Plant, Property, and Equipment (Schedule of Finite-Lived Intangible Assets by Major Class Table) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	$ 1,102	$ 1,105
Accumulated Amortization	684	658
Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	1,102	1,104
Accumulated Amortization	684	658
Plant additions	2,400	2,000
Plant retirements	361	220
Software development
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	840	856
Accumulated Amortization	592	568
Software development | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	840	856
Accumulated Amortization	592	568
Leasehold improvements
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	9	10
Accumulated Amortization	6	7
Leasehold improvements | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	9	10
Accumulated Amortization	6	7
Intangible Plant | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Plant additions	88	69
Plant retirements	91	65
Rights of way
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	211	197
Accumulated Amortization	60	57
Rights of way | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	211	197
Accumulated Amortization	60	57
Franchises and consents
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	16	16
Accumulated Amortization	10	10
Franchises and consents | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	16	16
Accumulated Amortization	10	10
Other intangible assets
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	26	26
Accumulated Amortization	16	16
Other intangible assets | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	26	25
Accumulated Amortization	$ 16	$ 16
Minimum | Software development
Public Utility, Property, Plant and Equipment [Line Items]
Amortization Life in Years	3 years
Minimum | Software development | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Amortization Life in Years	3 years
Minimum | Rights of way
Public Utility, Property, Plant and Equipment [Line Items]
Amortization Life in Years	50 years
Minimum | Rights of way | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Amortization Life in Years	50 years
Minimum | Franchises and consents
Public Utility, Property, Plant and Equipment [Line Items]
Amortization Life in Years	5 years
Minimum | Franchises and consents | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Amortization Life in Years	5 years
Maximum | Software development
Public Utility, Property, Plant and Equipment [Line Items]
Amortization Life in Years	15 years
Maximum | Software development | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Amortization Life in Years	15 years
Maximum | Rights of way
Public Utility, Property, Plant and Equipment [Line Items]
Amortization Life in Years	85 years
Maximum | Rights of way | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Amortization Life in Years	85 years
Maximum | Franchises and consents
Public Utility, Property, Plant and Equipment [Line Items]
Amortization Life in Years	50 years
Maximum | Franchises and consents | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Amortization Life in Years	50 years