Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 370,117	$ 328,289
Revenue unrelated to contracts with customers
Other	24,878	19,283
Total revenue unrelated to contracts with customers	24,878	19,283
Operating revenue, net	394,995	347,572
Electric customer credits	20,976	8,493
Deferred lease amortization	2,301	2,301
Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	177,367	172,455
Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	95,081	81,571
Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	63,026	61,110
Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	36,666	32,210
Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,570	3,461
Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		2,443
Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(20,976)	(8,340)
Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	160,809	128,956
Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	27,299	23,182
Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4,642	3,696
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		2,300
CLECO CAJUN
Revenue unrelated to contracts with customers
Lease revenue		15,600
Deferred lease amortization	2,300
OPERATING SEGMENTS
Revenue unrelated to contracts with customers
Operating revenue, net	401,009	353,076
Electric customer credits	20,976	8,493
OPERATING SEGMENTS | CLECO POWER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	259,368	231,554
Revenue unrelated to contracts with customers
Other	7,095	1,406
Total revenue unrelated to contracts with customers	7,095	1,406
Operating revenue, net	266,463	232,960
Electric customer credits	20,976	8,340
OPERATING SEGMENTS | CLECO POWER | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	177,367	172,455
OPERATING SEGMENTS | CLECO POWER | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	95,081	81,571
OPERATING SEGMENTS | CLECO POWER | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	63,026	61,110
OPERATING SEGMENTS | CLECO POWER | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	36,666	32,210
OPERATING SEGMENTS | CLECO POWER | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,570	3,461
OPERATING SEGMENTS | CLECO POWER | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		2,443
OPERATING SEGMENTS | CLECO POWER | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(20,976)	(8,340)
OPERATING SEGMENTS | CLECO POWER | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	61,722	42,229
OPERATING SEGMENTS | CLECO POWER | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	13,982	12,069
OPERATING SEGMENTS | CLECO POWER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4,642	3,695
OPERATING SEGMENTS | CLECO POWER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,655	1,106
OPERATING SEGMENTS | CLECO CAJUN
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	116,764	102,239
Revenue unrelated to contracts with customers
Other	17,782	17,877
Total revenue unrelated to contracts with customers	17,782	17,877
Operating revenue, net	134,546	120,116
Electric customer credits	0	153
Lease revenue	15,500
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
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	101,507	89,147
OPERATING SEGMENTS | CLECO CAJUN | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	15,257	12,931
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	0
OPERATING SEGMENTS | CLECO CAJUN | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	161
OTHER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	24,736	26,859
Revenue unrelated to contracts with customers
Other	1	0
Total revenue unrelated to contracts with customers	1	0
Operating revenue, net	24,737	26,859
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
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	0	1
OTHER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	27,156	29,278
ELIMINATIONS
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(30,751)	(32,363)
Revenue unrelated to contracts with customers
Other	0	0
Total revenue unrelated to contracts with customers	0	0
Operating revenue, net	(30,751)	(32,363)
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
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	(1,940)	(1,818)
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	$ (28,811)	$ (30,545)