Fair Value Accounting Instruments - Schedule of Fair Value of Financial Assets and Liabilities Measured on a Recurring Basis (Details) - Measured on a Recurring Basis - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Asset description
Short-term investments	$ 290,974	$ 179,241
Total assets	328,167	287,457
Liability description
Total liabilities	5,221	7,274
CLECO POWER
Asset description
Short-term investments	217,384	139,752
Total assets	222,364	142,322
Liability description
Total liabilities	4,609	4,864
FTRs
Asset description
Derivative assets	4,814	2,570
Liability description
Derivative liabilities	671	294
FTRs | CLECO POWER
Asset description
Derivative assets	4,814	2,570
Liability description
Derivative liabilities	671	294
Natural gas derivatives
Asset description
Derivative assets	32,379	105,646
Liability description
Derivative liabilities	4,550	6,980
Natural gas derivatives | CLECO POWER
Asset description
Derivative assets	166	0
Liability description
Derivative liabilities	3,938	4,570
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1)
Asset description
Short-term investments	290,974	179,241
Total assets	290,974	179,241
Liability description
Total liabilities	0	0
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | CLECO POWER
Asset description
Short-term investments	217,384	139,752
Total assets	217,384	139,752
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) | FTRs | CLECO POWER
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
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | Natural gas derivatives | CLECO POWER
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	32,379	105,646
Liability description
Total liabilities	4,550	6,980
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | CLECO POWER
Asset description
Short-term investments	0	0
Total assets	166	0
Liability description
Total liabilities	3,938	4,570
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) | FTRs | CLECO POWER
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	32,379	105,646
Liability description
Derivative liabilities	4,550	6,980
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | Natural gas derivatives | CLECO POWER
Asset description
Derivative assets	166	0
Liability description
Derivative liabilities	3,938	4,570
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Asset description
Short-term investments	0	0
Total assets	4,814	2,570
Liability description
Total liabilities	671	294
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | CLECO POWER
Asset description
Short-term investments	0	0
Total assets	4,814	2,570
Liability description
Total liabilities	671	294
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | FTRs
Asset description
Derivative assets	4,814	2,570
Liability description
Derivative liabilities	671	294
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | FTRs | CLECO POWER
Asset description
Derivative assets	4,814	2,570
Liability description
Derivative liabilities	671	294
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | Natural gas derivatives
Asset description
Derivative assets	0	0
Liability description
Derivative liabilities	0	0
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | Natural gas derivatives | CLECO POWER
Asset description
Derivative assets	0	0
Liability description
Derivative liabilities	$ 0	$ 0