Disclosures about Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Apr. 13, 2016
Revenue
Electric operations	$ 462,164	$ 386,388	$ 1,180,345	$ 1,019,501
Other operations	55,721	47,597	150,777	137,407
Affiliate revenue	0	0	0	0
Electric customer credits	(691)	(16,534)	(40,185)	(34,126)
Operating revenue, net	517,194	417,451	1,290,937	1,122,782
Net income	119,910	60,297	219,059	109,793
Depreciation and amortization	64,338	56,109	180,199	172,502
Interest income	941	910	2,416	2,964
Interest charges	34,629	34,060	101,812	103,923
Federal and state income tax expense	30,569	25,075	30,985	40,230
Other corporate costs and noncash items	71	(1,078)	(4,259)	6,807
EBITDA	248,576	173,553	525,380	430,291
Additions to property, plant, and equipment			209,960	215,692
Equity investment in investees	3,822		3,822		$ 9,072
Goodwill	1,490,797		1,490,797		1,490,797	$ 1,490,000
Total assets	8,395,807		8,395,807		7,725,569
CLECO POWER
Revenue
Electric operations	357,084	288,852	887,191	752,925
Other operations	22,779	17,775	57,674	49,443
Affiliate revenue	1,380	1,506	4,259	3,852
Electric customer credits	(691)	(16,534)	(40,429)	(33,974)
Operating revenue, net	380,552	291,599	908,695	772,246
Net income	56,561	36,092	102,407	76,156
Interest income	936	789	2,404	2,498
Interest charges	18,509	18,441	55,392	55,624
Federal and state income tax expense	548	18,076	(219)	30,770
Additions to property, plant, and equipment			202,940	205,765
Equity investment in investees	3,822		3,822		9,072
Total assets	5,256,041		5,256,041		4,766,147
Power supply agreements
Revenue
Amortization of intangible assets	6,400	6,400	19,200	19,200
OPERATING SEGMENTS
Revenue
Electric operations	464,584	388,808	1,187,606	1,026,761
Other operations	57,937	49,106	156,525	142,371
Affiliate revenue	1,380	1,506	4,259	4,056
Electric customer credits	(691)	(16,534)	(40,185)	(34,127)
Operating revenue, net	523,210	422,886	1,308,205	1,139,061
Net income	143,305	74,449	256,126	160,811
Depreciation and amortization	56,149	51,612	163,148	158,926
Interest income	940	799	2,414	2,767
Interest charges	19,626	17,957	56,178	55,271
Federal and state income tax expense	30,436	30,334	52,342	58,050
EBITDA	248,576	173,553	525,380	430,291
Additions to property, plant, and equipment			208,844	213,673
Equity investment in investees	3,822		3,822		9,072
Goodwill	1,490,797		1,490,797		1,490,797
Total assets	7,959,806		7,959,806		7,286,756
OPERATING SEGMENTS | CLECO POWER
Revenue
Electric operations	357,084	288,852	887,191	752,925
Other operations	22,779	17,775	57,674	49,443
Affiliate revenue	1,380	1,506	4,259	3,852
Electric customer credits	(691)	(16,534)	(40,429)	(33,974)
Operating revenue, net	380,552	291,599	908,695	772,246
Net income	56,561	36,092	102,407	76,156
Depreciation and amortization	43,526	40,268	126,534	125,541
Interest income	936	789	2,404	2,498
Interest charges	18,509	18,441	55,392	55,624
Federal and state income tax expense	548	18,076	(219)	30,770
EBITDA	118,208	112,088	281,710	285,593
Additions to property, plant, and equipment			202,940	205,765
Equity investment in investees	3,822		3,822		9,072
Goodwill	1,490,797		1,490,797		1,490,797
Total assets	6,746,838		6,746,838		6,256,944
OPERATING SEGMENTS | CLECO CAJUN
Revenue
Electric operations	107,500	99,956	300,415	273,836
Other operations	35,158	31,331	98,851	92,928
Affiliate revenue	0	0	0	204
Electric customer credits	0	0	244	(153)
Operating revenue, net	142,658	131,287	399,510	366,815
Net income	86,744	38,357	153,719	84,655
Depreciation and amortization	12,623	11,344	36,614	33,385
Interest income	4	10	10	269
Interest charges	1,117	(484)	786	(353)
Federal and state income tax expense	29,888	12,258	52,561	27,280
EBITDA	130,368	61,465	243,670	144,698
Additions to property, plant, and equipment			5,904	7,908
Equity investment in investees	0		0		0
Goodwill	0		0		0
Total assets	1,212,968		1,212,968		1,029,812
Amortization of deferred lease income	(2,300)	(2,300)	(6,900)	(6,900)
OPERATING SEGMENTS | CLECO CAJUN | Power supply agreements
Revenue
Amortization of intangible assets and liabilities	3,600	3,100	10,000	9,300
OTHER
Revenue
Electric operations	(2,420)	(2,420)	(7,260)	(7,260)
Other operations	1	1	4	2
Affiliate revenue	32,116	35,522	85,392	93,938
Electric customer credits	0	0	0	0
Operating revenue, net	29,697	33,103	78,136	86,680
Net income	(23,396)	(14,154)	(37,068)	(51,019)
Depreciation and amortization	8,189	4,497	17,052	13,575
Interest income	43	121	100	276
Interest charges	15,044	16,115	45,732	48,731
Federal and state income tax expense	133	(5,260)	(21,357)	(17,821)
Additions to property, plant, and equipment			1,116	2,019
Equity investment in investees	19,099		19,099		0
Goodwill	0		0		0
Total assets	685,410		685,410		595,217
OTHER | Power supply agreements | CLECO POWER
Revenue
Amortization of intangible assets	2,400	2,400	7,300	7,300
ELIMINATIONS
Revenue
Electric operations	0	0	(1)	0
Other operations	(2,217)	(1,510)	(5,752)	(4,966)
Affiliate revenue	(33,496)	(37,028)	(89,651)	(97,994)
Electric customer credits	0	0	0	1
Operating revenue, net	(35,713)	(38,538)	(95,404)	(102,959)
Net income	1	2	1	1
Depreciation and amortization	0	0	(1)	1
Interest income	(42)	(10)	(98)	(79)
Interest charges	(41)	(12)	(98)	(79)
Federal and state income tax expense	0	$ 1	0	1
Additions to property, plant, and equipment			0	$ 0
Equity investment in investees	(19,099)		(19,099)		0
Goodwill	0		0		0
Total assets	$ (249,409)		$ (249,409)		$ (156,404)