Summary of Significant Accounting Policies - AFUDC (Details) - CLECO POWER	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Public Utilities, General Disclosures [Line Items]
Composite AFUDC rate, including borrowed and other funds, pre-tax	10.14%	10.71%	9.58%
Public utilities, rate net of tax	7.96%	8.37%	7.08%

Effective rate, including composite rate, of cost of financing additions to qualifying regulated assets, commonly called allowance for funds used during construction.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 835
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6501662&loc=d3e56162-110433

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 835
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6501569&loc=d3e55921-110430

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