StellarConservation of Charge
Just like mass, charge is a conserved quantity. This means that in a closed system, its net charge will remain the same, and in an open system, a change in charge in the system must mean an equal and opposite change in charge in the environment.
However, the arrangement of charge in a system can change. A system may become polarized and have its charges separated. Even if the system is polarized, its total charge will still be the same before and after as long as no charge was exchanged between the system and the environment.