They got this down during the 90's. Cars like the EV1 and RAV4-EV had regenerative braking, with 4-wheel brakes. The electric motor can reclaim the energy when the car is braking from the drive wheels only. But brakes are still applied to all wheels just like in a normal car.
Think of it like using the engine to help brake your car you have now. You upshift, let out the clutch and the gas, and use the engine to slow your car down while you also apply brakes at the same time. In an EV, the car is basically doing the same thing, except the motor is reclaiming that energy instead of just wasting it.
The most ideal solution would be to use independent motors powering each wheel with each wheel also having brakes. That way you could use the motors for traction control in addition to drive and regenerative braking. But I'm expecting the Volt to have 4 disk brakes (or two front disk and two rear drums) with the front wheels supplying power and regenerative braking from one motor.
"The means of defense against foreign danger historically have become the instruments of tyranny at home." ~James Madison