Financings and Capitalization (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended
	Oct. 30, 2025	Dec. 31, 2024	Sep. 30, 2025	Sep. 30, 2025	Dec. 31, 2023
Financing And Capitalization [Line Items]
Notes payable		$ 65	$ 0	$ 0
Limitation on payment of stock dividends			$ 8,600	8,600
Dividends paid				$ 649
Stock offering program maximum value					$ 1,000
Number of shares (in shares)			2,100,000
Initial forward price (in dollars per share)			$ 72.42
Shares used if elected to settle contracts (in shares)			21,313	21,313
Cash used if elected to settle contracts			$ 2	$ 2
Settlement Of Forward Contracts
Financing And Capitalization [Line Items]
Shares subject to forward equity sale agreement (in shares)			5,000,000
Settlement of forward contracts through issuance of stock (in dollars per share)			$ 70.52	$ 70.52
Issuance of common stock			$ 349
Settlement Of Forward Contracts | Subsequent Event
Financing And Capitalization [Line Items]
Shares subject to forward equity sale agreement (in shares)	2,000,000
Settlement of forward contracts through issuance of stock (in dollars per share)	$ 72.73
Issuance of common stock	$ 147
Aggregate sales price	$ 8
Consumers Energy Company
Financing And Capitalization [Line Items]
Notes payable		65	0	$ 0
Unrestricted retained earnings			2,500	2,500
Consumers Energy Company | Credit Agreement | Related Party
Financing And Capitalization [Line Items]
Maximum borrowing capacity		$ 500
Basis spread on variable rate		(0.10%)
Notes payable			$ 0	$ 0
NorthStar Clean Energy
Financing And Capitalization [Line Items]
Supplier financing program, payment period			135 days	135 days
Supplier financing program, termination period			30 days	30 days
NorthStar Clean Energy | NorthStar Clean Energy's Supplier Financing Program
Financing And Capitalization [Line Items]
Supplier Finance Program, Obligation, Statement of Financial Position [Extensible Enumeration]			Accounts payable	Accounts payable
Supplier finance obligations			$ 79	$ 79
Commercial Paper | Consumers Energy Company
Financing And Capitalization [Line Items]
Short-term debt authorized borrowings				500
Short-term borrowings outstanding			$ 0	$ 0