This is going to vary substantially depending on where you are in cook county and the type of dwelling (condo, multi unit, single family home.)
You can find a lot of key stats at the website: http://www.city-data.com.
As far as electrical and heating cost goes, utilities generally provide a disclosure for the most recent year of billing. This can be requested when you are purchasing a home. It is required in the city of Chicago, I am unsure about Brookfield. I know ComED is the provider for electric, and I believe NICOR is for gas.
Heating cost will vary by size of the dwelling, insulation ratings, mechanical system type and efficiency, etc.
Tax data will vary by property, but you can get tax info from the cook county assessor.
Insurance is much more predictable. The average single family home will range from $750-1300 depending on coverage amount and type. Typically condos include hazard insurance in their assessments, but you can still purchase a policy to cover the possessions in the unit.
Best of Luck.
Electric inquiries ARE with ComEd- 1-800-EDISON-1.
Gas inquiries ARE with NiCor- 1-888-NiCor-4-U.
I hope this helps a little... (smile). Good luck, Jeff.