Summary of Significant Accounting Policies - Asset Retirement Obligation (Details)	12 Months Ended
Dec. 31, 2019 USD ($)
Asset Retirement Obligation [Line Items]
Increase (decrease) to ARO	$ 0
CLECO POWER
Asset Retirement Obligation [Line Items]
Increase (decrease) to ARO	0
Cleco Cajun
Asset Retirement Obligation [Line Items]
Increase (decrease) to ARO	$ 15,300,000

Amount of increase (decrease) in the asset retirement obligation from changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 35
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6392603&loc=d3e7123-110846

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(4)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Name:	us-gaap_AssetRetirementObligationRevisionOfEstimate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration