Fair Value Accounting Fair Value Accounting, Concentration of Risk (Details) (USD $)	3 Months Ended
	Mar. 31, 2012
Established guidelines for short-term investments to mitigate potential credit risk [Abstract]
Minimum assets under management in money market funds	$ 1,000,000,000
Minimum existence of investments (in years)	2 years
Maximum portfolios' composition securities issued by foreign entities (in hundredths)	50.00%
Maximum Amount of Loss [Member]
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Concentrations of credit risk through short-term investments	70,400,000
Concentrations of credit risk through their short-term investments in cash	39,800,000
Concentrations of credit risk through their short-term investments in restricted cash	30,600,000
Cleco Power [Member] | Maximum Amount of Loss [Member]
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Concentrations of credit risk through short-term investments	63,500,000
Concentrations of credit risk through their short-term investments in cash	33,000,000
Concentrations of credit risk through their short-term investments in restricted cash	$ 30,500,000