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Regulatory Matters (Schedule Of The Components Of PSCR And GCR Over/(Under) Recoveries) (Details) - USD ($) $ in Millions | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Public Utilities, General Disclosures [Line Items] |  |
Accrued rate refunds | $ 20 | $ 35
Consumers Energy Company |  |
Public Utilities, General Disclosures [Line Items] |  |
Accrued rate refunds | 20 | 35
Consumers Energy Company | PSCR overrecoveries/underrecoveries |  |
Public Utilities, General Disclosures [Line Items] |  |
Accrued rate refunds | 5 | 33
Consumers Energy Company | GCR overrecoveries/underrecoveries |  |
Public Utilities, General Disclosures [Line Items] |  |
Accrued rate refunds | $ 15 | $ 2

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