v3.25.4
Leases (Summary of Lease Right-of-Use Assets and Liabilities) (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Lessor, Lease, Description [Line Items]    
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 and finance leases Current portion of long-term debt and finance leases
Operating leases    
Right-of-use assets $ 22 $ 24
Lease liabilities    
Current lease liabilities 3 3
Noncurrent lease liabilities 19 21
Finance leases    
Right-of-use assets 140 119
Lease liabilities    
Current lease liabilities 6 4
Non-current lease liabilities $ 135 $ 112
Weighted-average remaining lease term (in years)    
Operating leases 20 years 20 years
Finance leases 24 years 26 years
Weighted-average discount rate    
Operating leases 5.30% 5.30%
Finance leases 5.90% 5.80%
Finance lease liability $ 141  
Consumers Energy Company    
Operating leases    
Right-of-use assets 18 $ 20
Lease liabilities    
Current lease liabilities 3 3
Noncurrent lease liabilities 15 17
Finance leases    
Right-of-use assets 90 76
Lease liabilities    
Current lease liabilities 6 4
Non-current lease liabilities $ 81 $ 69
Weighted-average remaining lease term (in years)    
Operating leases 20 years 19 years
Finance leases 19 years 22 years
Weighted-average discount rate    
Operating leases 5.40% 5.40%
Finance leases 4.90% 4.80%
Finance lease liability $ 87  
Related Party Lease    
Lease liabilities    
Current lease liabilities 1 $ 1
Weighted-average discount rate    
Finance lease liability $ 22 $ 22