Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 498,845	$ 396,924	$ 1,228,618	$ 1,063,613
Revenue unrelated to contracts with customers
Other	18,349	20,527	62,319	59,169
Total revenue unrelated to contracts with customers	18,349	20,527	62,319	59,169
Operating revenue, net	517,194	417,451	1,290,937	1,122,782
Electric customer credits	691	16,534	40,185	34,126
Deferred lease amortization			6,904	6,904
Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	280,394	217,090	653,675	573,294
Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	148,522	128,981	348,918	308,525
Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	82,711	68,220	214,129	190,905
Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	45,446	32,809	119,497	94,227
Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4,479	3,614	11,925	10,416
Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers				2,440
Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(764)	(16,534)	(40,794)	(33,219)
Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	179,912	149,752	475,924	406,715
Transmission, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	32,921	26,964	85,511	73,187
Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	5,618	3,118	13,508	10,417
Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
CLECO CAJUN
Revenue unrelated to contracts with customers
Lease revenue		15,200	45,400	46,000
Deferred lease amortization	2,300	2,300	6,900	6,900
OPERATING SEGMENTS
Revenue unrelated to contracts with customers
Operating revenue, net	523,210	422,886	1,308,205	1,139,061
Electric customer credits	691	16,534	40,185	34,127
OPERATING SEGMENTS | CLECO POWER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	379,458	288,586	898,742	765,974
Revenue unrelated to contracts with customers
Other	1,094	3,013	9,953	6,272
Total revenue unrelated to contracts with customers	1,094	3,013	9,953	6,272
Operating revenue, net	380,552	291,599	908,695	772,246
Electric customer credits	691	16,534	40,429	33,974
OPERATING SEGMENTS | CLECO POWER | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	280,394	217,090	653,675	573,294
OPERATING SEGMENTS | CLECO POWER | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	148,522	128,981	348,918	308,525
OPERATING SEGMENTS | CLECO POWER | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	82,711	68,220	214,129	190,905
OPERATING SEGMENTS | CLECO POWER | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	45,446	32,809	119,497	94,227
OPERATING SEGMENTS | CLECO POWER | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4,479	3,614	11,925	10,416
OPERATING SEGMENTS | CLECO POWER | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers				2,440
OPERATING SEGMENTS | CLECO POWER | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(764)	(16,534)	(40,794)	(33,219)
OPERATING SEGMENTS | CLECO POWER | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	74,831	52,216	182,769	140,139
OPERATING SEGMENTS | CLECO POWER | Transmission, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	17,235	14,656	44,530	38,273
Revenue unrelated to contracts with customers
Electric customer credits	100		400	800
OPERATING SEGMENTS | CLECO POWER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	5,618	3,118	13,509	10,416
OPERATING SEGMENTS | CLECO POWER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,380	1,506	4,259	3,852
OPERATING SEGMENTS | CLECO CAJUN
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	125,404	113,774	347,148	313,920
Revenue unrelated to contracts with customers
Other	17,254	17,513	52,362	52,895
Total revenue unrelated to contracts with customers	17,254	17,513	52,362	52,895
Operating revenue, net	142,658	131,287	399,510	366,815
Electric customer credits	0	0	(244)	153
Lease revenue	14,900
OPERATING SEGMENTS | CLECO CAJUN | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OPERATING SEGMENTS | CLECO CAJUN | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OPERATING SEGMENTS | CLECO CAJUN | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OPERATING SEGMENTS | CLECO CAJUN | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OPERATING SEGMENTS | CLECO CAJUN | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	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	0	0
OPERATING SEGMENTS | CLECO CAJUN | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	107,501	99,956	300,415	273,836
OPERATING SEGMENTS | CLECO CAJUN | Transmission, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	17,903	13,818	46,733	39,880
Revenue unrelated to contracts with customers
Electric customer credits			200	200
OPERATING SEGMENTS | CLECO CAJUN | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OPERATING SEGMENTS | CLECO CAJUN | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	204
OTHER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	29,696	33,102	78,132	86,678
Revenue unrelated to contracts with customers
Other	1	1	4	2
Total revenue unrelated to contracts with customers	1	1	4	2
Operating revenue, net	29,697	33,103	78,136	86,680
Electric customer credits	0	0	0	0
OTHER | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OTHER | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OTHER | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OTHER | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OTHER | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	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	0	0
OTHER | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(2,420)	(2,420)	(7,260)	(7,260)
OTHER | Transmission, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OTHER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OTHER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	32,116	35,522	85,392	93,938
ELIMINATIONS
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(35,713)	(38,538)	(95,404)	(102,959)
Revenue unrelated to contracts with customers
Other	0	0	0	0
Total revenue unrelated to contracts with customers	0	0	0	0
Operating revenue, net	(35,713)	(38,538)	(95,404)	(102,959)
Electric customer credits	0	0	0	(1)
ELIMINATIONS | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
ELIMINATIONS | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
ELIMINATIONS | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
ELIMINATIONS | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
ELIMINATIONS | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	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	0	0
ELIMINATIONS | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
ELIMINATIONS | Transmission, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(2,217)	(1,510)	(5,752)	(4,966)
ELIMINATIONS | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	(1)	1
ELIMINATIONS | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ (33,496)	$ (37,028)	$ (89,651)	$ (97,994)