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)	Retained Earnings (Accumulated Deficit) Cumulative Effect, Period of Adoption, Adjustment	Cumulative Preferred Stock	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 Cumulative Preferred Stock
Total Equity at Beginning of Period at Dec. 31, 2019	$ 5,055	$ 3	$ 5,113	$ (73)	$ (69)	$ (4)	$ (25)	$ (51)	$ 0	$ 37	$ 7,737	$ 841	$ 5,374	$ (28)	$ (28)	$ 1,513	$ 37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued			125						0
Common stock repurchased			(13)
Stockholder contribution													650
Net loss arising during the period, net of tax	(5)				(5)
Settlement arising during the period, net of tax	1				1
Amortization of net actuarial loss	3				3						1				1
Amortization of prior service credit	(1)				(1)
Unrealized gain (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							0									(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		0	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
Dividends declared per preferred stock Series C depositary share (in dollars per share)	$ 0
Total Equity at Beginning of Period at Jun. 30, 2020	$ 5,251	3	5,217	(76)	(68)	(8)	70	0	0	37	8,505	841	6,024	(28)	(28)	1,631	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued			8						0
Common stock repurchased			0
Stockholder contribution													0
Net loss arising during the period, net of tax	(5)				(5)
Settlement arising during the period, net of tax	1				1
Amortization of net actuarial loss	1				1						1				1
Amortization of prior service credit	0				0
Unrealized gain (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									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		0	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
Dividends declared per preferred stock Series C depositary share (in dollars per share)	$ 0
Total Equity at Beginning of Period at Dec. 31, 2020	$ 6,077	3	5,365	(86)	(80)	(6)	214	0	0	581	8,556	841	6,024	(36)	(36)	1,690	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued			41						224
Common stock repurchased			(9)
Stockholder contribution													575
Net loss arising during the period, net of tax	0				0
Settlement arising during the period, net of tax	0				0
Amortization of net actuarial loss	5				5						2				2
Amortization of prior service credit	(1)				(1)
Unrealized gain (loss) on derivative instruments	1					1
Reclassification adjustments included in net income	0					0
Net Income	696						714			(18)	712					712
Dividends declared on common stock							(378)									(570)
Dividends declared on preferred stock							(3)									(1)
Impact of purchase and consolidation of VIE										0
Sale of membership interest in VIE to tax equity investor										0
Contribution from noncontrolling interest										1
Distributions and other changes in noncontrolling interests										(1)
Total Equity at End of Period at Sep. 30, 2021	$ 6,653	3	5,397	(81)	(76)	(5)	547		224	563	9,274	841	6,599	(34)	(34)	1,831	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in dollars per share)	$ 1.3050
Dividends declared per preferred stock Series C depositary share (in dollars per share)	$ 0.3063
Total Equity at Beginning of Period at Jun. 30, 2021	$ 6,366	3	5,389	(82)	(77)	(5)	487	$ 0	0	569	8,977	841	6,299	(35)	(35)	1,835	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued			8						224
Common stock repurchased			0
Stockholder contribution													300
Net loss arising during the period, net of tax	0				0
Settlement arising during the period, net of tax	0				0
Amortization of net actuarial loss	1				1						1				1
Amortization of prior service credit	0				0
Unrealized gain (loss) on derivative instruments	0					0
Reclassification adjustments included in net income	0					0
Net Income	183						189			(6)	186					186
Dividends declared on common stock							(126)									(190)
Dividends declared on preferred stock							(3)									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, 2021	$ 6,653	$ 3	$ 5,397	$ (81)	$ (76)	$ (5)	$ 547		$ 224	$ 563	$ 9,274	$ 841	$ 6,599	$ (34)	$ (34)	$ 1,831	$ 37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in dollars per share)	$ 0.4350
Dividends declared per preferred stock Series C depositary share (in dollars per share)	$ 0.3063