Fair Value Accounting, Fair Value of Financial Assets and Liabilities Measured on a Recurring Basis (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Cash and Cash Equivalents [Member]
Asset Description
Institutional money market funds	$ 39,600
Restricted Cash and Cash Equivalents, Current [Member]
Asset Description
Institutional money market funds	3,300
Restricted Cash and Cash Equivalents, Noncurrent [Member]
Asset Description
Institutional money market funds	5,800
Restricted Investement, Noncurrent [Member]
Asset Description
Institutional money market funds	1,300
Available-for-sale Securities, Fair Value Disclosure	9,600
Measured On A Recurring Basis [Member] | Estimated Fair Value [Member]
Asset Description
Institutional money market funds	49,963	39,489
Available-for-sale Securities, Fair Value Disclosure	9,555	10,203
Total Assets	59,518	49,692
Liability Description
Long-term debt, excluding debt issuance costs	1,534,758	1,579,674
Total Liabilities	1,535,182	1,582,301
Measured On A Recurring Basis [Member] | Estimated Fair Value [Member] | Interest Rate Derivatives [Member]
Liability Description
Derivative liabilities	424	2,627
Measured On A Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Asset Description
Institutional money market funds	0	0
Available-for-sale Securities, Fair Value Disclosure	0	0
Total Assets	0	0
Liability Description
Long-term debt, excluding debt issuance costs	0	0
Total Liabilities	0	0
Measured On A Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Interest Rate Derivatives [Member]
Liability Description
Derivative liabilities	0	0
Measured On A Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member]
Asset Description
Institutional money market funds	49,963	39,489
Available-for-sale Securities, Fair Value Disclosure	9,555	10,203
Total Assets	59,518	49,692
Liability Description
Long-term debt, excluding debt issuance costs	1,534,758	1,579,674
Total Liabilities	1,535,182	1,582,301
Measured On A Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Derivatives [Member]
Liability Description
Derivative liabilities	424	2,627
Measured On A Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member]
Asset Description
Institutional money market funds	0	0
Available-for-sale Securities, Fair Value Disclosure	0	0
Total Assets	0	0
Liability Description
Long-term debt, excluding debt issuance costs	0	0
Total Liabilities	0	0
Measured On A Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Interest Rate Derivatives [Member]
Liability Description
Derivative liabilities	0	0
Cleco Power [Member] | Cash and Cash Equivalents [Member]
Asset Description
Institutional money market funds	37,600
Cleco Power [Member] | Restricted Cash and Cash Equivalents, Current [Member]
Asset Description
Institutional money market funds	3,300
Cleco Power [Member] | Restricted Cash and Cash Equivalents, Noncurrent [Member]
Asset Description
Institutional money market funds	5,700
Cleco Power [Member] | Restricted Investement, Noncurrent [Member]
Asset Description
Institutional money market funds	1,300
Available-for-sale Securities, Fair Value Disclosure	9,600
Cleco Power [Member] | Measured On A Recurring Basis [Member] | Estimated Fair Value [Member]
Asset Description
Institutional money market funds	47,867	33,292
Available-for-sale Securities, Fair Value Disclosure	9,555	10,203
Total Assets	57,422	43,495
Liability Description
Long-term debt, excluding debt issuance costs	1,519,758	1,554,674
Total Liabilities	1,520,182	1,557,301
Cleco Power [Member] | Measured On A Recurring Basis [Member] | Estimated Fair Value [Member] | Interest Rate Derivatives [Member]
Liability Description
Derivative liabilities	424	2,627
Cleco Power [Member] | Measured On A Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Asset Description
Institutional money market funds	0	0
Available-for-sale Securities, Fair Value Disclosure	0	0
Total Assets	0	0
Liability Description
Long-term debt, excluding debt issuance costs	0	0
Total Liabilities	0	0
Cleco Power [Member] | Measured On A Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Interest Rate Derivatives [Member]
Liability Description
Derivative liabilities	0	0
Cleco Power [Member] | Measured On A Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member]
Asset Description
Institutional money market funds	47,867	33,292
Available-for-sale Securities, Fair Value Disclosure	9,555	10,203
Total Assets	57,422	43,495
Liability Description
Long-term debt, excluding debt issuance costs	1,519,758	1,554,674
Total Liabilities	1,520,182	1,557,301
Cleco Power [Member] | Measured On A Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Derivatives [Member]
Liability Description
Derivative liabilities	424	2,627
Cleco Power [Member] | Measured On A Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member]
Asset Description
Institutional money market funds	0	0
Available-for-sale Securities, Fair Value Disclosure	0	0
Total Assets	0	0
Liability Description
Long-term debt, excluding debt issuance costs	0	0
Total Liabilities	0	0
Cleco Power [Member] | Measured On A Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Interest Rate Derivatives [Member]
Liability Description
Derivative liabilities	$ 0	$ 0