Jointly Owned Generation Units (Details) $ in Thousands	Dec. 31, 2020 USD ($) MW
Jointly Owned Utility Plant Interests [Line Items]
Utility plant in service	$ 319,137
Accumulated depreciation	103,409
Construction work in progress	4,554
RODEMACHER UNIT 2
Jointly Owned Utility Plant Interests [Line Items]
Utility plant in service	75,958
Accumulated depreciation	10,932
Construction work in progress	$ 1,090
Ownership interest percentage	30.00%
Rated capacity (MW) \| MW	523
Ownership interest (MW) \| MW	157
DOLET HILLS POWER STATION
Jointly Owned Utility Plant Interests [Line Items]
Utility plant in service	$ 186,971
Accumulated depreciation	86,030
Construction work in progress	$ 2,548
Ownership interest percentage	50.00%
Rated capacity (MW) \| MW	650
Ownership interest (MW) \| MW	325
BAYOU COVE
Jointly Owned Utility Plant Interests [Line Items]
Utility plant in service	$ 40,421
Accumulated depreciation	4,479
Construction work in progress	$ 0
Ownership interest percentage	75.00%
Rated capacity (MW) \| MW	300
Ownership interest (MW) \| MW	225
BIG CAJUN II - UNIT 3
Jointly Owned Utility Plant Interests [Line Items]
Utility plant in service	$ 15,787
Accumulated depreciation	1,968
Construction work in progress	$ 916
Ownership interest percentage	58.00%
Rated capacity (MW) \| MW	588
Ownership interest (MW) \| MW	341
CLECO POWER
Jointly Owned Utility Plant Interests [Line Items]
Utility plant in service	$ 554,605
Accumulated depreciation	388,638
Construction work in progress	3,638
CLECO POWER \| RODEMACHER UNIT 2
Jointly Owned Utility Plant Interests [Line Items]
Utility plant in service	150,138
Accumulated depreciation	85,112
Construction work in progress	$ 1,090
Ownership interest percentage	30.00%
Rated capacity (MW) \| MW	523
Ownership interest (MW) \| MW	157
CLECO POWER \| DOLET HILLS POWER STATION
Jointly Owned Utility Plant Interests [Line Items]
Utility plant in service	$ 404,467
Accumulated depreciation	303,526
Construction work in progress	$ 2,548
Ownership interest percentage	50.00%
Rated capacity (MW) \| MW	650
Ownership interest (MW) \| MW	325

The capacity (in megawatts) of the jointly owned generation unit.

No definition available.

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Data Type:	num:powerItemType
Balance Type:	na
Period Type:	instant

- Definition

The entity's ownership interest in the generation unit's name plate capacity (in megawatts).

+ References

No definition available.

+ Details

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Namespace Prefix:	cnl_
Data Type:	num:powerItemType
Balance Type:	na
Period Type:	instant

- Definition

The period end amount owned by the reporting utility of a jointly owned utility plant in service.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 360
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 10.C)
-URI http://asc.fasb.org/extlink&oid=115995737&loc=d3e659983-123033

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

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- Definition

The period end amount of construction work in progress at a jointly owned electricity generation plant.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The period end amount of accumulated depreciation in a jointly owned electricity generation plant.

+ References

+ Details

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

- Definition

The proportionate share of interest (percent) in a jointly owned utility plant.

+ References

+ Details

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Data Type:	num:percentItemType
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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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