Regulatory Matters (Schedule Of Regulatory Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Public Utilities, General Disclosures [Line Items]
Regulatory assets, current	$ 46	$ 42
Regulatory assets, noncurrent	2,259	2,653
Regulatory liabilities, current	146	151
Regulatory liability, noncurrent	3,802	3,744
Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets, current	46	42
Regulatory assets, noncurrent	2,259	2,653
Total regulatory assets	2,305	2,695
Regulatory liabilities, current	146	151
Regulatory liability, noncurrent	3,802	3,744
Total regulatory liabilities	3,948	3,895
Income taxes, net | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities, current	138	105
Regulatory liability, noncurrent	1,297	1,419
Reserve for customer refunds | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities, current	2	28
Voluntary transmission asset sale gain share | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities, current	0	14
Other | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities, current	6	4
Regulatory liability, noncurrent	16	11
Postretirement benefits | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory liability, noncurrent	54	0
Cost of removal | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory liability, noncurrent	2,375	2,245
Renewable energy grant | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory liability, noncurrent	47	49
Renewable energy plan | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory liability, noncurrent	13	9
ARO | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory liability, noncurrent	0	11
Energy Waste Reduction Plan Incentive | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets, current	42	34
Regulatory assets, noncurrent	46	42
Deferred capital spending | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets, current	0	6
Other | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets, current	4	2
Regulatory assets, noncurrent	19	11
Postretirement benefits | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	837	1,231
Costs of coal-fueled electric generating units to be retired | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	678	678
ARO | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	247	216
Securitized costs | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	193	221
Manufactured Gas Plant | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	112	120
Unamortized Loss On Reacquired Debt | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	104	108
Energy Waste Reduction Plan | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	13	16
Demand response program | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	$ 10	$ 10