Leases - Finance Lease (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) event	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Apr. 30, 2018 barge
Lessee, Lease, Description [Line Items]
Finance lease, number of cancellation events triggering early termination | event	1
Finance lease, number of cancellation events | event	4
CLECO POWER
Lessee, Lease, Description [Line Items]
Finance lease, principal interest | $	$ 2.2	$ 2.2	$ 2.0
Sublease income | $	$ 0.8	$ 1.7	$ 0.5
Maritime Equipment | CLECO POWER
Lessee, Lease, Description [Line Items]
Finance lease, number of leased assets | barge				42