Common and Preferred Stock, Long-Term Incentive Compensation Plan, Non-vested Stock and Common Stock Equivalent Units (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
LTICP [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Target and opportunity restricted shares and common stock equivalent units previously issued for which restrictions had not lapsed	683,318
2010 Long-Term Incentive Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Maximum number of shares of common stock authorized for issuance (in shares)	2,250,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,635,384
Restricted Stock [Member]
Non-Vested Stock and Common Stock Equivalent Units, Activity [Roll Forward]
Non-vested, beginning of period (in shares)	370,731
Granted (in shares)	148,186
Vested (in shares)	(114,061)
Forfeited (in shares)	(55,081)
Non-vested, end of period (in shares)	349,775		370,731
Non-Vested Stock, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted average grant date fair value, non-vested, beginning of period (in dollars per share)	$ 31.27
Weighted average grant date fair value, non-vested, granted (in dollars per share)	$ 38.41
Weighted average grant date fair value, non-vested, vested (in dollars per share)	$ 26.97
Weighted average grant date fair value, non-vested, forfeited (in dollars per share)	$ 34.93
Weighted average grant date fair value, non-vested, end of period (in dollars per share)	$ 35.12		$ 31.27
Non-Vested Stock and Common Stock Equivalent Units, Fair Value Assumptions [Abstract]
Expected term (in years)	3 years	[1]	3 years	[1]	3 years	[1]
Volatility of Cleco stock (in hundredths)	21.50%	[2]	28.50%	[2]	30.60%	[2]
Correlation between Cleco stock volatility and peer group (in hundredths)	65.98%		63.20%		60.60%
Expected dividend yield (in hundredths)	3.30%		3.30%		3.50%
Weighted average fair value (Monte Carlo model) (in dollars per share)	$ 41.56		$ 34.88		$ 27.92
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Non-vested shares of common stock, outstanding (in shares)	349,775		370,731
Number of shares of non-vested stock previously granted with only a service period requirement for which the service period had not ended	127,376
Nov-vested shares of common stock granted during the year (in shares)	148,186
Fair value of shares of non-vested stock vested during period	$ 3.1		$ 4.0		$ 2.4
Restricted Stock [Member] | 2000 Long-Term Incentive Compensation Plan [Member]
Non-Vested Stock and Common Stock Equivalent Units, Activity [Roll Forward]
Non-vested, end of period (in shares)	46,180
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Non-vested shares of common stock, outstanding (in shares)	46,180
Restricted Stock [Member] | 2010 Long-Term Incentive Compensation Plan [Member]
Non-Vested Stock and Common Stock Equivalent Units, Activity [Roll Forward]
Granted (in shares)	148,186
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Nov-vested shares of common stock granted during the year (in shares)	148,186
Common Stock Equivalent Units [Member]
Non-Vested Stock and Common Stock Equivalent Units, Activity [Roll Forward]
Non-vested, beginning of period (in shares)	59,884
Granted (in shares)	0
Vested (in shares)	(52,986)
Forfeited (in shares)	(6,898)
Non-vested, end of period (in shares)	0		59,884
Common Stock Equivalent Units, Weighted Average Fair Value [Roll Forward]
Weighted-average fair value, common stock equivalent units, beginning of period (in dollars per share)	$ 42.22
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)	$ 42.22
Weighted-average fair value, common stock equivalent units, forfeited (in dollars per share)	$ 42.22
Weighted-average fair value, common stock equivalent units, end of period (in dollars per share)	$ 0.00		$ 42.22
Non-Vested Stock and Common Stock Equivalent Units, Fair Value Assumptions [Abstract]
Expected term (in years)	0 years	[1]	0 years	[1]	3 years	[1]
Volatility of Cleco stock (in hundredths)	0.00%	[2]	0.00%	[2]	28.60%	[2]
Correlation between Cleco stock volatility and peer group (in hundredths)	0.00%		0.00%		62.50%
Expected dividend yield (in hundredths)	0.00%		0.00%		3.90%
Weighted average fair value (Monte Carlo model) (in dollars per share)	$ 0.00		$ 0.00		$ 32.81
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Non-vested shares of common stock, outstanding (in shares)	0		59,884
Nov-vested shares of common stock granted during the year (in shares)	0
Common Stock Equivalent Units [Member] | 2000 Long-Term Incentive Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Common Stock Equivalent Units, Outstanding (in shares)	0
Common Stock [Member] | Restricted Stock [Member] | 2010 Long-Term Incentive Compensation Plan [Member]
Non-Vested Stock and Common Stock Equivalent Units, Activity [Roll Forward]
Granted (in shares)	137,175
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Nov-vested shares of common stock granted during the year (in shares)	137,175
Treasury Stock [Member] | Restricted Stock [Member] | 2010 Long-Term Incentive Compensation Plan [Member]
Non-Vested Stock and Common Stock Equivalent Units, Activity [Roll Forward]
Granted (in shares)	11,011
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Nov-vested shares of common stock granted during the year (in shares)	11,011

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

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