Pension Plan and Employee Benefits - Benefit Obligation, Plan Assets, and Funded Status (Details) - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Change in benefit obligation
Plan amendments	$ 4,532,000	$ 0
Pension
Change in benefit obligation
Benefit obligation at beginning of period	494,864,000	525,482,000
Service cost	3,866,000	4,619,000	$ 4,977,000
Interest cost	27,105,000	26,140,000	26,423,000
Actuarial loss (gain)	5,913,000	(25,647,000)
Expenses paid	0	(3,396,000)
Transfer to Cleco Cajun Purchasers	0	(1,674,000)
Benefits paid	(31,247,000)	(30,660,000)
Benefit obligation at end of period	500,501,000	494,864,000	525,482,000
Change in plan assets
Fair value of plan assets at beginning of period	409,270,000	408,159,000
Actual gain on plan assets	48,686,000	11,091,000
Employer contributions	16,500,000	25,750,000	0
Expenses paid	(2,967,000)	(3,396,000)
Transfer to Cleco Cajun Purchasers	0	(1,674,000)
Benefits paid	(31,247,000)	(30,660,000)
Fair value of plan assets at end of period	440,242,000	409,270,000	408,159,000
Unfunded status	(60,259,000)	(85,594,000)
Accumulated benefit obligation	485,708,000	479,948,000
Other benefits
Change in benefit obligation
Benefit obligation at beginning of period	44,003,000	47,056,000
Service cost	1,578,000	1,907,000	1,472,000
Interest cost	2,343,000	2,322,000	2,285,000
Actuarial loss (gain)	1,346,000	(2,011,000)
Derecognition of Cleco Cajun liability	0	(380,000)
Benefits paid	(4,969,000)	(4,891,000)
Benefit obligation at end of period	48,833,000	44,003,000	47,056,000
Change in plan assets
Unfunded status	(48,833,000)	(44,003,000)
SERP BENEFITS
Change in benefit obligation
Benefit obligation at beginning of period	63,543,000	67,462,000
Service cost	58,000	134,000	142,000
Interest cost	3,454,000	3,343,000	3,604,000
Actuarial loss (gain)	1,177,000	(2,814,000)
Benefits paid	(4,603,000)	(4,582,000)
Benefit obligation at end of period	63,629,000	63,543,000	$ 67,462,000
Change in plan assets
Accumulated benefit obligation	$ 63,629,000	$ 63,543,000