| Cover | Aug. 12, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Aug. 12, 2021 |
| Entity File Number | 1-5611 |
| Entity Registrant Name | CONSUMERS ENERGY COMPANY |
| Entity Central Index Key | 0000201533 |
| Entity Tax Identification Number | 38-0442310 |
| Entity Incorporation, State or Country Code | MI |
| Entity Address, Address Line One | One Energy Plaza |
| Entity Address, City or Town | Jackson |
| Entity Address, State or Province | MI |
| Entity Address, Postal Zip Code | 49201 |
| City Area Code | 517 |
| Local Phone Number | 788-0550 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Consumers Energy Company Cumulative Preferred |
| Trading Symbol | CMS-PB |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
