Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended		9 Months Ended										3 Months Ended		9 Months Ended					3 Months Ended	9 Months Ended		3 Months Ended		9 Months Ended			9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Jul. 05, 2011	Jan. 28, 2011	Dec. 31, 2010	Sep. 30, 2011 Diversified Lands Mitigation Escrow Agreement [Member]	Dec. 31, 2010 Diversified Lands Mitigation Escrow Agreement [Member]	Dec. 31, 2010 GO Zone Project Costs [Member]	Sep. 30, 2011 Future Storm Restoration Costs [Member]	Dec. 31, 2010 Future Storm Restoration Costs [Member]	Sep. 30, 2011 Katrina/Rita Bond Payments [Member]	Mar. 31, 2011 Katrina/Rita Bond Payments [Member]	Sep. 30, 2011 Katrina/Rita Bond Payments [Member]	Dec. 31, 2010 Katrina/Rita Bond Payments [Member]	Sep. 30, 2011 Renewable Energy Grant [Member]	Sep. 30, 2011 Derivatives Not Designated As Hedging Instruments [Member] Fuel Cost Hedges [Member]	Dec. 31, 2010 Derivatives Not Designated As Hedging Instruments [Member] Fuel Cost Hedges [Member]	Sep. 30, 2010 Derivatives Not Designated As Hedging Instruments [Member] Economic Hedges [Member] Other Operations Revenue [Member]	Sep. 30, 2010 Derivatives Not Designated As Hedging Instruments [Member] Economic Hedges [Member] Other Operations Revenue [Member]	Sep. 30, 2011 Treasury Rate Locks [Member]	Sep. 30, 2011 Cleco Power [Member]	Sep. 30, 2010 Cleco Power [Member]	Sep. 30, 2011 Cleco Power [Member]	Sep. 30, 2010 Cleco Power [Member]	Dec. 31, 2010 Cleco Power [Member]	Sep. 30, 2010 Cleco Power [Member] Cash Flows Related To Accruals for Property, Plant and Equipment [Member] As Reported [Member]	Sep. 30, 2010 Cash Flows Related To Accruals for Property, Plant and Equipment [Member] As Reported [Member]
Property, Plant and Equipment [Abstract]
Regulated utility plants	$ 3,604,938,000		$ 3,604,938,000				$ 3,552,054,000
Other	254,683,000		254,683,000				258,842,000
Total property, plant and equipment	3,859,621,000		3,859,621,000				3,810,896,000																3,604,938,000		3,604,938,000		3,552,779,000
Accumulated depreciation	(1,218,818,000)		(1,218,818,000)				(1,162,456,000)																(1,142,414,000)		(1,142,414,000)		(1,085,945,000)
Net property, plant and equipment	2,640,803,000		2,640,803,000				2,648,440,000																2,462,524,000		2,462,524,000		2,466,834,000
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	28,903,000		28,903,000				41,048,000	97,000	97,000	6,137,000	24,652,000	25,992,000	3,554,000		3,554,000	8,822,000	600,000
Decrease in restricted cash due to bond principal payment													6,000,000	6,300,000
Decrease in restricted cash due to bond interest payment													3,700,000	3,800,000
Increase in restricted cash due to collections															14,500,000
Risk Management [Abstract]
Realized gains (losses)																				(300,000)	(800,000)
Mark-to-market gains (losses)																				200,000	200,000
Unrealized gains (losses)																		(5,700,000)	(15,100,000)
Deferred gains (losses)																		(1,300,000)	(1,600,000)
Net collateral deposited	500,000		500,000				4,300,000
Interest rate cash flow hedge [Abstract]
Description of hedged item																						interest rate exposure on coupon payments related to a forecasted debt issuance.
Reference Rate As Of Period End																						2.89%
Notional amount of Treasury rate lock																						150,000,000
Unrealized mark-to-market gain (loss) on treasury rate lock																						(30,000,000)
Reference Rate As Of Contract Date																						3.77%
Reclassifications [Abstract]
Accounts receivable			(18,274,000)	(30,329,000)																					(20,442,000)	(31,579,000)		(50,579,000)	(49,329,000)
Accounts payable			(34,986,000)	(13,277,000)																					(30,345,000)	(12,137,000)		(16,621,000)	(17,248,000)
Retainage payable			(2,481,000)	0																					(2,481,000)	0		745,000	745,000
Net cash provided by operating activities			262,642,000	192,368,000																					184,688,000	99,688,000		76,949,000	170,141,000
Additions to property, plant and equipment			(145,669,000)	(252,711,000)																					(131,014,000)	(98,399,000)		75,660,000	230,485,000
Net cash used in investing activities			(54,097,000)	(234,819,000)																					(112,856,000)	(72,519,000)		(49,780,000)	(212,592,000)
Net decrease in cash and cash equivalents			(32,896,000)	(77,357,000)																					(41,897,000)	(110,729,000)		(110,729,000)	(77,357,000)
Cash and cash equivalents at beginning of period			191,128,000	145,193,000																					184,912,000	138,113,000		138,113,000	145,193,000
Cash and cash equivalents at end of period	158,232,000	67,836,000	158,232,000	67,836,000																			143,015,000	27,384,000	143,015,000	27,384,000		27,384,000	67,836,000
Accrued additions to property, plant and equipment			11,491,000	5,314,000																					20,088,000	4,757,000		17,506,000	17,506,000
Calculation of basic and diluted earnings per share [Abstract]
Income from continuing operations	65,842,000	49,612,000	165,205,000	234,768,000																			53,833,000	52,335,000	119,557,000	123,584,000
Deduct: non-participating stock dividends (4.5% preferred stock)		12,000	26,000	35,000
Deduct: non-participating stock redemption costs (4.5% preferred stock)			112,000	0
Basic net income applicable to common stock	65,842,000	49,600,000	165,067,000	234,733,000
Diluted net income applicable to common stock	65,842,000	49,600,000	165,067,000	234,733,000
Shares [Abstract]
Average number of basic common shares outstanding (in shares)	60,467,595	60,471,183	60,549,860	60,405,388
Effect of dilutive securities
Add: stock option grants (in shares)	20,441	26,680	20,965	29,771
Add: restricted stock (LTICP) (in shares)	385,275	327,435	259,426	196,979
Average number of diluted common shares outstanding (in shares)	60,873,311	60,825,298	60,830,251	60,632,138
Per Share Amount [Abstract]
Basic net income applicable to common stock (in dollars per share)	$ 1.09	$ 0.82	$ 2.73	$ 3.89
Diluted net income applicable to common stock (in dollars per share)	$ 1.08	$ 0.82	$ 2.71	$ 3.87
Preferred Stock Redemption [Abstract]
Outstanding shares of preferred stock (in shares)	0		0				10,288
Dividend rate (in hundredths)			4.50%
Redemption date			Jun. 24, 2011
Redemption price (in dollars per share)	$ 101		$ 101
Redemption price, plus accrued and unpaid dividends to the redemption date (in dollars per share)	$ 101.296		$ 101.296
Stock-Based Compensation [Abstract]
Non-vested stock granted (in shares)					40,000	145,002
Equity classification
Non-vested stock	1,095,000	573,000	3,042,000	1,703,000																			225,000	150,000	748,000	418,000
Stock options	69,000	13,000	105,000	38,000
Total equity classification	1,164,000	586,000	3,147,000	1,741,000																			225,000	150,000	748,000	418,000
Liability classification
Common stock equivalent units	1,024,000	1,237,000	2,583,000	1,867,000																			435,000	537,000	1,020,000	885,000
Total pre-tax compensation expense	2,188,000	1,823,000	5,730,000	3,608,000																			660,000	687,000	1,768,000	1,303,000
Tax benefit (excluding income tax gross-up)	$ 842,000	$ 702,000	$ 2,205,000	$ 1,388,000																			$ 254,000	$ 264,000	$ 680,000	$ 501,000