Financings and Capitalization (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended	6 Months Ended		12 Months Ended
	Jan. 31, 2024	Dec. 31, 2023	Jun. 30, 2024	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Financing And Capitalization [Line Items]
Payment for purchase of first mortgage bonds				$ 433	$ 1,465
Notes payable		$ 93	$ 0	0		$ 93
Limitation on payment of stock dividends			7,800	7,800
Dividends paid				359
Stock offering program maximum value						1,000
Issuance of common stock				279	7
First mortgage bonds
Financing And Capitalization [Line Items]
Gain on extinguishment of debt			48	70
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	600
Payment for purchase of first mortgage bonds				15	$ 1,314
Unrestricted retained earnings			2,200	2,200
Consumers Energy Company | Related Party | First mortgage bonds
Financing And Capitalization [Line Items]
Principal (In Millions)			242	242
Payment for purchase of first mortgage bonds				169
Consumers Energy Company | Credit Agreement | Related Party
Financing And Capitalization [Line Items]
Maximum borrowing capacity		$ 500				$ 500
Basis spread on variable rate		(0.10%)
Notes payable			0	0
Consumers Energy Company | Commercial Paper
Financing And Capitalization [Line Items]
Short-term debt authorized borrowings				500
Short-term borrowings outstanding			$ 0	$ 0