Contingencies And Commitments (Guarantees) (Details) $ in Millions |
3 Months Ended |
|---|---|
|
Mar. 31, 2020
USD ($)
| |
| Guarantees | |
| Guarantees And Other Contingencies [Line Items] | |
| Guarantee Description | Guarantees |
| Expiration Date | indefinite |
| Maximum Obligation | $ 30 |
| Carrying Amount | $ 0 |
| Guarantees | Consumers Energy Company | |
| Guarantees And Other Contingencies [Line Items] | |
| Guarantee Description | Guarantee |
| Expiration Date | indefinite |
| Maximum Obligation | $ 30 |
| Carrying Amount | $ 0 |
| Indemnity Obligations From Stock And Asset Sales Agreements | |
| Guarantees And Other Contingencies [Line Items] | |
| Guarantee Description | Indemnity obligations from stock and asset sales agreements |
| Expiration Date | indefinite |
| Maximum Obligation | $ 153 |
| Carrying Amount | 2 |
| Tax And Other Indemnity Obligations | Consumers Energy Company | |
| Guarantees And Other Contingencies [Line Items] | |
| Carrying Amount | $ 1 |