CMS Energy was formed as a corporation in Michigan in 1987 and is an energy company operating primarily in Michigan. It is the parent holding company of several subsidiaries, including Consumers, an electric and gas utility, and CMS Enterprises, primarily a domestic independent power producer and marketer. Consumers serves individuals and businesses operating in the alternative energy, automotive, chemical, food, and metal products industries, as well as a diversified group of other industries. CMS Enterprises, through its subsidiaries and equity investments, is engaged in domestic independent power production, including the development and operation of renewable generation, and the marketing of independent power production.
CMS Energy manages its businesses by the nature of services each provides, and operates principally in three business segments: electric utility; gas utility; and enterprises, its non‑utility operations and investments. Consumers' consolidated operations account for the substantial majority of CMS Energy's total assets, income, and operating revenue. CMS Energy's consolidated operating revenue was $6.9 billion in 2018, $6.6 billion in 2017, and $6.4 billion in 2016.
For further information about operating revenue, income, and assets and liabilities attributable to all of CMS Energy's business segments and operations, see Item 6. Selected Financial Data and Item 8. Financial Statements and Supplementary Data-CMS Energy Consolidated Financial Statements and Notes to the Consolidated Financial Statements.