Debt - Principal Amounts Payable Under Finance Lease Agreement (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Years ending Dec. 31,
2021	$ 682
2022	755
2023	836
2024	925
2025	1,023
Thereafter	11,023
Cleco Power
Years ending Dec. 31,
2021	682
2022	755
2023	836
2024	925
2025	1,023
Thereafter	$ 11,023

Finance Lease Liability, Principal Only, To Be Paid, After Year Five

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

Finance Lease Liability, Principal Only, To Be Paid, Year Five

No definition available.

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Finance Lease Liability, Principal Only, To Be Paid, Year Four

No definition available.

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Finance Lease, Liability, Principal Only, To Be Paid, Year One

No definition available.

Name:	cnl_FinanceLeaseLiabilityPrincipalOnlyToBePaidYearOne
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Finance Lease Liability, Principal Only, To Be Paid, Year Three

No definition available.

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Finance Lease, Liability, Principal Only, To Be Paid, Year Two

No definition available.

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

No definition available.

Name:	us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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Balance Type:
Period Type: