Plant, Property, and Equipment (Summary of Accumulated Depreciation and Amortization) (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Public Utility, Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	$ 10,135	$ 9,569
Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Consumers accumulated depreciation and amortization	9,842	9,310
Non-utility plant assets
Public Utility, Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	297	262
Non-utility plant assets | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Consumers accumulated depreciation and amortization	4	3
Utility plant assets
Public Utility, Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	9,838	9,307
Utility plant assets | Consumers Energy Company
Public Utility, Property, Plant and Equipment [Line Items]
Consumers accumulated depreciation and amortization	$ 9,838	$ 9,307