Financings and Capitalization (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended
	Jan. 31, 2024	Dec. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Financing And Capitalization [Line Items]
Gain on extinguishment of debt			$ 22
Interest on long-term debt			172	$ 144
Notes payable		$ 93	0
Limitation on payment of stock dividends			7,700
Dividends paid			265
Stock offering program maximum value			1,000
Issuance of common stock			272	4
CMS Energy | First mortgage bonds
Financing And Capitalization [Line Items]
Principal (In Millions)			91
Payment for purchase of first mortgage bonds			69
Settlement Of Forward Contracts
Financing And Capitalization [Line Items]
Settlement of forward contracts through issuance of stock (in dollars per share)	$ 70.31
Issuance of common stock	$ 266
Consumers Energy Company
Financing And Capitalization [Line Items]
Principal (In Millions)			600
Interest on long-term debt			121	$ 99
Unrestricted retained earnings			2,100
Consumers Energy Company | Credit Agreement | Related Party
Financing And Capitalization [Line Items]
Maximum borrowing capacity			500
Notes payable			0
Consumers Energy Company | Credit Agreement | Related Party | SOFR
Financing And Capitalization [Line Items]
Basis spread on variable rate		(0.10%)
Consumers Energy Company | Commercial Paper
Financing And Capitalization [Line Items]
Short-term debt authorized borrowings			500
Short-term borrowings outstanding			$ 0