Disclosure of the amount of the entity's issued liability supported by a third-party credit enhancement.

No definition available.

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- Definition

Financial Instruments [Line Items]

+ References

No definition available.

+ Details

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Period Type:	instant

- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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Financial Instruments (Narrative) (Details) - USD ($)	3 Months Ended
Financial Instruments (Narrative) (Details) - USD ($)	Jun. 30, 2018	Jul. 26, 2018	Dec. 31, 2017
Financial Instruments [Line Items]
Portion of long-term debt supported by third-party credit enhancements	$ 35,000,000		$ 103,000,000
Consumers Energy Company
Financial Instruments [Line Items]
Portion of long-term debt supported by third-party credit enhancements	$ 35,000,000		$ 103,000,000
DB SERP \| Minimum
Financial Instruments [Line Items]
Debt security term	1 year
DB SERP \| Maximum
Financial Instruments [Line Items]
Debt security term	10 years
CMS Energy Note Payable [Member] \| Subsequent Event
Financial Instruments [Line Items]
Notes payable		$ 146,000,000
Interest Rate		4.10%