Miscellaneous Financial Information (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Quarterly Information [Line Items]
Operating revenue, net	$ 233,431	$ 297,372	$ 240,123	$ 222,773	$ 239,119	$ 351,581	$ 272,923	$ 253,690	$ 993,697	$ 1,117,313	$ 1,148,666
Operating income	49,766	103,347	74,243	54,294	48,647	115,500	69,581	64,518	281,651	298,247	292,959
Net income									163,648	195,848	255,391
Net income applicable to common stock	23,112	63,818	46,686	30,031	30,643	65,842	70,221	29,004	163,648	195,710	255,345
Distribution to Cleco Corporation (as sole member)									63,700	291,219	183,700
Basic net income per average share (in dollars per share)	$ 0.38	$ 1.06	$ 0.77	$ 0.50	$ 0.51	$ 1.09	$ 1.16	$ 0.48	$ 2.71	$ 3.24	$ 4.23
Diluted net income per average common share (in dollars per share)	$ 0.38	$ 1.05	$ 0.77	$ 0.50	$ 0.51	$ 1.08	$ 1.15	$ 0.48	$ 2.70	$ 3.22	$ 4.20
Dividends paid per common share (in dollars per share)	$ 0.3375	$ 0.3375	$ 0.3125	$ 0.3125	$ 0.3125	$ 0.28	$ 0.28	$ 0.25	$ 1.30	$ 1.1225	$ 0.975
Closing market price per share
High (in dollars per share)	$ 43.75	$ 45.30	$ 42.45	$ 40.10	$ 38.31	$ 36.14	$ 35.66	$ 34.51
Low (in dollars per share)	$ 38.46	$ 40.09	$ 38.16	$ 36.15	$ 32.36	$ 30.06	$ 33.68	$ 30.56
Cleco Power [Member]
Quarterly Information [Line Items]
Operating revenue, net	233,269	297,212	239,967	222,620	236,099	342,296	268,464	250,623	993,067	1,097,482	1,120,455
Operating income	54,584	97,510	76,792	58,306	52,959	109,495	74,834	67,105	287,194	304,393	290,270
Net income	24,975	57,783	37,284	26,805	23,278	53,833	35,694	30,030	146,848	142,835	147,405
Distribution to Cleco Corporation (as sole member)	$ 0	$ 18,000	$ 10,000	$ 30,000	$ 30,000	$ 50,000	$ 0	$ 50,000	$ 58,000	$ 130,000	$ 150,000