I think that god has complete control over everything except the devil, I think that because the devil was an angel and operates completely outside gods laws and rules and has his own collection of minions, souls and a home base and because he is not human that god does not have complete control over satan. I think that he is stronger than satan and can defeat him in battle but I don't think he has enough power over the devil to just make him release the souls in hell. I am probably wrong though, god is god, as it says in the bible his ways are not my ways and his thoughts not my thoughts. just as the thoughts and ways of a cow are not the thoughts and ways of a human. Who knows why he lets the devil stick around.