Financings and Capitalization (Major Long-Term Debt Issuances and Retirements) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2024 USD ($)
Debt Instrument [Line Items]
Principal Debt Issuances (In Millions)	$ 1,300
Principal Debt Retirements (In Millions)	500
Consumers Energy Company
Debt Instrument [Line Items]
Principal Debt Issuances (In Millions)	1,300
Principal Debt Retirements (In Millions)	250
First mortgage bonds | 4.600% First Mortgage Bonds Due May 2029 | Consumers Energy Company
Debt Instrument [Line Items]
Principal Debt Issuances (In Millions)	$ 600
Interest rate	4.60%
First mortgage bonds | 4.700% First Mortgage Bonds Due January 2030 | Consumers Energy Company
Debt Instrument [Line Items]
Principal Debt Issuances (In Millions)	$ 700
Interest rate	4.70%
First mortgage bonds | 3.125% First Mortgage Bonds Due August 2024 | Consumers Energy Company
Debt Instrument [Line Items]
Interest rate	3.125%
Principal Debt Retirements (In Millions)	$ 250
CMS Energy
Debt Instrument [Line Items]
Principal Debt Retirements (In Millions)	$ 250
CMS Energy | Senior notes | 3.875% Senior Notes Due March 2024
Debt Instrument [Line Items]
Interest rate	3.875%
Principal Debt Retirements (In Millions)	$ 250