Summary of Significant Accounting and Reporting Policies (Policies)	3 Months Ended
Mar. 31, 2018
Accounting Policies [Abstract]
Recently Issued Accounting Guidance	Effective January 1, 2018, NEP 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. NEP adopted the new revenue standard using the modified retrospective approach applying it only to contracts that were not complete at January 1, 2018. NEP did not recognize a cumulative effect adjustment on January 1, 2018 because revenue recognized under the new accounting standard remained consistent with historical practice. NEP's operating revenues are generated primarily from various non-affiliated parties under long-term power purchase agreements, FIT agreements and RESOP agreements (collectively, PPAs) and natural gas transportation agreements. Revenue is recognized as energy and any related renewable energy attributes are delivered, based on rates stipulated in the respective PPAs, or natural gas transportation services are performed. NEP believes that the obligation to deliver energy and provide the natural gas transportation services is satisfied over time as the customer simultaneously receives and consumes benefits provided by NEP. In addition, NEP believes that the obligation to deliver renewable energy attributes is satisfied at multiple points in time, with the control of the renewable energy attribute being transferred at the same time the related energy is delivered. Substantially all of the PPAs are accounted for as operating leases and are not considered contracts with customers within the scope of the new revenue standard. Summary of Significant Accounting and Reporting Policies Restricted Cash - In the fourth quarter of 2017, NEP 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 condensed consolidated statements of cash flows. NEP adopted the standards update retrospectively, which adoption did not have a material impact to the condensed consolidated statements of cash flows. Current restricted cash on NEP's condensed consolidated balance sheets and approximately $20 million and $19 million of other non-current assets on NEP's condensed consolidated balance sheets at March 31, 2018 and December 31, 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. Assets and Liabilities Associated with Assets Held for Sale - In March 2018, a subsidiary of NEP entered into an agreement to sell its indirect ownership interest in four wind generation facilities and two solar generation facilities located in Ontario, Canada with a generating capacity totaling approximately 396 MW. The transaction is expected to close in the second quarter of 2018, pending the receipt of necessary regulatory approvals and satisfaction of other customary closing conditions. The carrying amounts of the major classes of assets and liabilities related to the facilities that were classified as held for sale on NEP's condensed consolidated balance sheets primarily represent property, plant and equipment and the related long-term debt. Accounting for Partial Sales of Nonfinancial Assets - 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 to third-party investors. 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 condensed consolidated balance sheets at December 31, 2017. See the condensed consolidated statements of changes in equity. During the three months ended March 31, 2018, approximately $38 million was recorded as net loss attributable to noncontrolling interests in NEP's condensed consolidated statements of income as the third-party investors received their portion of the economic attributes of the related facilities. Prior to the adoption, the income related to differential membership interests was being recognized in benefits associated with differential membership interests - net in NEP's condensed consolidated statements of income. Additionally, net loss attributable to noncontrolling interests for the three months ended March 31, 2018 includes approximately $231 million (after-tax $211 million) related to the reduction of differential membership interests as a result of the change in federal corporate income tax rates effective January 1, 2018. Noncontrolling Interests - At March 31, 2018 and December 31, 2017, NEP's limited partner interest in NEP OpCo was approximately 34.9%. At March 31, 2018, NEE's 65.1% noncontrolling interest in NEP OpCo, a non-affiliated party's 10% interest in one of the Texas pipelines and the interests related to differential membership interests discussed above are reflected as noncontrolling interests on the condensed consolidated balance sheets. For the three months ended March 31, 2018, the net income attributable to NEE's noncontrolling interest and to the non-affiliated party's 10% interest reduced the net income attributable to NEP unitholders. Additionally, the net loss attributable to differential membership interests increased the net income attributable to NEP unitholders and the net income attributable to NEE's noncontrolling interest. The net impact of the noncontrolling interests is reflected as net (income) loss attributable to noncontrolling interests in the condensed consolidated statements of income. Leases - In February 2016, the Financial Accounting Standards Board (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 NEP beginning January 1, 2019. Early adoption is permitted. NEP is currently reviewing its 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 its consolidated financial statements. NEP is implementing a number of system enhancements to facilitate the identification, tracking and reporting of leases based upon the requirements of the new lease standard. NEP is continuing to assess the transition options and practical expedients and monitoring industry implementation issues.

Effective January 1, 2018, NEP 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. NEP adopted the new revenue standard using the modified retrospective approach applying it only to contracts that were not complete at January 1, 2018. NEP did not recognize a cumulative effect adjustment on January 1, 2018 because revenue recognized under the new accounting standard remained consistent with historical practice.

NEP's operating revenues are generated primarily from various non-affiliated parties under long-term power purchase agreements, FIT agreements and RESOP agreements (collectively, PPAs) and natural gas transportation agreements. Revenue is recognized as energy and any related renewable energy attributes are delivered, based on rates stipulated in the respective PPAs, or natural gas transportation services are performed. NEP believes that the obligation to deliver energy and provide the natural gas transportation services is satisfied over time as the customer simultaneously receives and consumes benefits provided by NEP. In addition, NEP believes that the obligation to deliver renewable energy attributes is satisfied at multiple points in time, with the control of the renewable energy attribute being transferred at the same time the related energy is delivered. Substantially all of the PPAs are accounted for as operating leases and are not considered contracts with customers within the scope of the new revenue standard.

Summary of Significant Accounting and Reporting Policies

Restricted Cash - In the fourth quarter of 2017, NEP 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 condensed consolidated statements of cash flows. NEP adopted the standards update retrospectively, which adoption did not have a material impact to the condensed consolidated statements of cash flows.

Current restricted cash on NEP's condensed consolidated balance sheets and approximately $20 million and $19 million of other non-current assets on NEP's condensed consolidated balance sheets at March 31, 2018 and December 31, 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.

Assets and Liabilities Associated with Assets Held for Sale - In March 2018, a subsidiary of NEP entered into an agreement to sell its indirect ownership interest in four wind generation facilities and two solar generation facilities located in Ontario, Canada with a generating capacity totaling approximately 396 MW. The transaction is expected to close in the second quarter of 2018, pending the receipt of necessary regulatory approvals and satisfaction of other customary closing conditions. The carrying amounts of the major classes of assets and liabilities related to the facilities that were classified as held for sale on NEP's condensed consolidated balance sheets primarily represent property, plant and equipment and the related long-term debt.

Accounting for Partial Sales of Nonfinancial Assets - 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 to third-party investors. 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 condensed consolidated balance sheets at December 31, 2017. See the condensed consolidated statements of changes in equity. During the three months ended March 31, 2018, approximately $38 million was recorded as net loss attributable to noncontrolling interests in NEP's condensed consolidated statements of income as the third-party investors received their portion of the economic attributes of the related facilities. Prior to the adoption, the income related to differential membership interests was being recognized in benefits associated with differential membership interests - net in NEP's condensed consolidated statements of income. Additionally, net loss attributable to noncontrolling interests for the three months ended March 31, 2018 includes approximately $231 million (after-tax $211 million) related to the reduction of differential membership interests as a result of the change in federal corporate income tax rates effective January 1, 2018.

Noncontrolling Interests - At March 31, 2018 and December 31, 2017, NEP's limited partner interest in NEP OpCo was approximately 34.9%. At March 31, 2018, NEE's 65.1% noncontrolling interest in NEP OpCo, a non-affiliated party's 10% interest in one of the Texas pipelines and the interests related to differential membership interests discussed above are reflected as noncontrolling interests on the condensed consolidated balance sheets. For the three months ended March 31, 2018, the net income attributable to NEE's noncontrolling interest and to the non-affiliated party's 10% interest reduced the net income attributable to NEP unitholders. Additionally, the net loss attributable to differential membership interests increased the net income attributable to NEP unitholders and the net income attributable to NEE's noncontrolling interest. The net impact of the noncontrolling interests is reflected as net (income) loss attributable to noncontrolling interests in the condensed consolidated statements of income.

Leases - In February 2016, the Financial Accounting Standards Board (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 NEP beginning January 1, 2019. Early adoption is permitted.

NEP is currently reviewing its 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 its consolidated financial statements. NEP is implementing a number of system enhancements to facilitate the identification, tracking and reporting of leases based upon the requirements of the new lease standard. NEP is continuing to assess the transition options and practical expedients and monitoring industry implementation issues.