Pension Plan and Employee Benefits - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Jun. 30, 2023	Apr. 30, 2024
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Estimated pension contributions through 2028			$ 94,200,000
Estimated pension contributions in 2024	$ 25,700,000
Pension Plan | Subsequent event
Defined Benefit Plan Disclosure [Line Items]
Estimated pension contributions in 2024				$ 3,500,000
Pension Plan | Other Subsidiaries
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan contributions by employer	500,000	$ 400,000
Other Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Assets held-in-trust, noncurrent	0
Other Benefits Plan | CLECO POWER
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan contributions by employer	1,100,000	900,000
SERP
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan contributions by employer	795,000	$ 867,000
SERP | CLECO POWER
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan contributions by employer	$ 100,000