Schedule I - Condensed Financial Information of Registrant (Condensed Statements Of Cash Flows) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash Flows from Operating Activities
Net cash provided by operating activities	$ 2,309	$ 855	$ 1,819
Cash Flows from Investing Activities
Net cash used in investing activities	(3,386)	(2,476)	(1,233)
Cash Flows from Financing Activities
Proceeds from issuance of debt	3,551	1,899	335
Issuance of common stock	192	69	26
Issuance of preferred stock, net of issuance costs	0	0	224
Retirement of long-term debt	(2,132)	(106)	(235)
Change in notes payable – intercompany	73	20	0
Net cash provided by (used in) financing activities	1,143	1,327	(295)
Net Increase (Decrease) in Cash and Cash Equivalents, Including Restricted Amounts	66	(294)	291
Cash and Cash Equivalents, Including Restricted Amounts, Beginning of Period	182	476	185
Cash and Cash Equivalents, Including Restricted Amounts, End of Period	248	182	476
CMS Energy
Cash Flows from Operating Activities
Net cash provided by operating activities	595	565	1,549
Cash Flows from Investing Activities
Investment in subsidiaries	(630)	(796)	(581)
Net cash used in investing activities	(868)	(510)	(664)
Cash Flows from Financing Activities
Proceeds from issuance of debt	800	0	0
Issuance of common stock	192	69	26
Issuance of preferred stock, net of issuance costs	0	0	224
Retirement of long-term debt	0	0	(200)
Payment of dividends on common and preferred stock	(579)	(544)	(507)
Debt issuance costs and financing fees	(20)	(11)	(10)
Net cash provided by (used in) financing activities	386	(409)	(495)
Net Increase (Decrease) in Cash and Cash Equivalents, Including Restricted Amounts	113	(354)	390
Cash and Cash Equivalents, Including Restricted Amounts, Beginning of Period	36	390	0
Cash and Cash Equivalents, Including Restricted Amounts, End of Period	149	36	390
CMS Energy | Related Party
Cash Flows from Investing Activities
Investment in debt securities - intercompany	293	0	0
Decrease (increase) in notes receivable – intercompany	(55)	286	(83)
Cash Flows from Financing Activities
Change in notes payable – intercompany	$ (7)	$ 77	$ (28)