Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 396,924	$ 467,647	$ 1,063,613	$ 1,173,792
Revenue unrelated to contracts with customers
Other	20,527	20,324	59,169	56,238
Total revenue unrelated to contracts with customers	20,527	20,324	59,169	56,238
Operating revenue, net	417,451	487,971	1,122,782	1,230,030
Deferred lease amortization			6,904	6,137
Electric customer credits	16,534	13,711	34,126	31,832
Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	217,090	254,604	573,294	643,612
Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	128,981	142,265	308,525	327,340
Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	68,220	84,816	190,905	218,209
Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	32,809	36,830	94,227	109,545
Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,614	4,234	10,416	11,391
Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		170	2,440	7,692
Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(16,534)	(13,711)	(33,219)	(30,565)
Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	149,752	181,564	406,715	445,629
Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	26,964	27,027	73,187	69,909
Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,118	4,452	10,417	14,642
Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
CLECO POWER
Revenue unrelated to contracts with customers
Deferred lease amortization		2,300	6,900	6,100
CLECO POWER | Price Risk Derivative
Revenue unrelated to contracts with customers
Other	3,000		6,300	11,700
CLECO POWER | Other | SSR
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers				3,200
CLECO POWER | Lost contribution to fixed cost
Revenue unrelated to contracts with customers
Other				2,600
CLECO CAJUN
Revenue unrelated to contracts with customers
Lease revenue		16,000	46,000	40,900
Deferred lease amortization	2,300
OPERATING SEGMENTS
Revenue unrelated to contracts with customers
Operating revenue, net	422,886	493,198	1,139,061	1,243,686
Electric customer credits	16,534	13,711	34,127	31,832
OPERATING SEGMENTS | CLECO POWER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	288,586	342,982	765,974	877,535
Revenue unrelated to contracts with customers
Other	3,013	1,995	6,272	9,158
Total revenue unrelated to contracts with customers	3,013	1,995	6,272	9,158
Operating revenue, net	291,599	344,977	772,246	886,693
Electric customer credits	16,534	13,711	33,974	30,565
OPERATING SEGMENTS | CLECO POWER | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	217,090	254,604	573,294	643,612
OPERATING SEGMENTS | CLECO POWER | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	128,981	142,265	308,525	327,340
OPERATING SEGMENTS | CLECO POWER | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	68,220	84,816	190,905	218,209
OPERATING SEGMENTS | CLECO POWER | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	32,809	36,830	94,227	109,545
OPERATING SEGMENTS | CLECO POWER | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,614	4,234	10,416	11,391
OPERATING SEGMENTS | CLECO POWER | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		170	2,440	7,692
OPERATING SEGMENTS | CLECO POWER | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(16,534)	(13,711)	(33,219)	(30,565)
OPERATING SEGMENTS | CLECO POWER | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	52,216	69,558	140,139	179,633
OPERATING SEGMENTS | CLECO POWER | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	14,656	14,034	38,273	38,679
Revenue unrelated to contracts with customers
Electric customer credits			800
OPERATING SEGMENTS | CLECO POWER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,118	4,452	10,416	14,640
Revenue unrelated to contracts with customers
Other miscellaneous fee revenue				11,400
OPERATING SEGMENTS | CLECO POWER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,506	334	3,852	971
OPERATING SEGMENTS | CLECO CAJUN
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	113,774	129,892	313,920	309,912
Revenue unrelated to contracts with customers
Other	17,513	18,329	52,895	47,081
Total revenue unrelated to contracts with customers	17,513	18,329	52,895	47,081
Operating revenue, net	131,287	148,221	366,815	356,993
Lease revenue	15,200
Electric customer credits	0	0	153	1,267
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	0	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	99,956	114,426	273,836	273,256
OPERATING SEGMENTS | CLECO CAJUN | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	13,818	15,435	39,880	36,625
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	0	0
OPERATING SEGMENTS | CLECO CAJUN | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	31	204	31
OTHER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	33,102	25,832	86,678	70,542
Revenue unrelated to contracts with customers
Other	1	0	2	0
Total revenue unrelated to contracts with customers	1	0	2	0
Operating revenue, net	33,103	25,832	86,680	70,542
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	0	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
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	2
OTHER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	35,522	28,252	93,938	77,800
ELIMINATIONS
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(38,538)	(31,059)	(102,959)	(84,197)
Revenue unrelated to contracts with customers
Other	0	0	0	(1)
Total revenue unrelated to contracts with customers	0	0	0	(1)
Operating revenue, net	(38,538)	(31,059)	(102,959)	(84,198)
Electric customer credits	0	0	(1)	0
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	0	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
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(1,510)	(2,442)	(4,966)	(5,395)
ELIMINATIONS | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	1	0
ELIMINATIONS | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ (37,028)	$ (28,617)	$ (97,994)	$ (78,802)