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Namespace Prefix:	cnl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The aggregate refunds recognized during an accounting period. Returns are a deduction from gross revenue in arriving at net income.

No definition available.

Name:	cnl_ElectricCustomerCredits
Namespace Prefix:	cnl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Public Utilities, Number Of Complaints

No definition available.

Name:	cnl_PublicUtilitiesNumberOfComplaints
Namespace Prefix:	cnl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

The low range of the return on equity which triggers a retail customer partial refund obligation.

No definition available.

Name:	cnl_PublicUtilitiesReturnOnEquityForCustomerRefundLowRange
Namespace Prefix:	cnl_
Data Type:	dtr-types:percentItemType
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Period Type:	duration

The percentage of retail earnings to be returned to retail customers as ordered by the regulatory agency when the return on equity falls within a certain range.

No definition available.

Name:	cnl_PublicUtilitiesReturnonEquityPercentageofretailearningsduetocustomerswithinrange
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The high range of the return on equity which triggers a retail customer partial refund obligation. All retail earnings must be returned to customers when the return on equity exceeds this high range.

No definition available.

Name:	cnl_PublicUtilitiesReturnonequityforcustomerrefundhighrange
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Tax Cuts And Jobs Act Of 2017, Bill Credit

No definition available.

Name:	cnl_TaxCutsAndJobsActOf2017BillCredit
Namespace Prefix:	cnl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Tax Cuts And Jobs Act Of 2017, Bill Credit, Change In Tax Rate

No definition available.

Name:	cnl_TaxCutsAndJobsActOf2017BillCreditChangeInTaxRate
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Tax Cuts And Jobs Act Of 2017, Bill Credit, Unprotected Excess ADIT

No definition available.

Name:	cnl_TaxCutsAndJobsActOf2017BillCreditUnprotectedExcessADIT
Namespace Prefix:	cnl_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Tax Cuts And Jobs Act Of 2017, Customer Refund Liability, Current

No definition available.

Name:	cnl_TaxCutsAndJobsActOf2017CustomerRefundLiabilityCurrent
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Data Type:	xbrli:monetaryItemType
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For transactions that are recognized separately from the acquisition of assets and assumptions of liabilities in the business combination, such as related to pre-existing relationships with the acquiree, this element represents the disclosure of the amount of acquisition related costs.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Current regulatory liabilities generally represent obligations to make refunds to customers for various reasons including overpayment.

No definition available.

Name:	us-gaap_CustomerRefundLiabilityCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Percentage of public utility's approved return on equity.

No definition available.

Name:	us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage
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Data Type:	dtr-types:percentItemType
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Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_PublicUtilitiesGeneralDisclosuresLineItems
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Data Type:	xbrli:stringItemType
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Period Type:	duration

The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 405
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6500807&loc=d3e48068-110394

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Data Type:	xbrli:monetaryItemType
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Amortization period for the recovery of regulatory liability, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_RegulatoryLiabilityAmortizationPeriod
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Data Type:	xbrli:durationItemType
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Period Type:	duration

The amount for the individual regulatory current liability as itemized in a table of regulatory current liabilities as of the end of the period.

Name:	us-gaap_RegulatoryLiabilityCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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Namespace Prefix:
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Balance Type:
Period Type:

Name:	us-gaap_RegulatoryLiabilityAxis=cnl_ExcessADITMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_RegulatoryAgencyAxis=cnl_FederalEnergyRegulatoryCommissionMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	dei_LegalEntityAxis=cnl_ClecoPowerMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=cnl_FRPMonitoringReportMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_RegulatoryLiabilityAxis=cnl_ClecoKatrinaRitaStormRecoveryChargesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsAxis=cnl_MergerCommitmentscharitablecontributiondisbursedover5yearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=cnl_FRPMember
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Data Type:	na
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