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v3.19.1

Revenue (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2019 | Mar. 31, 2018 | Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |
Uncollectable expense | $ 6 | $ 7 |
Unbilled receivables | 341 |  | $ 409
Consumers Energy Company |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |
Uncollectable expense | 6 | $ 7 |
Unbilled receivables | $ 341 |  | $ 409

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