Financings and Capitalization (Schedule of Revolving Credit Facilities) (Details) - USD ($)	1 Months Ended	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2024	Oct. 31, 2024
Senior notes | Delayed Draw Unsecured Term Loan Credit Facility
Line of Credit Facility [Line Items]
Amount of Facility	$ 400,000,000	$ 400,000,000
Basis spread on variable rate	0.85%
Senior notes | Subsequent Event | Delayed Draw Unsecured Term Loan Credit Facility
Line of Credit Facility [Line Items]
Amount Borrowed			$ 175,000,000
Interest rate at period end			5.694%
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	1,100,000,000
Amount Borrowed	0	0
Letters of Credit Outstanding	27,000,000	27,000,000
Amount Available	1,073,000,000	1,073,000,000
Consumers Energy Company | Revolving Credit Facilities November 18, 2024
Line of Credit Facility [Line Items]
Amount of Facility	250,000,000	250,000,000
Amount Borrowed	0	0
Letters of Credit Outstanding	57,000,000	57,000,000
Amount Available	193,000,000	193,000,000
CMS Energy | Revolving Credit Facilities December 14, 2027
Line of Credit Facility [Line Items]
Amount of Facility	550,000,000	550,000,000
Amount Borrowed	0	0
Letters of Credit Outstanding	30,000,000	30,000,000
Amount Available	520,000,000	520,000,000
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	50,000,000
Amount Borrowed	0	0
Letters of Credit Outstanding	50,000,000	50,000,000
Amount Available	0	0
NorthStar Clean Energy, Including Subsidiaries | Revolving Credit Facilities May 7, 2027
Line of Credit Facility [Line Items]
Amount of Facility	150,000,000	150,000,000
Amount Borrowed	150,000,000	150,000,000
Letters of Credit Outstanding	0	0
Amount Available	0	0
Equity interests	$ 396,000,000	$ 396,000,000
Basis spread on variable rate		1.75%
Interest rate adjustment	0.05%	0.05%
Interest rate at period end	6.795%	6.795%
NorthStar Clean Energy, Including Subsidiaries | Revolving Credit Facilities September 25, 2025
Line of Credit Facility [Line Items]
Amount of Facility	$ 37,000,000	$ 37,000,000
Amount Borrowed	0	0
Letters of Credit Outstanding	37,000,000	37,000,000
Amount Available	$ 0	$ 0