Summary of Significant Accounting Policies Summary of Significant Accounting Policies, Reclassifications (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended				3 Months Ended		6 Months Ended	9 Months Ended	12 Months Ended			3 Months Ended		6 Months Ended	9 Months Ended	12 Months Ended			3 Months Ended		6 Months Ended				3 Months Ended		6 Months Ended	9 Months Ended	12 Months Ended			3 Months Ended		6 Months Ended	9 Months Ended	12 Months Ended			3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2012 Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Mar. 31, 2011 Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Jun. 30, 2011 Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Sep. 30, 2011 Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Dec. 31, 2011 Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Dec. 31, 2010 Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Dec. 31, 2009 Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Mar. 31, 2012 Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Mar. 31, 2011 Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Jun. 30, 2011 Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Sep. 30, 2011 Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Dec. 31, 2011 Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Dec. 31, 2010 Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Dec. 31, 2009 Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Jun. 30, 2012 Cleco Power [Member]	Jun. 30, 2011 Cleco Power [Member]	Jun. 30, 2012 Cleco Power [Member]	Jun. 30, 2011 Cleco Power [Member]	Dec. 31, 2011 Cleco Power [Member]	Dec. 31, 2010 Cleco Power [Member]	Mar. 31, 2012 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Mar. 31, 2011 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Jun. 30, 2011 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Sep. 30, 2011 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Dec. 31, 2011 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Dec. 31, 2010 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Dec. 31, 2009 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member]	Mar. 31, 2012 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Mar. 31, 2011 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Jun. 30, 2011 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Sep. 30, 2011 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Dec. 31, 2011 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Dec. 31, 2010 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Dec. 31, 2009 Cleco Power [Member] Cash Flows Related To Contributions Received In Aid Of Construction [Member] Scenario, Previously Reported [Member]	Jun. 30, 2012 Reclassification Of Plant Acquisition Adjustment Amortization [Member]	Jun. 30, 2011 Reclassification Of Plant Acquisition Adjustment Amortization [Member]	Jun. 30, 2012 Reclassification Of Plant Acquisition Adjustment Amortization [Member]	Jun. 30, 2011 Reclassification Of Plant Acquisition Adjustment Amortization [Member]
Increase (Decrease) in Accounts Receivable			$ 1,620	$ 19,685			$ 6,408	$ (17,458)	$ (19,685)	$ (21,691)	$ (19,146)	$ (12,503)		$ 6,253	$ (13,958)	$ (19,923)	$ (18,274)	$ (15,798)	$ (16,156)				$ 2,468	$ 20,541			$ 5,922	$ (14,220)	$ (20,541)	$ (23,859)	$ (18,206)	$ (12,608)		$ 5,767	$ (10,720)	$ (20,779)	$ (20,442)	$ (14,858)	$ (16,261)
Depreciation	32,250	30,699	64,097	60,512																	30,559	28,996	60,648	57,111																	700	700	1,400	1,400
Increase (Decrease) in Other Noncurrent Assets and Liabilities, Net			(7,322)	2			(2,263)	2,999	2	2,181	4,305	(114)		(5,835)	2,313	(729)	(2,184)	(1,084)	1,813				(10,363)	(1,499)			(5,175)	(2,065)	(1,499)	(1,996)	(2,399)	(10,009)		(8,747)	1,379	(2,230)	(6,361)	(7,788)	(8,082)
Net Cash Provided by (Used in) Operating Activities, Continuing Operations			103,311	148,799			45,100	(512)	148,799	263,590	310,061	216,899		41,373	2,302	147,830	262,642	308,020	215,173				93,512	71,757			51,240	2,485	71,757	185,636	251,758	172,485		47,513	5,299	70,788	184,688	249,717	170,759
Payments to Acquire Property, Plant, and Equipment			(102,278)	(67,050)			(43,107)	(19,069)	(67,050)	(146,617)	(197,923)	(306,883)		(39,380)	(21,883)	(66,081)	(145,669)	(195,882)	(305,157)				(99,392)	(59,422)			(42,234)	(17,906)	(59,422)	(131,962)	(184,615)	(150,937)		(38,507)	(20,720)	(58,453)	(131,014)	(182,574)	(149,211)
Net Cash Provided by (Used in) Investing Activities			(99,825)	17,280			(44,552)	(16,723)	17,280	(55,045)	(103,716)	(308,631)		(40,825)	(19,537)	18,249	(54,097)	(101,675)	(306,905)				(91,584)	(49,559)			(34,486)	(6,141)	(49,559)	(113,804)	(172,234)	(136,398)		(30,759)	(8,955)	(48,590)	(112,856)	(170,193)	(134,672)
Cash and Cash Equivalents, Period Increase (Decrease)			(69,883)	(29,002)			(46,327)	(53,937)	(29,002)	(32,896)	(97,552)	45,935		(46,327)	(53,937)	(29,002)	(32,896)	(97,552)	45,935				(57,222)	(35,071)			(31,573)	(60,472)	(35,071)	(41,897)	(117,454)	46,799		(31,573)	(60,472)	(35,071)	(41,897)	(117,454)	46,799
Cash and Cash Equivalents, at Carrying Value	$ 23,693	$ 162,126	$ 23,693	$ 162,126	$ 93,576	$ 191,128	$ 47,249	$ 137,191	$ 162,126	$ 158,232	$ 93,576	$ 191,128	$ 145,193	$ 47,249	$ 137,191	$ 162,126	$ 158,232	$ 93,576	$ 191,128	$ 145,193	$ 10,236	$ 149,841	$ 10,236	$ 149,841	$ 67,458	$ 184,912	$ 35,885	$ 124,440	$ 149,841	$ 143,015	$ 67,458	$ 184,912	$ 138,113	$ 35,885	$ 124,440	$ 149,841	$ 143,015	$ 67,458	$ 184,912	$ 138,113