Business Combinations - Narrative (Details) $ in Thousands		1 Months Ended	3 Months Ended	12 Months Ended
	Feb. 04, 2019 USD ($) investor_owned_utility municipality cooperative MW	Jan. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jul. 14, 2020
Business Acquisition [Line Items]
Proceeds from long-term lines of credit				$ 185,000	$ 238,000	$ 108,000
Decrease in other operating income				(195,767)	(180,524)	(182,832)
Depreciation expense				237,415	219,363	216,320
NRG South Central
Business Acquisition [Line Items]
Repayments of long-term debt	$ 400,000	$ 400,000
Business combination, liabilities arising from contingencies, amount recognized	10,000
Business combination, indemnification assets, amount as of acquisition date	10,000
Purchase price consideration	962,200
Cash paid	1,000,000
Working capital adjustment	37,800
Business combination, finite-lived intangibles	98,900
Business combination, recognized identifiable assets and intangible liabilities	38,300
Business combination, deferred revenue	58,300
Net income						154,898
NRG South Central | Fair Value Adjustments
Business Acquisition [Line Items]
Regulated operating revenue, electric, non-nuclear			$ 500
Decrease in other operating income			100
Depreciation expense			$ 200
NRG South Central | Acquisition-related Costs
Business Acquisition [Line Items]
Net income						4,700
NRG South Central | Power supply agreements
Business Acquisition [Line Items]
Business combination, recognized identifiable assets and intangible liabilities	14,200
NRG South Central | LTSA
Business Acquisition [Line Items]
Business combination, recognized identifiable assets and intangible liabilities	$ 24,100
CLECO CAJUN
Business Acquisition [Line Items]
Number of customers served | investor_owned_utility	1
CLECO POWER
Business Acquisition [Line Items]
Public utilities, requested rate increase (decrease), amount		$ (4,000)
Proceeds from long-term lines of credit				185,000	150,000	33,000
Regulated operating revenue, electric, non-nuclear				1,202,249	1,015,018	1,130,928
Decrease in other operating income				(74,625)	(65,237)	(72,833)
Depreciation expense				$ 173,498	$ 166,987	$ 172,471
Cleco Holdings
Business Acquisition [Line Items]
Debt to capital ratio	0.65
Cleco Holdings | Senior notes, 3.375%, due 2029
Business Acquisition [Line Items]
Interest rate				3.375%			3.375%
Cleco Holdings | Revolving Credit Facility
Business Acquisition [Line Items]
Proceeds from credit facility	$ 75,000
Line of credit facility, maximum borrowing capacity	175,000
Proceeds from long-term lines of credit	75,000
Cleco Holdings | Bridge Loan
Business Acquisition [Line Items]
Debt instrument, face amount	300,000
Cleco Holdings | Loans Payable
Business Acquisition [Line Items]
Debt instrument, face amount	100,000
Cleco Holdings | NRG South Central
Business Acquisition [Line Items]
Cash paid	102,300
Cleco Group | NRG South Central
Business Acquisition [Line Items]
Business combination, equity interests issued and issuable	$ 384,900
Sterlington, Louisiana | Natural-gas-fired Generating Station | CLECO CAJUN
Business Acquisition [Line Items]
Number of megawatts in station or facility (mw) | MW	176
Jarreau, Louisiana | Natural-gas-fired Facility | CLECO CAJUN
Business Acquisition [Line Items]
Number of megawatts in station or facility (mw) | MW	220
Jarreau, Louisiana | Natural-gas-fired Peaking Facility | CLECO CAJUN
Business Acquisition [Line Items]
Number of megawatts in station or facility (mw) | MW	210
New Roads, Louisiana | Natural-gas-fired Generating Station | CLECO CAJUN
Business Acquisition [Line Items]
Number of megawatts in station or facility (mw) | MW	540
New Roads, Louisiana | Coal-fired Generating Facility | CLECO CAJUN
Business Acquisition [Line Items]
Number of megawatts in station or facility (mw) | MW	580
New Roads, Louisiana | Coal-fired Generating Station | CLECO CAJUN | Jointly Owned Electricity Generation Plant
Business Acquisition [Line Items]
Number of megawatts in station or facility (mw) | MW	588
Ownership interest percentage	58.00%
Jennings, Louisiana | Natural-gas-fired Peaking Facility | CLECO CAJUN | Jointly Owned Electricity Generation Plant
Business Acquisition [Line Items]
Number of megawatts in station or facility (mw) | MW	300
Ownership interest percentage	75.00%
Deweyville, Texas | Natural-gas-fired Generating Station | CLECO CAJUN
Business Acquisition [Line Items]
Number of megawatts in station or facility (mw) | MW	1,263
Louisiana | CLECO CAJUN
Business Acquisition [Line Items]
Number of customers served | cooperative	9
Arkansas, Louisiana, And Texas | CLECO CAJUN
Business Acquisition [Line Items]
Number of customers served | municipality	5