Repair crews have restored power for about 300,000 Commonwealth Edison customers, but the utility is still working to get the lights back on for about 48,000 customers in northern Illinois.
ComEd spokesman Tony Hernandez says most of the remaining outages should be fixed by Wednesday but a few customers will remain without service until Thursday. Hernandez says that's because repair crews are having to remove the downed trees from Sunday's storms before repairing the damaged ComEd equipment.
ComEd's repair crews are getting help from other utilities, including Ameren Illinois and Ameren Missouri.
Hernandez says about 440 ComEd crews are working to restore service, with the help of about 180 crews from neighboring utilities. And he says more help will arrive Wednesday.