Consolidated Statements of Changes In Equity (Unaudited) - USD ($) $ in Millions	Total	Common Stock	Other Paid-in Capital	Accumulated Other Comprehensive Loss	Retirement benefits liability	Investments	Derivative instruments	Derivative instruments	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 Investments	Consumers Energy Company Accumulated Deficit	Consumers Energy Company Preferred Stock
Total Equity at Beginning of Period at Dec. 31, 2017	$ 4,478	$ 3	$ 5,019	$ (50)	$ (50)	$ 0	$ 0		$ (531)	$ 37	$ 6,488	$ 841	$ 4,449	$ (12)	$ (24)	$ 12	$ 1,173	$ 37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued			47
Common stock repurchased			(10)
Common stock reissued			20
Stockholder contribution													250
Amortization of net actuarial loss	2				2						1				1
Amortization of prior service credit	(1)				(1)
Unrealized loss on investments	(1)					(1)					(1)					(1)
Unrealized loss on derivative instruments, net of tax of $(1), $-, $(1), and $-	0
Net income	381								380	1	394						394
Dividends declared on common stock									(203)								(245)
Dividends declared on preferred stock																	(1)
Distributions and other changes in noncontrolling interests										(1)
Total Equity at End of Period at Jun. 30, 2018	$ 4,709		5,076	(61)	(60)	(1)			(346)	37	6,888	841	4,699	(29)	(28)	(1)	1,340	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in dollars per share)	$ 0.7150
Total Equity at Beginning of Period at Dec. 31, 2017	$ 4,478	3	5,019	(50)	(50)	0	0		(531)	37	6,488	841	4,449	(12)	(24)	12	1,173	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized loss on derivative instruments, net of tax of $(1), $-, $(1), and $-							0
Total Equity at End of Period at Dec. 31, 2018	4,792	3	5,088	(65)	(63)	0		$ (2)	(271)	37	6,920	841	4,699	(21)	(21)	0	1,364	37
Total Equity at Beginning of Period at Mar. 31, 2018	4,633	3	5,037	(61)	(60)	(1)	0		(383)	37	6,713	841	4,549	(29)	(28)	(1)	1,315	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued			39
Common stock repurchased			0
Common stock reissued			0
Stockholder contribution													150
Amortization of net actuarial loss	1				1						0				0
Amortization of prior service credit	(1)				(1)
Unrealized loss on investments	0					0					0					0
Unrealized loss on derivative instruments, net of tax of $(1), $-, $(1), and $-	0						$ 0
Net income	140								139	1	152						152
Dividends declared on common stock									(102)								(126)
Dividends declared on preferred stock																	(1)
Distributions and other changes in noncontrolling interests										(1)
Total Equity at End of Period at Jun. 30, 2018	$ 4,709		5,076	(61)	(60)	(1)			(346)	37	6,888	841	4,699	(29)	(28)	(1)	1,340	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in dollars per share)	$ 0.3575
Total Equity at Beginning of Period at Dec. 31, 2018	$ 4,792	3	5,088	(65)	(63)	0		(2)	(271)	37	6,920	841	4,699	(21)	(21)	0	1,364	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued			17
Common stock repurchased			(8)
Common stock reissued			0
Stockholder contribution													675
Amortization of net actuarial loss	2				2						1				1
Amortization of prior service credit	(1)				(1)
Unrealized loss on investments	0					0					0					0
Unrealized loss on derivative instruments	(3)							(3)
Net income	307								306	1	324						324
Dividends declared on common stock									(217)								(272)
Dividends declared on preferred stock																	(1)
Distributions and other changes in noncontrolling interests										(1)
Total Equity at End of Period at Jun. 30, 2019	$ 4,888		5,097	(67)	(62)	0		(5)	(182)	37	7,647	841	5,374	(20)	(20)	0	1,415	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in dollars per share)	$ 0.7650
Total Equity at Beginning of Period at Mar. 31, 2019	$ 4,895	$ 3	5,087	(66)	(63)	0		(3)	(166)	37	7,324	841	5,049	(21)	(21)	0	1,418	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued			10
Common stock repurchased			0
Common stock reissued			0
Stockholder contribution													325
Amortization of net actuarial loss	1				1						1				1
Amortization of prior service credit	0				0
Unrealized loss on investments	0					0					0					0
Unrealized loss on derivative instruments	(2)							(2)
Net income	94								93	1	98						98
Dividends declared on common stock									(109)								(100)
Dividends declared on preferred stock																	(1)
Distributions and other changes in noncontrolling interests										(1)
Total Equity at End of Period at Jun. 30, 2019	$ 4,888		$ 5,097	$ (67)	$ (62)	$ 0		$ (5)	$ (182)	$ 37	$ 7,647	$ 841	$ 5,374	$ (20)	$ (20)	$ 0	$ 1,415	$ 37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in dollars per share)	$ 0.3825