Leases and Palisades Financing - Minimum Annual Rental Commitments post Topic 842 (Details) $ in Millions	Dec. 31, 2020 USD ($)
Operating Leases
2021	$ 10
2022	4
2023	2
2024	1
2025	1
2026 and thereafter	34
Total minimum lease payments	52
Less discount	18
Present value of minimum lease payments	34
Finance Leases
2021	22
2022	19
2023	18
2024	16
2025	14
2026 and thereafter	77
Total minimum lease payments	166
Less discount	106
Present value of minimum lease payments	60
Consumers Energy Company
Operating Leases
2021	8
2022	4
2023	2
2024	1
2025	1
2026 and thereafter	27
Total minimum lease payments	43
Less discount	15
Present value of minimum lease payments	28
Finance Leases
2021	22
2022	19
2023	18
2024	16
2025	14
2026 and thereafter	77
Total minimum lease payments	166
Less discount	106
Present value of minimum lease payments	60
Pipelines and PPAs
Finance Leases
2021	17
2022	14
2023	13
2024	13
2025	13
2026 and thereafter	66
Total minimum lease payments	136
Less discount	103
Present value of minimum lease payments	33
Pipelines and PPAs | Consumers Energy Company
Finance Leases
2021	17
2022	14
2023	13
2024	13
2025	13
2026 and thereafter	66
Total minimum lease payments	136
Less discount	103
Present value of minimum lease payments	33
Other
Finance Leases
2021	5
2022	5
2023	5
2024	3
2025	1
2026 and thereafter	11
Total minimum lease payments	30
Less discount	3
Present value of minimum lease payments	27
Other | Consumers Energy Company
Finance Leases
2021	5
2022	5
2023	5
2024	3
2025	1
2026 and thereafter	11
Total minimum lease payments	30
Less discount	3
Present value of minimum lease payments	$ 27