Financings and Capitalization (Schedule of Revolving Credit Facilities) (Details)	12 Months Ended
	Dec. 31, 2024 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	28,000,000
Amount Available	1,072,000,000
Consumers Energy Company | Revolving Credit Facilities November 18, 2024
Line of Credit Facility [Line Items]
Amount of Facility	250,000,000
Amount Borrowed	0
Letters of Credit Outstanding	58,000,000
Amount Available	192,000,000
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	31,000,000
Amount Available	519,000,000
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 7, 2027
Line of Credit Facility [Line Items]
Amount of Facility	150,000,000
Amount Borrowed	150,000,000
Letters of Credit Outstanding	0
Amount Available	0
Equity interests	396,000,000
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