Schedule II - Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Allowance for uncollectible accounts | |||
| SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Balance at Beginning of Period | $ 23 | $ 21 | $ 27 |
| Charged to Expense | 40 | 33 | 34 |
| Charged to Other Accounts | 0 | 0 | 0 |
| Deductions | 36 | 31 | 40 |
| Balance at End of Period | 27 | 23 | 21 |
| Allowance for uncollectible accounts | Consumers Energy Company | |||
| SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Balance at Beginning of Period | 23 | 21 | 27 |
| Charged to Expense | 40 | 33 | 34 |
| Charged to Other Accounts | 0 | 0 | 0 |
| Deductions | 36 | 31 | 40 |
| Balance at End of Period | 27 | 23 | 21 |
| Deferred tax valuation allowance | |||
| SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Balance at Beginning of Period | 1 | 2 | 2 |
| Charged to Expense | 1 | 0 | 0 |
| Charged to Other Accounts | 0 | 0 | 0 |
| Deductions | 0 | 1 | 0 |
| Balance at End of Period | $ 2 | $ 1 | $ 2 |