Summary of Significant Accounting and Reporting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
New Accounting Pronouncements	Effective January 1, 2018, NEE and FPL adopted an accounting standards update that provides guidance on the recognition of revenue from contracts with customers and requires additional disclosures regarding such contracts (new revenue standard). Under the new revenue standard, revenue is recognized when control of the promised goods or services is transferred to customers at an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. The promised goods or services in the majority of NEE’s contracts with customers is, at FPL, for the delivery of electricity and, at NEER, for the delivery of energy commodities and the availability of electric capacity and electric transmission. NEE and FPL adopted the new revenue standard using the modified retrospective approach applying it only to contracts that were not complete at January 1, 2018. Amendments to Presentation of Retirement Benefits - Effective January 1, 2018, NEE adopted an accounting standards update that requires certain changes in classification of components of net periodic pension and postretirement benefit costs within the income statement and allows only the service cost component to be eligible for capitalization. NEE adopted the standards update using the retrospective approach for presentation of the components of net periodic pension and postretirement benefit costs and the prospective approach for capitalization of service cost. Upon adoption, NEE, among other things, reclassified the non-service cost components noted in the net periodic benefit (income) cost table above from O&M expense to other net periodic benefit income in NEE's condensed consolidated statements of income. The adoption of this standards update did not have an impact on net income attributable to NEE and did not have any impact on FPL as NEE is the plan sponsor. Financial Instruments Accounting Standards Update - Effective January 1, 2018, NEE and FPL adopted an accounting standards update which modifies guidance for financial instruments and makes certain changes to presentation and disclosure requirements. The standards update requires that equity investments (except investments accounted for under the equity method and investments that are consolidated) be measured at fair value with changes in fair value recognized in net income. This standards update primarily impacts the equity securities in NEER's special use funds and is expected to result in increased earnings volatility in future periods based on market conditions. NEE and FPL adopted this standards update using the modified retrospective approach with the cumulative effect recognized as an adjustment to retained earnings on January 1, 2018. Upon adoption, NEE reclassified net unrealized after-tax gains of approximately $312 million from AOCI to retained earnings. The implementation of this standards update had no impact on FPL as changes in the fair value of equity securities in FPL's special use funds are deferred as regulatory assets or liabilities pursuant to accounting guidance for regulated operations. Goodwill and Other Intangible Assets - Effective January 1, 2018, NEE and FPL adopted an accounting standards update that clarified the definition of a business. The revised guidance affects the evaluation of whether a transaction should be accounted for as an acquisition or disposition of an asset or a business. NEE and FPL adopted this guidance on a prospective basis effective January 1, 2018. Restricted Cash - In the fourth quarter of 2017, NEE and FPL early adopted an accounting standards update which requires that restricted cash be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the consolidated statements of cash flows. NEE and FPL adopted the standards update retrospectively, which adoption did not have a material impact on NEE’s or FPL’s consolidated statements of cash flows. At March 31, 2018 and December 31, 2017, NEE had approximately $358 million ($116 million for FPL) and $269 million ($141 million for FPL), respectively, of restricted cash, of which approximately $345 million ($103 million for FPL) and $247 million ($128 million for FPL), respectively, is included in current other assets and the remaining balance is included in noncurrent other assets on NEE's and FPL's condensed consolidated balance sheets. Restricted cash is primarily related to debt service payments, bond proceeds held for construction at FPL and margin cash collateral requirements. In addition, where offsetting positions exist, restricted cash related to margin cash collateral is netted against derivative instruments, which totaled $2 million at March 31, 2018. See Note 4. Leases - In February 2016, the FASB issued an accounting standards update which requires, among other things, that lessees recognize a lease liability, initially measured at the present value of the future lease payments, and a right-of-use asset for all leases (with the exception of short-term leases) (new lease standard). The new lease standard also requires new qualitative and quantitative disclosures for both lessees and lessors. The new lease standard will be effective for NEE and FPL beginning January 1, 2019. Early adoption is permitted. NEE and FPL are currently reviewing their portfolio of contracts and evaluating the proper application of the new lease standard to these contracts in order to determine the impact the adoption will have on their consolidated financial statements, including timing of adoption. NEE and FPL are implementing a number of system enhancements to facilitate the identification, tracking and reporting of leases based upon the requirements of the new lease standard. NEE and FPL are continuing to assess the transition options and practical expedients and monitoring industry implementation issues. Accounting for Partial Sales of Nonfinancial Assets - Effective January 1, 2018, NEE and FPL adopted an accounting standards update regarding the accounting for partial sales of nonfinancial assets using the modified retrospective approach, resulting in cumulative effects being recognized on January 1, 2018. This standards update affects the accounting and related financial statement presentation for the sales of differential membership interests to third-party investors and the sales of NEER assets to indirect subsidiaries of NEP. The adoption of this standards update did not have an impact on FPL. For the sales of differential membership interests to third-party investors, NEE recorded an increase to retained earnings of approximately $34 million ($56 million pretax) and a reduction to additional paid-in capital of $77 million ($59 million after tax) on January 1, 2018. In addition, the liability reflected as deferral related to differential membership interests - VIEs on NEE's consolidated balance sheets at December 31, 2017 was reclassified to noncontrolling interests. In future periods, as the third-party investors receive their portion of the economic attributes of the related facilities, NEE records such amounts as net loss attributable to noncontrolling interests. Prior to the adoption of this standards update, the income related to differential membership interests was being recognized in benefits associated with differential membership interests - net in NEE's condensed consolidated statements of income. Additionally, net (income) loss attributable to noncontrolling interests for the three months ended March 31, 2018 includes approximately $497 million ($373 million after tax) related to a reduction of differential membership interests as a result of the change in federal income tax rates effective January 1, 2018. Also upon adoption of the standards update, the profit sharing liability associated with the sales of NEER assets to NEP was eliminated and NEE recorded an increase to additional paid-in capital of approximately $842 million ($652 million after tax) and a reduction to retained earnings of approximately $52 million ($69 million pretax) on January 1, 2018. Due to the deconsolidation of NEP, the previous accounting guidance would not have had an impact on NEE's 2018 financial statements, but rather the profit sharing liability would have increased the gain on NEP deconsolidation.
Derivative Instruments	NEE and FPL use derivative instruments (primarily swaps, options, futures and forwards) to manage the physical and financial risks inherent in the purchase and sale of fuel and electricity, as well as interest rate and foreign currency exchange rate risk associated primarily with outstanding and expected future debt issuances and borrowings, and to optimize the value of NEER's power generation and gas infrastructure assets. NEE and FPL do not utilize hedge accounting for their cash flow and fair value hedges. With respect to commodities related to NEE's competitive energy business, NEER employs risk management procedures to conduct its activities related to optimizing the value of its power generation and gas infrastructure assets, providing full energy and capacity requirements services primarily to distribution utilities, and engaging in power and gas marketing and trading activities to take advantage of expected future favorable price movements and changes in the expected volatility of prices in the energy markets. These risk management activities involve the use of derivative instruments executed within prescribed limits to manage the risk associated with fluctuating commodity prices. Transactions in derivative instruments are executed on recognized exchanges or via the OTC markets, depending on the most favorable credit terms and market execution factors. For NEER's power generation and gas infrastructure assets, derivative instruments are used to hedge all or a portion of the expected output of these assets. These hedges are designed to reduce the effect of adverse changes in the wholesale forward commodity markets associated with NEER's power generation and gas infrastructure assets. With regard to full energy and capacity requirements services, NEER is required to vary the quantity of energy and related services based on the load demands of the customers served. For this type of transaction, derivative instruments are used to hedge the anticipated electricity quantities required to serve these customers and reduce the effect of unfavorable changes in the forward energy markets. Additionally, NEER takes positions in energy markets based on differences between actual forward market levels and management's view of fundamental market conditions, including supply/demand imbalances, changes in traditional flows of energy, changes in short- and long-term weather patterns and anticipated regulatory and legislative outcomes. NEER uses derivative instruments to realize value from these market dislocations, subject to strict risk management limits around market, operational and credit exposure. Derivative instruments, when required to be marked to market, are recorded on NEE's and FPL's condensed consolidated balance sheets as either an asset or liability measured at fair value. At FPL, substantially all changes in the derivatives' fair value are deferred as a regulatory asset or liability until the contracts are settled, and, upon settlement, any gains or losses are passed through the fuel clause. For NEE's non-rate regulated operations, predominantly NEER, essentially all changes in the derivatives' fair value for power purchases and sales, fuel sales and trading activities are recognized on a net basis in operating revenues; the equity method investees' related activity is recognized in equity in earnings of equity method investees in NEE's condensed consolidated statements of income. Settlement gains and losses are included within the line items in the condensed consolidated statements of income to which they relate. Transactions for which physical delivery is deemed not to have occurred are presented on a net basis in the condensed consolidated statements of income. For commodity derivatives, NEE believes that, where offsetting positions exist at the same location for the same time, the transactions are considered to have been netted and therefore physical delivery has been deemed not to have occurred for financial reporting purposes. Settlements related to derivative instruments are primarily recognized in net cash provided by operating activities in NEE's and FPL's condensed consolidated statements of cash flows. For interest rate and foreign currency derivative instruments, essentially all changes in the derivatives' fair value, as well as the transaction gain or loss on foreign denominated debt, are recognized in interest expense and the equity method investees' related activity is recognized in equity in earnings of equity method investees in NEE's condensed consolidated statements of income.
Fair Value Measurements	Fair Value Measurements The fair value of assets and liabilities are determined using either unadjusted quoted prices in active markets (Level 1) or pricing inputs that are observable (Level 2) whenever that information is available and using unobservable inputs (Level 3) to estimate fair value only when relevant observable inputs are not available. NEE and FPL use several different valuation techniques to measure the fair value of assets and liabilities, relying primarily on the market approach of using prices and other market information for identical and/or comparable assets and liabilities for those assets and liabilities that are measured at fair value on a recurring basis. NEE's and FPL's assessment of the significance of any particular input to the fair value measurement requires judgment and may affect placement within the fair value hierarchy levels. Non-performance risk, including the consideration of a credit valuation adjustment, is also considered in the determination of fair value for all assets and liabilities measured at fair value. Cash Equivalents and Restricted Cash Equivalents - NEE and FPL hold investments in money market funds. The fair value of these funds is estimated using a market approach based on current observable market prices. Special Use Funds and Other Investments - NEE and FPL hold primarily debt and equity securities directly, as well as indirectly through commingled funds. Substantially all directly held equity securities are valued at their quoted market prices. For directly held debt securities, multiple prices and price types are obtained from pricing vendors whenever possible, which enables cross-provider validations. A primary price source is identified based on asset type, class or issue of each security. Commingled funds, which are similar to mutual funds, are maintained by banks or investment companies and hold certain investments in accordance with a stated set of objectives. The fair value of commingled funds is primarily derived from the quoted prices in active markets of the underlying securities. Because the fund shares are offered to a limited group of investors, they are not considered to be traded in an active market. Derivative Instruments - NEE and FPL measure the fair value of commodity contracts using a combination of market and income approaches utilizing prices observed on commodities exchanges and in the OTC markets, or through the use of industry-standard valuation techniques, such as option modeling or discounted cash flows techniques, incorporating both observable and unobservable valuation inputs. The resulting measurements are the best estimate of fair value as represented by the transfer of the asset or liability through an orderly transaction in the marketplace at the measurement date. Most exchange-traded derivative assets and liabilities are valued directly using unadjusted quoted prices. For exchange-traded derivative assets and liabilities where the principal market is deemed to be inactive based on average daily volumes and open interest, the measurement is established using settlement prices from the exchanges, and therefore considered to be valued using other observable inputs. NEE, through its subsidiaries, including FPL, also enters into OTC commodity contract derivatives. The majority of these contracts are transacted at liquid trading points, and the prices for these contracts are verified using quoted prices in active markets from exchanges, brokers or pricing services for similar contracts. NEE, through NEER, also enters into full requirements contracts, which, in most cases, meet the definition of derivatives and are measured at fair value. These contracts typically have one or more inputs that are not observable and are significant to the valuation of the contract. In addition, certain exchange and non-exchange traded derivative options at NEE have one or more significant inputs that are not observable, and are valued using industry-standard option models. In all cases where NEE and FPL use significant unobservable inputs for the valuation of a commodity contract, consideration is given to the assumptions that market participants would use in valuing the asset or liability. The primary input to the valuation models for commodity contracts is the forward commodity curve for the respective instruments. Other inputs include, but are not limited to, assumptions about market liquidity, volatility, correlation and contract duration as more fully described below in Significant Unobservable Inputs Used in Recurring Fair Value Measurements. In instances where the reference markets are deemed to be inactive or do not have transactions for a similar contract, the derivative assets and liabilities may be valued using significant other observable inputs and potentially significant unobservable inputs. In such instances, the valuation for these contracts is established using techniques including extrapolation from or interpolation between actively traded contracts, or estimated basis adjustments from liquid trading points. NEE and FPL regularly evaluate and validate the inputs used to determine fair value by a number of methods, consisting of various market price verification procedures, including the use of pricing services and multiple broker quotes to support the market price of the various commodities. In all cases where there are assumptions and models used to generate inputs for valuing derivative assets and liabilities, the review and verification of the assumptions, models and changes to the models are undertaken by individuals that are independent of those responsible for estimating fair value. NEE uses interest rate contracts and foreign currency contracts to mitigate and adjust interest rate and foreign currency exchange exposure related primarily to certain outstanding and expected future debt issuances and borrowings when deemed appropriate based on market conditions or when required by financing agreements. NEE estimates the fair value of these derivatives using an income approach based on a discounted cash flows valuation technique utilizing the net amount of estimated future cash inflows and outflows related to the agreements.