v3.25.4
Income Taxes (Summary of Significant Components of Income Tax Expense) (Details) - USD ($)
$ in Millions
 1 Months Ended 12 Months Ended
Jun. 30, 2025
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Current income taxes        
Federal   $ 34 $ 34 $ 5
State and local   9 0 1
Total current income tax expense   43 34 6
Deferred income taxes        
Federal   107 70 107
State and local   100 76 38
Total deferred income tax expense   207 146 145
Deferred income tax credit   (4) (4) (4)
Income tax expense   246 176 147
Consumers Energy Company        
Current income taxes        
Federal   207 78 3
State and local   33 7 2
Total current income tax expense   240 85 5
Deferred income taxes        
Federal   (27) 51 117
State and local $ 12 79 68 43
Total deferred income tax expense   52 119 160
Deferred income tax credit   (4) (4) (4)
Income tax expense   $ 288 $ 200 $ 161