Debt, Principal amounts payable under long-term debt agreement(Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
2017	$ 19,193,000
2018	20,571,000
2019	11,055,000
2020	300,000,000
2021	25,000,000
Thereafter	2,350,000,000
Debt Instrument, Fee Amount	11,600,000	$ 11,700,000
Long-term debt, net	2,836,105,000	2,738,571,000
Cleco Power [Member]
Debt Instrument [Line Items]
Unsecured Debt	1,375,819,000	1,268,715,000
2017	19,193,000
2018	20,571,000
2019	11,055,000
2020	0
2021	25,000,000
Thereafter	1,300,000,000
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
Long-term Debt, Current Maturities	19,193,000	17,896,000
Capital Lease Obligations, Current	0	1,819,000
Debt Instrument, Unamortized Discount	6,010,000	6,342,000
Debt Instrument, Fee Amount	9,141,000	9,421,000
Long-term debt, net	1,341,475,000	1,235,056,000
Cleco Holdings [Member]
Debt Instrument [Line Items]
Long Term Debt. Reconciliation, Fair Value Adjustment	147,146,000	155,776,000
2017	0
2018	0
2019	0
2020	300,000,000
2021	0
Thereafter	1,050,000,000
Long-term Line of Credit	0
Debt Instrument, Fee Amount	2,516,000	2,261,000
Cleco Power's senior notes, 2.94%, due 2022 [Member] | Cleco Power [Member]
Debt Instrument [Line Items]
Unsecured Debt	25,000,000	0
Cleco Power's senior notes, 3.68%, due 2025 [Member] [Member] | Cleco Power [Member]
Debt Instrument [Line Items]
Unsecured Debt	75,000,000	75,000,000
Cleco Corporate Holdings debt, variable rate, due 2021 [Member] | Cleco Holdings [Member]
Debt Instrument [Line Items]
Loans Payable to Bank	300,000,000	300,000,000
Cleco Power's senior notes, 3.08%, due 2023 [Member] | Cleco Power [Member]
Debt Instrument [Line Items]
Unsecured Debt	$ 100,000,000	$ 0