Schedule II - Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Allowance for uncollectible accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 21	$ 27	$ 20
Charged to Expense	33	34	50
Charged to Other Accounts	0	0	0
Deductions	31	40	43
Balance at End of Period	23	21	27
Allowance for uncollectible accounts | Consumers Energy Company
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	21	27	20
Charged to Expense	33	34	50
Charged to Other Accounts	0	0	0
Deductions	31	40	43
Balance at End of Period	23	21	27
Deferred tax valuation allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	2	2	2
Charged to Expense	0	0	0
Charged to Other Accounts	0	0	0
Deductions	1	0	0
Balance at End of Period	$ 1	$ 2	$ 2