Financings and Capitalization (Summary of Long-Term Debt Outstanding) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Oct. 31, 2022	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Principal amounts outstanding		$ 15,272,000,000	$ 13,188,000,000
Current amounts		(1,486,000,000)	(1,111,000,000)
Unamortized discounts		(33,000,000)	(27,000,000)
Unamortized issuance costs		(119,000,000)	(99,000,000)
Long-term debt		13,634,000,000	11,951,000,000
Consumers Energy Company
Debt Instrument [Line Items]
Principal amounts outstanding		8,197,000,000	7,322,000,000
Current amounts		(364,000,000)	(202,000,000)
Unamortized discounts		(29,000,000)	(23,000,000)
Unamortized issuance costs		(62,000,000)	(49,000,000)
Long-term debt		7,742,000,000	7,048,000,000
Certificates of deposit | EnerBank Certificates Of Deposit | EnerBank
Debt Instrument [Line Items]
Certificates of deposit		$ 2,805,000,000	$ 2,389,000,000
Weighted-average interest rate		1.621%	2.445%
Certificate of deposit face value		$ 1,000
First Mortgage Bonds | Consumers Energy Company
Debt Instrument [Line Items]
Principal amounts outstanding		$ 7,897,000,000	$ 6,961,000,000
First Mortgage Bonds | Consumers Energy Company | 3.770% Percent First Mortgage Bonds Due 2020
Debt Instrument [Line Items]
Interest rate		3.77%
Principal amounts outstanding		$ 0	100,000,000
First Mortgage Bonds | Consumers Energy Company | 2.850% First Mortgage Bonds Due 2022
Debt Instrument [Line Items]
Interest rate		2.85%
Principal amounts outstanding		$ 0	375,000,000
First Mortgage Bonds | Consumers Energy Company | 5.300% First Mortgage Bonds Due 2022
Debt Instrument [Line Items]
Interest rate		5.30%
Principal amounts outstanding		$ 0	250,000,000
First Mortgage Bonds | Consumers Energy Company | 3.375% First Mortgage Bonds Due 2023
Debt Instrument [Line Items]
Interest rate		3.375%
Principal amounts outstanding		$ 325,000,000	325,000,000
First Mortgage Bonds | Consumers Energy Company | 0.350% First Mortgage Bonds Due 2023
Debt Instrument [Line Items]
Interest rate		0.35%
Principal amounts outstanding		$ 300,000,000	0
First Mortgage Bonds | Consumers Energy Company | 3.125% First Mortgage Bonds Due 2024
Debt Instrument [Line Items]
Interest rate		3.125%
Principal amounts outstanding		$ 250,000,000	250,000,000
First Mortgage Bonds | Consumers Energy Company | 3.190% First Mortgage Bonds Due 2024
Debt Instrument [Line Items]
Interest rate		3.19%
Principal amounts outstanding		$ 52,000,000	52,000,000
First Mortgage Bonds | Consumers Energy Company | 3.680% First Mortgage Bonds Due 2027
Debt Instrument [Line Items]
Interest rate		3.68%
Principal amounts outstanding		$ 100,000,000	100,000,000
First Mortgage Bonds | Consumers Energy Company | 3.390 % First Mortgage Bonds Due 2027
Debt Instrument [Line Items]
Interest rate		3.39%
Principal amounts outstanding		$ 35,000,000	35,000,000
First Mortgage Bonds | Consumers Energy Company | 3.800% First Mortgage Bonds Due 2028
Debt Instrument [Line Items]
Interest rate		3.80%
Principal amounts outstanding		$ 300,000,000	300,000,000
First Mortgage Bonds | Consumers Energy Company | 3.180% First Mortgage Bonds Due 2032
Debt Instrument [Line Items]
Interest rate		3.18%
Principal amounts outstanding		$ 100,000,000	100,000,000
First Mortgage Bonds | Consumers Energy Company | 5.800 % First Mortgage Bonds Due 2035
Debt Instrument [Line Items]
Interest rate		5.80%
Principal amounts outstanding		$ 175,000,000	175,000,000
First Mortgage Bonds | Consumers Energy Company | 3.520% First Mortgage Bonds Due 2037
Debt Instrument [Line Items]
Interest rate		3.52%
Principal amounts outstanding		$ 335,000,000	335,000,000
First Mortgage Bonds | Consumers Energy Company | 4.010% First Mortgage Bonds Due 2038
Debt Instrument [Line Items]
Interest rate		4.01%
Principal amounts outstanding		$ 215,000,000	215,000,000
First Mortgage Bonds | Consumers Energy Company | 6.170% First Mortgage Bonds Due 2040
Debt Instrument [Line Items]
Interest rate		6.17%
Principal amounts outstanding		$ 50,000,000	50,000,000
First Mortgage Bonds | Consumers Energy Company | 4.970% First Mortgage Bonds Due 2040
Debt Instrument [Line Items]
Interest rate		4.97%
Principal amounts outstanding		$ 50,000,000	50,000,000
First Mortgage Bonds | Consumers Energy Company | 4.310% First Mortgage Bonds Due 2042
Debt Instrument [Line Items]
Interest rate		4.31%
Principal amounts outstanding		$ 263,000,000	263,000,000
First Mortgage Bonds | Consumers Energy Company | 3.950% First Mortgage Bonds Due 2043
Debt Instrument [Line Items]
Interest rate		3.95%
Principal amounts outstanding		$ 425,000,000	425,000,000
First Mortgage Bonds | Consumers Energy Company | 4.100% First Mortgage Bonds Due 2045
Debt Instrument [Line Items]
Interest rate		4.10%
Principal amounts outstanding		$ 250,000,000	250,000,000
First Mortgage Bonds | Consumers Energy Company | 3.250% First Mortgage Bonds Due 2046
Debt Instrument [Line Items]
Interest rate		3.25%
Principal amounts outstanding		$ 450,000,000	450,000,000
First Mortgage Bonds | Consumers Energy Company | 3.950% First Mortgage Bonds Due 2047
Debt Instrument [Line Items]
Interest rate		3.95%
Principal amounts outstanding		$ 350,000,000	350,000,000
First Mortgage Bonds | Consumers Energy Company | 4.050% First Mortgage Bonds Due 2048
Debt Instrument [Line Items]
Interest rate		4.05%
Principal amounts outstanding		$ 550,000,000	550,000,000
First Mortgage Bonds | Consumers Energy Company | 4.350% First Mortgage Bonds Due 2049
Debt Instrument [Line Items]
Interest rate		4.35%
Principal amounts outstanding		$ 550,000,000	550,000,000
First Mortgage Bonds | Consumers Energy Company | 3.750% First Mortgage Bonds Due 2050
Debt Instrument [Line Items]
Interest rate		3.75%
Principal amounts outstanding		$ 300,000,000	300,000,000
First Mortgage Bonds | Consumers Energy Company | 3.100% First Mortgage Bonds Due 2050
Debt Instrument [Line Items]
Interest rate		3.10%
Principal amounts outstanding		$ 550,000,000	550,000,000
First Mortgage Bonds | Consumers Energy Company | 3.500% First Mortgage Bonds Due 2051
Debt Instrument [Line Items]
Interest rate		3.50%
Principal amounts outstanding		$ 575,000,000	0
First Mortgage Bonds | Consumers Energy Company | 3.860% First Mortgage Bonds Due 2052
Debt Instrument [Line Items]
Interest rate		3.86%
Principal amounts outstanding		$ 50,000,000	50,000,000
First Mortgage Bonds | Consumers Energy Company | 4.280% First Mortgage Bonds Due 2057
Debt Instrument [Line Items]
Interest rate		4.28%
Principal amounts outstanding		$ 185,000,000	185,000,000
First Mortgage Bonds | Consumers Energy Company | 2.500% First Mortgage Bonds Due 2060
Debt Instrument [Line Items]
Interest rate		2.50%
Principal amounts outstanding		$ 525,000,000	0
First Mortgage Bonds | Consumers Energy Company | 4.350% First Mortgage Bonds Due 2064
Debt Instrument [Line Items]
Interest rate		4.35%
Principal amounts outstanding		$ 250,000,000	250,000,000
First Mortgage Bonds | Consumers Energy Company | Variable Rate First Mortgage Bonds Due 2069
Debt Instrument [Line Items]
Principal amounts outstanding		76,000,000	76,000,000
First Mortgage Bonds | Consumers Energy Company | Variable Rate First Mortgage Bonds Due 2070
Debt Instrument [Line Items]
Principal amounts outstanding		134,000,000	0
First Mortgage Bonds | Consumers Energy Company | Variable Rate First Mortgage Bonds Due 2070
Debt Instrument [Line Items]
Principal amounts outstanding		$ 127,000,000	0
First Mortgage Bonds | Consumers Energy Company | Variable Rate First Mortgage Bonds
Debt Instrument [Line Items]
Interest rate at period end		0.00%
Three-month LIBOR plus a spread		0.30%
Tax Exempt Revenue Bonds | Consumers Energy Company
Debt Instrument [Line Items]
Principal amounts outstanding		$ 75,000,000	110,000,000
Tax Exempt Revenue Bonds | Consumers Energy Company | Tax Exempt Revenue Bonds Due 2035
Debt Instrument [Line Items]
Principal amounts outstanding		0	35,000,000
Tax Exempt Revenue Bonds | Consumers Energy Company | 1.800% Tax Exempt Revenue Bonds Due 2049
Debt Instrument [Line Items]
Principal amounts outstanding		$ 75,000,000	75,000,000
Weighted average interest rate		1.80%
Securitization bonds | Consumers Energy Company | Securitization Bonds
Debt Instrument [Line Items]
Principal amounts outstanding		$ 225,000,000	$ 251,000,000
Weighted average interest rate		3.25%	3.22%
CMS Energy
Debt Instrument [Line Items]
Principal amounts outstanding		$ 4,185,000,000	$ 3,385,000,000
Long-term debt		3,926,000,000	3,334,000,000
CMS Energy | Senior notes
Debt Instrument [Line Items]
Principal amounts outstanding		$ 1,975,000,000	2,275,000,000
CMS Energy | Senior notes | 5.050% Senior Notes Due 2022
Debt Instrument [Line Items]
Interest rate		5.05%
Principal amounts outstanding		$ 0	300,000,000
CMS Energy | Senior notes | 3.875% Senior Notes Due 2024
Debt Instrument [Line Items]
Interest rate		3.875%
Principal amounts outstanding		$ 250,000,000	250,000,000
CMS Energy | Senior notes | 3.600% Senior Notes Due 2025
Debt Instrument [Line Items]
Interest rate		3.60%
Principal amounts outstanding		$ 250,000,000	250,000,000
CMS Energy | Senior notes | 3.000% Senior Notes Due 2026
Debt Instrument [Line Items]
Interest rate		3.00%
Principal amounts outstanding		$ 300,000,000	300,000,000
CMS Energy | Senior notes | 2.950% Senior Notes Due 2027
Debt Instrument [Line Items]
Interest rate		2.95%
Principal amounts outstanding		$ 275,000,000	275,000,000
CMS Energy | Senior notes | 3.450% Senior Notes Due 2027
Debt Instrument [Line Items]
Interest rate		3.45%
Principal amounts outstanding		$ 350,000,000	350,000,000
CMS Energy | Senior notes | 4.700% Senior Notes Due 2043
Debt Instrument [Line Items]
Interest rate		4.70%
Principal amounts outstanding		$ 250,000,000	250,000,000
CMS Energy | Senior notes | 4.875% Senior Notes Due 2044
Debt Instrument [Line Items]
Interest rate		4.875%
Principal amounts outstanding		$ 300,000,000	300,000,000
CMS Energy | Term loans and revolving credit agreements | Term Loan Facility Due 2021
Debt Instrument [Line Items]
Principal amounts outstanding		$ 200,000,000	0
Interest rate at period end		0.60%
Three-month LIBOR plus a spread		0.50%
CMS Energy | Junior subordinated notes
Debt Instrument [Line Items]
Principal amounts outstanding		$ 2,010,000,000	1,110,000,000
CMS Energy | Junior subordinated notes | 4.750% Junior Subordinated Notes Due 2050
Debt Instrument [Line Items]
Interest rate		4.75%
Principal amounts outstanding		$ 500,000,000	0
CMS Energy | Junior subordinated notes | 3.750% Junior Subordinated Notes Due 2050
Debt Instrument [Line Items]
Interest rate		3.75%
Principal amounts outstanding		$ 400,000,000	0
CMS Energy | Junior subordinated notes | 5.625% Junior Subordinated Notes Due 2078
Debt Instrument [Line Items]
Interest rate		5.625%
Principal amounts outstanding		$ 200,000,000	200,000,000
CMS Energy | Junior subordinated notes | 5.875% Junior Subordinated Notes Due 2078
Debt Instrument [Line Items]
Interest rate		5.875%
Principal amounts outstanding		$ 280,000,000	280,000,000
CMS Energy | Junior subordinated notes | 5.875% Junior Subordinated Notes Due 2079
Debt Instrument [Line Items]
Interest rate		5.875%
Principal amounts outstanding		$ 630,000,000	630,000,000
CMS Enterprises Including Subsidiaries | Term loans and revolving credit agreements | Term Loan Facility Due 2025
Debt Instrument [Line Items]
Principal amounts outstanding		$ 85,000,000	$ 92,000,000
Interest rate at period end		1.754%	3.445%
Three-month LIBOR plus a spread		1.50%
Fixed interest rate		4.702%
Forecast | CMS Enterprises Including Subsidiaries | Term loans and revolving credit agreements | Term Loan Facility Due 2025
Debt Instrument [Line Items]
Three-month LIBOR plus a spread	1.75%
Fixed interest rate	4.952%