Financings and Capitalization (Schedule of Revolving Credit Facilities) (Details)	Sep. 30, 2022 USD ($)
Consumers Energy Company | Revolving Credit Facilities June 5, 2024
Line of Credit Facility [Line Items]
Amount of Facility	$ 850,000,000
Amount Borrowed	0
Letters of Credit Outstanding	29,000,000
Amount Available	821,000,000
Consumers Energy Company | Revolving Credit Facilities November 19, 2023
Line of Credit Facility [Line Items]
Amount of Facility	250,000,000
Amount Borrowed	0
Letters of Credit Outstanding	62,000,000
Amount Available	188,000,000
CMS Energy | Revolving Credit Facilities June 5, 2024
Line of Credit Facility [Line Items]
Amount of Facility	550,000,000
Amount Borrowed	0
Letters of Credit Outstanding	14,000,000
Amount Available	536,000,000
CMS Energy | Revolving Credit Facilities September 23, 2022
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 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