Litigation, Other Commitments and Contingencies, and Disclosures about Guarantees - Off-Balance Sheet Commitments and Guarantees (Details)	12 Months Ended
	Dec. 31, 2018 USD ($)
Guarantor Obligations [Line Items]
Assets held as collateral for third parties	$ 0
Performance Guarantee
Guarantor Obligations [Line Items]
Maximum amount of potential payment	42,400,000
Indemnification Agreement
Guarantor Obligations [Line Items]
Maximum amount of potential payment	40,000,000.0
Indemnification Agreement, Including Fundamental Organizational Structure
Guarantor Obligations [Line Items]
Maximum amount of potential payment	400,000,000.0
CLECO POWER | Indemnification Agreement
Guarantor Obligations [Line Items]
Maximum amount of potential payment	40,000,000.0
CLECO POWER | Indemnification Agreement, Including Fundamental Organizational Structure
Guarantor Obligations [Line Items]
Maximum amount of potential payment	400,000,000.0
CLECO POWER | Guarantee Issued to Entergy Mississippi on behalf of Attala
Guarantor Obligations [Line Items]
Maximum amount of potential payment	$ 91,400,000