A multi-mode transmission for a powertrain system includes a high-voltage electrical system with a high-voltage battery and high-voltage electrical bus coupled to a power inverter electrically coupled to torque machines configured to transform electric power to torque. A method for controlling the multi-mode transmission includes monitoring voltage and current on the high-voltage electrical bus, and estimating electric power limits for the high-voltage electric bus including a constrained battery power command based upon a total motor torque electrical power for the torque machines. Torque commands for the torque machines are constrained in response to the estimated electric power limits for the high-voltage electric bus. Operation of the torque machines of the multi-mode transmission is controlled in response to the torque commands for the torque machines.