Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 1,418,776	$ 1,561,424
Total revenue from contracts with customers
Other	79,370	78,181
Total revenue unrelated to contracts with customers	79,370	78,181
Operating revenue, net	1,498,146	1,639,605	$ 1,231,044
Electric customer credits	53,271	39,963	33,195
Sales-type lease, lease income	70,088	65,520
Recognition of deferred lease income	9,205	8,439	0
TOTAL SEGMENTS
Total revenue from contracts with customers
Operating revenue, net	1,519,645	1,659,988	1,241,596
Electric customer credits	53,272	39,963	33,195
OTHER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	119,446	99,389
Total revenue from contracts with customers
Other	3	0
Total revenue unrelated to contracts with customers	3	0
Operating revenue, net	119,449	99,389	64,913
Electric customer credits	0	0	0
ELIMINATIONS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(140,948)	(119,772)
Total revenue from contracts with customers
Other	0	0
Total revenue unrelated to contracts with customers	0	0
Operating revenue, net	(140,948)	(119,772)	(75,465)
Electric customer credits	(1)	0	0
Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	761,401	855,448
Total retail revenue | OTHER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Total retail revenue | ELIMINATIONS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	402,050	415,242
Residential | OTHER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Residential | ELIMINATIONS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	256,964	289,197
Commercial | OTHER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Commercial | ELIMINATIONS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	137,920	149,711
Industrial | OTHER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Industrial | ELIMINATIONS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Other retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	14,235	15,046
Other retail | OTHER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Other retail | ELIMINATIONS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Surcharge
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,440	22,132
Surcharge | OTHER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Surcharge | ELIMINATIONS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Electric customer credits
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(52,208)	(35,880)
Electric customer credits | OTHER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Electric customer credits | ELIMINATIONS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Wholesale, net
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	548,062	591,932
Wholesale, net | OTHER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(9,680)	(9,680)
Wholesale, net | ELIMINATIONS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	(1)
Transmission, net
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	94,150	94,718
Transmission, net | OTHER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Transmission, net | ELIMINATIONS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(6,463)	(7,471)
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	15,163	19,326
Other | OTHER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	2
Other | ELIMINATIONS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	0
Affiliate
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Affiliate | OTHER
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	129,126	109,067
Affiliate | ELIMINATIONS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(134,486)	(112,300)
CLECO POWER | FTRs
Total revenue from contracts with customers
Other		12,400
CLECO POWER | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,023,070	1,155,749
Total revenue from contracts with customers
Other	9,222	12,621
Total revenue unrelated to contracts with customers	9,222	12,621
Operating revenue, net	1,032,292	1,168,370	1,241,596
Electric customer credits	53,119	38,516	$ 33,195
CLECO POWER | Total retail revenue | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	761,401	855,448
CLECO POWER | Residential | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	402,050	415,242
CLECO POWER | Commercial | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	256,964	289,197
CLECO POWER | Industrial | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	137,920	149,711
CLECO POWER | Other retail | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	14,235	15,046
CLECO POWER | Surcharge | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,440	22,132
CLECO POWER | Electric customer credits | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(52,208)	(35,880)
CLECO POWER | Wholesale, net | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	192,187	226,978
CLECO POWER | Transmission, net | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	49,164	50,874
Total revenue from contracts with customers
Electric customer credits	900	2,600
CLECO POWER | Other | SSR
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers		3,200
CLECO POWER | Other | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	15,162	19,324
Total revenue from contracts with customers
Other miscellaneous fee revenue		16,100
CLECO POWER | Affiliate | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,156	3,125
CLECO POWER | Lost contribution to fixed cost
Total revenue from contracts with customers
Other		200
CLECO CAJUN
Total revenue from contracts with customers
Sales-type lease, lease income		57,100
Recognition of deferred lease income	9,200	8,400
CLECO CAJUN | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	417,208	426,058
Total revenue from contracts with customers
Other	70,145	65,560
Total revenue unrelated to contracts with customers	70,145	65,560
Operating revenue, net	487,353	491,618
Sales-type lease, lease income	60,900
CLECO CAJUN | Total retail revenue | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
CLECO CAJUN | Residential | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
CLECO CAJUN | Commercial | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
CLECO CAJUN | Industrial | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
CLECO CAJUN | Other retail | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
CLECO CAJUN | Surcharge | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
CLECO CAJUN | Electric customer credits | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
CLECO CAJUN | Wholesale, net | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	365,555	374,635
Total revenue from contracts with customers
Electric customer credits		800
CLECO CAJUN | Transmission, net | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	51,449	51,315
Total revenue from contracts with customers
Electric customer credits	200	700
CLECO CAJUN | Other | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
CLECO CAJUN | Affiliate | TOTAL SEGMENTS
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 204	$ 108