Disclosures about Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014 entity	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014 entity	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Number of transmission interconnection facility subsidiaries	2								2
Revenue
Electric operations									$ 1,225,960	$ 1,047,548	$ 944,169
Tolling operations									0	0	0
Other operations									67,055	51,002	50,158
Electric customer credits									(23,530)	(1,836)	(630)
Affiliate revenue									0	0	0
Operating revenue, net	304,643	371,386	309,070	284,387	263,109	328,763	263,894	240,947	1,269,485	1,096,714	993,697
Depreciation									146,505	142,860	132,407
Merger transaction costs									17,848	0	0
Interest charges									73,606	84,254	84,156
Interest income									1,768	1,105	346
Federal and state income tax expense									67,116	79,575	65,327
Net Income									154,739	160,685	163,648
Additions to property, plant, and equipment									207,636	191,876	232,724
Equity investment in investees	14,540				14,540				14,540	14,540	14,540
Total segment assets	4,379,073				4,215,262				4,379,073	4,215,262	4,147,349
Operating Segments [Member] | Other Segments [Member]
Revenue
Electric operations									1,225,960	1,047,548	944,169
Tolling operations									0	0	0
Other operations									64,893	48,909	48,156
Electric customer credits									(23,530)	(1,836)	(630)
Affiliate revenue									1,326	1,338	1,372
Operating revenue, net									1,268,649	1,095,959	993,067
Depreciation									144,026	135,717	125,486
Merger transaction costs									0
Interest charges									74,673	82,677	80,502
Interest income									1,707	1,100	333
Federal and state income tax expense									76,974	79,381	68,133
Net Income									154,316	150,410	146,848
Additions to property, plant, and equipment									206,607	184,684	222,104
Equity investment in investees	14,532				14,532				14,532	14,532	14,532
Total segment assets	4,242,986				3,943,712				4,242,986	3,943,712	3,871,729
Operating Segments [Member] | Midstream [Member]
Revenue
Electric operations										0	0
Tolling operations										31,670	25,559
Other operations										2	3
Electric customer credits										0	0
Affiliate revenue										0	0
Operating revenue, net										31,672	25,562
Depreciation										6,043	6,006
Interest charges										(331)	770
Interest income										0	0
Federal and state income tax expense										7,110	6,404
Net Income										4,372	9,155
Additions to property, plant, and equipment										4,106	8,759
Equity investment in investees					0					0	0
Total segment assets					225,832					225,832	215,342
Operating Segments [Member] | Corporate and Other [Member]
Revenue
Electric operations									0	0	0
Tolling operations									5,467		0
Other operations									2,163	2,091	1,998
Electric customer credits									0	0	0
Affiliate revenue									56,031	55,145	52,063
Operating revenue, net									63,661	57,236	54,061
Depreciation									2,479	1,100	916
Merger transaction costs									17,848
Interest charges									(1,538)	1,274	2,269
Interest income									(410)	(628)	(602)
Federal and state income tax expense									(9,858)	(6,917)	(9,210)
Net Income									424	5,903	7,645
Additions to property, plant, and equipment									1,029	3,086	1,861
Equity investment in investees	8				8				8	8	8
Total segment assets	248,654				88,234				248,654	88,234	201,678
Intersegment Eliminations [Member]
Revenue
Electric operations									0	0	0
Tolling operations									(5,467)	(31,670)	(25,559)
Other operations									(1)	0	1
Electric customer credits									0	0	0
Affiliate revenue									(57,357)	(56,483)	(53,435)
Operating revenue, net									(62,825)	(88,153)	(78,993)
Depreciation									0	0	(1)
Merger transaction costs									0
Interest charges									471	634	615
Interest income									471	633	615
Federal and state income tax expense									0	1	0
Net Income									(1)	0	0
Additions to property, plant, and equipment									0	0	0
Equity investment in investees	0				0				0	0	0
Total segment assets	(112,567)				(42,516)				(112,567)	(42,516)	(141,400)
Cleco Power [Member]
Revenue
Electric operations									1,225,960	1,047,548	944,169
Other operations									64,893	48,909	48,156
Electric customer credits									(23,530)	(1,836)	(630)
Affiliate revenue									1,326	1,338	1,372
Operating revenue, net	304,432	371,178	308,859	284,180	262,900	328,556	263,725	240,778	1,268,649	1,095,959	993,067
Depreciation									144,026	135,717	125,486
Interest charges									74,673	82,677	80,502
Interest income									1,707	1,100	333
Federal and state income tax expense									76,974	79,381	68,133
Net Income									154,316	150,410	146,848
Equity investment in investees	14,532				14,532				14,532	14,532
Total segment assets	$ 4,242,986				$ 3,943,712				$ 4,242,986	$ 3,943,712