Litigation, Other Commitments and Contingencies, and Disclosures about Guarantees - Litigation (Details) $ in Thousands					1 Months Ended					3 Months Ended		9 Months Ended		24 Months Ended	30 Months Ended
	Oct. 20, 2021 USD ($)	Jun. 01, 2020	May 21, 2020	Jan. 01, 2020	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015 USD ($)	Dec. 31, 2014 claim	Nov. 30, 2014 claim	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	May 31, 2016	Mar. 29, 2021 USD ($)	Sep. 27, 2019 recommendation finding
Loss Contingencies [Line Items]
Electric customer credits										$ 691	$ 16,534	$ 40,185	$ 34,126
Loss contingency, estimate of possible loss										4,100		4,100
South Central Generating
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss										1,500		1,500
FERC | MISO Transmission Rates
Loss Contingencies [Line Items]
Public utilities, requested rate increase (decrease), percentage (in hundredths)									0.50%
Gulf Coast Spinning start up costs
Loss Contingencies [Line Items]
Allegations by plaintiff, failure to perform							$ 6,500
Gulf Coast Spinning construction of cotton spinning facility
Loss Contingencies [Line Items]
Allegations by plaintiff, failure to perform							$ 60,000
Actions filed in the 9th Judicial District Court | Alleged Breach of Fiduciary Duties
Loss Contingencies [Line Items]
Number of actions filed | claim									4
Actions filed in the Civil District Court | Alleged Breach of Fiduciary Duties
Loss Contingencies [Line Items]
Number of actions filed | claim								3	3
CLECO POWER
Loss Contingencies [Line Items]
Electric customer credits										691	$ 16,534	40,429	$ 33,974
CLECO POWER | Deferred storm restoration costs - Winter Storms Uri & Viola
Loss Contingencies [Line Items]
Capitalized storm restoration costs										$ 8,400		8,400				$ 50,000
CLECO POWER | LPSC 2018-2019 Fuel Audit
Loss Contingencies [Line Items]
Fuel expense														$ 565,800
CLECO POWER | MISO Transmission Rates
Loss Contingencies [Line Items]
Public utilities, proposed return on equity, percentage (in hundredths)		10.52%		10.38%	10.32%	9.70%
CLECO POWER | LPSC | Subsequent event
Loss Contingencies [Line Items]
Environmental expense	$ 26,200
CLECO POWER | FERC
Loss Contingencies [Line Items]
Number of findings | finding																	12
Number of recommendations | recommendation																	59
Electric customer credits												$ 4,400
CLECO POWER | FERC | MISO Transmission Rates
Loss Contingencies [Line Items]
Public utilities, approved return on equity, percentage (In hundredths)															12.38%
Public utilities, proposed return on equity, percentage (in hundredths)			10.02%		9.88%										6.68%