Debt - Credit Facilities (Details)			12 Months Ended
	Feb. 05, 2019 USD ($)	Feb. 04, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Line of Credit Facility [Line Items]
Payments on credit facilities			$ 108,000,000	$ 0	$ 179,000,000
Line of Credit
Line of Credit Facility [Line Items]
Unrestricted member's equity			1,010,000,000
Cleco Holdings
Line of Credit Facility [Line Items]
Ratio of total indebtedness to total capitalization		0.65
Cleco Holdings | Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 175,000,000
Line of credit facility, remaining borrowing capacity			$ 475,000,000
Increase in credit facility capacity		$ 75,000,000.0
Commitment fees			0.275%
Higher fees if downgraded			0.075%
Additional interest if downgraded			0.50%
Payments on credit facilities	$ 75,000,000
Cleco Holdings | Line of Credit | MAXIMUM
Line of Credit Facility [Line Items]
Ratio of total indebtedness to total capitalization			0.65
Cleco Holdings | Line of Credit | ABR
Line of Credit Facility [Line Items]
Basis spread on variable rate			0.75%
Cleco Holdings | Line of Credit | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate			1.75%
CLECO POWER
Line of Credit Facility [Line Items]
Payments on credit facilities			$ 33,000,000	$ 0	$ 106,000,000
CLECO POWER | MAXIMUM
Line of Credit Facility [Line Items]
Ratio of total indebtedness to total capitalization			0.65
CLECO POWER | Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 300,000,000
Unrestricted member's equity			$ 989,000,000
Higher fees if downgraded			0.05%
Additional interest if downgraded			0.125%
CLECO POWER | Line of Credit | MAXIMUM
Line of Credit Facility [Line Items]
Ratio of total indebtedness to total capitalization			0.65
CLECO POWER | Line of Credit | ABR
Line of Credit Facility [Line Items]
Basis spread on variable rate			0.125%
CLECO POWER | Line of Credit | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate			1.125%