Litigation, Other Commitments and Contingencies, and Disclosures about Guarantees, Off-Balance Sheet Commitments (Details) - USD ($) $ in Millions	Sep. 30, 2015	Jan. 31, 2006
Guarantee Issued to Entergy Mississippi on behalf of Attala [Member] | Cleco Corporation [Member]
Other Commitments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted		$ 0.5
Guarantee Issued to Entergy Mississippi on behalf of Attala [Member] | Cleco Power [Member]
Other Commitments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 69.3
Obligations Under Standby Letter of Credit [Member] | Cleco Power [Member]
Other Commitments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 3.7
Percentage of average losses on which letter of credit is based (in hundredths)	110.00%
Performance Guarantee [Member]
Other Commitments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 42.4
Evangeline [Member] | Indemnification Agreement [Member]
Other Commitments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	40.0
Evangeline [Member] | Indemnification Agreement [Member] | Cleco Power [Member]
Other Commitments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	40.0
Evangeline [Member] | Indemnification Agreement INCLUDING fundamental organizational structure [Member]
Other Commitments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	400.0
Evangeline [Member] | Indemnification Agreement INCLUDING fundamental organizational structure [Member] | Cleco Power [Member]
Other Commitments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	400.0
MISO [Member] | Obligations Under Standby Letter of Credit [Member] | Cleco Power [Member]
Other Commitments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 2.0