Common 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, 2014	Dec. 31, 2013	Dec. 31, 2012
Restricted Stock [Member]
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)	$ 38.26
Weighted average grant date fair value, non-vested, granted (in dollars per share)	$ 48.65
Weighted average grant date fair value, non-vested, vested (in dollars per share)	$ 37.66
Weighted average grant date fair value, non-vested, forfeited (in dollars per share)	$ 44.16
Weighted average grant date fair value, non-vested, end of period (in dollars per share)	$ 42.90	$ 38.26
Non-Vested Stock, Activity [Roll Forward]
Shares, non-vested, beginning of period (in shares)	340,998
Shares, granted (in shares)	135,379
Shares, vested (in shares)	(155,310)
Shares, forfeited (in shares)	(9,350)
Shares, non-vested, end of period (in shares)	311,717	340,998
Non-Vested Stock, Fair Value Assumptions [Abstract]
Expected term (in years)	3 years	3 years	3 years
Volatility of Cleco stock (in hundredths)	17.30%	18.10%	21.50%
Correlation between Cleco stock volatility and peer group (in hundredths)	66.50%	69.70%	66.00%
Expected dividend yield (in hundredths)	3.00%	3.20%	3.30%
Weighted average fair value (Monte Carlo model) (in dollars per share)	$ 54.58	$ 42.66	$ 41.56
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Non-vested shares of common stock granted during the year (in shares)	135,379
Fair value of shares of non-vested stock vested during period	$ 5.8	$ 5.2	$ 3.1
Restricted Stock [Member] | LTICP [Member]
Non-Vested Stock, Activity [Roll Forward]
Shares, non-vested, end of period (in shares)	154,047
Restricted Stock [Member] | 2010 Long-Term Incentive Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Target and opportunity shares for which restrictions had not lapsed	570,622
Non-vested shares granted with only a service period requirement that had not yet been completed	85,187
Common Stock Equivalent Units [Member]
Non-Vested Stock, Activity [Roll Forward]
Shares, granted (in shares)	0	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Non-vested shares of common stock granted during the year (in shares)	0	0	0
Treasury Stock [Member] | Restricted Stock [Member] | 2010 Long-Term Incentive Compensation Plan [Member]
Non-Vested Stock, Activity [Roll Forward]
Shares, granted (in shares)	135,379
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Non-vested shares of common stock granted during the year (in shares)	135,379