| Summary of Significant Accounting and Reporting Policies | Summary of Significant Accounting and Reporting Policies Basis of Presentation - NEP’s consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the U.S., or GAAP. The consolidated financial statements include NEP’s accounts and operations and those of its subsidiaries in which NEP has a controlling interest. The acquisitions from NEER in 2016 and 2017 described in Note 3 (the common control acquisitions) were a transfer of assets between entities under common control, which required them to be accounted for as if the transfers occurred since the inception of common control, with prior periods retrospectively adjusted to furnish comparative information. Accordingly, the consolidated financial statements were retrospectively adjusted to include the historical results of the common control acquisitions prior to their respective acquisition dates. Adjustments related to the historical results of the common control acquisitions were attributable to noncontrolling interests for all periods prior to the date the project was acquired by NEP. All intercompany transactions have been eliminated in consolidation. Certain amounts included in prior years' consolidated financial statements have been reclassified to conform to the current year's presentation. The preparation of financial statements requires the use of estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates. Disposal of Canadian Holdings - In June 2018, a subsidiary of NEP completed the sale of NextEra Energy Canada Partners Holdings, ULC and subsidiaries (Canadian Holdings) for cash proceeds of approximately CAD $740 million (USD $563 million at June 29, 2018), subject to post-closing working capital adjustments of approximately $1 million . In addition, the purchaser assumed approximately $676 million of existing debt. Canadian Holdings owned four wind generation facilities and two solar generation facilities located in Ontario, Canada with a generating capacity totaling approximately 396 megawatts (MW). NEP recognized a gain of approximately $153 million ( $201 million after tax). Income before income taxes associated with Canadian Holdings, excluding the financial statement impacts resulting from the sale in 2018, was approximately $47 million , $68 million and $43 million for the years ended December 31, 2018, 2017 and 2016, respectively. Revenue Recognition - R evenue is generated primarily from various non-affiliated parties under long-term power purchase agreements, and prior to the sale of Canadian Holdings in 2018, Feed-in-Tariff agreements and Renewable Energy Standard Offer Program agreements (collectively, PPAs), and natural gas transportation agreements. Revenue is recognized as energy and any related renewable energy attributes are delivered, which is when revenue is earned based on energy delivered at rates stipulated in the respective PPAs, or natural gas transportation services are performed. See Note 4 . In 2018 , 2017 and 2016 approximately $234 million , $275 million and $265 million , respectively, of NEP's consolidated revenues were attributable to foreign countries, primarily related to its Canadian operations and its contract with a Mexican counterparty. Income Taxes - For periods through December 31, 2017, when NEP acquired a NEER project, income taxes were calculated on the predecessor method using the separate return method applied to the group of renewable energy projects acquired. As a result of the governance changes discussed in Note 3 , beginning in January 2018, acquisitions from NEER are no longer treated as common control acquisitions, and income taxes are calculated on the successor method under which taxes are calculated for NEP as a single taxpaying corporation for U.S. federal and state income taxes (based on its election to be taxed as a corporation). Because NEP OpCo is a limited partnership, NEP only recognizes in income its applicable ownership share of U.S. income taxes related to the U.S. projects and, prior to the sale of Canadian Holdings, the Canadian projects. NEP's former Canadian subsidiaries were all Canadian taxpayers, and therefore NEP recognized in income all of the Canadian taxes. Income taxes include NEP's applicable ownership share of U.S. taxes and 100% of Canadian taxes. Net income or loss attributable to noncontrolling interests includes no U.S. taxes and NEER's applicable ownership share of Canadian taxes. Net income attributable to NEP includes NEP's applicable ownership share of U.S. and Canadian taxes. Foreign Operations and Currency Translation - NEP’s reporting currency is the U.S. dollar. Prior to the disposal of Canadian Holdings, the functional currency for the Canadian project companies was the Canadian dollar because Canada was the primary economic environment in which they conducted their Canadian operations. The assets and liabilities of the Canadian project companies were translated to U.S. dollars at exchange rates at the balance sheet date. The income and expenses of the Canadian project companies were translated to U.S. dollars at exchange rates in effect during each respective period. The translation adjustment was recorded in accumulated other comprehensive income (loss) (AOCI). Differential Membership Interests - Prior to being acquired by NEP, certain subsidiaries of NEER sold Class B membership interests in entities that have ownership interests in 20 wind projects to third-party investors. Although the third-party investors own equity interests in the wind projects, NEP retains a controlling interest in the entities and therefore presents the Class B member interests as noncontrolling interests. Noncontrolling interests represents the portion of net assets in consolidated entities that are not owned by NEP and are reported as a component of equity in NEP’s consolidated balance sheet. The third-party investors are allocated earnings, tax attributes and cash flows in accordance with the respective limited liability company agreements. Those economics are allocated primarily to the third-party investors until they receive a targeted return (the flip date) and thereafter to NEP. NEP has the unilateral right to call the third-party interests at specified amounts if and when the flip date occurs. NEP has determined the allocation of economics between the controlling party and third-party investor should not follow the respective ownership percentages for each wind project but rather the hypothetical liquidation of book value (HLBV) method based on the governing provisions in each respective limited liability company agreement. Under the HLBV method, the amounts of income and loss attributable to the noncontrolling interests reflects changes in the amount the owners would hypothetically receive at each balance sheet date under the respective liquidation provisions, assuming the net assets of these entities were liquidated at the recorded amounts, after taking into account any capital transactions, such as contributions and distributions, between the entities and the owners. At the point in time that the third-party, in hypothetical liquidation, would achieve its targeted return, NEP attributes the additional hypothetical proceeds to the Class B membership interests based on the call price. A loss attributable to noncontrolling interests on NEP’s consolidated statements of income represents earnings attributable to NEP. Effective January 1, 2018, NEP adopted an accounting standards update regarding the accounting for partial sales of nonfinancial assets using the modified retrospective approach. This standards update affects the accounting and related financial statement presentation for the sales of differential membership interests. The primary impact of adopting the standards update was an increase to noncontrolling interests which includes the reclassification of the $1,442 million liability reflected as deferral related to differential membership interests on NEP's consolidated balance sheets at December 31, 2017. See the consolidated statements of changes in equity. During 2018, approximately $139 million of income related to the differential membership interests was reflected as net loss attributable to noncontrolling interests in NEP's consolidated statements of income as the third-party investors received their portion of the economic attributes of the related facilities. Additionally, net loss attributable to noncontrolling interests for the year ended December 31, 2018 includes approximately $231 million ( $211 million after tax) related to the reduction of differential membership interests as a result of the change in federal corporate income tax rates effective January 1, 2018. Prior to 2018, the proceeds received on the sale of the Class B membership interests were deferred and recorded as a liability in deferral related to differential membership interests on NEP's consolidated balance sheets. At December 31, 2017 , this liability included approximately $8 million of deferred financing costs, net of accumulated amortization. The deferred amount was being recognized in benefits associated with differential membership interests - net in NEP's consolidated statements of income as the third-party investors received their portion of the economic attributes. NEP operates and manages the 20 wind projects, and consolidates the entities that directly and indirectly own the 20 wind projects. Equity - Equity reflects the financial position of the parties with an ownership interest in the consolidated financial statements. NextEra Energy Partners GP, Inc. has a total equity interest in NEP of $10,000 at December 31, 2018 and 2017 . Limited partners' equity in common units at December 31, 2018 and 2017 reflects the investment of NEP common unitholders, changes to net income attributable to NEP, distributions of available cash to common unitholders and other contributions from or distributions to NEP common unitholders. Accumulated other comprehensive income (loss) at December 31, 2018 and 2017 reflects comprehensive income attributable to NEP. Noncontrolling Interests - At December 31, 2018 , NEE's 64.4% noncontrolling interest in NEP OpCo, a non-affiliated party's 10% interest in one of the Texas pipelines, the interests related to differential membership interests discussed above and the Class B noncontrolling interest in NEP Renewables, LLC (NEP Renewables) sold in 2018 (see Note 11 - Equity) are reflected as noncontrolling interests on the consolidated balance sheets. Distributions related to NEE's noncontrolling interest are reflected as Partners/Members' distributions in the consolidated statements of cash flows. Details of the activity in noncontrolling interests for the year ended December 31, 2018 is below: Noncontrolling Ownership Interest in NEP OpCo Subsidiary (a) Differential Membership Interests Noncontrolling Ownership Interests in NEP OpCo and Texas pipeline Total Noncontrolling (millions) Balances, December 31, 2017 $ — $ — $ 34 $ 34 Sale of noncontrolling interest in a NEP OpCo subsidiary 750 — — $ 750 Acquisition of subsidiaries with differential membership interests — 941 — $ 941 Related party note receivable — — 31 $ 31 Net income (loss) attributable to noncontrolling interests 1 (370 ) (b) 444 $ 75 Other comprehensive income — — 12 $ 12 Related party contributions — — 4 $ 4 Related party distributions — — (204 ) $ (204 ) Changes in non-economic ownership interests and equity method investee — — (7 ) $ (7 ) Differential membership investment contributions, net of distributions — 35 — $ 35 Disposal of Canadian Holdings — — 105 $ 105 Adoption of accounting standards update — 1,413 3 $ 1,416 Balances, December 31, 2018 $ 751 $ 2,019 $ 422 $ 3,192 ____________________ (a) See Note 10 and Note 11 - Equity for additional information about the sale of a noncontrolling Class B ownership interest in NEP Renewables. (b) Represents the benefits associated with differential membership interests recognized as the third-party investors received their portion of the economic attributes of the related facilities. Approximately $240 million of the loss attributable to differential membership interests benefits NEE's noncontrolling interest and $130 million is reflected as net income attributable to NEP. Property, Plant and Equipment - net - Property, plant and equipment consists primarily of development, engineering and construction costs for the renewable energy assets, equipment, land, substations, transmission lines and pipeline facilities. Property, plant and equipment, excluding land and perpetual rights-of-way, is recorded at cost and depreciated on a straight-line basis over the estimated useful lives ranging from three to 50 years , commencing on the date the assets are placed in service or acquired. See Note 8 . Maintenance and repairs of property, plant and equipment are charged to O&M expense as incurred. Property, plant and equipment - net on the consolidated balance sheets includes construction work in progress which reflects construction materials, other equipment, third-party engineering costs, capitalized interest and other costs directly associated with the development and construction of the various projects. There was no interest capitalized in 2018 and 2017 . Interest capitalized for the year ended 2016 was approximately $7 million . Upon commencement of plant or pipeline operations, costs associated with construction work in progress are transferred to the appropriate category in property, plant and equipment - net. Convertible investment tax credits (CITCs) of approximately $703 million and $707 million at December 31, 2018 and 2017 , respectively, are recorded as a reduction in property, plant and equipment - net on the consolidated balance sheets and are amortized as a corresponding reduction to depreciation expense over the estimated life of the related asset. Total net long-lived assets, including construction work in progress, held by operations located in Canada amounted to approximately $912 million at December 31, 2017 . Cash and Cash Equivalents - Cash equivalents consist of short-term, highly liquid investments with original maturities of three months or less. NEP primarily holds such investments in money market funds. Accounts Receivable and Allowance for Doubtful Accounts - Accounts receivable are reported at the invoiced or estimated amount adjusted for any write-offs and any estimated allowance for doubtful accounts on the consolidated balance sheets. The allowance for doubtful accounts is reviewed periodically based on amounts past due and significance. There was no allowance for doubtful accounts recorded at December 31, 2018 and 2017 . Restricted Cash - Current restricted cash on NEP's consolidated balance sheets and approximately $11 million and $19 million of other non-current assets on NEP's consolidated balance sheets at December 31, 2018 and 2017 , respectively, are held by certain subsidiaries to pay for certain capital or operating expenditures, as well as to fund required equity contributions pursuant to restrictions contained in the subsidiaries' debt agreements. Restricted cash reported as current assets are recorded as such based on the anticipated use of these funds. Concentration of Credit Risk - Financial instruments which potentially subject NEP to concentrations of credit risk consist primarily of accounts receivable and derivative instruments. Accounts receivable are comprised primarily of amounts due from various non-affiliated parties who are counterparties to the PPAs or natural gas transportation agreements. NEP has a limited number of counterparties, the majority of which are in the energy industry, and this concentration may impact the overall exposure to credit risk, either positively or negatively, in that the counterparties may be similarly affected by changes in economic, industry or other conditions. If any of these customers’ receivable balances should be deemed uncollectible, it could have a material adverse effect on NEP’s consolidated results of operations and financial condition. Substantially all amounts due from such counterparties at December 31, 2018 have been collected. During 2018 , NEP derived approximately 18% and 18% of its consolidated revenue from its contracts with Pacific Gas and Electric Company (PG&E) and Mex Gas Supply S.L., respectively. See Note 15 - PG&E Bankruptcy. Inventories - Spare parts inventories are carried at the lower of weighted-average cost and net realizable value and are included in other current assets on NEP’s consolidated balance sheets. Spare parts inventories were approximately $19 million and $21 million at December 31, 2018 and 2017 , respectively. Impairment of Long-Lived Assets and Finite-Lived Intangible Assets - Long-lived assets that are held and used and finite-lived intangible assets are reviewed for impairment when events or changes in circumstances indicate that the carrying amount may not be recoverable. An impairment loss is required to be recognized if the carrying value of the asset exceeds the undiscounted future net cash flows associated with that asset. The impairment loss to be recognized is the amount by which the carrying value of the asset exceeds the asset's fair value. In most instances, the fair value is determined by discounting estimated future cash flows using an appropriate interest rate. During the years ended December 31, 2018 and 2017 , no impairment adjustments were necessary. Business Combinations - For projects acquired in a business combination, NEP allocates the cost of the acquisition to assets acquired and liabilities assumed based on fair values as of the acquisition date. Goodwill acquired in connection with business combinations represents the excess of consideration over the fair value of net assets acquired. Certain assumptions and estimates are employed in determining the fair value of assets acquired and evaluating the fair value of liabilities assumed. See Note 3 . Effective January 1, 2018, NEP 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. NEP adopted this guidance on a prospective basis effective January 1, 2018. Goodwill and Indefinite-Lived Intangible Assets - Goodwill and indefinite-lived intangible assets are assessed for impairment at least annually by applying a fair value-based analysis. NEP completed the annual impairment test for goodwill and indefinite-lived intangibles using an assessment date of October 1 and determined, based on the results, that no goodwill impairment charge was required. As a result of the sale of Canadian Holdings discussed above, goodwill was reduced by approximately $44 million during 2018. Intangible Asset - Customer Relationships - At December 31, 2018 and 2017 , NEP's consolidated balance sheets reflect intangible asset - customer relationships related to the acquisition of the Texas pipelines in 2015. Intangible asset - customer relationships are amortized on a straight-line basis over the estimated useful life of approximately 40 years . For the years ended December 31, 2018 , 2017 and 2016 amortization expense was approximately $17 million , $17 million and $18 million , respectively, and is expected to be approximately $17 million in each of the next five years. Intangible Asset - PPAs - At December 31, 2018 and 2017 , NEP's consolidated balance sheets reflect intangible asset - PPAs primarily related to the acquisition from NEER in 2018 (see Note 3 ). Intangible asset - PPAs are amortized into operating revenues on a straight-line basis over the remaining contract terms of the related PPAs. At December 31, 2018 , amortization of the intangible asset - PPAs is expected to be approximately $35 million in each of the next five years. Derivative Instruments and Hedging Activities - Derivative instruments, when required to be marked to market, are recorded on NEP’s consolidated balance sheets as either an asset or a liability measured at fair value. See Note 7 . Fair Value Measurements - NEP uses 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 or comparable assets and liabilities for those assets and liabilities that are measured on a recurring basis. Certain financial instruments may be valued using multiple inputs including discount rates, counterparty credit ratings and credit enhancements. NEP’s assessment of the significance of any particular input to the fair value measurement requires judgment and may affect the fair value measurement of its assets and liabilities and the placement of those assets and liabilities within the fair value hierarchy levels. See Note 6 . Long-term Debt Costs - NEP recognizes interest expense using the effective interest method over the life of the related debt. Certain of NEP’s debt obligations include escalating interest rates that are incorporated into the effective interest rate for the related debt. Deferred interest includes interest expense recognized in excess of the interest payments accrued for the related debt’s stated interest payments and is recorded in other non-current liabilities on NEP’s consolidated balance sheets. Debt issuance costs include fees and costs incurred to obtain long-term debt and are amortized over the life of the related debt using the effective interest rate established at debt issuance. NEP incurred approximately $24 million of debt issuance costs during the year ended December 31, 2017 . The amortization of debt issuance costs totaled approximately $12 million , $11 million and $9 million for the years ended December 31, 2018 , 2017 and 2016 , respectively, and is included in interest expense in NEP’s consolidated statements of income. See Note 11 - Debt. Asset Retirement Obligations - Asset retirement obligations are those for which a legal obligation exists under laws, statutes, and written or oral contracts, including obligations arising under the doctrine of promissory estoppel, and for which the timing or method of settlement may be conditioned on a future event. NEP accounts for asset retirement obligations and conditional asset retirement obligations (collectively, AROs) under accounting guidance that requires a liability for the fair value of an ARO to be recognized in the period in which it is incurred if it can be reasonably estimated, with the offsetting associated asset retirement costs capitalized as part of the carrying amount of the long-lived asset. The asset retirement cost is subsequently allocated to expense using a systematic and rational method over the asset’s estimated useful life. Changes in the ARO resulting from the passage of time are recognized as an increase in the carrying amount of the liability and as accretion expense, which is included in depreciation and amortization expense in NEP’s consolidated statements of income. Changes resulting from revisions to the timing or amount of the original estimate of cash flows are recognized as an increase or a decrease in the asset retirement cost, or income when the asset retirement cost is depleted. NEP recorded accretion expense of approximately $4 million in each of the years ended December 31, 2018 , 2017 and 2016 . Additional AROs were established amounting to approximately $24 million in 2018 related to the acquisition of NEP Renewables (see Note 3 ), partly offset by a decrease of $13 million related to the sale of Canadian Holdings . Investments in Unconsolidated Entities - NEP accounts for the investments in its unconsolidated entities under the equity method. NEP’s share of earnings (losses) in the unconsolidated entities is included in equity in earnings (losses) of non-economic ownership interests and equity in earnings of equity method investee in the consolidated statements of income. NEP records losses of the unconsolidated entities only to the extent of its investment. All equity in earnings (losses) of the non-economic ownership interests is allocated to net income attributable to noncontrolling interests. See Note 9 and Note 10 . Variable Interest Entities (VIEs) - An entity is considered to be a VIE when its total equity investment at risk is not sufficient to permit the entity to finance its activities without additional subordinated financial support, or its equity investors, as a group, lack the characteristics of having a controlling financial interest. A reporting company is required to consolidate a VIE as its primary beneficiary when it has both the power to direct the activities of the VIE that most significantly impact the VIE's economic performance, and the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE. NEP evaluates whether an entity is a VIE whenever reconsideration events as defined by the accounting guidance occur. See Note 10 . Leases - During the fourth quarter of 2018, NEP elected to early adopt an accounting standards update which requires, among other things, that lessees recognize a right-of-use asset and a lease liability for all leases (new lease standard). Certain amounts included in prior years' consolidated financial statements have been retrospectively adjusted for the new lease standard. See Note 14 . |
