Asset Sales and Exit Activities	12 Months Ended
Asset Sales and Exit Activities	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset Sales and Exit Activities	Asset Sales and Exit Activities Enterprises In April 2019, DIG completed a sale of transmission equipment to ITC and recognized a pre-tax gain of $16 million within maintenance and other operating expenses on CMS Energy’s consolidated statements of income. Consumers Asset Sale: In September 2019, Consumers completed a sale of a portion of its electric utility’s substation transmission equipment to METC. In December 2019, Consumers filed an application with the MPSC requesting approval to share voluntarily half of the gain from the sale with customers. As a result, during 2019, Consumers recorded a regulatory liability of $17 million and recognized a pre-tax gain of $17 million within maintenance and other operating expenses on its consolidated statements of income. For additional details on the sharing of the gain with customers, see Note 3, Regulatory Matters. Exit Activities: Under its Clean Energy Plan, Consumers plans to retire the D.E. Karn 1 & 2 coal-fueled electric generating units in 2023. For additional details on Consumers’ plans to request recovery of the remaining book value of the two units upon their retirement, see Note 3, Regulatory Matters. In October 2019, Consumers announced a retention incentive program to ensure necessary staffing at the D.E. Karn generating complex through the anticipated retirement of the coal-fueled electric generating units. Based on the number of employees that have chosen to participate, the aggregate cost of the program through 2023 is estimated to be $35 million. Consumers will seek recovery of these costs from customers. In 2019, Consumers’ electric utility recognized $6 million related to retention and severance benefits within maintenance and other operating expenses on Consumers’ consolidated statements of income. The amount was reported as other liabilities on its consolidated balance sheets at December 31, 2019, which included $2 million of current liabilities.
Consumers Energy Company
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset Sales and Exit Activities	Asset Sales and Exit Activities Enterprises In April 2019, DIG completed a sale of transmission equipment to ITC and recognized a pre-tax gain of $16 million within maintenance and other operating expenses on CMS Energy’s consolidated statements of income. Consumers Asset Sale: In September 2019, Consumers completed a sale of a portion of its electric utility’s substation transmission equipment to METC. In December 2019, Consumers filed an application with the MPSC requesting approval to share voluntarily half of the gain from the sale with customers. As a result, during 2019, Consumers recorded a regulatory liability of $17 million and recognized a pre-tax gain of $17 million within maintenance and other operating expenses on its consolidated statements of income. For additional details on the sharing of the gain with customers, see Note 3, Regulatory Matters. Exit Activities: Under its Clean Energy Plan, Consumers plans to retire the D.E. Karn 1 & 2 coal-fueled electric generating units in 2023. For additional details on Consumers’ plans to request recovery of the remaining book value of the two units upon their retirement, see Note 3, Regulatory Matters. In October 2019, Consumers announced a retention incentive program to ensure necessary staffing at the D.E. Karn generating complex through the anticipated retirement of the coal-fueled electric generating units. Based on the number of employees that have chosen to participate, the aggregate cost of the program through 2023 is estimated to be $35 million. Consumers will seek recovery of these costs from customers. In 2019, Consumers’ electric utility recognized $6 million related to retention and severance benefits within maintenance and other operating expenses on Consumers’ consolidated statements of income. The amount was reported as other liabilities on its consolidated balance sheets at December 31, 2019, which included $2 million of current liabilities.