Summary of Significant Accounting Policies, Reclassifications (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
Accounts receivable	$ 12,059	$ 7,812
Depreciation	34,032	31,846
Other deferred accounts	2,121	(1,883)
Net cash provided by (used in) operating activities	103,447	45,719
Additions to property, plant, and equipment	(44,887)	(43,487)
Net cash provided by (used in) investing activities	(49,710)	(44,932)
Net increase (decrease) in cash and cash equivalents	15,447	(46,327)
Cash and cash equivalents	46,467	47,249	31,020	93,576
Cash Flows Related To Contributions Received In Aid Of Construction [Member]
Accounts receivable		7,812
Other deferred accounts		(1,883)
Net cash provided by (used in) operating activities		45,719
Additions to property, plant, and equipment		(43,487)
Net cash provided by (used in) investing activities		(44,932)
Net increase (decrease) in cash and cash equivalents		(46,327)
Cash and cash equivalents		47,249		93,576
Cash Flows Related To Contributions Received In Aid Of Construction [Member] | Scenario, Previously Reported [Member]
Accounts receivable		6,253
Other deferred accounts		(5,835)
Net cash provided by (used in) operating activities		41,373
Additions to property, plant, and equipment		(39,380)
Net cash provided by (used in) investing activities		(40,825)
Net increase (decrease) in cash and cash equivalents		(46,327)
Cash and cash equivalents		47,249		93,576
Cleco Power [Member]
Accounts receivable	12,098	7,326
Depreciation	32,330	30,090
Other deferred accounts	1,650	(4,795)
Net cash provided by (used in) operating activities	63,098	51,667
Additions to property, plant, and equipment	(43,599)	(42,661)
Net cash provided by (used in) investing activities	(36,331)	(34,913)
Net increase (decrease) in cash and cash equivalents	19,071	(31,573)
Cash and cash equivalents	42,439	35,885	23,368	67,458
Cleco Power [Member] | Cash Flows Related To Contributions Received In Aid Of Construction [Member]
Accounts receivable		7,326
Other deferred accounts		(4,795)
Net cash provided by (used in) operating activities		51,667
Additions to property, plant, and equipment		(42,661)
Net cash provided by (used in) investing activities		(34,913)
Net increase (decrease) in cash and cash equivalents		(31,573)
Cash and cash equivalents		35,885		67,458
Cleco Power [Member] | Cash Flows Related To Contributions Received In Aid Of Construction [Member] | Scenario, Previously Reported [Member]
Accounts receivable		5,767
Other deferred accounts		(8,747)
Net cash provided by (used in) operating activities		47,513
Additions to property, plant, and equipment		(38,507)
Net cash provided by (used in) investing activities		(30,759)
Net increase (decrease) in cash and cash equivalents		(31,573)
Cash and cash equivalents		35,885		67,458
Reclassification Of Plant Acquisition Adjustment Amortization [Member]
Depreciation		$ 700