Summary of Significant Accounting Policies - Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	5 Months Ended	6 Months Ended	12 Months Ended
	May 31, 2024	Dec. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Jun. 30, 2024
Public Utility, Property, Plant and Equipment [Line Items]
DOE congressional appropriation					$ 9,000
Other expense, net			$ (13,021)	$ (694)	(11,240)
Capitalized software, net		$ 171,400	171,400	156,700
Capitalized software costs, amortization			19,981	11,092	11,881
Property, Plant and Equipment, Net
Generation		1,914,812	1,914,812	1,944,260
Distribution		1,693,668	1,693,668	1,585,742
Transmission		878,833	878,833	844,897
Other utility plant		490,975	490,975	454,329
Other property, plant, and equipment		13,286	13,286	9,766
Total property, plant, and equipment		4,991,574	4,991,574	4,838,994
Accumulated depreciation		(1,050,376)	(1,050,376)	(924,624)
Net property, plant, and equipment		3,941,198	3,941,198	3,914,370
Reclassification Of Deferred Project Costs
Public Utility, Property, Plant and Equipment [Line Items]
Other expense, net		10,800
Acadia Unit 1 acquisition costs
Public Utilities, Property, Plant and Equipment, Acquisition Adjustments
Plant acquisition adjustment		76,116	76,116	76,116
Accumulated amortization		(27,749)	(27,749)	(24,566)
Net plant acquisition adjustment		48,367	$ 48,367	51,550
Minimum
Utility Plants
Generation			10 years
Distribution			15 years
Transmission			5 years
Other utility plant			5 years
Other property, plant, and equipment			5 years
Maximum
Utility Plants
Generation			55 years
Distribution			50 years
Transmission			55 years
Other utility plant			45 years
Other property, plant, and equipment			45 years
CLECO POWER
Public Utility, Property, Plant and Equipment [Line Items]
Construction work in progress		11,800	$ 11,800	10,300
Additional costs for project						$ 500
Other expense, net			(11,151)	(28)	(7,081)
Retained earnings, congressional appropriation		7,500	7,500
Construction work in progress, reimbursement from congressional appropriation		400	400
Capitalized software, net		170,000	170,000	154,900
Capitalized software costs, amortization	$ 7,100		19,574	10,650	$ 11,614
Property, Plant and Equipment, Net
Generation		2,300,880	2,300,880	2,339,410
Distribution		2,129,721	2,129,721	2,022,257
Transmission		1,089,964	1,089,964	1,056,218
Other utility plant		592,652	592,652	551,470
Total property, plant, and equipment		6,113,217	6,113,217	5,969,355
Accumulated depreciation		(2,348,169)	(2,348,169)	(2,244,217)
Net property, plant, and equipment		3,765,048	3,765,048	3,725,138
CLECO POWER | Reclassification Of Deferred Project Costs
Public Utility, Property, Plant and Equipment [Line Items]
Other expense, net		10,800
CLECO POWER | Acadia Unit 1 acquisition costs
Public Utilities, Property, Plant and Equipment, Acquisition Adjustments
Plant acquisition adjustment		95,578	95,578	95,578
Accumulated amortization		(47,211)	(47,211)	(44,028)
Net plant acquisition adjustment		$ 48,367	$ 48,367	$ 51,550
CLECO POWER | Minimum
Utility Plants
Generation			10 years
Distribution			15 years
Transmission			5 years
Other utility plant			5 years
Other property, plant, and equipment			5 years
CLECO POWER | Maximum
Utility Plants
Generation			55 years
Distribution			50 years
Transmission			55 years
Other utility plant			45 years
Other property, plant, and equipment			45 years