Consolidated Statements of Changes In Equity (Unaudited) - USD ($) $ in Millions	Total	Common Stock	Other Paid-in Capital	Accumulated Other Comprehensive Loss	Retirement benefits liability	Derivative instruments	Retained Earnings (Accumulated Deficit)	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 Retained Earnings (Accumulated Deficit)	Consumers Energy Company Preferred Stock	Cumulative effect of change in accounting principle Retained Earnings (Accumulated Deficit)
Total Equity at Beginning of Period at Dec. 31, 2018	$ 4,792	$ 3	$ 5,088	$ (65)	$ (63)	$ (2)	$ (271)	$ 37	$ 6,920	$ 841	$ 4,699	$ (21)	$ (21)	$ 1,364	$ 37	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued			25
Net loss arising during the period	0				0
Settlement arising during the period	0				0
Common stock repurchased			(9)
Stockholder contribution											675
Amortization of net actuarial loss	2				2				1				1
Amortization of prior service credit	(1)				(1)
Unrealized loss on derivative instruments	(3)					(3)
Reclassification adjustments included in net income	0					0
Net income	514						513	1	537					537
Dividends declared on common stock							(325)							(396)
Dividends declared on preferred stock														(1)
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								(1)
Total Equity at End of Period at Sep. 30, 2019	$ 4,994	3	5,104	(67)	(62)	(5)	(83)	37	7,736	841	5,374	(20)	(20)	1,504	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in dollars per share)	$ 1.1475
Total Equity at Beginning of Period at Jun. 30, 2019	$ 4,888	3	5,097	(67)	(62)	(5)	(182)	37	7,647	841	5,374	(20)	(20)	1,415	37	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued			8
Net loss arising during the period	0				0
Settlement arising during the period	0				0
Common stock repurchased			(1)
Stockholder contribution											0
Amortization of net actuarial loss	0				0				0				0
Amortization of prior service credit	0				0
Unrealized loss on derivative instruments	0					0
Reclassification adjustments included in net income	0					0
Net income	207						207	0	213					213
Dividends declared on common stock							(108)							(124)
Dividends declared on preferred stock														0
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								0
Total Equity at End of Period at Sep. 30, 2019	$ 4,994	3	5,104	(67)	(62)	(5)	(83)	37	7,736	841	5,374	(20)	(20)	1,504	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in dollars per share)	$ 0.3825
Total Equity at Beginning of Period at Dec. 31, 2019	$ 5,055	3	5,113	(73)	(69)	(4)	(25)	37	7,737	841	5,374	(28)	(28)	1,513	37	(51)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued			125
Net loss arising during the period	(5)				(5)
Settlement arising during the period	1				1
Common stock repurchased			(13)
Stockholder contribution											650
Amortization of net actuarial loss	3				3				1				1
Amortization of prior service credit	(1)				(1)
Unrealized loss on derivative instruments	(5)					(5)
Reclassification adjustments included in net income	1					1
Net income	590						597	(7)	625					625
Dividends declared on common stock							(350)							(449)
Dividends declared on preferred stock														(1)
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								(1)
Total Equity at End of Period at Sep. 30, 2020	$ 5,898	3	5,225	(79)	(71)	(8)	171	578	8,563	841	6,024	(27)	(27)	1,688	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in dollars per share)	$ 1.2225
Total Equity at Beginning of Period at Jun. 30, 2020	$ 5,251	3	5,217	(76)	(68)	(8)	70	37	8,505	841	6,024	(28)	(28)	1,631	37	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued			8
Net loss arising during the period	(5)				(5)
Settlement arising during the period	1				1
Common stock repurchased			0
Stockholder contribution											0
Amortization of net actuarial loss	1				1				1				1
Amortization of prior service credit	0				0
Unrealized loss on derivative instruments	(1)					(1)
Reclassification adjustments included in net income	1					1
Net income	210						218	(8)	230					230
Dividends declared on common stock							(117)							(173)
Dividends declared on preferred stock														0
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								0
Total Equity at End of Period at Sep. 30, 2020	$ 5,898	$ 3	$ 5,225	$ (79)	$ (71)	$ (8)	$ 171	$ 578	$ 8,563	$ 841	$ 6,024	$ (27)	$ (27)	$ 1,688	$ 37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in dollars per share)	$ 0.4075