At the peak of the outages, nearly 140,000 customers were affected by the storms that blew across northern Illinois early Sunday.
The city of Chicago and its near-west suburbs were among the hardest hit by the lightning and 65 mile-per-hour winds.
National Weather Service meteorologist Casey Sullivan says the agency received reports of quarter-sized hail.
It was the fifth time storms had damaged ComEd's power grid in a ten-day period.
