Leases - Schedule of Lessee Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash paid for amounts included in the measurement of lease liabilities
Cash used in operating activities for operating leases	$ 6	$ 8
Cash used in operating activities for finance leases	14	16
Cash used in financing activities for finance leases	13	7
Lease liabilities arising from obtaining right-of-use assets
Operating leases	10	2
Finance leases	36	0
Consumers Energy Company
Cash paid for amounts included in the measurement of lease liabilities
Cash used in operating activities for operating leases	6	8
Cash used in operating activities for finance leases	14	16
Cash used in financing activities for finance leases	12	7
Lease liabilities arising from obtaining right-of-use assets
Operating leases	10	2
Finance leases	$ 12	$ 0