Contingencies and Commitments (Narrative) (Details) $ in Millions	1 Months Ended		12 Months Ended
	Jul. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2023 USD ($) MW $ / MWh facility	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Loss Contingencies [Line Items]
Environmental Loss Contingency, Statement Of Financial Position, Extensible Enumeration, Not Disclosed Flag			recorded liability
Regulatory assets			$ 3,683	$ 3,595
Consumers Energy Company
Loss Contingencies [Line Items]
Regulatory assets			$ 3,683	3,595
Consumers Energy Company | MCV PPA
Loss Contingencies [Line Items]
PPA maximum quantity required | MW			1,240
PPA fixed energy charge per MWh, on-peak (in dollars per MWh) | $ / MWh			6.30
PPA fixed energy charge per MWh, off-peak (in dollars per MWh) | $ / MWh			6.00
Annual contribution to renewable resources program by counterparty			$ 5
Purchases			$ 340	519	$ 348
Consumers Energy Company | MCV PPA | Year End Through March 2025
Loss Contingencies [Line Items]
PPA capacity charge per MWh (in dollars per MWh) | $ / MWh			10.14
Consumers Energy Company | MCV PPA | March 2025 Through Termination
Loss Contingencies [Line Items]
PPA capacity charge per MWh (in dollars per MWh) | $ / MWh			5.00
Consumers Energy Company | Other PPAs
Loss Contingencies [Line Items]
Purchases			$ 498	510	$ 338
Consumers Energy Company | MGP sites
Loss Contingencies [Line Items]
Regulatory assets			$ 99	$ 108
Consumers Energy Company | Ludington
Loss Contingencies [Line Items]
Ownership share			51.00%
Consumers Energy Company | Ludington Plant Overhaul Contract Dispute
Loss Contingencies [Line Items]
Damages sought		$ 15
Consumers Energy Company | J.H. Campbell 3 Plant Retirement Contract Dispute
Loss Contingencies [Line Items]
Damages sought	$ 37
Bay Harbor
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies			$ 45
Discount rate			4.34%
Accrual for environmental loss contingencies, inflation rate			1.00%
Accrual for environmental loss contingencies, gross			$ 57
NREPA | Electric Utility | Consumers Energy Company
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies			2
NREPA | Gas Utility | Consumers Energy Company
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies			1
NREPA | Minimum | Electric Utility | Consumers Energy Company
Loss Contingencies [Line Items]
Remediation and other response activity costs			2
NREPA | Maximum | Electric Utility | Consumers Energy Company
Loss Contingencies [Line Items]
Remediation and other response activity costs			4
NREPA | Maximum | Gas Utility | Consumers Energy Company
Loss Contingencies [Line Items]
Remediation and other response activity costs			1
CERCLA Liability | Consumers Energy Company
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies			3
CERCLA Liability | Minimum | Consumers Energy Company
Loss Contingencies [Line Items]
Remediation and other response activity costs			3
CERCLA Liability | Maximum | Consumers Energy Company
Loss Contingencies [Line Items]
Remediation and other response activity costs			8
MGP sites | Consumers Energy Company
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies			$ 62
Number of former MGPs | facility			23
Regulatory asset collection period			10 years