Financings and Capitalization (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2024	Mar. 31, 2025	Dec. 31, 2023
Financing And Capitalization [Line Items]
Notes payable	$ 65	$ 0
Supplier Finance Program, Obligation, Statement of Financial Position [Extensible Enumeration]		Accounts payable
Limitation on payment of stock dividends		$ 8,100
Dividends paid		$ 271
Stock offering program maximum value			$ 1,000
Shares used if elected to settle contracts (in shares)		92,864
Cash used if elected to settle contracts		$ 7
Consumers Energy Company
Financing And Capitalization [Line Items]
Notes payable	65	0
Unrestricted retained earnings		2,400
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
NorthStar Clean Energy
Financing And Capitalization [Line Items]
Supplier financing program, payment period		135 days
Supplier financing program, termination period		30 days
NorthStar Clean Energy | NorthStar Clean Energy's Supplier Financing Program
Financing And Capitalization [Line Items]
Supplier finance obligations		$ 27
Commercial Paper | Consumers Energy Company
Financing And Capitalization [Line Items]
Short-term debt authorized borrowings		500
Short-term borrowings outstanding		$ 0