Schedule I Financial Statements of Cleco Corporation, Summary of Significant Accounting Policies (Details) - Cleco Holdings [Member] $ in Millions	Dec. 31, 2017 USD ($)
Summary of Significant Accounting Policies [Abstract]
Restricted net assets of consolidated subsidiaries	$ 1,210
Percent of restricted consolidated net assets of consolidated subsidiaries exceeding total consolidated net assets (in hundredths)	25.00%

Percent of restricted net assets of consolidated subsidiaries exceeding total consolidated net assets resulting in the inclusion of parent company only financial statements as required by Regulation S-X 5-04.

No definition available.

Name:	cnl_Requirementforparentcompanyfinancialstatementspercentofrestrictednetassetsofconsolidatedsubsidiariesexceedingtotalconsolidatednetassets
Namespace Prefix:	cnl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant