Asset Sales - Schedule of Assets Held For Sale (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total assets	$ 39	$ 0
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant, property, and equipment, net	34
Construction work in progress	5
Total assets	39
Consumers Energy Company
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total assets	35	$ 0
Consumers Energy Company | Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant, property, and equipment, net	30
Construction work in progress	5
Total assets	$ 35