Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2018
Accounting Policies [Abstract]
Principles of Consolidation	The accompanying Condensed Consolidated Financial Statements of Cleco include the accounts of Cleco Holdings and its majority-owned subsidiaries after elimination of intercompany accounts and transactions.
Basis of Presentation	The Condensed Consolidated Financial Statements of Cleco and Cleco Power have been prepared in accordance with GAAP for interim financial information and with the instructions to the Form 10-Q and Regulation S-X. Accordingly, these Condensed Consolidated Financial Statements do not include all of the information and notes required by GAAP for annual financial statements. The year-end Condensed Consolidated Balance Sheet data was derived from audited financial statements. Because the interim Condensed Consolidated Financial Statements and the accompanying notes do not include all of the information and notes required by GAAP for annual financial statements, the Condensed Consolidated Financial Statements and other information included in this quarterly report should be read in conjunction with the Consolidated Financial Statements and accompanying notes in the Registrants’ Combined Annual Report on Form 10-K for the year ended December 31, 2017. These Condensed Consolidated Financial Statements, in the opinion of management, reflect all normal recurring adjustments that are necessary to fairly state the financial position and results of operations of Cleco and Cleco Power. Amounts reported in Cleco and Cleco Power’s interim financial statements are not necessarily indicative of amounts expected for the annual periods due to the effects of seasonal temperature variations on energy consumption, regulatory rulings, the timing of maintenance on electric generating units, changes in mark-to-market valuations, changing commodity prices, discrete income tax items, and other factors. In preparing financial statements that conform to GAAP, management must make estimates and assumptions that affect the reported amounts of assets and liabilities, the reported amounts of revenues and expenses, and the disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates. For information on recent authoritative guidance and its effect on financial results, see Note 3 — “Recent Authoritative Guidance.”
Restricted Cash and Cash Equivalents	Various agreements to which Cleco is subject contain covenants that restrict its use of cash. As certain provisions under these agreements are met, cash is transferred out of related escrow accounts and becomes available for its intended purposes and/or general corporate purposes. Cleco Katrina/Rita has the right to bill and collect storm restoration costs from Cleco Power’s customers. As cash is collected, it is restricted for payment of administration fees, interest, and principal on storm recovery bonds.
Fair Value Measurements and Disclosures	Various accounting pronouncements require certain assets and liabilities to be measured at their fair values. Some assets and liabilities are required to be measured at their fair value each reporting period, while others are required to be measured only one time, generally the date of acquisition or debt issuance. Cleco and Cleco Power disclose the fair value of certain assets and liabilities by one of three levels when required for recognition purposes.
Risk Management	Market risk inherent in Cleco’s market risk-sensitive instruments and positions includes potential changes in value arising from changes in interest rates and the commodity market prices of power, FTRs, and natural gas in the industry on different energy exchanges. Cleco’s Energy Market Risk Management Policy authorizes the use of various derivative instruments, including exchange traded futures and option contracts, forward purchase and sales contracts, and swap transactions to reduce exposure to fluctuations in the price of power, FTRs, and natural gas. Cleco evaluates derivatives and hedging activities to determine whether the market risk-sensitive instruments and positions are required to be marked-to-market. Cleco Power may also enter into risk mitigating positions that would not meet the requirements of a normal-purchase, normal-sale transaction in order to attempt to mitigate the volatility in customer fuel costs. These positions would be marked-to-market with the resulting gain or loss recorded on Cleco and Cleco Power’s Condensed Consolidated Balance Sheets as a component of energy risk management assets or liabilities. Such gain or loss would be deferred as a component of deferred fuel assets or liabilities in accordance with regulatory policy. When these positions close, actual gains or losses would be included in the FAC and reflected on customers’ bills as a component of the fuel charge. Cleco Power purchases FTRs in auctions facilitated by MISO. The majority of its FTRs are purchased in annual auctions during the second quarter, but Cleco Power may purchase additional FTRs in monthly auctions. FTRs are derivative instruments that represent economic hedges of future congestion charges that will be incurred in serving Cleco Power’s customer load. FTRs are not designated as hedging instruments for accounting purposes. Cleco Power records FTRs at their estimated fair value when purchased. Each accounting period, Cleco Power adjusts the carrying value of FTRs to their estimated fair value based on the most recent MISO FTR auction prices. Unrealized gains or losses on FTRs held by Cleco Power are included in Accumulated deferred fuel on Cleco Power’s Condensed Consolidated Balance Sheets. Realized gains or losses on settled FTRs are recorded in Fuel used for electric generation on Cleco Power’s Condensed Consolidated Statements of Income. Cleco and Cleco Power maintain a master netting agreement policy and monitor credit risk exposure through review of counterparty credit quality, aggregate counterparty credit exposure, and aggregate counterparty concentration levels. Cleco manages these risks by establishing appropriate credit and concentration limits on transactions with counterparties and requiring contractual guarantees, cash deposits, or letters of credit from counterparties or their affiliates, as deemed necessary. Cleco Power has agreements in place with various counterparties that authorize the netting of financial buys and sells and contract payments to mitigate credit risk for transactions entered into for risk management purposes. Cleco and Cleco Power may enter into contracts to mitigate the volatility in interest rate risk. These contracts include, but are not limited to, interest rate swaps and treasury rate locks.
Revenue Recognition	Cleco adopted the accounting guidance for revenue recognition and all related amendments on January 1, 2018, using the modified retrospective method. The guidance affects entities that enter into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards. The core principle of this guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Application of the new revenue standard did not result in a cumulative effect adjustment to the opening balance of retained earnings. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. The impact of the adoption of the new standard is not material to the results of operations, financial condition, or cash flows of the Registrants.
Recent Authoritative Guidance	The Registrants adopted, or will adopt, the recent authoritative guidance listed below on their respective effective dates. In February 2016, FASB amended the guidance to account for leases. This guidance is intended to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. The adoption of this guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those years. In transition, lessees and lessors can recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. Alternatively, an additional transition method is available which allows an entity to initially apply the new lease standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Management expects to elect this practical expedient, as well as those that permit the Registrants to retain their current lease assessment and classifications for existing leases at the effective date and to not apply the new guidance to land easements that exist or expire before the effective date. Management is currently working through an adoption plan which includes the evaluation of lease contracts, new business processes, including changes to current recordkeeping systems, and the need for additional internal controls. Other than an expected increase in assets and liabilities, the full impact of the amended guidance has not been determined. Management will continue to evaluate the impact of this guidance, including any additional clarifying amendments issued during implementation. The amended guidance could have a material impact on the results of operations, financial condition, or cash flows of the Registrants. In November 2016, FASB amended guidance for certain cash flow issues. The amended guidance requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash. Therefore, amounts generally described as restricted cash and cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The adoption of this guidance was effective for fiscal years beginning after December 15, 2017, including interim periods within those years. The amended guidance was adopted at January 1, 2018, by moving the presentation of restricted cash and restricted cash equivalents in the statement of cash flows to net cash flows of total cash, cash equivalents, restricted cash, and restricted cash equivalents. This amendment was applied using a retrospective transition method to each period presented. This guidance impacted the presentation of the cash flows statement, as noted above, but did not have an impact on the results of operations or financial condition of the Registrants. In March 2017, FASB amended guidance related to defined benefit pension and other postretirement benefit plans. The new amendment requires an entity to present service cost in the same line item as other current employee compensation costs and to present the remaining components of net benefit cost in a separate line item outside of operating items. The amendment also allows only the service cost component of net benefit cost to be eligible for capitalization within property, plant, and equipment. The non-service costs will continue to be capitalized and recovered from ratepayers as approved by FERC. Beginning January 1, 2018, the non-service costs capitalized for ratemaking purposes were reflected as a regulatory asset or liability for GAAP. The adoption of this guidance was effective for annual periods beginning after December 15, 2017, including interim periods within those years. This amendment was applied retrospectively for the presentation of the service cost in the income statement while the capitalization of the service cost was applied prospectively. This guidance did not have a significant impact on the results of operations, financial condition, or cash flows of the Registrants. Cleco’s change in presentation resulted in a decrease in Other operations expenses and an increase in Other expense of $2.7 million and $8.4 million for the three and nine months ended September 30, 2017, respectively. Cleco Power’s change in presentation resulted in a decrease in Other operations expenses and an increase in Other expense of $1.9 million and $5.7 million for the three and nine months ended September 30, 2017, respectively. In February 2018, FASB amended guidance that permits, but does not require, companies to reclassify stranded tax effects from the TCJA from AOCI to retained earnings. The adoption of this guidance is effective for annual reporting periods beginning after December 15, 2018, including interim periods within those years. Early adoption is permitted. Management is currently evaluating this guidance and the impact it may have on the results of operations, financial condition, or cash flows of the Registrants. In August 2018, FASB issued guidance that allows for the deferral of certain implementation costs incurred in a cloud computing arrangement. The adoption of this guidance is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those years. Early adoption is permitted. Management is currently evaluating this guidance and the impact it may have on the results of operations, financial condition, or cash flows of the Registrants. In August 2018, FASB issued guidance updating the disclosure framework for Defined Benefit Plans. Under the new guidance, entities will no longer be required to disclose the amount in other comprehensive income expected to be recognized as a component of net periodic benefit cost over the next fiscal year or the impact of a one-percentage point increase and a one-percentage point decrease in the assumed health care cost trend. The new framework will require additional disclosures including a narrative description of the reasons for significant gains/losses affecting the benefit obligation. The adoption of this guidance is effective for fiscal years ending after December 15, 2020. Early adoption is permitted. Management does not expect this guidance to have a significant impact on the results of operations, financial condition, or cash flows of the Registrants. In August 2018, FASB issued guidance updating the disclosure framework for Fair Value Measurement. Under the new guidance, entities will no longer be required to disclose the amount of and reasons for transfers between level 1 and level 2 of the fair value hierarchy, the policy of timing of transfers between levels, or the valuation policies and procedures for level 3 fair value measurements. The new framework will require additional disclosures around level 3 fair value measurements, including the range, weighted average, and time period used to develop significant unobservable inputs. The adoption of this guidance is effective for fiscal years beginning after December 15, 2019. Early adoption is permitted. Management does not expect this guidance to have a significant impact on the results of operations, financial condition, or cash flows of the Registrants.
Regulatory Assets and Liabilities	Cleco capitalizes or defers certain costs for recovery from customers and recognizes a liability for amounts expected to be returned to customers based on regulatory approval and management’s ongoing assessment that it is probable these items will be recovered or refunded through the ratemaking process. Under the current regulatory environment, Cleco believes these regulatory assets will be fully recoverable; however, if in the future, as a result of regulatory changes or competition, Cleco’s ability to recover these regulatory assets would no longer be probable, then to the extent that such regulatory assets were determined not to be recoverable, Cleco would be required to write-down such assets. In addition, potential deregulation of the industry or possible future changes in the method of rate regulation of Cleco could require discontinuance of the application of the authoritative guidance on regulated operations.
Pension Plan and Employee Benefits	Cleco’s 401(k) Plan is intended to provide active, eligible employees with voluntary, long-term savings and investment opportunities. The 401(k) Plan is a defined contribution plan and is subject to the applicable provisions of the Employee Retirement Income Security Act of 1974. In accordance with the 401(k) Plan, employer contributions are made in the form of cash. Cash contributions are invested in proportion to the participant’s voluntary contribution investment choices. Participation in the 401(k) Plan is voluntary, and all active Cleco employees are eligible to participate. Cleco’s retirees may be eligible to receive Other Benefits. Dependents of Cleco’s retirees may also be eligible to receive Other Benefits with the exception of life insurance benefits. Cleco recognizes expected costs of Other Benefits during the periods in which the benefits are earned. Certain Cleco officers are covered by SERP. In 2014, SERP was closed to new participants; however, with regard to current SERP participants, including former employees or their beneficiaries, all terms of SERP will continue, other than as described below. SERP is a non-qualified, non-contributory, defined benefit pension plan. Generally, benefits under the plan reflect an employee’s years of service, age at retirement and the sum of (a) the highest base salary paid out over the last five calendar years and (b) the average of the three highest cash bonuses paid during the 60 months prior to retirement. SERP benefits are reduced by retirement benefits received from any other defined benefit pension plan, supplemental executive retirement plan, or Cleco contributions under the enhanced 401(k) Plan to the extent such contributions exceed the amount the employee would have received under the terms of the original 401(k) Plan. In accordance with the SERP plan document and the Merger Agreement, four executive officers received enhanced benefits, and upon termination of employment, two of these executive officers received accelerated vesting. Another executive officer received enhanced SERP benefits, net of other postretirement benefits, as part of a separation agreement. Two executive officers’ SERP benefits were capped as of December 31, 2017, with regard to final compensation; however, adjustments will continue with regard to age and tenure with Cleco. Additionally, these executive officers had their annual bonuses set at target rather than actual awards for the years 2016 and 2017 for the average incentive award portion of their SERP benefit calculation. A third executive officer’s SERP benefit amount will be set at a specified amount based upon the year of separation. Management reviews current market trends as it evaluates Cleco’s future compensation strategy. Cleco does not fund the SERP liability, but instead pays for current benefits out of the general funds available. Cleco Power has formed a rabbi trust. The life insurance policies issued on SERP participants designate the rabbi trust as the beneficiary. Market conditions could have a significant impact on the cash surrender value of the life insurance policies. Proceeds from the life insurance policies are expected to be used to pay the SERP participants’ death benefits, as well as future SERP payments. However, because SERP is a non-qualified plan, the assets of the trust could be used to satisfy general creditors of Cleco Power in the event of insolvency. All SERP benefits are paid out of the general cash available of the respective companies that employed the officer. Cleco Power is the plan sponsor and Support Group is the plan administrator. The non-service components of net periodic benefit cost related to SERP are included in Other expense within Cleco and Cleco Power’s Condensed Consolidated Statements of Income.
Income Taxes	Cleco classifies income tax penalties as a component of other expense. Cleco classifies all interest related to uncertain tax positions as a component of interest payable and interest expense.
Segment Reporting	The financial results in the following tables are presented on an accrual basis. Management evaluates the performance of its segment and allocates resources to it based on segment profit and the requirements to implement new strategic initiatives and projects to meet current business objectives. Material intercompany transactions occur on a regular basis. These intercompany transactions relate primarily to joint and common administrative support services.
Equity Method Investments	Cleco and Cleco Power apply the equity method of accounting to report the investment in Oxbow in the consolidated financial statements. Under the equity method, the assets and liabilities of this entity are reported as Equity investment in investee on Cleco and Cleco Power’s Condensed Consolidated Balance Sheets. The revenue and expenses (excluding income taxes) of this entity are netted and reported as equity income or loss from investees on Cleco and Cleco Power’s Condensed Consolidated Statements of Income.
Variable Interest Entities	Cleco and Cleco Power apply the equity method of accounting to report the investment in Oxbow in the consolidated financial statements. Under the equity method, the assets and liabilities of this entity are reported as Equity investment in investee on Cleco and Cleco Power’s Condensed Consolidated Balance Sheets. The revenue and expenses (excluding income taxes) of this entity are netted and reported as equity income or loss from investees on Cleco and Cleco Power’s Condensed Consolidated Statements of Income.