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, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Income available to common stockholders
Income from continuing operations	$ 272	$ 247	$ 760	$ 692
Loss attributable to noncontrolling interests	(5)	(6)	(22)	(46)
Preferred stock dividends	2	2	7	7
Income from continuing operations available to common stockholders – basic and diluted	$ 275	$ 251	$ 775	$ 731
Average common shares outstanding
Weighted average shares - basic (in shares)	299.7	298.0	298.8	297.5
Dilutive nonvested stock awards (in shares)	0.6	0.8	0.6	0.7
Dilutive forward equity sale contracts (in shares)	0.1	0.0	0.0	0.0
Weighted average shares - diluted (in shares)	300.4	298.8	299.4	298.2
Income from continuing operations per average common share available to common stockholders
Basic (in dollars per share)	$ 0.92	$ 0.84	$ 2.59	$ 2.45
Diluted (in dollars per share)	$ 0.92	$ 0.84	$ 2.59	$ 2.45