Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	9 Months Ended
	Apr. 12, 2016	Sep. 30, 2016	Sep. 30, 2016	Sep. 30, 2015
Predecessor [Member]
Operating activities [Abstract]
Net (loss) income	$ (3,960)			$ 111,819
Adjustments to reconcile net (loss) income to net cash provided by operating activities [Abstract]
Depreciation and amortization	45,869			117,831
Gain on sale of asset	(1,095)			0
Unearned compensation expense	3,276			4,819
Allowance for equity funds used during construction	(724)			(2,197)
Net deferred income taxes	2,219			62,871
Deferred fuel costs	977			1,010
Cash surrender value of company-/trust-owned life insurance	(840)			2,258
Provision for merger commitments	0			0
Changes in assets and liabilities [Abstract]
Accounts receivable	(1,865)			(24,890)
Accounts and notes receivable, affiliate	0			0
Unbilled revenue	563			(2,019)
Fuel inventory and materials and supplies	19,312			(3,422)
Prepayments	2,395			3,659
Accounts payable	8,348			(32,248)
Customer deposits	3,342			9,357
Postretirement benefit obligations	9,746			10,430
Regulatory assets and liabilities, net	5,178			13,858
Other deferred accounts	6,878			(8,029)
Taxes accrued	10,820			24,878
Interest accrued	17,909			13,115
Deferred compensation	(793)			(1,335)
Other operating	2,224			2,239
Net cash provided by operating activities	129,779			304,004
Investing activities [Abstract]
Additions to property, plant, and equipment	(42,392)			(116,678)
Allowance for equity funds used during construction	724			2,197
Proceeds from sale of property	1,932			429
Premiums paid on trust-owned life insurance	0			(2,571)
Contributions to equity investment in investee	(2,450)			(1,840)
Return of equity investment in tax credit fund	476			1,649
Contributions to tax credit fund	0			(4,091)
Transfer of cash (to) from restricted accounts, net	4,847			4,536
Other investing	53			173
Net cash used in investing activities	(36,810)			(116,196)
Financing activities [Abstract]
Draws on credit facilities	3,000			108,000
Payments on credit facilities	(10,000)			(147,000)
Issuance of long-term debt	0			0
Repayment of long-term debt	(8,546)			(100,824)
Payment of financing costs	(43)			(186)
Dividends paid	(24,579)			(73,076)
Contribution from member	0			0
Distributions to parent	0			0
Other financing	(717)			(1,816)
Net cash provided by (used in) financing activities	(40,885)			(214,902)
Net (decrease) increase in cash and cash equivalents	52,084			(27,094)
Cash and cash equivalents at beginning of period	68,246	$ 120,330	$ 68,246	44,423
Cash and cash equivalents at end of period	120,330			17,329
Supplementary cash flow information [Abstract]
Interest paid, net of amount capitalized	2,478			42,201
Income taxes paid (refunded), net	(481)			1,434
Supplementary non-cash investing and financing activities [Abstract]
Accrued additions to property, plant, and equipment	10,619			4,869
Additions to property, plant, and equipment - ARO	961			0
Successor [Member]
Operating activities [Abstract]
Net (loss) income		(42,294)
Adjustments to reconcile net (loss) income to net cash provided by operating activities [Abstract]
Depreciation and amortization		104,561
Gain on sale of asset		0
Unearned compensation expense		769
Allowance for equity funds used during construction		(2,056)
Net deferred income taxes		(25,681)
Deferred fuel costs		(11,489)
Cash surrender value of company-/trust-owned life insurance		(2,198)
Provision for merger commitments		40,357
Changes in assets and liabilities [Abstract]
Accounts receivable		(23,157)
Accounts and notes receivable, affiliate		(3,794)
Unbilled revenue		(13,643)
Fuel inventory and materials and supplies		19,464
Prepayments		(236)
Accounts payable		(15,294)
Customer deposits		5,421
Postretirement benefit obligations		2,267
Regulatory assets and liabilities, net		9,640
Other deferred accounts		(2,065)
Taxes accrued		5,006
Interest accrued		13,479
Deferred compensation		(987)
Other operating		8,633
Net cash provided by operating activities		66,703
Investing activities [Abstract]
Additions to property, plant, and equipment		(102,677)
Allowance for equity funds used during construction		2,056
Proceeds from sale of property		263
Premiums paid on trust-owned life insurance		0
Contributions to equity investment in investee		0
Return of equity investment in tax credit fund		901
Contributions to tax credit fund		0
Transfer of cash (to) from restricted accounts, net		(33,943)
Other investing		137
Net cash used in investing activities		(133,263)
Financing activities [Abstract]
Draws on credit facilities		15,000
Payments on credit facilities		(15,000)
Issuance of long-term debt		1,350,000
Repayment of long-term debt		(1,358,268)
Payment of financing costs		(6,860)
Dividends paid		(572)
Contribution from member		100,720
Distributions to parent		(56,000)
Other financing		(1,220)
Net cash provided by (used in) financing activities		27,800
Net (decrease) increase in cash and cash equivalents		(38,760)
Cash and cash equivalents at beginning of period		120,330
Cash and cash equivalents at end of period	120,330	81,570	81,570
Supplementary cash flow information [Abstract]
Interest paid, net of amount capitalized		42,963
Income taxes paid (refunded), net		256
Supplementary non-cash investing and financing activities [Abstract]
Accrued additions to property, plant, and equipment		15,853
Additions to property, plant, and equipment - ARO		0
Cleco Power [Member]
Operating activities [Abstract]
Net (loss) income			12,222	119,080
Adjustments to reconcile net (loss) income to net cash provided by operating activities [Abstract]
Depreciation and amortization			120,703	115,160
Gain on sale of asset			(1,095)	0
Unearned compensation expense			1,394	1,465
Allowance for equity funds used during construction			(2,780)	(2,197)
Net deferred income taxes			5,201	34,073
Deferred fuel costs			(10,512)	1,010
Provision for merger commitments			40,357	0
Changes in assets and liabilities [Abstract]
Accounts receivable			(24,378)	(24,847)
Accounts and notes receivable, affiliate			1,647	6,558
Unbilled revenue			(13,080)	(2,019)
Fuel inventory and materials and supplies			38,776	(3,422)
Prepayments			1,368	1,741
Accounts payable			(9,485)	(29,097)
Accounts and notes payable, affiliate			(2,583)	(2,377)
Customer deposits			8,763	9,357
Postretirement benefit obligations			3,656	5,366
Regulatory assets and liabilities, net			13,893	13,858
Other deferred accounts			4,813	(6,560)
Taxes accrued			1,607	58,915
Interest accrued			15,147	12,681
Other operating			8,832	1,602
Net cash provided by operating activities			214,466	310,347
Investing activities [Abstract]
Additions to property, plant, and equipment			(144,637)	(116,360)
Allowance for equity funds used during construction			2,780	2,197
Proceeds from sale of property			2,195	429
Contributions to equity investment in investee			(2,450)	(1,840)
Transfer of cash (to) from restricted accounts, net			(29,096)	4,536
Other investing			190	173
Net cash used in investing activities			(171,018)	(110,865)
Financing activities [Abstract]
Draws on credit facilities			15,000	63,000
Payments on credit facilities			(15,000)	(83,000)
Repayment of long-term debt			(16,814)	(100,824)
Contribution from member			50,000	0
Distributions to parent			(85,000)	(100,000)
Other financing			(2,070)	(1,999)
Net cash provided by (used in) financing activities			(53,884)	(222,823)
Net (decrease) increase in cash and cash equivalents			(10,436)	(23,341)
Cash and cash equivalents at beginning of period	$ 65,705		65,705	39,162
Cash and cash equivalents at end of period		$ 55,269	55,269	15,821
Supplementary cash flow information [Abstract]
Interest paid, net of amount capitalized			40,153	42,165
Income taxes paid (refunded), net			(485)	565
Supplementary non-cash investing and financing activities [Abstract]
Accrued additions to property, plant, and equipment			15,837	4,860
Additions to property, plant, and equipment - ARO			$ 961	$ 0