The present paper unifies some aspects concerning the vertical Liouville distributions on the tangent (cotangent) bundle of a Finsler (Cartan) space in the context of generalized geometry. More exactly, we consider the big-tangent manifold T M associated to a Finsler space (M, F ) and of its L-dual which is a Cartan space (M, K) and we define three Liouville distributions on T M which are integrable. We also find geometric properties of both leaves of Liouville distribution and the vertical distribution in our context.