Asset Retirement Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	$ 746	$ 628
Incurred	11	1
Settled	(28)	(39)
Accretion	33	28
Cash Flow Revisions	9	128
ARO Liability, end of period	771	746
Consumers Energy Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	722	605
Incurred	4	1
Settled	(28)	(39)
Accretion	32	27
Cash Flow Revisions	9	128
ARO Liability, end of period	739	722
Renewable generation assets
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	24	23
Incurred	7	0
Settled	0	0
Accretion	1	1
Cash Flow Revisions	0	0
ARO Liability, end of period	32	24
Renewable generation assets | Consumers Energy Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	95	93
Incurred	4	0
Settled	0	0
Accretion	3	2
Cash Flow Revisions	0	0
ARO Liability, end of period	102	95
Coal ash disposal areas | Consumers Energy Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	272	157
Incurred	0	0
Settled	(15)	(20)
Accretion	11	7
Cash Flow Revisions	0	128
ARO Liability, end of period	268	272
Gas distribution cut, purge, and cap | Consumers Energy Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	287	282
Incurred	0	1
Settled	(10)	(11)
Accretion	14	15
Cash Flow Revisions	(1)	0
ARO Liability, end of period	290	287
Asbestos abatement | Consumers Energy Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	39	38
Incurred	0	0
Settled	(1)	(1)
Accretion	3	2
Cash Flow Revisions	10	0
ARO Liability, end of period	51	39
Gas wells plug and abandon | Consumers Energy Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	29	35
Incurred	0	0
Settled	(2)	(7)
Accretion	1	1
Cash Flow Revisions	0	0
ARO Liability, end of period	$ 28	$ 29