Schedule I - Condensed Financial Information of Registrant (Condensed Statements of Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Expenses
Other operating expenses	$ (1,687)	$ (1,669)	$ (1,610)
Total operating expenses	(6,227)	(7,372)	(6,183)
Operating income	1,235	1,224	1,146
Other Income (Expense)
Equity earnings of subsidiaries	7	3	10
Non-operating retirement benefits, net	180	205	165
Other income	195	19	30
Other expense	(13)	(27)	(18)
Total other income	362	197	177
Interest Charges
Interest on long-term debt	616	509	481
Total interest charges	643	519	500
Income Before Income Taxes	954	902	823
Income tax expense (benefit)	147	93	95
Income From Continuing Operations	807	809	728
Income from discontinued operations, net of tax	1	4	602
Net Income Attributable to CMS Energy	887	837	1,353
Preferred Stock Dividends	10	10	5
Net Income Available to Common Stockholders	877	827	1,348
Related Party
Interest Charges
Intercompany interest expense and other	12	12	12
CMS Energy
Operating Expenses
Other operating expenses	10	7	7
Total operating expenses	10	7	7
Operating income	(10)	(7)	(7)
Other Income (Expense)
Non-operating retirement benefits, net	(1)	(1)	(1)
Other income	31	5	2
Other expense	0	(1)	0
Total other income	959	983	1,483
Interest Charges
Interest on long-term debt	201	181	183
Total interest charges	211	189	190
Income Before Income Taxes	738	787	1,286
Income tax expense (benefit)	(20)	(50)	(60)
Income From Continuing Operations	758	837	1,346
Income from discontinued operations, net of tax	0	0	7
Net Income Attributable to CMS Energy	758	837	1,353
Preferred Stock Dividends	10	10	5
Net Income Available to Common Stockholders	748	827	1,348
CMS Energy | Related Party
Other Income (Expense)
Equity earnings of subsidiaries	929	980	1,482
Interest Charges
Intercompany interest expense and other	$ 10	$ 8	$ 7