Leases and Palisades Financing - Assets and Liabilities of Lessee (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Operating leases
Right-of-use assets	$ 26	$ 32
Lease liabilities
Current lease liabilities	3	7
Noncurrent lease liabilities	23	25
Finance leases
Right-of-use assets	57	65
Lease liabilities
Current lease liabilities	6	7
Non-current lease liabilities	$ 46	$ 53
Weighted-average remaining lease term (in years)
Operating leases	23 years	19 years
Finance leases	12 years	12 years
Weighted-average discount rate
Operating leases	4.00%	3.90%
Finance leases	1.70%	1.80%
Finance lease liability	$ 52
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other	Other
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other current liabilities	Other current liabilities
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other non‑current liabilities	Other non‑current liabilities
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Plant, property, and equipment, net	Plant, property, and equipment, net
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Current portion of long-term debt, finance leases, and other financing	Current portion of long-term debt, finance leases, and other financing
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Non-current portion of finance leases and other financing	Non-current portion of finance leases and other financing
Consumers Energy Company
Operating leases
Right-of-use assets	$ 22	$ 28
Lease liabilities
Current lease liabilities	3	7
Noncurrent lease liabilities	19	21
Finance leases
Right-of-use assets	57	65
Lease liabilities
Current lease liabilities	6	7
Non-current lease liabilities	$ 46	$ 53
Weighted-average remaining lease term (in years)
Operating leases	21 years	18 years
Finance leases	12 years	12 years
Weighted-average discount rate
Operating leases	3.90%	3.80%
Finance leases	1.70%	1.80%
Finance lease liability	$ 52
Related Party Lease
Lease liabilities
Current lease liabilities	1	$ 1
Weighted-average discount rate
Finance lease liability	$ 25	$ 25