The full record information may contain the following information (not every record includes all this information):
Number, Date of Report, Name, Gender & Color, Age at Death, Occupation, Date of Death, Marital Status, Nationality, Where Born, Length of Residency in Illinois, Place of Death, Cause of Death, Complication, Duration of Disease, Place of Burial, Date of Burial, Name of Undertaker, Place of Business, Name and Address of Physician.
Also, the state recommended records of deaths be kept in 1877, but it did not become a requirement until 1916 so many deaths were not recorded.
The LDS microfilm of the full record information is on permanent loan at the Family History Center in O'Fallon IL, and the film can be rented from any other Family History Center.