Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	$ 2,124,740	$ 2,096,357	$ 2,046,763
Amounts reclassified from accumulated other comprehensive loss
Reclassification of net gain to interest charges			0
Balance, ending	2,643,006	2,124,740	2,096,357
CLECO POWER
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	1,594,533	1,550,679	1,535,202
Other comprehensive income before reclassifications
Postretirement benefit adjustments incurred during the year	(10,344)	954	(948)
Amounts reclassified from accumulated other comprehensive loss
Amortization of postretirement benefit net loss	687	1,789	476
Reclassification of net gain to interest charges	254	254	211
Reclassification of effect of tax rate change		(2,496)
Balance, ending	1,713,392	1,594,533	1,550,679
POSTRETIREMENT BENEFIT NET GAIN (LOSS)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	1,786	(2,921)	1,500
Other comprehensive income before reclassifications
Postretirement benefit adjustments incurred during the year	(18,877)	3,681	(3,898)
Amounts reclassified from accumulated other comprehensive loss
Amortization of postretirement benefit net loss	(422)	1,615	(523)
Reclassification of effect of tax rate change		(589)
Balance, ending	(17,513)	1,786	(2,921)
POSTRETIREMENT BENEFIT NET GAIN (LOSS) | CLECO POWER
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	(7,060)	(8,377)	(7,905)
Other comprehensive income before reclassifications
Postretirement benefit adjustments incurred during the year	(10,344)	954	(948)
Amounts reclassified from accumulated other comprehensive loss
Amortization of postretirement benefit net loss	687	1,789	476
Reclassification of net gain to interest charges	0	0
Reclassification of effect of tax rate change		(1,426)
Balance, ending	(16,717)	(7,060)	(8,377)
NET (LOSS) GAIN ON CASH FLOW HEDGES | CLECO POWER
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	(6,122)	(5,306)	(5,517)
Amounts reclassified from accumulated other comprehensive loss
Reclassification of net gain to interest charges	254	254	211
Reclassification of effect of tax rate change		(1,070)
Balance, ending	(5,868)	(6,122)	(5,306)
TOTAL AOCI
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	1,786	(2,921)	1,500
Amounts reclassified from accumulated other comprehensive loss
Reclassification of effect of tax rate change		(589)
Balance, ending	(17,513)	1,786	(2,921)
TOTAL AOCI | CLECO POWER
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	(13,182)	(13,683)	(13,422)
Amounts reclassified from accumulated other comprehensive loss
Reclassification of effect of tax rate change		(2,496)
Balance, ending	$ (22,585)	$ (13,182)	$ (13,683)