Financings and Capitalization (Schedule of Revolving Credit Facilities) (Details)	12 Months Ended
	Dec. 31, 2025 USD ($)
Consumers Energy Company | Secured Revolving Credit Facility, Expiring November 2030
Line of Credit Facility [Line Items]
Amount of Facility	$ 1,100,000,000
Amount Borrowed	0
Letters of Credit Outstanding	6,000,000
Amount Available	1,094,000,000
Consumers Energy Company | Secured Revolving Credit Facility, Expiring November 2028
Line of Credit Facility [Line Items]
Amount of Facility	300,000,000
Amount Borrowed	0
Letters of Credit Outstanding	0
Amount Available	300,000,000
Consumers Energy Company | Secured Letter Of Credit Facility, Expiring May 2027
Line of Credit Facility [Line Items]
Amount of Facility	100,000,000
Amount Borrowed	0
Letters of Credit Outstanding	100,000,000
Amount Available	0
Consumers Energy Company | Unsecured Letter Of Credit Facility, Expiring March 2028
Line of Credit Facility [Line Items]
Amount of Facility	50,000,000
Amount Borrowed	0
Letters of Credit Outstanding	43,000,000
Amount Available	7,000,000
Consumers Energy Company | Unsecured Letter Of Credit Facility
Line of Credit Facility [Line Items]
Amount of Facility	100,000,000
Amount Borrowed	0
Letters of Credit Outstanding	97,000,000
Amount Available	3,000,000
Consumers Energy Company | Unsecured Letter Of Credit Facility
Line of Credit Facility [Line Items]
Amount of Facility	100,000,000
Amount Borrowed	0
Letters of Credit Outstanding	100,000,000
Amount Available	0
Consumers Energy Company | Letter of Credit
Line of Credit Facility [Line Items]
Borrowings	0
CMS Energy | Unsecured Revolving Credit Facility, Expiring November 2030
Line of Credit Facility [Line Items]
Amount of Facility	750,000,000
Amount Borrowed	0
Letters of Credit Outstanding	35,000,000
Amount Available	715,000,000
Borrowings	0
CMS Energy | Unsecured Letter Of Credit Facility, Expiring September 2026
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 | Secured Revolving Credit Facility, Expiring May 2028
Line of Credit Facility [Line Items]
Amount of Facility	250,000,000
Amount Borrowed	235,000,000
Letters of Credit Outstanding	10,000,000
Amount Available	5,000,000
Equity interests	514,000,000
NorthStar Clean Energy, Including Subsidiaries | Secured Letter Of Credit Facility, Expiring September 2028
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 | Secured Letter Of Credit Facility
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