Schedule I - Condensed Financial Information of Registrant (Condensed Statements of Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Operating Expenses
Other operating expenses	$ (1,727)	$ (1,638)	$ (1,687)
Total operating expenses	(6,812)	(6,028)	(6,227)
Operating Loss	1,727	1,487	1,235
Other Income (Expense)
Equity earnings of subsidiaries	5	7	7
Non-operating retirement benefits, net	186	169	180
Other expense	(27)	(32)	(13)
Total other income	310	344	362
Interest Charges
Interest on long-term debt	798	700	616
Total interest charges	789	708	643
Income (Loss) Before Income Taxes	1,248	1,123	954
Income Tax Expense	246	176	147
Net Income	1,071	1,003	887
Preferred Stock Dividends	10	10	10
Net Income (Loss) Available to Common Stockholders	1,061	993	877
Related Party
Interest Charges
Intercompany interest expense and other	11	12	12
CMS Energy
Operating Expenses
Other operating expenses	9	10	10
Total operating expenses	9	10	10
Operating Loss	(9)	(10)	(10)
Other Income (Expense)
Non-operating retirement benefits, net	(1)	(1)	(1)
Other income	69	45	31
Other expense	(2)	0	0
Total other income	1,255	1,105	959
Interest Charges
Interest on long-term debt	266	205	201
Total interest charges	276	215	211
Income (Loss) Before Income Taxes	970	880	738
Income Tax Expense	(39)	(19)	(20)
Net Income	1,009	899	758
Preferred Stock Dividends	10	10	10
Net Income (Loss) Available to Common Stockholders	999	889	748
CMS Energy | Related Party
Other Income (Expense)
Equity earnings of subsidiaries	1,189	1,061	929
Interest Charges
Intercompany interest expense and other	$ 10	$ 10	$ 10