Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									$ 1,561,424	$ 1,189,178
Total revenue from contracts with customers
Other									78,181	41,866
Total revenue unrelated to contracts with customers									78,181	41,866
Operating revenue, net	$ 409,575	$ 487,971	$ 397,873	$ 344,186	$ 296,767	$ 358,256	$ 299,261	$ 276,760	1,639,605	1,231,044	$ 1,175,646
Electric customer credits									39,963	33,195	1,566
Sales-type lease, lease income									65,520
Recognition of deferred lease income									8,439	0	0
Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									855,448	896,927
Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									415,242	435,610
Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									289,197	288,791
Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									149,711	167,001
Other retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									15,046	15,582
Surcharge
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									22,132	23,138
Electric customer credits
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									(35,880)	(33,195)
Wholesale, net
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									591,932	209,918
Transmission, net
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									94,718	54,531
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									19,326	27,802
Affiliate
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
CLECO POWER | Other
Total revenue from contracts with customers
Other miscellaneous fee revenue									16,100	18,200
CLECO POWER | Lost contribution to fixed cost
Total revenue from contracts with customers
Other									200	2,600
CLECO POWER | SSR | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									3,200	9,600
CLECO CAJUN
Total revenue from contracts with customers
Recognition of deferred lease income									8,400
Operating Segments | CLECO POWER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,155,749	1,199,730
Total revenue from contracts with customers
Other									12,621	41,866
Total revenue unrelated to contracts with customers									12,621	41,866
Operating revenue, net									1,168,370	1,241,596	1,185,196
Electric customer credits									38,516	33,195	1,566
Operating Segments | CLECO POWER | Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									855,448	896,927
Operating Segments | CLECO POWER | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									415,242	435,610
Operating Segments | CLECO POWER | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									289,197	288,791
Operating Segments | CLECO POWER | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									149,711	167,001
Operating Segments | CLECO POWER | Other retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									15,046	15,582
Operating Segments | CLECO POWER | Surcharge
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									22,132	23,138
Operating Segments | CLECO POWER | Electric customer credits
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									(35,880)	(33,195)
Operating Segments | CLECO POWER | Wholesale, net
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									226,978	219,598
Operating Segments | CLECO POWER | Transmission, net
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									50,874	54,531
Total revenue from contracts with customers
Electric customer credits									2,600
Operating Segments | CLECO POWER | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									19,324	27,800
Operating Segments | CLECO POWER | Affiliate
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									3,125	874
Operating Segments | CLECO CAJUN
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									426,058
Total revenue from contracts with customers
Other									65,560
Total revenue unrelated to contracts with customers									65,560
Operating revenue, net									491,618
Sales-type lease, lease income									57,100
Operating Segments | CLECO CAJUN | Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Operating Segments | CLECO CAJUN | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Operating Segments | CLECO CAJUN | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Operating Segments | CLECO CAJUN | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Operating Segments | CLECO CAJUN | Other retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Operating Segments | CLECO CAJUN | Surcharge
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Operating Segments | CLECO CAJUN | Electric customer credits
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Operating Segments | CLECO CAJUN | Wholesale, net
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									374,635
Total revenue from contracts with customers
Electric customer credits									800
Operating Segments | CLECO CAJUN | Transmission, net
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									51,315
Total revenue from contracts with customers
Electric customer credits									700
Operating Segments | CLECO CAJUN | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Operating Segments | CLECO CAJUN | Affiliate
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									108
OTHER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									99,389	64,913
Total revenue from contracts with customers
Other									0	0
Total revenue unrelated to contracts with customers									0	0
Operating revenue, net									99,389	64,913	48,469
Electric customer credits									0	0	0
OTHER | Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
OTHER | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
OTHER | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
OTHER | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
OTHER | Other retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
OTHER | Surcharge
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
OTHER | Electric customer credits
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
OTHER | Wholesale, net
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									(9,680)	(9,680)
OTHER | Transmission, net
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
OTHER | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2	2
OTHER | Affiliate
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									109,067	74,591
ELIMINATIONS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									(119,772)	(75,465)
Total revenue from contracts with customers
Other									0	0
Total revenue unrelated to contracts with customers									0	0
Operating revenue, net									(119,772)	(75,465)	(58,019)
Electric customer credits									0	0	$ 0
ELIMINATIONS | Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
ELIMINATIONS | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
ELIMINATIONS | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
ELIMINATIONS | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
ELIMINATIONS | Other retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
ELIMINATIONS | Surcharge
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
ELIMINATIONS | Electric customer credits
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
ELIMINATIONS | Wholesale, net
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									(1)	0
ELIMINATIONS | Transmission, net
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									(7,471)	0
ELIMINATIONS | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0	0
ELIMINATIONS | Affiliate
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									(112,300)	(75,465)
Price Risk Derivative | CLECO POWER | Other
Total revenue from contracts with customers
Other									$ 12,400	$ 39,300