Superman defeats Mageddon, the primordial annihilator via absorbing its anti-sun core which negates his own energy and is complely fine while overcoming its telepathy.
Just how powerful was Mageddon? It was powerful enough to force the angels of Pax-Dei to create a new universe because it was going to destroy this universe.
The whole of humanity gets the powers of superman.
Mageddon was killing thousands of these supermen with each blast and would've killed whole of humanity in minutes according to batman.
Here is one more thing about this feat. Oracle notes that the Mageddon anti sun was going hypernova.
A hypernova only occurs in the stars at least 30 times more mass than Earth's sun and this anti sun must have been even more huge so to destroy half the galaxy.
https://www.quora.com/What-is-a-hypernova-explosion
And here the anti sun goes off as Orion says the detonation has been done. Superman actually tanks it and absorbs all the energy.
Confirmed in DC encyclopedia.
https://static.comicvine.com/uploads/original/11133/111332122/6131512-rco192_1473735651.jpg
And JLA secret files 3.
https://static.comicvine.com/uploads/original/11133/111332122/6131513-jla_secretfiles_003_33.jpg
That cheeky Grant Morrison.