At typical intra-cluster distances of 1 Megaparsec–3×10^24 cm, a magnetic field of that strength has about 10^61 ergs of energy. That’s about the total energy output of a galaxy like the Milky way for a few billion years. Equally important, the velocity such a field can impart to plasma of the density of intra-cluster gas is quite comparbale to the velocites galaxies move at.
