Legal Question in Real Estate Law in Illinois

Assuming the line was there when you moved to the house and there is no recorded easement for your subdivision that grants specific rights and obligations to the utility company, the utility company already had an easement from its utility poles for the line strung to serve your neighbor's house. The utility company has a right (and obligation) to maintain the easement "in the air" meaning if it has to temporarily remove the line to clear the tree, it can do so. But the easement belongs to the utility company, and their only right and responsibility is to put the line back up when they're done, in the same place. So if it would cost money to move the line so it doesn't overhang your property, they are giving you that option but at your cost. You might ask your neighbor to go in 50/50 with you, but otherwise the utility company is not required to move its line if it costs extra to do so even if it would be "convenient" for you.