Financings and Capitalization (Summary of Long-Term Debt) (Details) - USD ($) $ in Millions			1 Months Ended	12 Months Ended
	Dec. 01, 2030	Jun. 01, 2030	Oct. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total principal amount outstanding				$ 12,568	$ 12,467
Current amounts				(373)	(571)
Unamortized discounts				(31)	(33)
Unamortized issuance costs				(118)	(119)
Long-term debt				12,046	11,744
Consumers Energy Company
Debt Instrument [Line Items]
Total principal amount outstanding				8,505	8,197
Current amounts				(365)	(364)
Unamortized discounts				(28)	(29)
Unamortized issuance costs				(62)	(62)
Long-term debt				8,050	7,742
First Mortgage Bonds | Consumers Energy Company
Debt Instrument [Line Items]
Total principal amount outstanding				$ 8,197	7,897
First Mortgage Bonds | Consumers Energy Company | 0.350% First Mortgage Bonds Due 2023
Debt Instrument [Line Items]
Interest rate				0.35%
Total principal amount outstanding				$ 300	300
First Mortgage Bonds | Consumers Energy Company | 3.375% First Mortgage Bonds Due 2023
Debt Instrument [Line Items]
Interest rate				3.375%
Total principal amount outstanding				$ 325	325
First Mortgage Bonds | Consumers Energy Company | 3.125% First Mortgage Bonds Due 2024
Debt Instrument [Line Items]
Interest rate				3.125%
Total principal amount outstanding				$ 250	250
First Mortgage Bonds | Consumers Energy Company | 3.190% First Mortgage Bonds Due 2024
Debt Instrument [Line Items]
Interest rate				3.19%
Total principal amount outstanding				$ 52	52
First Mortgage Bonds | Consumers Energy Company | 3.680% First Mortgage Bonds Due 2027
Debt Instrument [Line Items]
Interest rate				3.68%
Total principal amount outstanding				$ 100	100
First Mortgage Bonds | Consumers Energy Company | 3.390 % First Mortgage Bonds Due 2027
Debt Instrument [Line Items]
Interest rate				3.39%
Total principal amount outstanding				$ 35	35
First Mortgage Bonds | Consumers Energy Company | 3.800% First Mortgage Bonds Due 2028
Debt Instrument [Line Items]
Interest rate				3.80%
Total principal amount outstanding				$ 300	300
First Mortgage Bonds | Consumers Energy Company | 3.180% First Mortgage Bonds Due 2032
Debt Instrument [Line Items]
Interest rate				3.18%
Total principal amount outstanding				$ 100	100
First Mortgage Bonds | Consumers Energy Company | 5.800 % First Mortgage Bonds Due 2035
Debt Instrument [Line Items]
Interest rate				5.80%
Total principal amount outstanding				$ 175	175
First Mortgage Bonds | Consumers Energy Company | 3.520% First Mortgage Bonds Due 2037
Debt Instrument [Line Items]
Interest rate				3.52%
Total principal amount outstanding				$ 335	335
First Mortgage Bonds | Consumers Energy Company | 4.010% First Mortgage Bonds Due 2038
Debt Instrument [Line Items]
Interest rate				4.01%
Total principal amount outstanding				$ 215	215
First Mortgage Bonds | Consumers Energy Company | 6.170% First Mortgage Bonds Due 2040
Debt Instrument [Line Items]
Interest rate				6.17%
Total principal amount outstanding				$ 50	50
First Mortgage Bonds | Consumers Energy Company | 4.970% First Mortgage Bonds Due 2040
Debt Instrument [Line Items]
Interest rate				4.97%
Total principal amount outstanding				$ 50	50
First Mortgage Bonds | Consumers Energy Company | 4.310% First Mortgage Bonds Due 2042
Debt Instrument [Line Items]
Interest rate				4.31%
Total principal amount outstanding				$ 263	263
First Mortgage Bonds | Consumers Energy Company | 3.950% First Mortgage Bonds Due 2043
Debt Instrument [Line Items]
Interest rate				3.95%
Total principal amount outstanding				$ 425	425
First Mortgage Bonds | Consumers Energy Company | 4.100% First Mortgage Bonds Due 2045
Debt Instrument [Line Items]
Interest rate				4.10%
Total principal amount outstanding				$ 250	250
First Mortgage Bonds | Consumers Energy Company | 3.250% First Mortgage Bonds Due 2046
Debt Instrument [Line Items]
Interest rate				3.25%
Total principal amount outstanding				$ 450	450
First Mortgage Bonds | Consumers Energy Company | 3.950% First Mortgage Bonds Due 2047
Debt Instrument [Line Items]
Interest rate				3.95%
Total principal amount outstanding				$ 350	350
First Mortgage Bonds | Consumers Energy Company | 4.050% First Mortgage Bonds Due 2048
Debt Instrument [Line Items]
Interest rate				4.05%
Total principal amount outstanding				$ 550	550
First Mortgage Bonds | Consumers Energy Company | 4.350% First Mortgage Bonds Due 2049
Debt Instrument [Line Items]
Interest rate				4.35%
Total principal amount outstanding				$ 550	550
First Mortgage Bonds | Consumers Energy Company | 3.750% First Mortgage Bonds Due 2050
Debt Instrument [Line Items]
Interest rate				3.75%
Total principal amount outstanding				$ 300	300
First Mortgage Bonds | Consumers Energy Company | 3.100% First Mortgage Bonds Due 2050
Debt Instrument [Line Items]
Interest rate				3.10%
Total principal amount outstanding				$ 550	550
First Mortgage Bonds | Consumers Energy Company | 3.500% First Mortgage Bonds Due 2051
Debt Instrument [Line Items]
Interest rate				3.50%
Total principal amount outstanding				$ 575	575
First Mortgage Bonds | Consumers Energy Company | 2.650% First Mortgage Bonds Due 2052
Debt Instrument [Line Items]
Interest rate				2.65%
Total principal amount outstanding				$ 300	0
First Mortgage Bonds | Consumers Energy Company | 3.860% First Mortgage Bonds Due 2052
Debt Instrument [Line Items]
Interest rate				3.86%
Total principal amount outstanding				$ 50	50
First Mortgage Bonds | Consumers Energy Company | 4.280% First Mortgage Bonds Due 2057
Debt Instrument [Line Items]
Interest rate				4.28%
Total principal amount outstanding				$ 185	185
First Mortgage Bonds | Consumers Energy Company | 2.500% First Mortgage Bonds Due 2060
Debt Instrument [Line Items]
Interest rate				2.50%
Total principal amount outstanding				$ 525	525
First Mortgage Bonds | Consumers Energy Company | 4.350% First Mortgage Bonds Due 2064
Debt Instrument [Line Items]
Interest rate				4.35%
Total principal amount outstanding				$ 250	250
First Mortgage Bonds | Consumers Energy Company | Variable Rate First Mortgage Bonds Due 2069
Debt Instrument [Line Items]
Total principal amount outstanding				76	76
First Mortgage Bonds | Consumers Energy Company | Variable Rate First Mortgage Bonds Due 2070
Debt Instrument [Line Items]
Total principal amount outstanding				134	134
First Mortgage Bonds | Consumers Energy Company | Variable Rate First Mortgage Bonds Due 2070
Debt Instrument [Line Items]
Total principal amount outstanding				$ 127	$ 127
First Mortgage Bonds | Consumers Energy Company | Variable Rate First Mortgage Bonds
Debt Instrument [Line Items]
Basis spread on variable rate				0.30%
Interest rate at period end				0.00%	0.00%
Tax Exempt Revenue Bonds | Consumers Energy Company
Debt Instrument [Line Items]
Total principal amount outstanding				$ 110	$ 75
Tax Exempt Revenue Bonds | Consumers Energy Company | 0.875% Tax Exempt Revenue Bonds Due 2035
Debt Instrument [Line Items]
Interest rate				0.875%
Total principal amount outstanding				$ 35	0
Tax Exempt Revenue Bonds | Consumers Energy Company | 1.800% Tax Exempt Revenue Bonds Due 2049
Debt Instrument [Line Items]
Interest rate				1.80%
Total principal amount outstanding				$ 75	$ 75
Securitization bonds | Consumers Energy Company | Securitization Bonds
Debt Instrument [Line Items]
Weighted average interest rate				3.29%	3.25%
Total principal amount outstanding				$ 198	$ 225
CMS Energy
Debt Instrument [Line Items]
Total principal amount outstanding				3,985	4,185
Long-term debt				3,928	3,926
CMS Energy | Senior notes
Debt Instrument [Line Items]
Total principal amount outstanding				$ 1,975	1,975
CMS Energy | Senior notes | 3.875% Senior Notes Due 2024
Debt Instrument [Line Items]
Interest rate				3.875%
Total principal amount outstanding				$ 250	250
CMS Energy | Senior notes | 3.600% Senior Notes Due 2025
Debt Instrument [Line Items]
Interest rate				3.60%
Total principal amount outstanding				$ 250	250
CMS Energy | Senior notes | 3.000% Senior Notes Due 2026
Debt Instrument [Line Items]
Interest rate				3.00%
Total principal amount outstanding				$ 300	300
CMS Energy | Senior notes | 2.950% Senior Notes Due 2027
Debt Instrument [Line Items]
Interest rate				2.95%
Total principal amount outstanding				$ 275	275
CMS Energy | Senior notes | 3.450% Senior Notes Due 2027
Debt Instrument [Line Items]
Interest rate				3.45%
Total principal amount outstanding				$ 350	350
CMS Energy | Senior notes | 4.700% Senior Notes Due 2043
Debt Instrument [Line Items]
Interest rate				4.70%
Total principal amount outstanding				$ 250	250
CMS Energy | Senior notes | 4.875% Senior Notes Due 2044
Debt Instrument [Line Items]
Interest rate				4.875%
Total principal amount outstanding				$ 300	300
CMS Energy | Term loan facility | Term Loan Facility Due 2021
Debt Instrument [Line Items]
Total principal amount outstanding				0	200
CMS Energy | Junior subordinated notes
Debt Instrument [Line Items]
Total principal amount outstanding				$ 2,010	2,010
CMS Energy | Junior subordinated notes | 4.750% Junior Subordinated Notes Due 2050
Debt Instrument [Line Items]
Interest rate				4.75%
Total principal amount outstanding				$ 500	500
CMS Energy | Junior subordinated notes | 3.750% Junior Subordinated Notes Due 2050
Debt Instrument [Line Items]
Interest rate				3.75%
Total principal amount outstanding				$ 400	400
CMS Energy | Junior subordinated notes | 5.625% Junior Subordinated Notes Due 2078
Debt Instrument [Line Items]
Interest rate				5.625%
Total principal amount outstanding				$ 200	200
CMS Energy | Junior subordinated notes | 5.875% Junior Subordinated Notes Due 2078
Debt Instrument [Line Items]
Interest rate				5.875%
Total principal amount outstanding				$ 280	280
CMS Energy | Junior subordinated notes | 5.875% Junior Subordinated Notes Due 2079
Debt Instrument [Line Items]
Interest rate				5.875%
Total principal amount outstanding				$ 630	630
CMS Enterprises Including Subsidiaries | Term loan facility | Term Loan Facility Due 2025
Debt Instrument [Line Items]
Total principal amount outstanding				$ 78	$ 85
Basis spread on variable rate				1.50%
Interest rate at period end				1.724%	1.754%
Fixed interest rate				4.702%
Forecast | CMS Energy | Junior subordinated notes | 4.750% Junior Subordinated Notes Due 2050 | US Treasury (UST) Interest Rate
Debt Instrument [Line Items]
Basis spread on variable rate		4.116%
Forecast | CMS Energy | Junior subordinated notes | 3.750% Junior Subordinated Notes Due 2050 | US Treasury (UST) Interest Rate
Debt Instrument [Line Items]
Basis spread on variable rate	2.90%
Forecast | CMS Enterprises Including Subsidiaries | Term loan facility | Term Loan Facility Due 2025
Debt Instrument [Line Items]
Basis spread on variable rate			1.75%
Fixed interest rate			4.952%