Financings and Capitalization (Major Long-Term Debt Issuances and Retirements) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	May 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Principal (In Millions)	$ 2,410
CMS Energy
Debt Instrument [Line Items]
Principal (In Millions)	800
NorthStar Clean Energy, Including Subsidiaries
Debt Instrument [Line Items]
Principal (In Millions)	85
Consumers Energy Company
Debt Instrument [Line Items]
Principal (In Millions)	1,525
Convertible debt | 3.375% Convertible Senior Notes Due 2028 | CMS Energy
Debt Instrument [Line Items]
Principal (In Millions)	$ 800	$ 800
Interest rate	3.375%	3.375%
Term loan facility | Term Loan Facility Due 2023 | NorthStar Clean Energy, Including Subsidiaries
Debt Instrument [Line Items]
Principal (In Millions)	$ 85
Interest rate	6.102%
Maximum borrowing capacity			$ 185
Total principal amount outstanding	$ 185
Term loan facility | Term Loan Facility Due 2024
Debt Instrument [Line Items]
Repayments of debt	1,000
First mortgage bonds | 4.650% First Mortgage Bonds Due March 2028 | Consumers Energy Company
Debt Instrument [Line Items]
Principal (In Millions)	$ 425
Interest rate	4.65%
First mortgage bonds | 4.625% First Mortgage Bonds Due May 2033 | Consumers Energy Company
Debt Instrument [Line Items]
Principal (In Millions)	$ 700
Interest rate	4.625%
First mortgage bonds | 5.240% First Mortgage Bonds Due May 2026 | Consumers Energy Company
Debt Instrument [Line Items]
Principal (In Millions)	$ 115
Interest rate	5.24%
First mortgage bonds | 5.070% First Mortgage Bonds Due May 2029 | Consumers Energy Company
Debt Instrument [Line Items]
Principal (In Millions)	$ 50
Interest rate	5.07%
First mortgage bonds | 5.170% First Mortgage Bonds Due May 2032 | Consumers Energy Company
Debt Instrument [Line Items]
Principal (In Millions)	$ 95
Interest rate	5.17%
First mortgage bonds | 5.380% First Mortgage Bonds Due May 2037 | Consumers Energy Company
Debt Instrument [Line Items]
Principal (In Millions)	$ 140
Interest rate	5.38%
First mortgage bonds | 0.350% First Mortgage Bonds Due 2023 | Consumers Energy Company
Debt Instrument [Line Items]
Repayments of debt	$ 300
Interest rate	0.35%