v3.25.2
Financings and Capitalization (Schedule of Revolving Credit Facilities) (Details)
 6 Months Ended
Jun. 30, 2025
USD ($)
Consumers Energy Company | Letter of Credit  
Line of Credit Facility [Line Items]  
Borrowings $ 0
Consumers Energy Company | Revolving Credit Facilities December 14, 2027  
Line of Credit Facility [Line Items]  
Amount of Facility 1,100,000,000
Amount Borrowed 0
Letters of Credit Outstanding 10,000,000
Amount Available 1,090,000,000
Consumers Energy Company | Revolving Credit Facilities November 18, 2025  
Line of Credit Facility [Line Items]  
Amount of Facility 250,000,000
Amount Borrowed 0
Letters of Credit Outstanding 72,000,000
Amount Available 178,000,000
Consumers Energy Company | Revolving Credit Facilities March 31, 2028  
Line of Credit Facility [Line Items]  
Amount of Facility 50,000,000
Amount Borrowed 0
Letters of Credit Outstanding 24,000,000
Amount Available 26,000,000
CMS Energy | Revolving Credit Facilities December 14, 2027  
Line of Credit Facility [Line Items]  
Amount of Facility 550,000,000
Amount Borrowed 0
Letters of Credit Outstanding 38,000,000
Amount Available 512,000,000
CMS Energy | Revolving Credit Facilities December 14, 2027 | Letter of Credit  
Line of Credit Facility [Line Items]  
Borrowings 0
CMS Energy | Revolving Credit Facilities September 30, 2025  
Line of Credit Facility [Line Items]  
Amount of Facility 50,000,000
Amount Borrowed 0
Letters of Credit Outstanding 50,000,000
Amount Available 0
NorthStar Clean Energy, Including Subsidiaries | Revolving Credit Facilities May 30, 2028  
Line of Credit Facility [Line Items]  
Amount of Facility 250,000,000
Amount Borrowed 160,000,000
Letters of Credit Outstanding 0
Amount Available 90,000,000
Equity interests 505,000,000
NorthStar Clean Energy, Including Subsidiaries | Revolving Credit Facilities September 25, 2025  
Line of Credit Facility [Line Items]  
Amount of Facility 37,000,000
Amount Borrowed 0
Letters of Credit Outstanding 37,000,000
Amount Available 0
NorthStar Clean Energy, Including Subsidiaries | Revolving Credit Facilities Upon Completion of Construction Project  
Line of Credit Facility [Line Items]  
Amount of Facility 19,000,000
Amount Borrowed 0
Letters of Credit Outstanding 12,000,000
Amount Available $ 7,000,000