Consolidated Statements Of Changes In Equity - USD ($) $ in Millions	Total	Common Stock	Other Paid-in Capital	Accumulated Other Comprehensive Loss	Retirement benefits liability	Retirement benefits liability Cumulative Effect, Period of Adoption, Adjustment	Derivative instruments	Retained Earnings (Accumulated Deficit)	Retained Earnings (Accumulated Deficit) Cumulative Effect, Period of Adoption, Adjustment	Noncontrolling Interests	Consumers Energy Company	Consumers Energy Company Common Stock	Consumers Energy Company Other Paid-in Capital	Consumers Energy Company Accumulated Other Comprehensive Loss	Consumers Energy Company Retirement benefits liability	Consumers Energy Company Retirement benefits liability Cumulative Effect, Period of Adoption, Adjustment	Consumers Energy Company Investments	Consumers Energy Company Investments Cumulative Effect, Period of Adoption, Adjustment	Consumers Energy Company Retained Earnings (Accumulated Deficit)	Consumers Energy Company Retained Earnings (Accumulated Deficit) Cumulative Effect, Period of Adoption, Adjustment	Consumers Energy Company Cumulative Preferred Stock
Total Equity at Beginning of Period at Dec. 31, 2017	$ 4,478	$ 3	$ 5,019	$ (50)	$ (50)	$ (11)	$ 0	$ (531)	$ 8	$ 37	$ 6,488	$ 841	$ 4,449	$ (12)	$ (24)	$ (5)	$ 12	$ (12)	$ 1,173	$ 19	$ 37
Beginning of period (in shares) at Dec. 31, 2017		281,647,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued (in shares)		1,554,000
Common stock issued			59
Common stock repurchased (in shares)		(224,000)
Common stock repurchased			(10)
Common stock reissued (in shares)		423,000
Common stock reissued			20
Common stock reacquired (in shares)		(26,000)
Common stock reacquired			0
Stockholder contribution													250
Net loss arising during the period	(4)				(4)						6				6
Settlement arising during the period	0				0
Prior service credit adjustment	(1)				(1)
Amortization of net actuarial loss	4				4						2				2
Amortization of prior service credit	(1)				(1)
Unrealized gain (loss) on investments											(1)						(1)
Reclassification adjustments included in net income											1						1
Unrealized loss on derivative instruments	(2)						(2)
Reclassification adjustments included in net income	0						0
Net Income	659							657		2	705								705
Dividends declared on common stock								(405)											(531)
Dividends declared on preferred stock																			(2)
Impact of purchase and consolidation of VIE										0
Sale of membership interest in VIE to tax equity investor										0
Contribution from noncontrolling interest										0
Distributions and other changes in noncontrolling interests										(2)
End of period (in shares) at Dec. 31, 2018		283,374,000
Total Equity at End of Period at Dec. 31, 2018	$ 4,792	$ 3	5,088	(65)	(63)	0	(2)	(271)	0	37	6,920	841	4,699	(21)	(21)	0	0	0	1,364	0	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in dollars per share)	$ 1.43
Common stock issued (in shares)		710,000
Common stock issued			35
Common stock repurchased (in shares)		(181,000)
Common stock repurchased			(10)
Common stock reissued (in shares)		8,000
Common stock reissued			0
Common stock reacquired (in shares)		(47,000)
Common stock reacquired			0
Stockholder contribution													675
Net loss arising during the period	$ (7)				(7)						(8)				(8)
Settlement arising during the period	0				0
Prior service credit adjustment	0				0
Amortization of net actuarial loss	3				3						1				1
Amortization of prior service credit	(2)				(2)
Unrealized gain (loss) on investments											0						0
Reclassification adjustments included in net income											0						0
Unrealized loss on derivative instruments	(3)						(3)
Reclassification adjustments included in net income	1						1
Net Income	$ 682							680		2	$ 743								743
Dividends declared on common stock								(434)											(592)
Dividends declared on preferred stock																			(2)
Impact of purchase and consolidation of VIE										0
Sale of membership interest in VIE to tax equity investor										0
Contribution from noncontrolling interest										0
Distributions and other changes in noncontrolling interests										(2)
End of period (in shares) at Dec. 31, 2019	283,900,000	283,864,000									84,100,000
Total Equity at End of Period at Dec. 31, 2019	$ 5,055	$ 3	5,113	(73)	(69)	$ 0	(4)	(25)	$ (51)	37	$ 7,737	841	5,374	(28)	(28)	$ 0	0	$ 0	1,513	$ 0	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in dollars per share)	$ 1.53
Common stock issued (in shares)		5,609,000
Common stock issued			265
Common stock repurchased (in shares)		(216,000)
Common stock repurchased			(13)
Common stock reissued (in shares)		12,000
Common stock reissued			1
Common stock reacquired (in shares)		(329,000)
Common stock reacquired			(1)
Stockholder contribution													650
Net loss arising during the period	$ (15)				(15)						(9)				(9)
Settlement arising during the period	1				1
Prior service credit adjustment	(1)				(1)
Amortization of net actuarial loss	5				5						1				1
Amortization of prior service credit	(1)				(1)
Unrealized gain (loss) on investments											0						0
Reclassification adjustments included in net income											0						0
Unrealized loss on derivative instruments	(4)						(4)
Reclassification adjustments included in net income	2						2
Net Income	$ 752							755		(3)	$ 816								816
Dividends declared on common stock								(465)											(637)
Dividends declared on preferred stock																			(2)
Impact of purchase and consolidation of VIE										101
Sale of membership interest in VIE to tax equity investor										417
Contribution from noncontrolling interest										31
Distributions and other changes in noncontrolling interests										(2)
End of period (in shares) at Dec. 31, 2020	288,900,000	288,940,000									84,100,000
Total Equity at End of Period at Dec. 31, 2020	$ 6,077	$ 3	$ 5,365	$ (86)	$ (80)		$ (6)	$ 214		$ 581	$ 8,556	$ 841	$ 6,024	$ (36)	$ (36)		$ 0		$ 1,690		$ 37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in dollars per share)	$ 1.63