Leases and Palisades Financing - Palisades Financing (Details) - Financing Obligation - Consumers Energy Company - Palisades Power Purchase Agreement $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) MW	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2007
Other Commitments [Line Items]
Finance obligation term				15 years
Annual average capacity (in MW) | MW	798
Amortization and interest expense	$ 14	$ 14	$ 15
Palisades asset	3
Palisades financing obligation	$ 3