Quarterly Financial And Common Stock Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Quarterly Financial Data [Abstract]
Operating Revenue	$ 2,033	$ 1,725	$ 1,558	$ 2,013	$ 1,727	$ 1,507	$ 1,382	$ 1,802	$ 7,329	$ 6,418	$ 6,624
Operating income	204	260	252	430	307	340	248	335	1,146	1,230	1,115
Income from continuing operations	114	153	153	308	138	198	129	229	728	694	633
Income From Discontinued Operations, Net of Tax	520	30	18	34	24	12	8	14	602	58	49
Net Income	634	183	171	342	162	210	137	243	1,330	752	682
Income (loss) attributable to noncontrolling interests	(5)	(6)	(5)	(7)	4	(8)	1	0	(23)	(3)	2
Net Income Attributable to CMS Energy	639	189	176	349					1,353	755	680
Preferred Stock Dividends	2	3	0	0					5	0	0
Net Income Available to Common Stockholders	$ 637	$ 186	$ 176	$ 349	$ 158	$ 218	$ 136	$ 243	$ 1,348	$ 755	$ 680
Income from continuing operations per average common share available to common stockholders - Basic (in dollars per share)	$ 0.40	$ 0.54	$ 0.55	$ 1.09	$ 0.47	$ 0.72	$ 0.45	$ 0.81	$ 2.58	$ 2.45	$ 2.23
Income from discontinued operations per average common share available to common stockholders - Basic (in dollars per share)	1.80	0.10	0.06	0.12	0.08	0.04	0.03	0.05	2.08	0.20	0.17
Basic earnings per average common share (in dollars per share)	2.20	0.64	0.61	1.21	0.55	0.76	0.48	0.86	4.66	2.65	2.40
Income from continuing operations per average common share available to common stockholders - Diluted (in dollars per share)	0.40	0.54	0.55	1.09	0.47	0.72	0.45	0.80	2.58	2.44	2.22
Income from discontinued operations per average common share available to common stockholders - Diluted (in dollars per share)	1.80	0.10	0.06	0.12	0.08	0.04	0.03	0.05	2.08	0.20	0.17
Diluted earnings per average common share (in dollars per share)	$ 2.20	$ 0.64	$ 0.61	$ 1.21	$ 0.55	$ 0.76	$ 0.48	$ 0.85	$ 4.66	$ 2.64	$ 2.39