Consolidated Statements Of Changes In Equity (USD $) In Millions, except Share data	Consumers Energy Company [Member] CMS Energy Common Stock [Member]	Consumers Energy Company [Member] Other Paid-in Capital [Member]	Consumers Energy Company [Member] Accumulated Other Comprehensive Income (Loss) [Member]	Consumers Energy Company [Member] Retirement Benefits Liability [Member]	Consumers Energy Company [Member] Investments [Member]	Consumers Energy Company [Member] Retained Earnings (Accumulated Deficit) [Member]	Consumers Energy Company [Member] Preferred Stock [Member]	Consumers Energy Company [Member]	CMS Energy Common Stock [Member]	Other Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retirement Benefits Liability [Member]	Investments [Member]	Derivative Instruments [Member]	Retained Earnings (Accumulated Deficit) [Member]	Noncontrolling Interest [Member]	Total
Total Equity, beginning at Dec. 31, 2010	$ 841	$ 2,832		$ (16)	$ 16	$ 463	$ 44	$ 4,180	$ 2	$ 4,588	$ (40)	$ (39)		$ (1)	$ (1,757)	$ 44	$ 2,837
Beginning of period, shares at Dec. 31, 2010										249,628,000
Common stock issued									1	40
Number of Shares Issued										4,541,000
Common stock reissued										5
Common stock reissued, shares										269,000
Common stock repurchased										(6)
Common stock repurchased, shares										(323,000)
Common stock reacquired, value
Common stock reacquired, shares										(15,000)
Stockholder contribution		125						125
Net gain (loss) arising during the period				(4)				(4)				(11)					(11)
Prior service credit adjustment
Amortization of net actuarial loss				1				1				2					2
Unrealized gain (loss) on investments, net of tax					1			1
Reclassification adjustments included in net income, net of tax
Net income attributable to CMS Energy															415
Net income						467		467									417
Common stock dividends declared						(374)									(211)
Preferred stock dividends and distributions declared						(2)
Income attributable to noncontrolling interests																2	2
Distributions, redemptions, and other changes in noncontrolling interests																(2)
Preferred stock redeemed
Total Equity, end at Dec. 31, 2011	841	2,957	(2)	(19)	17	554	44	4,394	3	4,627	(49)	(48)		(1)	(1,553)	44	3,072
End of period, shares at Dec. 31, 2011										254,100,000
Net income								76									67
Total Equity, end at Mar. 31, 2012
Total Equity, beginning at Dec. 31, 2011	841	2,957	(2)	(19)	17	554	44	4,394	3	4,627	(49)	(48)		(1)	(1,553)	44	3,072
Beginning of period, shares at Dec. 31, 2011										254,100,000
Common stock issued										45
Number of Shares Issued										10,107,000
Common stock reissued										6
Common stock reissued, shares										272,000
Common stock repurchased										(9)
Common stock repurchased, shares										(389,000)
Common stock reacquired, value
Common stock reacquired, shares										(18,000)
Stockholder contribution		150						150
Net gain (loss) arising during the period				(8)				(8)				(10)					(10)
Prior service credit adjustment
Amortization of net actuarial loss				2				2				2					2
Unrealized gain (loss) on investments, net of tax					3			3					2				2
Reclassification adjustments included in net income, net of tax					(3)			3
Net income attributable to CMS Energy															382
Net income						439		439									384
Common stock dividends declared						(393)									(252)
Preferred stock dividends and distributions declared						(2)
Income attributable to noncontrolling interests																2	2
Distributions, redemptions, and other changes in noncontrolling interests																(2)
Preferred stock redeemed
Total Equity, end at Dec. 31, 2012	841	3,107	(8)	(25)	17	598	44	4,582	3	4,669	(55)	(56)	2	(1)	(1,423)	44	3,238
End of period, shares at Dec. 31, 2012								84,100,000		264,072,000							264,100,000
Total Equity, beginning at Sep. 30, 2012
Net income								78									67
Total Equity, end at Dec. 31, 2012	841		(8)					4,582			(55)			(1)			3,238
End of period, shares at Dec. 31, 2012								84,100,000									264,100,000
Common stock issued																	20
Number of Shares Issued																	735,873
Net income								162									144
Total Equity, end at Mar. 31, 2013
Total Equity, beginning at Dec. 31, 2012	841	3,107	(8)	(25)	17	598	44	4,582	3	4,669	(55)	(56)	2	(1)	(1,423)	44	3,238
Beginning of period, shares at Dec. 31, 2012								84,100,000		264,072,000							264,100,000
Common stock issued										51
Number of Shares Issued										2,238,000
Common stock reissued										5
Common stock reissued, shares										205,000
Common stock repurchased										(10)
Common stock repurchased, shares										(356,000)
Common stock reacquired, value
Common stock reacquired, shares										(22,000)
Stockholder contribution		150						150
Net gain (loss) arising during the period				5				5				26					26
Prior service credit adjustment												5					(5)
Amortization of net actuarial loss				3				3				4					4
Unrealized gain (loss) on investments, net of tax					1			1					(2)				(2)
Reclassification adjustments included in net income, net of tax					(3)			3
Net income attributable to CMS Energy															452
Net income						534		534									454
Common stock dividends declared						(406)									(271)
Preferred stock dividends and distributions declared						(2)
Income attributable to noncontrolling interests																2	2
Distributions, redemptions, and other changes in noncontrolling interests																(9)
Preferred stock redeemed							(7)
Total Equity, end at Dec. 31, 2013	841	3,257	(2)	(17)	15	724	37	4,857	3	4,715	(22)	(21)		(1)	(1,242)	37	3,491
End of period, shares at Dec. 31, 2013								84,100,000		266,137,000							266,100,000
Total Equity, beginning at Sep. 30, 2013
Net income								119									102
Total Equity, end at Dec. 31, 2013	$ 841		$ (2)					$ 4,857			$ (22)			$ (1)			$ 3,491
End of period, shares at Dec. 31, 2013								84,100,000									266,100,000