Consolidated Balance Sheets - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Current Assets [Abstract]
Cash and cash equivalents	$ 119,040,000	$ 23,077,000
Restricted cash and cash equivalents	13,081,000	23,084,000
Customer accounts receivable (less allowance for doubtful accounts)	60,117,000	56,780,000
Other accounts receivable	30,806,000	19,778,000
Unbilled revenue	36,398,000	34,268,000
Fuel inventory, at average cost	87,520,000	46,410,000
Materials and supplies, at average cost	85,404,000	81,818,000
Energy risk management assets	7,396,000	7,884,000
Accumulated deferred fuel	13,980,000	20,787,000
Cash surrender value of company-/trust-owned life insurance policies	83,117,000	77,225,000
Prepayments	9,050,000	7,813,000
Regulatory assets	24,670,000	26,803,000
Other current assets	1,146,000	1,315,000
Total current assets	571,725,000	427,042,000
Property, Plant, and Equipment [Abstract]
Property, plant, and equipment	3,594,525,000	3,476,581,000
Accumulated depreciation	(192,348,000)	(75,816,000)
Net property, plant, and equipment	3,402,177,000	3,400,765,000
Construction work in progress	186,629,000	78,577,000
Total property, plant, and equipment, net	3,588,806,000	3,479,342,000
Equity investment in investee	18,172,000	18,672,000
Goodwill	1,490,797,000	1,490,797,000
Prepayments	1,887,000	4,731,000
Restricted cash and cash equivalents	20,081,000	23,410,000
Regulatory assets, deferred taxes, net	0	237,449,000
Regulatory assets	432,358,000	454,644,000
Net investment in direct financing lease	0	13,420,000
Intangible assets	114,850,000	142,634,000
Tax credit fund investment, net	4,355,000	11,888,000
Other deferred charges	35,351,000	39,115,000
Total assets	6,278,382,000	6,343,144,000
Current Liabilities [Abstract]
Long-term debt due within one year	19,193,000	19,715,000
Accounts payable	147,562,000	112,087,000
Customer deposits	58,582,000	56,599,000
Provision for rate refund	4,206,000	3,974,000
Provisions for Merger Commitments, Current	2,582,000	14,371,000
Taxes payable, net	22,698,000	3,942,000
Interest accrued	14,703,000	14,783,000
Energy risk management liabilities	352,000	201,000
Deferred compensation	12,132,000	11,654,000
Other current liabilities	18,344,000	14,850,000
Total current liabilities	300,354,000	252,176,000
Long-term liabilities and deferred credits
Accumulated deferred federal and state income taxes, net	614,812,000	1,033,055,000
Accumulated deferred investment tax credits	2,089,000	2,751,000
Postretirement benefit obligations	242,135,000	223,003,000
Regulatory liabilities, deferred taxes, net	140,426,000	0
Restricted storm reserve	14,469,000	17,385,000
Other deferred credits	31,635,000	29,440,000
Total long-term liabilities and deferred credits	1,045,566,000	1,305,634,000
Long-term debt, net	2,836,105,000	2,738,571,000
Total liabilities	4,182,025,000	4,296,381,000
Commitments and contingencies (Note 15)
Member's Equity [Abstract]
Membership interest	2,069,376,000	2,069,376,000
Retained earnings (Accumulated deficit)	29,902,000	(24,113,000)
Accumulated other comprehensive (loss) income	(2,921,000)	1,500,000
Total member's equity	2,096,357,000	2,046,763,000
Total liabilities and member’s equity	6,278,382,000	6,343,144,000
Cleco Power [Member]
Current Assets [Abstract]
Cash and cash equivalents	69,816,000	21,482,000
Restricted cash and cash equivalents	13,081,000	23,084,000
Customer accounts receivable (less allowance for doubtful accounts)	60,117,000	56,780,000
Accounts receivable - affiliate	1,355,000	1,406,000
Other accounts receivable	30,680,000	19,457,000
Taxes receivable, net	0	12,490,000
Unbilled revenue	36,398,000	34,268,000
Fuel inventory, at average cost	87,520,000	46,410,000
Materials and supplies, at average cost	85,404,000	81,818,000
Energy risk management assets	7,396,000	7,884,000
Accumulated deferred fuel	13,980,000	20,787,000
Cash surrender value of company-/trust-owned life insurance policies	20,278,000	20,018,000
Prepayments	7,236,000	5,892,000
Regulatory assets	15,812,000	17,721,000
Other current assets	475,000	577,000
Total current assets	449,548,000	370,074,000
Property, Plant, and Equipment [Abstract]
Property, plant, and equipment	4,893,484,000	4,790,565,000
Accumulated depreciation	(1,712,590,000)	(1,618,241,000)
Net property, plant, and equipment	3,180,894,000	3,172,324,000
Construction work in progress	185,507,000	77,306,000
Total property, plant, and equipment, net	3,366,401,000	3,249,630,000
Equity investment in investee	18,172,000	18,672,000
Prepayments	1,887,000	4,731,000
Restricted cash and cash equivalents	20,060,000	23,389,000
Regulatory assets, deferred taxes, net	0	237,449,000
Regulatory assets	257,408,000	268,016,000
Intangible assets	41,701,000	58,473,000
Other deferred charges	33,564,000	37,014,000
Total assets	4,188,741,000	4,267,448,000
Current Liabilities [Abstract]
Long-term debt due within one year	19,193,000	19,715,000
Accounts payable	134,374,000	101,874,000
Accounts payable - affiliate	8,697,000	7,190,000
Customer deposits	58,582,000	56,599,000
Provision for rate refund	4,206,000	3,974,000
Provisions for Merger Commitments, Current	2,582,000	14,371,000
Taxes payable, net	31,611,000	0
Interest accrued	7,083,000	7,141,000
Energy risk management liabilities	352,000	201,000
Other current liabilities	13,238,000	9,951,000
Total current liabilities	279,918,000	221,016,000
Long-term liabilities and deferred credits
Accumulated deferred federal and state income taxes, net	656,362,000	1,068,592,000
Accumulated deferred investment tax credits	2,089,000	2,751,000
Postretirement benefit obligations	173,747,000	159,107,000
Regulatory liabilities, deferred taxes, net	140,426,000	0
Restricted storm reserve	14,469,000	17,385,000
Other deferred credits	29,576,000	28,339,000
Total long-term liabilities and deferred credits	1,016,669,000	1,276,174,000
Long-term debt, net	1,341,475,000	1,235,056,000
Total capitalization	2,892,154,000	2,770,258,000
Commitments and contingencies (Note 15)
Member's Equity [Abstract]
Total member's equity	1,550,679,000	1,535,202,000
Total liabilities and member’s equity	$ 4,188,741,000	$ 4,267,448,000