Pension Plan and Employee Benefits, Amounts Recognized in Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 387,776		$ 330,193
Amounts recognized in other comprehensive income [Abstract]
Net actuarial loss (gain) occurring during year	32,177		20,389
Net actuarial loss (gain) amortized during year	8,346		5,556
Transition obligation (asset) amortized during year	0		0
Prior service cost (credit) amortized during year	(71)		(71)
Amounts in accumulated other comprehensive income to be recognized in next fiscal year [Abstract]
Net actuarial loss (gain)	12,513
Transition obligation (asset)	0
Prior service cost (credit)	(71)
Amounts in accumulated other comprehensive income [Abstract]
Net actuarial loss (gain)	157,017		133,186
Transition obligation (asset)	0		0
Prior service cost (credit)	(559)		(630)
Other Benefits [Member]
Amounts recognized in other comprehensive income [Abstract]
Net actuarial loss (gain) occurring during year	2,461		141
Net actuarial loss (gain) amortized during year	1,479		1,010
Transition obligation (asset) amortized during year	20		20
Prior service cost (credit) amortized during year	0		(206)
Amounts in accumulated other comprehensive income to be recognized in next fiscal year [Abstract]
Net actuarial loss (gain)	1,176	[1]
Transition obligation (asset)	20
Prior service cost (credit)	0
Prescription Drug Subsidy Receipts, Next Twelve Months	194
Amounts in accumulated other comprehensive income [Abstract]
Net actuarial loss (gain)	13,602		12,620
Transition obligation (asset)	35		55
Prior service cost (credit)	0		0
SERP Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	53,350		42,410
Amounts recognized in other comprehensive income [Abstract]
Net actuarial loss (gain) occurring during year	11,651		2,529
Net actuarial loss (gain) amortized during year	1,764		940
Prior service cost (credit) amortized during year	54		54
Amounts in accumulated other comprehensive income to be recognized in next fiscal year [Abstract]
Net actuarial loss (gain)	2,155
Prior service cost (credit)	54
Amounts in accumulated other comprehensive income [Abstract]
Net actuarial loss (gain)	25,444		15,588
Prior service cost (credit)	$ 280		$ 334

[1] (1) In 2013, Cleco received $194 thousand in Medicare Part D subsidies for the 2012 plan year, which will reduce the net actuarial loss for 2013.