Financings and Capitalization (Narrative) (Details) - USD ($)	1 Months Ended	9 Months Ended
	Dec. 31, 2022	Sep. 30, 2023
Financing And Capitalization [Line Items]
Notes payable	$ 20,000,000	$ 247,000,000
Limitation on payment of stock dividends		7,000,000,000
Dividends paid		$ 461,000,000
Consumers Energy Company
Financing And Capitalization [Line Items]
Supplier financing program, payment period		60 days
Supplier financing program, termination period		30 days
Payables under supplier finance program	1,000,000	$ 0
Unrestricted retained earnings		2,000,000,000
Consumers Energy Company | Related Party
Financing And Capitalization [Line Items]
Notes payable	75,000,000	75,000,000
Consumers Energy Company | Credit Agreement | Related Party
Financing And Capitalization [Line Items]
Maximum borrowing capacity	$ 500,000,000
Notes payable		$ 63,000,000
Interest rate at period end		5.218%
Consumers Energy Company | Credit Agreement | Related Party | SOFR
Financing And Capitalization [Line Items]
Basis spread on variable rate	(0.10%)
Consumers Energy Company | Credit Agreement | Subsidiaries
Financing And Capitalization [Line Items]
Maximum borrowing capacity		$ 40,000,000
Notes payable		$ 12,000,000
Interest rate at period end		7.079%
Consumers Energy Company | Credit Agreement | Subsidiaries | SOFR
Financing And Capitalization [Line Items]
Basis spread on variable rate		1.75%
Consumers Energy Company | Commercial Paper
Financing And Capitalization [Line Items]
Short-term debt authorized borrowings		$ 500,000,000
Short-term borrowings outstanding		$ 247,000,000
Interest rate		5.529%