Regulatory Matters - Quarterly Narrative (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Jan. 31, 2022
Public Utilities, General Disclosures [Line Items]
Operating Revenue			$ 1,920	$ 1,558	$ 4,294	$ 3,571
Regulatory assets	$ 3,367		3,367		3,367		$ 2,259
Regulatory liabilities	3,873		3,873		3,873		3,802
Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Operating Revenue			1,802	$ 1,493	4,085	$ 3,430
Regulatory assets	3,367		3,367		3,367		2,259
Regulatory liabilities	3,873		3,873		3,873		3,802
Consumers Energy Company | Radio Tower Assets
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities	$ 7		7		7
Consumers Energy Company | J.H. Campbell Generating Units
Public Utilities, General Disclosures [Line Items]
Rate of return on equity authorized	9.00%
Regulatory assets	$ 1,300		1,300		1,300
Consumers Energy Company | Electric Rate Case
Public Utilities, General Disclosures [Line Items]
Estimate of disallowed costs	22		22		22
Recommended disallowed costs								$ 11
Additional annual rate increase authorized		$ 5
Consumers Energy Company | Energy Waste Reduction Plan Incentive
Public Utilities, General Disclosures [Line Items]
Requested recovery/collection	46		46		46
Operating Revenue							$ 46
Consumers Energy Company | GCR underrecoveries
Public Utilities, General Disclosures [Line Items]
Underrecovery for gas fuel and power supply costs	23		23		23
Consumers Energy Company | PSCR underrecoveries
Public Utilities, General Disclosures [Line Items]
Underrecovery for gas fuel and power supply costs	$ 153		$ 153		$ 153