Regulatory Matters (Schedule Of Assets and Liabilities for PSCR And GCR Over/(Under) Recoveries) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Public Utilities, General Disclosures [Line Items]
Accrued rate refunds	$ 12	$ 20
Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Accounts receivable and accrued revenue	25	0
Accrued rate refunds	12	20
Consumers Energy Company | PSCR overrecoveries/underrecoveries
Public Utilities, General Disclosures [Line Items]
Accrued rate refunds	12	5
Consumers Energy Company | GCR overrecoveries/underrecoveries
Public Utilities, General Disclosures [Line Items]
Accounts receivable and accrued revenue	25	0
Accrued rate refunds	$ 0	$ 15