Guarantor Obligations, Collateral Held Directly Or By Third Parties, Amount

No definition available.

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

- Definition

Letters Of Credit Outstanding, Margin Call

+ References

No definition available.

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_GuaranteeObligationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12069-110248

+ Details

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- Details

Name:	dei_LegalEntityAxis=cnl_ClecoPowerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=cnl_ClecoHoldingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=cnl_ClecoCajunMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_PerformanceGuaranteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_IndemnificationGuaranteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=cnl_IndemnificationAgreementIncludingFundamentalOrganizationalStructureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_FinancialGuaranteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Litigation, Other Commitments and Contingencies, and Disclosures about Guarantees - Off-Balance Sheet Commitments and Guarantees (Details) - USD ($)			12 Months Ended
	Feb. 25, 2021	Feb. 24, 2021	Dec. 31, 2020	Jun. 30, 2020	May 31, 2020
CLECO POWER
Guarantor Obligations [Line Items]
Assets held as collateral for third parties			$ 0
CLECO POWER \| Subsequent Event
Guarantor Obligations [Line Items]
Margin call, transmission amount		$ 21,000,000.0
CLECO POWER \| Letter of Credit \| Subsequent Event
Guarantor Obligations [Line Items]
Margin call, transmission amount	$ 21,000,000.0
Cleco Holdings
Guarantor Obligations [Line Items]
Assets held as collateral for third parties			0
Cleco Holdings \| Letter of Credit
Guarantor Obligations [Line Items]
Letters of credit				$ 1,300,000	$ 34,500,000
Cleco Cajun \| Subsequent Event
Guarantor Obligations [Line Items]
Margin call, transmission amount		$ 5,000,000.0
Cleco Cajun \| Letter of Credit \| Subsequent Event
Guarantor Obligations [Line Items]
Margin call, transmission amount	$ 5,000,000.0
Performance Guarantee
Guarantor Obligations [Line Items]
Maximum amount of potential payment			42,400,000
Indemnification Agreement
Guarantor Obligations [Line Items]
Maximum amount of potential payment			40,000,000.0
Indemnification Agreement \| CLECO POWER
Guarantor Obligations [Line Items]
Maximum amount of potential payment			40,000,000.0
Indemnification Agreement, Including Fundamental Organizational Structure
Guarantor Obligations [Line Items]
Maximum amount of potential payment			400,000,000.0
Indemnification Agreement, Including Fundamental Organizational Structure \| CLECO POWER
Guarantor Obligations [Line Items]
Maximum amount of potential payment			400,000,000.0
Guarantee Issued to Entergy Mississippi on behalf of Attala \| CLECO POWER
Guarantor Obligations [Line Items]
Maximum amount of potential payment			$ 32,600,000