Fair Value Accounting, Fair Value Measurements and Disclosures(Details)	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2017 USD ($) $ / MW	Sep. 30, 2016 USD ($)	Apr. 12, 2016 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) $ / MW	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) $ / MW
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
FTR Forward Price - per MWh, Low | $ / MW	(3.07)				(3.07)		(3.61)
FTRs Forward Price - per MWh, High | $ / MW	5.87				5.87		6.04
Fair Value, Concentration of Risk, Amount of Money Market Funds in Cash and Cash Equivalents	$ 1,800,000				$ 1,800,000		$ 20,000,000
Fair Value, Assets and Liabilities, Transfers between Levels, Amount	0				0		0
Restricted Cash and Cash Equivalents, Current
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Concentration of Risk, Amount of Money Market Funds in Institutional Money Market Funds	8,900,000				8,900,000		23,100,000
Restricted Cash and Cash Equivalents, Noncurrent
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Concentration of Risk, Amount of Money Market Funds in Institutional Money Market Funds	24,400,000				24,400,000		23,300,000
Measured On A Recurring Basis
Asset Description [Abstract]
Institutional money market funds	35,117,000				35,117,000		66,410,000
FTR assets	13,425,000				13,425,000		7,884,000
Total Assets	48,542,000				48,542,000		74,294,000
Liability Description [Abstract]
FTR liabilities	538,000				538,000		201,000
Total Liabilities	538,000				538,000		201,000
Price Risk Derivative
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	17,943,000	$ 13,618,000
Unrealized gains (losses)	1,591,000	1,840,000
Purchases	419,000	164,000
Settlements	(7,066,000)	(6,046,000)
Ending balance	12,887,000	9,576,000		$ 9,576,000	12,887,000	$ 9,576,000
Quoted Prices in Active Markets for Identical Assets (Level 1) | Measured On A Recurring Basis
Asset Description [Abstract]
Institutional money market funds	0				0		0
FTR assets	0				0		0
Total Assets	0				0		0
Liability Description [Abstract]
FTR liabilities	0				0		0
Total Liabilities	0				0		0
Significant Other Observable Inputs (Level 2) | Measured On A Recurring Basis
Asset Description [Abstract]
Institutional money market funds	35,117,000				35,117,000		66,410,000
FTR assets	0				0		0
Total Assets	35,117,000				35,117,000		66,410,000
Liability Description [Abstract]
FTR liabilities	0				0		0
Total Liabilities	0				0		0
Significant Unobservable Inputs (Level 3) | Measured On A Recurring Basis
Asset Description [Abstract]
Institutional money market funds	0				0		0
FTR assets	13,425,000				13,425,000		7,884,000
Total Assets	13,425,000				13,425,000		7,884,000
Liability Description [Abstract]
FTR liabilities	538,000				538,000		201,000
Total Liabilities	538,000				538,000		201,000
Successor | Price Risk Derivative
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance				3,458,000	7,683,000
Unrealized gains (losses)				2,529,000	(791,000)
Purchases				12,772,000	23,537,000
Settlements				(9,183,000)	(17,542,000)
Ending balance	12,887,000	9,576,000	$ 3,458,000	9,576,000	12,887,000	9,576,000
Predecessor | Price Risk Derivative
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance			7,398,000	3,458,000		7,398,000
Unrealized gains (losses)			(1,031,000)
Purchases			2,070,000
Settlements			(4,979,000)
Ending balance			3,458,000
Cleco Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Concentration of Risk, Amount of Money Market Funds in Cash and Cash Equivalents	500,000				500,000		18,700,000
Cleco Power [Member] | Restricted Cash and Cash Equivalents, Current
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Concentration of Risk, Amount of Money Market Funds in Institutional Money Market Funds	8,900,000				8,900,000		23,100,000
Cleco Power [Member] | Restricted Cash and Cash Equivalents, Noncurrent
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Concentration of Risk, Amount of Money Market Funds in Institutional Money Market Funds	24,400,000				24,400,000		23,300,000
Cleco Power [Member] | Measured On A Recurring Basis
Asset Description [Abstract]
Institutional money market funds	33,796,000				33,796,000		65,089,000
FTR assets	13,425,000				13,425,000		7,884,000
Total Assets	47,221,000				47,221,000		72,973,000
Liability Description [Abstract]
FTR liabilities	538,000				538,000		201,000
Total Liabilities	538,000				538,000		201,000
Cleco Power [Member] | Price Risk Derivative
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	17,943,000	13,618,000	$ 7,398,000		7,683,000	7,398,000
Unrealized gains (losses)	1,591,000	1,840,000			(791,000)	1,498,000
Purchases	419,000	164,000			23,537,000	14,842,000
Settlements	(7,066,000)	(6,046,000)			(17,542,000)	(14,162,000)
Ending balance	12,887,000	$ 9,576,000		$ 9,576,000	12,887,000	$ 9,576,000
Cleco Power [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) | Measured On A Recurring Basis
Asset Description [Abstract]
Institutional money market funds	0				0		0
FTR assets	0				0		0
Total Assets	0				0		0
Liability Description [Abstract]
FTR liabilities	0				0		0
Total Liabilities	0				0		0
Cleco Power [Member] | Significant Other Observable Inputs (Level 2) | Measured On A Recurring Basis
Asset Description [Abstract]
Institutional money market funds	33,796,000				33,796,000		65,089,000
FTR assets	0				0		0
Total Assets	33,796,000				33,796,000		65,089,000
Liability Description [Abstract]
FTR liabilities	0				0		0
Total Liabilities	0				0		0
Cleco Power [Member] | Significant Unobservable Inputs (Level 3) | Measured On A Recurring Basis
Asset Description [Abstract]
Institutional money market funds	0				0		0
FTR assets	13,425,000				13,425,000		7,884,000
Total Assets	13,425,000				13,425,000		7,884,000
Liability Description [Abstract]
FTR liabilities	538,000				538,000		201,000
Total Liabilities	$ 538,000				$ 538,000		$ 201,000