Financings and Capitalization (Narrative) (Details) $ / shares in Units, $ in Millions		1 Months Ended		12 Months Ended
	Feb. 11, 2025 USD ($)	Dec. 31, 2024 USD ($) $ / shares shares	Jan. 31, 2024 USD ($) $ / shares	Dec. 31, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($)
Financing And Capitalization [Line Items]
Principal (In Millions)		$ 1,790		$ 1,790
Payment for purchase of first mortgage bonds				952	$ 2,132	$ 106
Interest on long-term debt				700	616	509
Notes payable		$ 65		$ 65	$ 93
Supplier Finance Program, Obligation, Statement of Financial Position [Extensible Enumeration]		Accounts payable		Accounts payable
Limitation on payment of stock dividends		$ 8,000		$ 8,000
Dividends paid				$ 795
Common stock authorized (in shares) | shares		350,000,000.0		350,000,000.0	350,000,000.0
Common stock, par value (in dollars per share) | $ / shares		$ 0.01		$ 0.01
Preferred stock authorized (in shares) | shares		10,000,000		10,000,000
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.01		$ 0.01
Stock offering program maximum value					$ 1,000
Issuance of common stock				$ 286	192	69
Settlement Of Forward Contracts
Financing And Capitalization [Line Items]
Settlement of forward contracts through issuance of stock (in dollars per share) | $ / shares			$ 70.31
Issuance of common stock			$ 266
CMS Energy
Financing And Capitalization [Line Items]
Principal (In Millions)		$ 490		490
Payment for purchase of first mortgage bonds				250	0	0
Interest on long-term debt				205	201	181
Issuance of common stock				$ 286	$ 192	69
Series C Preferred Stock Depositary Shares
Financing And Capitalization [Line Items]
Preferred stock authorized (in shares) | shares		9,200,000		9,200,000	9,200,000
Preferred stock, par value (in dollars per share) | $ / shares		$ 25		$ 25	$ 25
Depositary share conversion ratio		0.001		0.001
Trading symbol				CMS PRC
Consumers Energy Company Cumulative Preferred Stock, $100 par value: $4.50 Series
Financing And Capitalization [Line Items]
Trading symbol				CMS-PB
Consumers Energy Company
Financing And Capitalization [Line Items]
Principal (In Millions)		$ 1,300		$ 1,300
Payment for purchase of first mortgage bonds				389	$ 1,654	28
Interest on long-term debt				488	415	325
Notes payable		65		65	$ 93
Unrestricted retained earnings		$ 2,300		$ 2,300
Common stock authorized (in shares) | shares		125,000,000.0		125,000,000.0	125,000,000.0
Preferred stock authorized (in shares) | shares		7,500,000		7,500,000	7,500,000
Preferred stock, par value (in dollars per share) | $ / shares		$ 4.50		$ 4.50	$ 4.50
Consumers Energy Company | Commercial Paper
Financing And Capitalization [Line Items]
Short-term debt authorized borrowings				$ 500
Short-term borrowings outstanding		$ 65		$ 65
Weighted average interest rate		4.675%		4.675%
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
Related Party | Consumers Energy Company
Financing And Capitalization [Line Items]
Principal (In Millions)		$ 835		$ 835	$ 431
Related Party | Consumers Energy Company | Credit Agreement
Financing And Capitalization [Line Items]
Maximum borrowing capacity		$ 500		500
Basis spread on variable rate		(0.10%)
Notes payable		$ 0		0
Construction Loans | Construction Financing Agreement | NorthStar Clean Energy, Including Subsidiaries | Subsequent Event
Financing And Capitalization [Line Items]
Maximum borrowing capacity	$ 334
Borrowings	$ 32
Interest Rate (%)	6.60%
First mortgage bonds
Financing And Capitalization [Line Items]
Gain on extinguishment of debt				110	131	$ 0
First mortgage bonds | Repurchased Debt
Financing And Capitalization [Line Items]
Interest on long-term debt				19	5
First mortgage bonds | Related Party | Consumers Energy Company
Financing And Capitalization [Line Items]
Principal (In Millions)		$ 404		404	431
Payment for purchase of first mortgage bonds				$ 289	$ 293