions to the non-singlet charged current deep-inelastic scattering
structure functions $F_L^{W^+}(x,Q^2)-F_L^{W^-}(x,Q^2)$ and
$F_2^{W^+}(x,Q^2)-F_2^{W^-}(x,Q^2)$ in the asymptotic region $Q^2 \gg m^2$ to
3-loop order in Quantum Chromodynamics (QCD) at general values of the Mellin
variable $N$ and the momentum fraction $x$. Besides the heavy quark pair
production, also the single heavy flavor excitation $s \rightarrow c$
contributes. Numerical results are presented for the charm quark contributions
and consequences on the unpolarized Bjorken sum rule and Adler sum rule are
discussed.
