Quarterly Financial And Common Stock Information (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Operating Revenue	$ 1,736		$ 1,445		$ 1,406		$ 1,979		$ 1,670		$ 1,507		$ 1,333		$ 1,743		$ 6,566		$ 6,253		$ 6,503
Operating Income (Loss)	264		317		232		329		212		343		260		188		1,142		1,003		1,003
Income From Continuing Operations	102		127		81		144		67		149		101		60		454		377		415
Income From Discontinued Operations, Net															7				7	[1]	2	[2]
Net Income	102		127		81		144		67		149		101		67		454		384		417
Income Attributable to Noncontrolling Interests			1		1						1		1				2		2		2
Net Income Available to Common Stockholders	102		126		80		144		67		148		100		67		452		382		415
Earnings from continuing operations per average common share - basic	$ 0.38	[3]	$ 0.48	[3]	$ 0.30	[3]	$ 0.55	[3]	$ 0.26	[3]	$ 0.56	[3]	$ 0.38	[3]	$ 0.23	[3]	$ 1.71		$ 1.43		$ 1.65
Earnings from continuing operations per average common share - diluted	$ 0.37	[3]	$ 0.46	[3]	$ 0.29	[3]	$ 0.53	[3]	$ 0.25	[3]	$ 0.55	[3]	$ 0.37	[3]	$ 0.22	[3]	$ 1.66		$ 1.39		$ 1.57
Basic earnings per average common share	$ 0.38	[3]	$ 0.48	[3]	$ 0.30	[3]	$ 0.55	[3]	$ 0.26	[3]	$ 0.56	[3]	$ 0.38	[3]	$ 0.26	[3]	$ 1.71		$ 1.46		$ 1.66
Diluted earnings per average common share	$ 0.37	[3]	$ 0.46	[3]	$ 0.29	[3]	$ 0.53	[3]	$ 0.25	[3]	$ 0.55	[3]	$ 0.37	[3]	$ 0.25	[3]	$ 1.66		$ 1.42		$ 1.58
CMS Energy [Member]
Operating Income (Loss)																	(6)		(8)		(3)
Income From Continuing Operations																	452		382		415
Net Income																	452		382		415
Net Income Available to Common Stockholders																	452		382		415
Consumers Energy Company [Member]
Operating Revenue	1,674		1,386		1,342		1,919		1,608		1,448		1,282		1,675		6,321		6,013		6,253
Operating Income (Loss)	258		314		227		319		207		334		260		183		1,118		984		985
Net Income	119		153		100		162		78		163		122		76		534		439		467
Preferred stock dividends and distribution			1		1						1		1				2		2		2
Net Income Available to Common Stockholders	$ 119		$ 152		$ 99		$ 162		$ 78		$ 162		$ 121		$ 76		$ 532		$ 437		$ 465
Maximum [Member] | CMS Energy Common Stock [Member]
Share price	$ 28.05	[4]	$ 28.52	[4]	$ 29.94	[4]	$ 27.94	[4]	$ 24.70	[4]	$ 24.81	[4]	$ 23.87	[4]	$ 22.31	[4]	$ 28.05	[4]	$ 24.70	[4]
Minimum [Member] | CMS Energy Common Stock [Member]
Share price	$ 25.90	[4]	$ 25.86	[4]	$ 25.95	[4]	$ 24.76	[4]	$ 22.79	[4]	$ 22.70	[4]	$ 21.52	[4]	$ 21.33	[4]	$ 25.90	[4]	$ 22.79	[4]

[1] Includes an $11 million ($7 million net of tax) reversal of a loss on disposal due to the elimination of a liability associated with the 2003 sale of Panhandle.

[2] Includes an operating gain of $3 million related to a litigation settlement at CMS Viron.

[3] The sum of the quarters may not equal annual EPS due to changes in the number of shares outstanding.

[4] Based on New York Stock Exchange composite transactions.