Earnings Per Share - CMS Energy (Basic And Diluted EPS Computations) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income available to common stockholders
Income from continuing operations	$ 173	$ 163	$ 556	$ 646
Loss attributable to noncontrolling interests	(3)	(2)	(21)	(16)
Preferred stock dividends	2	2	7	7
Income from continuing operations available to common stockholders – basic and diluted	$ 174	$ 163	$ 570	$ 655
Average common shares outstanding
Weighted average shares - basic (in shares)	291.0	289.6	290.9	289.5
Dilutive nonvested stock awards (in shares)	0.4	0.4	0.4	0.4
Dilutive forward equity sale contracts (in shares)	0.0	0.1	0.0	0.1
Weighted average shares - diluted (in shares)	291.4	290.1	291.3	290.0
Income from continuing operations per average common share available to common stockholders
Basic (in dollars per share)	$ 0.60	$ 0.56	$ 1.96	$ 2.26
Diluted (in dollars per share)	$ 0.60	$ 0.56	$ 1.96	$ 2.26