What city is "RoboCop" set in?

"RoboCop" dropped audiences into a nightmare (and totally unrealistic) version of America where corporations run everything, crime is completely out of control, and the only solution involves turning a dead cop into a cyborg law enforcement machine. Director Paul Verhoeven needed a real American city that would make the movie's brutal satire feel uncomfortably real. What city serves as the setting for "RoboCop"?