Asset Retirement Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	$ 771	$ 746
Incurred	1	11
Settled	(69)	(28)
Accretion	35	33
Cash Flow Revisions	(10)	9
ARO Liability, end of period	728	771
Consumers Energy Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	739	722
Incurred	1	4
Settled	(69)	(28)
Accretion	33	32
Cash Flow Revisions	(10)	9
ARO Liability, end of period	694	739
Renewable generation assets
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	32	24
Incurred	0	7
Settled	0	0
Accretion	2	1
Cash Flow Revisions	0	0
ARO Liability, end of period	34	32
Renewable generation assets | Consumers Energy Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	102	95
Incurred	0	4
Settled	0	0
Accretion	3	3
Cash Flow Revisions	0	0
ARO Liability, end of period	105	102
Coal ash disposal areas | Consumers Energy Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	268	272
Incurred	1	0
Settled	(51)	(15)
Accretion	12	11
Cash Flow Revisions	0	0
ARO Liability, end of period	230	268
Gas distribution cut, purge, and cap | Consumers Energy Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	290	287
Incurred	0	0
Settled	(9)	(10)
Accretion	15	14
Cash Flow Revisions	(1)	(1)
ARO Liability, end of period	295	290
Asbestos abatement | Consumers Energy Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	51	39
Incurred	0	0
Settled	(7)	(1)
Accretion	2	3
Cash Flow Revisions	(9)	10
ARO Liability, end of period	37	51
Gas wells plug and abandon | Consumers Energy Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO Liability, at beginning of period	28	29
Incurred	0	0
Settled	(2)	(2)
Accretion	1	1
Cash Flow Revisions	0	0
ARO Liability, end of period	$ 27	$ 28