Debt, Total Indebtedness (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
2017	$ 19,193,000
Unamortized Debt Issuance Costs	(11,600,000)	$ (11,700,000)
Long-term debt, net	2,836,105,000	2,738,571,000
Long-term Debt, Maturities, Repayments of Principal in Year Two	20,571,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	11,055,000
Long-term Debt, Maturities, Repayments of Principal in Year Four	300,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Five	25,000,000
Long-term Debt, Maturities, Repayments of Principal after Year Five	2,350,000,000
Cleco Holdings [Member]
Debt Instrument [Line Items]
2017	0
Long-term Line of Credit	0
Unamortized Debt Issuance Costs	(2,516,000)	(2,261,000)
Long Term Debt. Reconciliation, Fair Value Adjustment	147,146,000	155,776,000
Long-term Debt, Maturities, Repayments of Principal in Year Two	0
Long-term Debt, Maturities, Repayments of Principal in Year Three	0
Long-term Debt, Maturities, Repayments of Principal in Year Four	300,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Five	0
Long-term Debt, Maturities, Repayments of Principal after Year Five	1,050,000,000
Cleco Holdings [Member] \| Cleco Holdings' senior notes, 3.250%, due 2023 [Member]
Debt Instrument [Line Items]
Unsecured Debt	165,000,000	165,000,000
Cleco Holdings [Member] \| Cleco Holdings' senior notes, 3.743%, due 2026 [Member]
Debt Instrument [Line Items]
Unsecured Debt	535,000,000	535,000,000
Cleco Holdings [Member] \| Cleco Holdings' senior notes, 4.973%, due 2046 [Member]
Debt Instrument [Line Items]
Unsecured Debt	350,000,000	350,000,000
Cleco Power [Member]
Debt Instrument [Line Items]
2017	19,193,000
Unsecured Debt	1,375,819,000	1,268,715,000
Long-term Line of Credit	0
Capital Lease Obligations	0	1,819,000
Long-term Debt, Gross	1,375,819,000	1,270,534,000
Less: Long-term Debt due within one year	19,193,000	17,896,000
Capital Lease Obligations, Current	0	1,819,000
Unamortized Debt Discount	(6,010,000)	(6,342,000)
Unamortized Debt Issuance Costs	(9,141,000)	(9,421,000)
Long-term debt, net	1,341,475,000	1,235,056,000
Long-term Debt, Maturities, Repayments of Principal in Year Two	20,571,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	11,055,000
Long-term Debt, Maturities, Repayments of Principal in Year Four	0
Long-term Debt, Maturities, Repayments of Principal in Year Five	25,000,000
Long-term Debt, Maturities, Repayments of Principal after Year Five	1,300,000,000
Cleco Power [Member] \| Cleco Power's senior notes, 2.94%, due 2022 [Member]
Debt Instrument [Line Items]
Unsecured Debt	25,000,000	0
Cleco Power [Member] \| Cleco Power's senior notes, 3.08%, due 2023 [Member]
Debt Instrument [Line Items]
Unsecured Debt	100,000,000	0
Cleco Power [Member] \| Cleco Power's senior notes, 3.68%, due 2025 [Member] [Member]
Debt Instrument [Line Items]
Unsecured Debt	75,000,000	75,000,000
Cleco Power [Member] \| Cleco Power's senior notes, 3.47%, due 2026 [Member]
Debt Instrument [Line Items]
Unsecured Debt	130,000,000	130,000,000
Cleco Power [Member] \| Cleco Powers Senior Notes 4.33% due 2027 [Member]
Debt Instrument [Line Items]
Unsecured Debt	50,000,000	50,000,000
Cleco Power [Member] \| Cleco Power's senior notes, 3.57%, due 2028 [Member]
Debt Instrument [Line Items]
Unsecured Debt	200,000,000	200,000,000
Cleco Power [Member] \| Cleco Power's senior notes, 6.50%, due 2035 [Member]
Debt Instrument [Line Items]
Unsecured Debt	295,000,000	295,000,000
Cleco Power [Member] \| Cleco Power's senior notes, 6.00%, due 2040 [Member]
Debt Instrument [Line Items]
Unsecured Debt	250,000,000	250,000,000
Cleco Power [Member] \| Cleco Power's senior notes 5.12% due 2041 [Member]
Debt Instrument [Line Items]
Unsecured Debt	100,000,000	100,000,000
Cleco Power [Member] \| Series A GO Zone bonds, 2.00%, due 2038, mandatory tender in 2020 [Member]
Debt Instrument [Line Items]
Unsecured Debt	50,000,000	50,000,000
Cleco Power [Member] \| Series B GO Zone bonds, 4.25%, due 2036 [Member]
Debt Instrument [Line Items]
Unsecured Debt	50,000,000	50,000,000
Cleco Power [Member] \| Cleco Katrina/Rita's storm recovery bonds, 4.41%, due 2020 [Member]
Debt Instrument [Line Items]
Unsecured Debt	0	1,115,000
Cleco Power [Member] \| Cleco Katrina/Rita's storm recovery bonds, 5.61%, due 2023 [Member]
Debt Instrument [Line Items]
Unsecured Debt	$ 50,819,000	$ 67,600,000

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Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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Amount of the fee that accompanies borrowing money under the debt instrument.

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