Income Taxes, Deferred Tax Assets and Liabilities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Deferred Federal and State Income Tax Assets and Liabilities [Line Items]
Deferred Tax Liabilities, Other Comprehensive Income	$ (490,000)
Increase (Decrease) in Accumulated Deferred Income Tax Liability	394,900,000
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	0	$ 0
Components of deferred tax assets and liabilities [Abstract]
Depreciation and property basis differences	(596,824,000)	(943,552,000)
Net operating loss carryforward	12,873,000	54,727,000
NMTC	96,917,000	89,411,000
Fuel costs	(3,283,000)	(8,802,000)
Other comprehensive income		3,399,000
Regulated operations regulatory liability, net	(54,471,000)	(91,734,000)
Postretirement benefits other than pension	23,642,000	22,733,000
Merger, fair value adjustment	(58,251,000)	(124,254,000)
Other	(34,925,000)	(34,983,000)
Accumulated deferred federal and state income taxes, net	(614,812,000)	(1,033,055,000)
Unrecognized Tax Benefits, Interest on Income Taxes Expense	0	0	$ 0
Unrecognized Tax Benefits		0
Liability for Uncertainty in Income Taxes, Noncurrent		0
Unrecognized Tax Benefits, Income Tax Penalties Expense	0	0	0
Cleco Power [Member]
Accumulated Deferred Federal and State Income Tax Assets and Liabilities [Line Items]
Increase (Decrease) in Accumulated Deferred Income Tax Liability	362,900,000
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	0	0	$ 0
Components of deferred tax assets and liabilities [Abstract]
Depreciation and property basis differences	(597,838,000)	(941,166,000)
Net operating loss carryforward	470,000	(362,000)
Fuel costs	(3,282,000)	(8,802,000)
Other comprehensive income	5,250,000	8,021,000
Regulated operations regulatory liability, net	(54,471,000)	(91,734,000)
Postretirement benefits other than pension	6,266,000	1,288,000
Other	(12,757,000)	(35,837,000)
Accumulated deferred federal and state income taxes, net	$ (656,362,000)	$ (1,068,592,000)