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, 2024	Dec. 31, 2023
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	$ 989	$ 1,052
Accumulated Amortization	583	640
Plant additions	2,100	3,100
Plant retirements	390	856
Software development
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	679	772
Accumulated Amortization	481	543
Leasehold improvements
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	13	11
Accumulated Amortization	7	7
Intangible plant
Public Utility, Property, Plant and Equipment [Line Items]
Plant additions	90	80
Plant retirements	153	142
Rights of way
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	253	229
Accumulated Amortization	68	64
Franchises and consents
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	16	16
Accumulated Amortization	11	11
Other intangible assets
Public Utility, Property, Plant and Equipment [Line Items]
Gross cost	28	24
Accumulated Amortization	$ 16	$ 15
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