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Financings And Capitalization (Narrative) (Details) | 6 Months Ended
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Jun. 30, 2017 USD ($)
Financing And Capitalization [Line Items] |
Unrestricted retained earnings | $ 4,400,000,000
Common stock dividends from Consumers | 236,000,000
Term Loan [Member] |
Financing And Capitalization [Line Items] |
Debt issuance | $ 180,000,000
Debt instrument, extension term | 1 year
Consumers Energy Company [Member] |
Financing And Capitalization [Line Items] |
Unrestricted retained earnings | $ 1,100,000,000
Consumers Energy Company [Member] | Commercial Paper [Member] |
Financing And Capitalization [Line Items] |
Short-term debt, authorized borrowings | 500,000,000
Short-term borrowings outstanding | $ 0

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