Financings and Capitalization (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended			12 Months Ended
	Jan. 31, 2024	Dec. 31, 2023	Nov. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing And Capitalization [Line Items]
Notes payable		$ 93		$ 93	$ 20
Limitation on payment of stock dividends		$ 7,300		7,300
Dividends paid				$ 695
Common stock authorized (in shares)		350,000,000.0		350,000,000.0	350,000,000.0
Common stock, par value (in dollars per share)		$ 0.01		$ 0.01
Preferred stock authorized (in shares)		10,000,000		10,000,000
Preferred stock, par value (in dollars per share)		$ 0.01		$ 0.01
Stock offering program maximum value				$ 1,000
Issuance of common stock				192	$ 69	$ 26
CMS Energy
Financing And Capitalization [Line Items]
Issuance of common stock				192	69	$ 26
Settlement Of Forward Contracts
Financing And Capitalization [Line Items]
Settlement of forward contracts through issuance of stock (in dollars per share)			$ 68.05
Issuance of common stock			$ 178
Settlement Of Forward Contracts | Subsequent Event
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]
Payables under supplier finance program		$ 0		0	$ 1
Unrestricted retained earnings		$ 2,100		$ 2,100
Common stock authorized (in shares)		125,000,000.0		125,000,000.0	125,000,000.0
Preferred stock authorized (in shares)		7,500,000		7,500,000	7,500,000
Preferred stock, par value (in dollars per share)		$ 4.50		$ 4.50	$ 4.50
Consumers Energy Company | Consumers' Supplier Financing Program
Financing And Capitalization [Line Items]
Supplier financing program, payment period		60 days		60 days
Supplier financing program, termination period		30 days		30 days
Consumers Energy Company | Related Party
Financing And Capitalization [Line Items]
Notes payable		$ 0		$ 0	$ 75
Consumers Energy Company | Credit Agreement | Related Party
Financing And Capitalization [Line Items]
Maximum borrowing capacity		500		500
Notes payable		$ 0		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		$ 93		$ 93
Weighted average interest rate		5.609%		5.609%