Summary of Significant Accounting Policies, Property, Plant, and Equipment (Details) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Apr. 12, 2016	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Apr. 13, 2016
Property, Plant, and Equipment [Abstract]
Capitalized software, net		$ 10,000,000	$ 7,900,000	$ 10,000,000
Property, Plant and Equipment, Net [Abstract]
Utility Plants, Generation		1,866,601,000	1,908,344,000	1,866,601,000
Utility Plants, Distribution		955,126,000	1,015,472,000	955,126,000
Utility Plants, Transmission		503,996,000	512,428,000	503,996,000
Utility Plants, Other		146,976,000	153,900,000	146,976,000
Other property, plant, and equipment		3,882,000	4,381,000	3,882,000
Total property, plant, and equipment		3,476,581,000	3,594,525,000	3,476,581,000
Accumulated depreciation		(75,816,000)	(192,348,000)	(75,816,000)		$ 0
Net property, plant, and equipment		3,400,765,000	3,402,177,000	3,400,765,000
Successor [Member]
Property, Plant, and Equipment [Abstract]
Capitalized software costs, amortization		2,351,000	$ 2,367,000
Predecessor [Member]
Property, Plant, and Equipment [Abstract]
Capitalized software costs, amortization	$ 921,000				$ 2,194,000
Minimum [Member]
Estimated Useful Lives [Abstract]
Utility Plants, Generation (in years)			10 years
Utility Plants, Distribution (in years)			15 years
Utility Plants, Transmission (in years)			5 years
Utility Plants, Other (in years)			5 years
Other property, plant, and equipment (in years)			5 years
Maximum [Member]
Estimated Useful Lives [Abstract]
Utility Plants, Generation (in years)			95 years
Utility Plants, Distribution (in years)			50 years
Utility Plants, Transmission (in years)			55 years
Utility Plants, Other (in years)			45 years
Other property, plant, and equipment (in years)			45 years
Cleco Power [Member]
Property, Plant, and Equipment [Abstract]
Capitalized software, net		8,200,000	$ 6,600,000	8,200,000
Capitalized software costs, amortization			$ 1,887,000	$ 2,405,000	$ 1,718,000
Annual depreciation provisions expressed as a percentage of average depreciable property (in hundredths)			2.72%	2.68%	2.68%
Property, Plant and Equipment, Net [Abstract]
Utility Plants, Generation		2,406,572,000	$ 2,442,987,000	$ 2,406,572,000
Utility Plants, Distribution		1,405,703,000	1,462,193,000	1,405,703,000
Utility Plants, Transmission		719,052,000	725,199,000	719,052,000
Utility Plants, Other		259,238,000	263,105,000	259,238,000
Total property, plant, and equipment		4,790,565,000	4,893,484,000	4,790,565,000
Accumulated depreciation		(1,618,241,000)	(1,712,590,000)	(1,618,241,000)
Net property, plant, and equipment		$ 3,172,324,000	$ 3,180,894,000	$ 3,172,324,000