Debt, Credit Facilities (Details)	12 Months Ended
	Dec. 31, 2017 USD ($)
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 400,000,000
Cleco Holdings [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	100,000,000
Long-term Line of Credit	$ 0
Commitment fees (in hundredths)	0.275%
Cleco Holdings [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Unrestricted member's equity	$ 721,500,000
Cleco Holdings [Member] | Line of Credit [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Ratio of indebtedness to net capital (in hundredths)	0.65
Cleco Holdings [Member] | Line of Credit [Member] | ABR [Member]
Line of Credit Facility [Line Items]
Credit facility, Basis Spread on Variable Rate (in hundredths)	0.75%
Cleco Holdings [Member] | Line of Credit [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Credit facility, Basis Spread on Variable Rate (in hundredths)	1.75%
Cleco Power [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 300,000,000
Long-term Line of Credit	$ 0
Commitment fees (in hundredths)	0.125%
Cleco Power [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Ratio of indebtedness to net capital (in hundredths)	0.65
Cleco Power [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Unrestricted member's equity	$ 888,900,000
Cleco Power [Member] | Line of Credit [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Ratio of indebtedness to net capital (in hundredths)	0.65
Cleco Power [Member] | Line of Credit [Member] | ABR [Member]
Line of Credit Facility [Line Items]
Credit facility, Basis Spread on Variable Rate (in hundredths)	0.125%
Cleco Power [Member] | Line of Credit [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Credit facility, Basis Spread on Variable Rate (in hundredths)	1.125%