Fair Value Accounting Instruments - Carrying Value and Estimated Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deferred debt issuance costs not included in the carrying value of long-term debt	$ 18,300	$ 11,600
CARRYING VALUE
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	3,300,793	2,922,003
FAIR VALUE
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	3,179,215	2,716,251
CLECO POWER
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deferred debt issuance costs not included in the carrying value of long-term debt	17,400	10,100
CLECO POWER | CARRYING VALUE
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	2,208,240	1,822,061
CLECO POWER | FAIR VALUE
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 2,232,569	$ 1,800,633