The subdomain structures of lamellar and reverse hexagonal phases of P84/water/p-xylene ternary system have been investigated by contrast varied small angle neutron scattering (SANS) measurements. As the neutron scattering length density of either polar or apolar domain was varied, the scattering intensities of the first Bragg peaks changed as expected, but the intensities of the second Bragg peaks did not change significantly. This variation of the relative peak intensities can not be explained by the typical simple models where the polar and apolar domains are regarded as homogeneous mixtures of PEO + water and PPO + oil, respectively, in which case the relative intensities of Bragg peaks do not change. For both lamellar and reverse hexagonal Pluronic ternary systems, the analysis of the contrast varied SANS intensities with subdomain structure models reproduce the experimental data very successfully, showing that a water-rich layer exists in the middle of the polar domain and water- and oil-depleted layers exist at the polar/apolar interfaces.