Earnings Per Share - CMS Energy (Basic And Diluted EPS Computations) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income available to common stockholders
Income from continuing operations	$ 142	$ 153	$ 483	$ 461
Loss attributable to noncontrolling interests	(6)	(5)	(14)	(12)
Preferred stock dividends	3	0	5	0
Income from continuing operations available to common stockholders – basic and diluted	$ 145	$ 158	$ 492	$ 473
Average common shares outstanding
Weighted average shares - basic (in shares)	289.5	289.0	289.4	288.8
Dilutive nonvested stock awards (in shares)	0.4	0.4	0.4	0.5
Dilutive forward equity sale contracts (in shares)	0.2	0.0	0.2	0.0
Weighted average shares - diluted (in shares)	290.1	289.4	290.0	289.3
Income from continuing operations per average common share available to common stockholders
Basic (in dollars per share)	$ 0.50	$ 0.55	$ 1.70	$ 1.64
Diluted (in dollars per share)	$ 0.50	$ 0.55	$ 1.70	$ 1.64