Plant, Property, and Equipment (Summary of Accumulated Depreciation and Amortization) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Public Utility, Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	$ 9,007	$ 8,960
Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Consumers accumulated depreciation and amortization	8,796	8,791
Non-utility plant assets
Public Utility, Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	217	175
Non-utility plant assets | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Consumers accumulated depreciation and amortization	6	6
Utility plant assets
Public Utility, Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	8,790	8,785
Utility plant assets | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Consumers accumulated depreciation and amortization	$ 8,790	$ 8,785