Miscellaneous Financial Information (Unaudited) (Details) - USD ($) $ in Thousands		3 Months Ended										9 Months Ended		12 Months Ended
	Apr. 12, 2016	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Jun. 30, 2016	Apr. 12, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Successor [Member]
Quarterly Information [Line Items]
Operating revenue, net		$ 277,985	$ 338,499	$ 308,661	$ 250,501	$ 266,642	$ 342,860		$ 243,502				$ 853,005	$ 1,175,646
Operating income (loss)		50,130	95,112	70,249	38,798	53,299	93,143		(110,148)				36,291	254,289
Net income (loss)		61,040	45,304	25,444	6,292	18,180	39,621		(81,914)			$ (24,113)	$ (24,113)	138,080
Contributions from member/parent						0	0		100,720
Distributions to member/parent		110	28,300	26,700	28,955	32,765	28,000		$ 28,000			$ 88,765		84,065
Predecessor [Member]
Quarterly Information [Line Items]
Operating revenue, net	$ 32,903									$ 299,870	$ 266,968					$ 1,209,402
Operating income (loss)	(29,832)									20,363	50,192					287,339
Net income (loss)	(23,328)									$ (3,960)	19,368					133,669
Contributions from member/parent	0										0
Distributions to member/parent	$ 0										0
Cleco Power [Member]
Quarterly Information [Line Items]
Operating revenue, net		280,093	340,614	310,787	253,702	269,017	345,131	$ 278,343			266,682			1,185,196	$ 1,159,173	1,208,467
Operating income (loss)		58,907	99,493	74,533	44,700	59,156	99,420	(81,841)			52,265			277,633	129,000	294,201
Net income (loss)		42,299	54,852	35,733	17,854	26,906	52,572	(61,229)			20,879			150,738	39,128	141,350
Contribution from member/parent								50,000							50,000
Distributions to member/parent		$ 60,000	$ 15,000	$ 25,000	$ 35,000	$ 25,000	$ 50,000	$ 10,000			$ 25,000			$ 135,000	$ 110,000	$ 135,000