Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 328,289	$ 330,690
Revenue unrelated to contracts with customers
Other	19,283	13,496
Total revenue unrelated to contracts with customers	19,283	13,496
Operating revenue, net	347,572	344,186
Electric customer credits	8,493	8,160
Deferred lease amortization	2,301	1,440
Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	172,455	191,240
Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	81,571	87,148
Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	61,110	65,380
Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	32,210	37,870
Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,461	3,681
Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,443	5,321
Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(8,340)	(8,160)
Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	128,956	111,317
Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	23,182	21,306
Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,696	6,827
Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
CLECO POWER
Revenue unrelated to contracts with customers
Deferred lease amortization		1,400
CLECO POWER | LCFC
Revenue unrelated to contracts with customers
Other		(2,600)
CLECO POWER | Price Risk Derivative
Revenue unrelated to contracts with customers
Other	1,400	4,800
CLECO POWER | SSR | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		2,400
CLECO CAJUN
Revenue unrelated to contracts with customers
Lease revenue		9,800
Deferred lease amortization	2,300
Operating Segments | CLECO POWER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	231,554	266,516
Revenue unrelated to contracts with customers
Other	1,406	2,229
Total revenue unrelated to contracts with customers	1,406	2,229
Operating revenue, net	232,960	268,745
Electric customer credits	8,340	8,160
Operating Segments | CLECO POWER | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	172,455	191,240
Operating Segments | CLECO POWER | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	81,571	87,148
Operating Segments | CLECO POWER | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	61,110	65,380
Operating Segments | CLECO POWER | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	32,210	37,870
Operating Segments | CLECO POWER | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,461	3,681
Operating Segments | CLECO POWER | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,443	5,321
Operating Segments | CLECO POWER | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(8,340)	(8,160)
Operating Segments | CLECO POWER | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	42,229	55,546
Operating Segments | CLECO POWER | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	12,069	12,579
Operating Segments | CLECO POWER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,695	6,851
Revenue unrelated to contracts with customers
Other miscellaneous fee revenue	3,700	4,400
Operating Segments | CLECO POWER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,106	300
Operating Segments | CLECO CAJUN
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	102,239	66,892
Revenue unrelated to contracts with customers
Other	17,877	11,267
Total revenue unrelated to contracts with customers	17,877	11,267
Operating revenue, net	120,116	78,159
Electric customer credits	153	0
Lease revenue	15,600
Operating Segments | CLECO CAJUN | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
Operating Segments | CLECO CAJUN | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
Operating Segments | CLECO CAJUN | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
Operating Segments | CLECO CAJUN | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
Operating Segments | CLECO CAJUN | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
Operating Segments | CLECO CAJUN | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
Operating Segments | CLECO CAJUN | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
Operating Segments | CLECO CAJUN | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	89,147	58,191
Operating Segments | CLECO CAJUN | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	12,931	8,727
Revenue unrelated to contracts with customers
Electric customer credits	200
Operating Segments | CLECO CAJUN | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	(26)
Operating Segments | CLECO CAJUN | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	161	0
OTHER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	26,859	24,117
Revenue unrelated to contracts with customers
Other	0	0
Total revenue unrelated to contracts with customers	0	0
Operating revenue, net	26,859	24,117
Electric customer credits	0	0
OTHER | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(2,420)	(2,420)
OTHER | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1	2
OTHER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	29,278	26,535
ELIMINATIONS
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(32,363)	(26,835)
Revenue unrelated to contracts with customers
Other	0	0
Total revenue unrelated to contracts with customers	0	0
Operating revenue, net	(32,363)	(26,835)
Electric customer credits	0	0
ELIMINATIONS | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(1,818)	0
ELIMINATIONS | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ (30,545)	$ (26,835)