Regulatory Assets and Liabilities, Additional Disclosures (Details) - USD ($) $ in Millions		3 Months Ended
Mar. 01, 2017	Sep. 30, 2017
Regulatory Assets [Line Items]
Derecognized fair value adjustment and debt issuance costs related to debt redemption	$ 0.7
Cleco Power [Member] \| Emergency declarations
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period		3 years

Amortization period for the recovery of regulatory asset, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_RegulatoryAssetAmortizationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration