Financings and Capitalization (Schedule of Revolving Credit Facilities) (Details) $ in Millions	Mar. 31, 2024 USD ($)
Consumers Energy Company | Revolving Credit Facilities December 14, 2027
Line of Credit Facility [Line Items]
Amount of Facility	$ 1,100
Amount Borrowed	0
Letters of Credit Outstanding	27
Amount Available	1,073
Consumers Energy Company | Revolving Credit Facilities November 18, 2024
Line of Credit Facility [Line Items]
Amount of Facility	250
Amount Borrowed	0
Letters of Credit Outstanding	53
Amount Available	197
CMS Energy | Revolving Credit Facilities December 14, 2027
Line of Credit Facility [Line Items]
Amount of Facility	550
Amount Borrowed	0
Letters of Credit Outstanding	29
Amount Available	521
CMS Energy | Revolving Credit Facilities September 22, 2024
Line of Credit Facility [Line Items]
Amount of Facility	50
Amount Borrowed	0
Letters of Credit Outstanding	50
Amount Available	0
NorthStar Clean Energy, Including Subsidiaries | Revolving Credit Facilities September 25, 2025
Line of Credit Facility [Line Items]
Amount of Facility	37
Amount Borrowed	0
Letters of Credit Outstanding	37
Amount Available	$ 0