Fair Value Accounting - Effect of Derivatives On Consolidated Statements of Income (Details) - Derivatives Not Designated as Hedging Instrument - Price Risk Derivative - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ (7,814)	$ 35,093	$ 18,317
Electric operations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount of gain recognized in income on derivatives	13,043	39,659	23,826
Purchased power
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount of loss recognized in income on derivatives	(15,685)	(4,566)	(5,509)
Fuel Used For Electric Generation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount of loss recognized in income on derivatives	(5,172)	0	0
Accumulated Deferred Fuel
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gains (losses) associated with FTRs	(1,700)	11,900	(1,400)
CLECO POWER
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	6,981	35,093	18,317
CLECO POWER | Electric operations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount of gain recognized in income on derivatives	13,047	39,659	23,826
CLECO POWER | Purchased power
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount of loss recognized in income on derivatives	(6,066)	(4,566)	(5,509)
CLECO POWER | Accumulated Deferred Fuel
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gains (losses) associated with FTRs	$ (900)	$ 11,900	$ (1,400)