Common and Preferred Stock, Non-vested Stock and Common Stock Equivalent Units (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 Y		Dec. 31, 2010 Y		Dec. 31, 2009 Y
LTICP 2010 [Member]
WEIGHTED-AVERAGE FAIR VALUE
Maximum number of shares authorized for issuance (in shares)			2,250,000
Non-vested Stock [Member]
Non-Vested Stock and Common Stock Equivalent Units [Abstract]
Number of shares of non-vested stock previously granted with only a service period requirement for which the service period had not ended	151,314
Fair value assumptions [Abstract]
Expected term (in years)	3.0	[1]	3.0	[1]	3.0	[1]
Volatility of Cleco stock (in hundredths)	28.50%	[2]	30.60%	[2]	29.90%	[2]
Correlation between Cleco stock volatility and peer group (in hundredths)	63.20%		60.60%		62.50%
Expected dividend yield (in hundredths)	3.30%		3.50%		4.10%
Weighted average fair value (Monte Carlo model) (in dollars per share)	$ 34.88		$ 27.92		$ 25.93
Non-vested stock activity [Roll Forward]
Non-vested, beginning of period (in shares)	263,709
Granted (in shares)	223,662
Vested (in shares)	(112,049)
Forfeited (in shares)	(4,591)
Non-vested, end of period (in shares)	370,731		263,709
WEIGHTED-AVERAGE GRANT DATE FAIR VALUE
Weighted average grant date fair value, non-vested, beginning of period (in dollars per share)	$ 25.34
Weighted average grant date fair value, non-vested, granted (in dollars per share)	$ 34.72
Weighted average grant date fair value, non-vested, vested (in dollars per share)	$ 24.78
Weighted average grant date fair value, non-vested, forfeited (in dollars per share)	$ 34.88
Weighted average grant date fair value, non-vested, end of period (in dollars per share)	$ 31.05		$ 25.34
WEIGHTED-AVERAGE FAIR VALUE
Fair value of shares of non-vested stock vested during period	$ 4.0		$ 2.4		$ 2.6
Non-vested Stock [Member] | LTICP 2000 [Member]
Non-vested stock activity [Roll Forward]
Non-vested, end of period (in shares)	62,386
Common Stock Equivalent Units [Member]
Fair value assumptions [Abstract]
Expected term (in years)	0.0	[1]	3.0	[1]	3.0	[1]
Volatility of Cleco stock (in hundredths)	0.00%	[2]	28.60%	[2]	30.00%	[2]
Correlation between Cleco stock volatility and peer group (in hundredths)	0.00%		62.50%		63.00%
Expected dividend yield (in hundredths)	0.00%		3.90%		4.00%
Weighted average fair value (Monte Carlo model) (in dollars per share)	$ 0.00		$ 32.81		$ 30.81
Non-vested stock activity [Roll Forward]
Non-vested, beginning of period (in shares)	126,547
Granted (in shares)	0
Vested (in shares)	(66,663)
Forfeited (in shares)	0
Non-vested, end of period (in shares)	59,884		126,547
WEIGHTED-AVERAGE FAIR VALUE
Weighted-average fair value, common stock equivalent units, beginning of period (in dollars per share)	$ 38.86
Weighted-average fair value, common stock equivalent units, granted (in dollars per share)	$ 0.00
Weighted-average fair value, common stock equivalent units, vested (in dollars per share)	$ 73.62
Weighted-average fair value, common stock equivalent units, forfeited (in dollars per share)	$ 0.00
Weighted-average fair value, common stock equivalent units, end of period (in dollars per share)	$ 42.22		$ 38.86
Non-Vested Stock and Common Stock Equivalent Units [Member]
Non-Vested Stock and Common Stock Equivalent Units [Abstract]
Target and opportunity restricted shares and common stock equivalent units previously issued for which restrictions had not lapsed (in shares)	825,254
WEIGHTED-AVERAGE FAIR VALUE
Non-vested share-based compensation arrangements granted and expected to vest (in shares)	167,248
Non-vested share-based compensation arrangements, average vesting period	1 year 3 months
Total unrecognized before-tax compensation cost	$ 4.8

[1] The expected term was based on the service period of the award

[2] The volatility rate is based on historical stock prices over an appropriate period, generally equal to the expected term.