Schedule I - Condensed Financial Information of Registrant (Condensed Statements Of Cash Flows) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash Flows from Operating Activities
Net cash provided by operating activities	$ 2,370	$ 2,309	$ 855
Cash Flows from Investing Activities
Net cash used in investing activities	(3,054)	(3,386)	(2,476)
Cash Flows from Financing Activities
Proceeds from issuance of debt	1,962	3,551	1,899
Issuance of common stock	286	192	69
Retirement of long-term debt	(952)	(2,132)	(106)
Increase (decrease) in notes payable	(28)	73	20
Net cash provided by financing activities	614	1,143	1,327
Net Increase (Decrease) in Cash and Cash Equivalents, Including Restricted Amounts	(70)	66	(294)
Cash and Cash Equivalents, Including Restricted Amounts, Beginning of Period	248	182	476
Cash and Cash Equivalents, Including Restricted Amounts, End of Period	178	248	182
Capital Expenditures
Cash Flows from Investing Activities
Capital expenditures	(3,018)	(2,407)	(2,374)
CMS Energy
Cash Flows from Operating Activities
Net cash provided by operating activities	774	595	565
Cash Flows from Investing Activities
Investment in subsidiaries	(535)	(630)	(796)
Net cash used in investing activities	(803)	(868)	(510)
Cash Flows from Financing Activities
Proceeds from issuance of debt	490	800	0
Issuance of common stock	286	192	69
Retirement of long-term debt	(250)	0	0
Payment of dividends on common and preferred stock	(626)	(579)	(544)
Debt issuance costs and financing fees	(10)	(20)	(11)
Net cash provided by financing activities	(116)	386	(409)
Net Increase (Decrease) in Cash and Cash Equivalents, Including Restricted Amounts	(145)	113	(354)
Cash and Cash Equivalents, Including Restricted Amounts, Beginning of Period	149	36	390
Cash and Cash Equivalents, Including Restricted Amounts, End of Period	4	149	36
CMS Energy | Capital Expenditures
Cash Flows from Investing Activities
Capital expenditures	(1)	0	0
CMS Energy | Related Party
Cash Flows from Investing Activities
Investment in debt securities – intercompany	(288)	(293)	0
Decrease (increase) in notes receivable – intercompany	21	55	286
Cash Flows from Financing Activities
Increase (decrease) in notes payable	$ (6)	$ (7)	$ 77