v3.25.4
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, 2025
Dec. 31, 2024
Public Utility, Property, Plant and Equipment [Line Items]    
Gross cost $ 987 $ 989
Accumulated Amortization 602 583
Plant additions 3,100 2,100
Plant retirements 387 390
Software development    
Public Utility, Property, Plant and Equipment [Line Items]    
Gross cost 649 679
Accumulated Amortization 492 481
Rights of way    
Public Utility, Property, Plant and Equipment [Line Items]    
Gross cost 274 253
Accumulated Amortization 72 68
Franchises and consents    
Public Utility, Property, Plant and Equipment [Line Items]    
Gross cost 16 16
Accumulated Amortization 12 11
Leasehold improvements    
Public Utility, Property, Plant and Equipment [Line Items]    
Gross cost 15 13
Accumulated Amortization 9 7
Other intangible assets    
Public Utility, Property, Plant and Equipment [Line Items]    
Gross cost 33 28
Accumulated Amortization 17 16
Intangible plant    
Public Utility, Property, Plant and Equipment [Line Items]    
Plant additions 62 90
Plant retirements $ 64 $ 153
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