Subsequent Event - Plan of Acquisition (Details) - Subsequent Event [Member] $ in Millions	Feb. 06, 2018 USD ($)
Subsequent Event [Line Items]
Business Acquisition, Transaction Price Agreed Upon	$ 1,000.0
Cleco Holdings [Member] | Acquisition Loan Facility, NRG South Central Acquisition [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	300.0
Cleco Holdings [Member] | Term Loan Facility, NRG South Central Acquisition [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	300.0
Cleco Holdings [Member] | Incremental Revolving Facility, NRG Acquisition [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	$ 75.0