Plant, Property, and Equipment (Summary of Finite-Lived Intangible Assets by Major Class) (Details) - Consumers Energy Company - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	$ 1,052	$ 1,114
Accumulated Amortization	640	686
Plant additions	3,100	2,300
Plant retirements	856	290
Software development
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	772	846
Accumulated Amortization	543	593
Leasehold improvements
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	11	9
Accumulated Amortization	7	6
Intangible plant
Public Utility, Property, Plant and Equipment [Line Items]
Plant additions	80	116
Plant retirements	142	104
Rights of way
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	229	218
Accumulated Amortization	64	61
Franchises and consents
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	16	16
Accumulated Amortization	11	10
Other intangible assets
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	24	25
Accumulated Amortization	$ 15	$ 16
Minimum | Software development
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 | Franchises and consents
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 | Rights of way
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