Fair Value Accounting - Fair Value of Financial Assets and Liabilities Measured On A Recurring Basis (Details) - Measured On A Recurring Basis - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Asset description
Institutional money market funds	$ 199,531	$ 144,302
FTRs	23,163	7,396
Total assets	222,694	151,698
Liability description
FTRs	903	352
Total liabilities	903	352
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1)
Asset description
Institutional money market funds	0	0
FTRs	0	0
Total assets	0	0
Liability description
FTRs	0	0
Total liabilities	0	0
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)
Asset description
Institutional money market funds	199,531	144,302
FTRs	0	0
Total assets	199,531	144,302
Liability description
FTRs	0	0
Total liabilities	0	0
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Asset description
Institutional money market funds	0	0
FTRs	23,163	7,396
Total assets	23,163	7,396
Liability description
FTRs	903	352
Total liabilities	903	352
CLECO POWER
Asset description
Institutional money market funds	78,110	95,681
FTRs	23,163	7,396
Total assets	101,273	103,077
Liability description
FTRs	903	352
Total liabilities	903	352
CLECO POWER \| QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1)
Asset description
Institutional money market funds	0	0
FTRs	0	0
Total assets	0	0
Liability description
FTRs	0	0
Total liabilities	0	0
CLECO POWER \| SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)
Asset description
Institutional money market funds	78,110	95,681
FTRs	0	0
Total assets	78,110	95,681
Liability description
FTRs	0	0
Total liabilities	0	0
CLECO POWER \| SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Asset description
Institutional money market funds	0	0
FTRs	23,163	7,396
Total assets	23,163	7,396
Liability description
FTRs	903	352
Total liabilities	$ 903	$ 352

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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Fair value of financial and nonfinancial obligations.

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Fair value as of the balance sheet date of price risk derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets on the balance sheet.

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Fair value as of the balance sheet date of price risk derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities on the balance sheet.

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