Regulatory Matters (Schedule of Liabilities for PSCR and GCR Overrecoveries) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Public Utilities, General Disclosures [Line Items]
Accrued rate refunds	$ 38	$ 54
Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Accrued rate refunds	38	54
Consumers Energy Company | PSCR underrecoveries
Public Utilities, General Disclosures [Line Items]
Accrued rate refunds	13	10
Consumers Energy Company | GCR underrecoveries
Public Utilities, General Disclosures [Line Items]
Accrued rate refunds	$ 25	$ 44