Leases (Summary of Minimum Annual Rental Commitments) (Details) $ in Millions	Dec. 31, 2024 USD ($)
Operating Leases
2025	$ 4
2026	3
2027	2
2028	2
2029	2
2028 and thereafter	29
Total minimum lease payments	42
Less discount	18
Present value of minimum lease payments	24
Finance Leases
2025	20
2026	20
2027	18
2028	18
2029	18
2028 and thereafter	190
Total minimum lease payments	284
Less discount	168
Present value of minimum lease payments	116
Consumers Energy Company
Operating Leases
2025	4
2026	3
2027	2
2028	2
2029	1
2028 and thereafter	23
Total minimum lease payments	35
Less discount	15
Present value of minimum lease payments	20
Finance Leases
2025	17
2026	17
2027	16
2028	15
2029	15
2028 and thereafter	84
Total minimum lease payments	164
Less discount	91
Present value of minimum lease payments	73
Pipelines and PPAs
Finance Leases
2025	13
2026	13
2027	13
2028	13
2029	13
2028 and thereafter	13
Total minimum lease payments	78
Less discount	50
Present value of minimum lease payments	28
Pipelines and PPAs | Consumers Energy Company
Finance Leases
2025	13
2026	13
2027	13
2028	13
2029	13
2028 and thereafter	13
Total minimum lease payments	78
Less discount	50
Present value of minimum lease payments	28
Land and Other
Finance Leases
2025	7
2026	7
2027	5
2028	5
2029	5
2028 and thereafter	177
Total minimum lease payments	206
Less discount	118
Present value of minimum lease payments	88
Land and Other | Consumers Energy Company
Finance Leases
2025	4
2026	4
2027	3
2028	2
2029	2
2028 and thereafter	71
Total minimum lease payments	86
Less discount	41
Present value of minimum lease payments	$ 45