Disclosures about Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011 entity	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011 entity	Dec. 31, 2010	Dec. 31, 2009
Revenue
Electric operations									$ 1,051,956	$ 1,086,102	$ 808,646
Tolling operations									19,004	26,067	0
Other operations									52,962	44,529	33,651
Electric customer credits									(6,811)	(9,596)	0
Affiliate revenue									202	1,564	11,461
Operating revenue, net	239,119	351,581	272,923	253,690	256,584	343,892	275,903	272,287	1,117,313	1,148,666	853,758
Depreciation expense									119,790	112,203	78,204
Interest charges									70,658	95,776	51,055
Interest income									891	409	1,512
Equity income (loss) from investees, before tax									62,050	38,849	(17,423)
Gain on toll settlement									0	148,402	0
Federal and state income tax expense									102,897	142,498	9,579
Segment profit (loss)									195,848	255,391	106,307
Additions to long-lived assets									211,695	453,221	236,420
Equity investment in investees	14,540				86,732				14,540	86,732	251,617
Total segment assets	4,050,202				4,161,410				4,050,202	4,161,410	3,694,847
Reconciliation of segment profit to consolidated profit:
Number of transmission interconnection facility subsidiaries	2								2
Unallocated items:
Preferred dividends requirements									26	46	46
Preferred stock redemption costs									112	0	0
Net income applicable to common stock	30,643	65,842	70,221	29,004	20,613	49,600	35,174	149,958	195,710	255,345	106,261
Midstream [Member]
Revenue
Electric operations									0	0	0
Tolling operations									19,004	26,067
Other operations									9	3	1
Electric customer credits									0	0
Affiliate revenue									45	960	8,748
Operating revenue, net									19,058	27,030	8,749
Depreciation expense									5,872	5,779	177
Interest charges									(28,996)	7,140	7,408
Interest income									25	0	0
Equity income (loss) from investees, before tax									62,053	38,848	(19,339)
Gain on toll settlement										148,402
Federal and state income tax expense									44,637	71,255	(11,027)
Segment profit (loss)									42,792	114,467	(17,730)
Additions to long-lived assets									8,437	2,113	55
Equity investment in investees	0				73,648				0	73,648	223,652
Total segment assets	233,666				316,165				233,666	316,165	270,713
Reconciling Items [Member]
Revenue
Electric operations									0	0	0
Tolling operations									0	0
Other operations									2,011	1,959	102
Electric customer credits									0	0
Affiliate revenue									53,068	47,924	46,308
Operating revenue, net									55,079	49,883	46,410
Depreciation expense									1,072	838	963
Interest charges									2,405	10,551	(9,717)
Interest income									77	675	5,261
Equity income (loss) from investees, before tax									(3)	1	1,916
Gain on toll settlement										0
Federal and state income tax expense									(11,149)	(3,864)	5,309
Segment profit (loss)									10,221	(6,480)	12,871
Additions to long-lived assets									1,278	2,056	980
Equity investment in investees	8				11				8	11	15,093
Total segment assets	201,074				401,663				201,074	401,663	383,058
Eliminations [Member]
Revenue
Electric operations									0	0	0
Tolling operations									0	0
Other operations									(6)	(11)	(10)
Electric customer credits									0	0
Affiliate revenue									(54,300)	(48,691)	(44,990)
Operating revenue, net									(54,306)	(48,702)	(45,000)
Depreciation expense									0	0	0
Interest charges									159	(646)	(5,198)
Interest income									159	(645)	(5,198)
Equity income (loss) from investees, before tax									0	0	0
Gain on toll settlement										0
Federal and state income tax expense									0	0	0
Segment profit (loss)									0	(1)	0
Additions to long-lived assets									0	0	0
Equity investment in investees	0				0				0	0	(1)
Total segment assets	(111,009)				(351,623)				(111,009)	(351,623)	(322,886)
Unallocated Amount to Segment [Member]
Unallocated items:
Preferred dividends requirements									26	46	46
Preferred stock redemption costs									112
Cleco Power [Member]
Revenue
Electric operations									1,051,956	1,086,102	808,646
Tolling operations									0	0
Other operations									50,948	42,578	33,558
Electric customer credits									(6,811)	(9,596)	0
Affiliate revenue									1,389	1,371	1,395
Operating revenue, net	236,099	342,296	268,464	250,623	253,251	332,477	271,200	263,527	1,097,482	1,120,455	843,599
Depreciation expense									112,846	105,586	77,064
Interest charges									97,090	78,731	58,562
Interest income									630	379	1,449
Equity income (loss) from investees, before tax									0	0	0
Gain on toll settlement										0
Federal and state income tax expense									69,409	75,107	15,297
Segment profit (loss)	23,278	53,833	35,694	30,030	23,821	52,335	39,089	32,160	142,835	147,405	111,166
Additions to long-lived assets									201,980	449,052	235,385
Equity investment in investees	14,532				13,073				14,532	13,073	12,873
Total segment assets	$ 3,726,471				$ 3,795,205				$ 3,726,471	$ 3,795,205	$ 3,363,962