We report measurements of branching fractions and time-dependent CP asymmetries in $B^{0} to D^{+}D^{-}$ and $B^{0} to D^{*pm}D^{mp}$ decays using a data sample that contains $(772 pm 11)times 10^6 Bbar{B}$ pairs collected at the $Upsilon(4S)$ resona
nce with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We determine the branching fractions to be $mathcal{B}(B^{0} to D^{+}D^{-})=(2.12 pm 0.16 pm 0.18)times 10^{-4}$ and $mathcal{B}(B^{0} to D^{*pm}D^{mp}=(6.14 pm 0.29 pm 0.50)times 10^{-4}$. We measure CP asymmetry parameters $mathcal{S}_{D^{+}D^{-}} = -1.06_{-0.14}^{+0.21} pm 0.08$ and $mathcal{C}_{D^{+}D^{-}} = -0.43 pm 0.16 pm 0.05$ in $B^{0} to D^{+}D^{-}$ and $mathcal{A}_{D^{*}D} = +0.06 pm 0.05 pm 0.02$, $mathcal{S}_{D^{*}D} = -0.78 pm 0.15 pm 0.05$, $mathcal{C}_{D^{*}D} = -0.01 pm 0.11 pm 0.04$, $Deltamathcal{S}_{D^{*}D} = -0.13 pm 0.15 pm 0.04$ and $Deltamathcal{C}_{D^{*}D} = +0.12 pm 0.11 pm 0.03$ in $B^{0} to D^{*pm}D^{mp}$, where the first uncertainty is statistical and the second is systematic. We exclude the conservation of CP symmetry in both decays at equal to or greater than $4sigma$ significance.
