Disclosures about Segments (Details) $ in Thousands		3 Months Ended									9 Months Ended		12 Months Ended
	Apr. 12, 2016 USD ($)	Dec. 31, 2017 USD ($) entity	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Apr. 12, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) entity	Dec. 31, 2015 USD ($)	Apr. 13, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of transmission interconnection facility subsidiaries | entity		2											2
Revenue
Equity investment in investee		$ 18,172				$ 18,672					$ 18,672	$ 18,672	$ 18,172
Goodwill		1,490,797				1,490,797					1,490,797	1,490,797	1,490,797		$ 1,490,797
Total segment assets		6,278,382				6,343,144					6,343,144	6,343,144	6,278,382
Predecessor [Member]
Revenue
Electric operations									$ 281,154					$ 1,142,389
Other operations									19,080					69,186
Electric customer credits									(364)					(2,173)
Affiliate revenue									0					0
Operating revenue, net	$ 32,903								299,870	$ 266,968				1,209,402
Depreciation and amortization									44,076					149,579
Merger transaction and commitment costs									34,912					4,591
Interest charges									22,123					77,991
Interest income									265					895
Federal and state income tax expense (benefit)									3,468					77,704
Net income (loss)	$ (23,328)								(3,960)	$ 19,368				133,669
Additions to property, plant, and equipment									42,392					156,819
Equity investment in investee														16,822
Total segment assets														4,323,354
Predecessor [Member] | Operating Segments [Member] | Cleco Power [Member]
Revenue
Electric operations									281,154					1,142,389
Other operations									18,493					67,109
Electric customer credits									(364)					(2,173)
Affiliate revenue									263					1,142
Operating revenue, net									299,546					1,208,467
Depreciation and amortization									43,698					147,839
Merger transaction and commitment costs									0					0
Interest charges									21,840					76,560
Interest income									208					725
Federal and state income tax expense (benefit)									12,993					79,294
Net income (loss)									21,548					141,350
Additions to property, plant, and equipment									42,353					156,357
Equity investment in investee														16,822
Total segment assets														4,233,337
Predecessor [Member] | Operating Segments [Member] | Corporate and Other [Member]
Revenue
Electric operations									0					0
Other operations									587					2,078
Electric customer credits									0					0
Affiliate revenue									15,024					57,323
Operating revenue, net									15,611					59,401
Depreciation and amortization									377					1,739
Merger transaction and commitment costs									34,928					4,592
Interest charges									295					1,149
Interest income									69					(111)
Federal and state income tax expense (benefit)									(9,525)					(1,590)
Net income (loss)									(25,508)					(7,681)
Additions to property, plant, and equipment									39					462
Equity investment in investee														0
Total segment assets														21,471
Predecessor [Member] | Intersegment Eliminations [Member]
Revenue
Electric operations									0					0
Other operations									0					(1)
Electric customer credits									0					0
Affiliate revenue									(15,287)					(58,465)
Operating revenue, net									(15,287)					(58,466)
Depreciation and amortization									1					1
Merger transaction and commitment costs									(16)					(1)
Interest charges									(12)					282
Interest income									(12)					281
Federal and state income tax expense (benefit)									0					0
Net income (loss)									0					0
Additions to property, plant, and equipment									$ 0					0
Equity investment in investee														0
Total segment assets														$ 68,546
Successor [Member]
Revenue
Electric operations												802,592	1,097,632
Other operations												51,562	79,580
Electric customer credits												(1,149)	(1,566)
Affiliate revenue												0	0
Operating revenue, net		277,985	$ 338,499	$ 308,661	$ 250,501	266,642	$ 342,860	$ 243,502				853,005	1,175,646
Depreciation and amortization												109,739	166,439
Merger transaction and commitment costs												174,696	287
Interest charges												89,766	122,913
Interest income												840	1,424
Federal and state income tax expense (benefit)												(22,822)	7,079
Net income (loss)		61,040	$ 45,304	$ 25,444	$ 6,292	18,180	$ 39,621	$ (81,914)			(24,113)	(24,113)	138,080
Additions to property, plant, and equipment												144,444	236,932
Equity investment in investee		18,172				18,672					18,672	18,672	18,172
Goodwill		1,490,797				1,490,797					1,490,797	1,490,797	1,490,797
Total segment assets		6,278,382				6,343,144					6,343,144	6,343,144	6,278,382
Successor [Member] | Operating Segments [Member] | Cleco Power [Member]
Revenue
Electric operations												810,075	1,108,389
Other operations												50,080	77,522
Electric customer credits												(1,149)	(1,566)
Affiliate revenue												621	851
Operating revenue, net												859,627	1,185,196
Depreciation and amortization												102,444	157,999
Merger transaction and commitment costs												151,501	0
Interest charges												54,606	69,362
Interest income												652	1,283
Federal and state income tax expense (benefit)												5,376	67,331
Net income (loss)												17,580	150,738
Additions to property, plant, and equipment												143,790	235,252
Equity investment in investee		18,172				18,672					18,672	18,672	18,172
Goodwill		1,490,797				1,490,797					1,490,797	1,490,797	1,490,797
Total segment assets		5,679,538				5,758,245					5,758,245	5,758,245	5,679,538
Successor [Member] | Operating Segments [Member] | Corporate and Other [Member]
Revenue
Electric operations												(7,482)	(10,757)
Other operations												1,482	2,058
Electric customer credits												0	0
Affiliate revenue												35,602	57,168
Operating revenue, net												29,602	48,469
Depreciation and amortization												7,296	8,439
Merger transaction and commitment costs												23,195	287
Interest charges												35,246	53,725
Interest income												275	316
Federal and state income tax expense (benefit)												(28,198)	(60,252)
Net income (loss)												(41,692)	(12,659)
Additions to property, plant, and equipment												654	1,680
Equity investment in investee		0				0					0	0	0
Goodwill		0				0					0	0	0
Total segment assets		619,943				614,959					614,959	614,959	619,943
Successor [Member] | Intersegment Eliminations [Member]
Revenue
Electric operations												(1)	0
Other operations												0	0
Electric customer credits												0	0
Affiliate revenue												(36,223)	(58,019)
Operating revenue, net												(36,224)	(58,019)
Depreciation and amortization												(1)	1
Merger transaction and commitment costs												0	0
Interest charges												(86)	(174)
Interest income												(87)	(175)
Federal and state income tax expense (benefit)												0	0
Net income (loss)												(1)	1
Additions to property, plant, and equipment												0	0
Equity investment in investee		0				0					0	0	0
Goodwill		0				0					0	0	0
Total segment assets		$ (21,099)				$ (30,060)					$ (30,060)	$ (30,060)	$ (21,099)