system
Given the following post, respond as if you're commenting on Reddit:
human
(DC) What if Superman was raised by Batman?

Bruce Wayne still goes about his career as Batman. He still has Nightwing (Though obviously under a different name) and still has Red Hood, Red Robin and Damian. However as he travels for Batman Inc, Kal-El's ship crashes before him. Bruce raises the alien child as his own. 

How different does Superman become?
gpt
The most important thing to remember is that despite how ruthless he can be, Bruce Wayne is also compassionate. He knows what it's like to be an orphan, and has helped guide orphans to adulthood before. 

Of course, an infant Kal-El is an entirely new ball game. Bruce probably brings him back to Gotham to get advice from Alfred. With Wayne Enterprises resources, they fabricate an adoption background and name him Clark Wayne. As they raise him in life of a "normal" billionaire, Lucius Fox is busy overseeing the reverse engineering of Kal-El's ship. 

Clark is probably raised half the time by Bruce and Alfred, and half the time by Alfred alone, since Bruce will still be busy with Batman, Inc. As he gets older, his abilities begin to manifest, and Bruce devotes more attention to him.

By the time he's 10, Clark has remarkable superhuman abilities, but Bruce and Alfred have successfully trained him to manage them. He's also comfortable living two lives. Publicly, he's the well-known but camera-shy celebrity adoption child of Bruce Wayne, and every kid wishes they had his life. He goes to the best private schools, has incredible teachers, and everything a child could want.

But privately, he's being raised by the members of Batman, Inc. and is eager to join the family business. Knowing his father, a normal human, is Batman, he's excited to find out just what he can do to help people. He insists on being trained like his father.

Bruce develops unique forms of martial arts that will allow Clark to use his Kryptonian abilities to perfection. But having learned of Kryptonite from Fox's efforts with the ship, the two agree that he can't simply depend on being powerful. They develop a training regimen that involves periodic exposure to Kryptonite, so that young Clark knows how to fight as a human and as a Kryptonian. Clark also probably spends a lot of with Oracle learning intelligence gathering. With super-hearing and x-ray vision, he's the perfect intelligence asset. 

I imagine that his debut as a crime fighter is a globally coordinated strike against organized crime. After years of investigation, Batman, Inc. strikes simultaneously around the planet against mobsters and supercriminals alike. Aryan Brotherhood, MS-13, the Yakuza, Italian and Russian Mafia, Chinese Triads, etc. all fold in a matter of hours. 

Likewise, Batman's arch-enemies, if currently loose, are rounded up. Traditional powerhouses like Killer Croc, Mr. Freeze, and Clayface don't pose the slightest challenge to Clark Wayne.