Schedule I - Condensed Financial Information of Registrant (Condensed Statements of Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating Expenses
Other operating expenses	$ (1,638)	$ (1,687)	$ (1,669)
Total operating expenses	(6,028)	(6,227)	(7,372)
Operating income	1,487	1,235	1,224
Other Income (Expense)
Equity earnings of subsidiaries	7	7	3
Non-operating retirement benefits, net	169	180	205
Other expense	(32)	(13)	(27)
Total other income	344	362	197
Interest Charges
Interest on long-term debt	700	616	509
Total interest charges	708	643	519
Income (Loss) Before Income Taxes	1,123	954	902
Income Tax Expense	176	147	93
Net Income	1,003	887	837
Preferred Stock Dividends	10	10	10
Net Income (Loss) Available to Common Stockholders	993	877	827
Related Party
Interest Charges
Intercompany interest expense and other	12	12	12
CMS Energy
Operating Expenses
Other operating expenses	10	10	7
Total operating expenses	10	10	7
Operating income	(10)	(10)	(7)
Other Income (Expense)
Non-operating retirement benefits, net	(1)	(1)	(1)
Other income	45	31	5
Other expense	0	0	(1)
Total other income	1,105	959	983
Interest Charges
Interest on long-term debt	205	201	181
Total interest charges	215	211	189
Income (Loss) Before Income Taxes	880	738	787
Income Tax Expense	(19)	(20)	(50)
Net Income	899	758	837
Preferred Stock Dividends	10	10	10
Net Income (Loss) Available to Common Stockholders	889	748	827
CMS Energy | Related Party
Other Income (Expense)
Equity earnings of subsidiaries	1,061	929	980
Interest Charges
Intercompany interest expense and other	$ 10	$ 10	$ 8