Fair Value Accounting, Effect of Derivatives on Consolidated Statements of Income (Details) (USD $)		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	12 Months Ended
	Dec. 31, 2011 MMBTU	Sep. 30, 2012 Derivatives Not Designated As Hedging Instruments [Member]	Sep. 30, 2011 Derivatives Not Designated As Hedging Instruments [Member]	Sep. 30, 2012 Derivatives Not Designated As Hedging Instruments [Member]	Sep. 30, 2011 Derivatives Not Designated As Hedging Instruments [Member]	Sep. 30, 2012 Derivatives Not Designated As Hedging Instruments [Member] Fuel Cost Hedges [Member] Fuel Used For Electric Generation [Member]	Sep. 30, 2011 Derivatives Not Designated As Hedging Instruments [Member] Fuel Cost Hedges [Member] Fuel Used For Electric Generation [Member]	Sep. 30, 2012 Derivatives Not Designated As Hedging Instruments [Member] Fuel Cost Hedges [Member] Fuel Used For Electric Generation [Member]	Sep. 30, 2011 Derivatives Not Designated As Hedging Instruments [Member] Fuel Cost Hedges [Member] Fuel Used For Electric Generation [Member]	Sep. 30, 2012 Derivatives Designated as Hedging Instruments [Member] Interest Rate Derivatives [Member]	Sep. 30, 2011 Derivatives Designated as Hedging Instruments [Member] Interest Rate Derivatives [Member]	Sep. 30, 2012 Derivatives Designated as Hedging Instruments [Member] Interest Rate Derivatives [Member]	Sep. 30, 2011 Derivatives Designated as Hedging Instruments [Member] Interest Rate Derivatives [Member]	Sep. 30, 2012 Cleco Power [Member]	Dec. 31, 2011 Cleco Power [Member]	Sep. 30, 2012 AccumulatedDeferredFuel [Member] Derivatives Not Designated As Hedging Instruments [Member] Fuel Cost Hedges [Member]	Dec. 31, 2011 AccumulatedDeferredFuel [Member] Derivatives Not Designated As Hedging Instruments [Member] Fuel Cost Hedges [Member]	Sep. 30, 2012 Maximum [Member] AccumulatedDeferredFuel [Member] Derivatives Not Designated As Hedging Instruments [Member] Fuel Cost Hedges [Member]
Derivative, gain (loss) recognized in income [Abstract]
Amount of loss recognized in income on derivatives		$ (595,000)	$ (5,678,000)	$ (8,210,000)	$ (14,675,000)	$ (595,000)	$ (5,678,000)	$ (8,210,000)	$ (14,675,000)
Unrealized gains (losses)																	(5,300,000)	0
Deferred gains (losses)																(100,000)	(1,200,000)
Amount of (loss) gain recognized in OCI										802,000	(29,962,000)	(733,000)	(29,962,000)
Amount of (loss) gain reclassified from accumulated OCI into income (effective portion)										17,000	89,000	(39,000)	267,000
Cash flow hedge gain (loss) expected to be reclassed from accumulated OCI over the next 12 months												(400,000)
Amount of ineffectiveness related to the interest rate derivative												$ 2,600,000
Natural gas requirements hedged [Abstract]
Millions MMBtus hedged for natural gas fuel costs	2,200,000
Estimated natural gas requirements covered (in hundredths)	3.00%
Estimated natural gas requirements period (in years)														0	2 years