Pension Plan and Employee Benefits, Pension Plan and Other Benefits Plan (Details) - USD ($)	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Apr. 12, 2016	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Pension Plan [Member]
Components of periodic benefit costs [Abstract]
Service cost	$ 2,260,000	$ 2,229,000
Interest cost	5,412,000	5,455,000
Expected return on plan assets	(6,016,000)	(6,001,000)
Prior period service (credit) cost	(18,000)	(18,000)
Net loss (gain)	2,502,000	3,365,000
Total benefit cost	4,140,000	5,030,000
Pension Plan [Member] | Other Subsidiaries [Member]
Components of periodic benefit costs [Abstract]
Total benefit cost	500,000	400,000
Pension Plan [Member] | Successor
Components of periodic benefit costs [Abstract]
Service cost				$ 4,122,000	$ 6,779,000
Interest cost				10,124,000	16,235,000
Expected return on plan assets				(11,195,000)	(18,048,000)
Prior period service (credit) cost				(33,000)	(53,000)
Net loss (gain)				5,211,000	7,506,000
Total benefit cost				8,229,000	12,419,000
Pension Plan [Member] | Successor | Other Subsidiaries [Member]
Components of periodic benefit costs [Abstract]
Total benefit cost				800,000	1,400,000
Pension Plan [Member] | Predecessor
Components of periodic benefit costs [Abstract]
Service cost			$ 2,563,000
Interest cost			6,242,000
Expected return on plan assets			(6,812,000)
Prior period service (credit) cost			(20,000)
Net loss (gain)			2,798,000
Total benefit cost			4,771,000
Pension Plan [Member] | Predecessor | Other Subsidiaries [Member]
Components of periodic benefit costs [Abstract]
Total benefit cost			500,000
Other Postretirement Benefits Plan [Member]
Components of periodic benefit costs [Abstract]
Service cost	314,000	380,000
Interest cost	372,000	420,000
Expected return on plan assets	0	0
Prior period service (credit) cost	0	0
Net loss (gain)	(32,000)	0
Total benefit cost	654,000	800,000
Assets Held-in-trust, Noncurrent	0				0
Current portion of other benefits liability	3,854,000				3,854,000		$ 3,854,000
Noncurrent portion of other benefits liability	39,296,000				39,296,000		40,196,000
Other Postretirement Benefits Plan [Member] | Successor
Components of periodic benefit costs [Abstract]
Service cost				709,000	1,084,000
Interest cost				784,000	1,176,000
Expected return on plan assets				0	0
Prior period service (credit) cost				0	0
Net loss (gain)				0	(37,000)
Total benefit cost				$ 1,493,000	2,223,000
Other Postretirement Benefits Plan [Member] | Predecessor
Components of periodic benefit costs [Abstract]
Service cost			431,000
Interest cost			476,000
Expected return on plan assets			0
Prior period service (credit) cost			34,000
Net loss (gain)			181,000
Total benefit cost			$ 1,122,000
Cleco Power [Member] | Other Postretirement Benefits Plan [Member]
Components of periodic benefit costs [Abstract]
Total benefit cost	800,000	$ 800,000			2,500,000	$ 2,500,000
Current portion of other benefits liability	3,345,000				3,345,000		3,345,000
Noncurrent portion of other benefits liability	$ 34,147,000				$ 34,147,000		$ 34,892,000