Affiliate Transactions (Details) - USD ($)	3 Months Ended									9 Months Ended		12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Successor [Member]
Affiliate Transaction [Line Items]
Affiliate revenue											$ 0	$ 0
Distributions to parent	$ 110,000	$ 28,300,000	$ 26,700,000	$ 28,955,000	$ 32,765,000	$ 28,000,000		$ 28,000,000		$ 88,765,000		84,065,000
Cleco Power [Member]
Affiliate Transaction [Line Items]
Contribution from parent							$ 50,000,000						$ 50,000,000
Affiliate revenue												851,000	884,000	$ 1,142,000
Other income												494,000	31,000	13,000
Total Affiliate Revenue												1,345,000	915,000	1,155,000
Accounts receivable - affiliate	1,355,000				1,406,000					1,406,000	1,406,000	1,355,000	1,406,000
Accounts payable - affiliate	8,697,000				7,190,000					7,190,000	7,190,000	8,697,000	7,190,000
Distributions to parent	60,000,000	$ 15,000,000	$ 25,000,000	$ 35,000,000	25,000,000	$ 50,000,000	$ 10,000,000		$ 25,000,000			135,000,000	110,000,000	135,000,000
Cleco Power [Member] | Cleco Group [Member]
Affiliate Transaction [Line Items]
Contribution from parent												0
Other income												494,000	19,000	3,000
Accounts receivable - affiliate	743,000				3,000					3,000	3,000	743,000	3,000
Accounts payable - affiliate	113,000				119,000					119,000	119,000	113,000	119,000
Distributions to parent												135,000,000	110,000,000	135,000,000
Non-cash equity contributions from parent													0
Cleco Power [Member] | Support Group [Member]
Affiliate Transaction [Line Items]
Affiliate revenue												851,000	884,000	1,142,000
Accounts receivable - affiliate	608,000				1,402,000					1,402,000	1,402,000	608,000	1,402,000
Accounts payable - affiliate	8,582,000				7,071,000					7,071,000	7,071,000	8,582,000	7,071,000
Transfer of pension plan liability and an equal amount of assets												1,812,000	1,771,000
Cleco Power [Member] | Evangeline [Member]
Affiliate Transaction [Line Items]
Accounts receivable - affiliate	4,000				1,000					1,000	1,000	4,000	1,000
Accounts payable - affiliate	2,000				0					0	0	2,000	0
Cleco Power [Member] | Diversified Lands [Member]
Affiliate Transaction [Line Items]
Other income												0	0	10,000
Cleco Power [Member] | Perryville [Member]
Affiliate Transaction [Line Items]
Other income												0	6,000	0
Cleco Power [Member] | Attala [Member]
Affiliate Transaction [Line Items]
Other income												0	6,000	0
Cleco Power [Member] | Other Operations [Member] | Support Group [Member]
Affiliate Transaction [Line Items]
Expenses from transactions with related parties												(48,533,000)	(46,116,000)	(53,079,000)
Cleco Power [Member] | Maintenance [Member] | Support Group [Member]
Affiliate Transaction [Line Items]
Expenses from transactions with related parties												(2,039,000)	(2,255,000)	(1,807,000)
Cleco Power [Member] | Taxes other than income taxes [Member] | Support Group [Member]
Affiliate Transaction [Line Items]
Expenses from transactions with related parties												(13,000)	(10,000)	(3,000)
Cleco Power [Member] | Other Expense [Member] | Cleco Group [Member]
Affiliate Transaction [Line Items]
Expenses from transactions with related parties												(361,000)	0	0
Cleco Power [Member] | Other Expense [Member] | Support Group [Member]
Affiliate Transaction [Line Items]
Expenses from transactions with related parties												(255,000)	(106,000)	$ (403,000)
Cleco Holdings [Member]
Affiliate Transaction [Line Items]
Accounts receivable - affiliate	6,880,000				7,070,000					7,070,000	7,070,000	6,880,000	7,070,000
Accounts payable - affiliate	5,621,000				14,521,000					14,521,000	14,521,000	5,621,000	14,521,000
Cleco Holdings [Member] | Cleco Group [Member]
Affiliate Transaction [Line Items]
Accounts receivable - affiliate	600,000											600,000
Accounts payable - affiliate	$ 0				0					0	0	0	0
Cleco Holdings [Member] | Successor [Member] | Cleco Group [Member]
Affiliate Transaction [Line Items]
Contribution from parent											100,700,000	0
Distributions to parent											88,800,000	$ 84,100,000
Cleco Holdings [Member] | Maximum [Member] | Cleco Group [Member]
Affiliate Transaction [Line Items]
Accounts receivable - affiliate					$ 100,000					$ 100,000	$ 100,000		$ 100,000