A powertrain system for a vehicle is described, and includes an internal combustion engine mechanically coupled to an electric machine to generate propulsion torque and electric power storable on an energy storage device. A method for controlling the powertrain system includes determining a first desired powertrain output power associated with a road load and determining a second desired powertrain output power associated with a feed-forward state-of-charge (SOC) for the energy storage device. The internal combustion engine and the electric machine are controlled responsive to the first and second desired powertrain output powers.