Fair Value Accounting - Narrative (Details) MWh in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) MWh	Dec. 31, 2017 USD ($) MWh
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 103.8	$ 111.1
Restricted Cash and Cash Equivalents, Current
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash and cash equivalents	11.2	13.1
Restricted Cash and Cash Equivalents, Noncurrent
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash and cash equivalents	18.7	20.1
CLECO POWER
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 26.1	$ 62.5
Volume of FTRs held (MWh) | MWh	8.7	9.0
CLECO POWER | Restricted Cash and Cash Equivalents, Current
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash and cash equivalents	$ 11.2	$ 13.1
CLECO POWER | Restricted Cash and Cash Equivalents, Noncurrent
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash and cash equivalents	$ 18.6	$ 20.1