Fair Value Accounting Instruments - Fair Value of Financial Assets and Liabilities Measured On A Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Asset Description
Short-term investments	$ 334,353	$ 153,972
Total assets	342,318	165,266
Liability Description
Total liabilities	11,835	256
FTRs
Asset Description
Derivative assets	5,513	2,084
Liability Description
Derivative liabilities	945	256
Natural gas derivatives
Asset Description
Derivative assets	2,452	9,210
Liability Description
Derivative liabilities	10,890	0
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1)
Asset Description
Short-term investments	334,353	153,972
Total assets	334,353	153,972
Liability Description
Total liabilities	0	0
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | FTRs
Asset Description
Derivative assets	0	0
Liability Description
Derivative liabilities	0	0
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | Natural gas derivatives
Asset Description
Derivative assets	0	0
Liability Description
Derivative liabilities	0	0
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)
Asset Description
Short-term investments	0	0
Total assets	2,452	9,210
Liability Description
Total liabilities	10,890	0
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | FTRs
Asset Description
Derivative assets	0	0
Liability Description
Derivative liabilities	0	0
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | Natural gas derivatives
Asset Description
Derivative assets	2,452	9,210
Liability Description
Derivative liabilities	10,890	0
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Asset Description
Short-term investments	0	0
Total assets	5,513	2,084
Liability Description
Total liabilities	945	256
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | FTRs
Asset Description
Derivative assets	5,513	2,084
Liability Description
Derivative liabilities	945	256
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | Natural gas derivatives
Asset Description
Derivative assets	0	0
Liability Description
Derivative liabilities	0	0
CLECO POWER
Asset Description
Short-term investments	326,128	147,648
Total assets	334,093	158,942
Liability Description
Total liabilities	11,835	256
CLECO POWER | FTRs
Asset Description
Derivative assets	5,513	2,084
Liability Description
Derivative liabilities	945	256
CLECO POWER | Natural gas derivatives
Asset Description
Derivative assets	2,452	9,210
Liability Description
Derivative liabilities	10,890	0
CLECO POWER | QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1)
Asset Description
Short-term investments	326,128	147,648
Total assets	326,128	147,648
Liability Description
Total liabilities	0	0
CLECO POWER | QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | FTRs
Asset Description
Derivative assets	0	0
Liability Description
Derivative liabilities	0	0
CLECO POWER | QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | Natural gas derivatives
Asset Description
Derivative assets	0	0
Liability Description
Derivative liabilities	0	0
CLECO POWER | SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)
Asset Description
Short-term investments	0	0
Total assets	2,452	9,210
Liability Description
Total liabilities	10,890	0
CLECO POWER | SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | FTRs
Asset Description
Derivative assets	0	0
Liability Description
Derivative liabilities	0	0
CLECO POWER | SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | Natural gas derivatives
Asset Description
Derivative assets	2,452	9,210
Liability Description
Derivative liabilities	10,890	0
CLECO POWER | SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Asset Description
Short-term investments	0	0
Total assets	5,513	2,084
Liability Description
Total liabilities	945	256
CLECO POWER | SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | FTRs
Asset Description
Derivative assets	5,513	2,084
Liability Description
Derivative liabilities	945	256
CLECO POWER | SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | Natural gas derivatives
Asset Description
Derivative assets	0	0
Liability Description
Derivative liabilities	$ 0	$ 0