Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Buckthorn Solar Drop Down Asset [Member] Buckthorn Solar Drop Down Asset [Member] Buckthorn Solar Drop Down Asset [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Letter of Credit [Member] Letter of Credit [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] NRG Yield Revolving Credit Facility [Member] NRG Yield Revolving Credit Facility [Member] NRG Yield Revolving Credit Facility [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Line of Credit Facility, Fair Value of Amount Outstanding Line of Credit Facility, Fair Value of Amount Outstanding Proceeds from Issuance of Debt Proceeds from Issuance of Debt Letters of Credit Outstanding, Amount Letters of Credit Outstanding, Amount Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Maximum Borrowing Capacity Long-term Debt Long-term Debt Debt Instrument, Basis Spread on Variable Rate Debt Instrument, Basis Spread on Variable Rate Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage Accounting Policies [Abstract] Summary of Significant Accounting Policies [Table] Summary of Significant Accounting Policies [Table] Summary of Significant Accounting Policies [Table] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Energy Revenue [Member] Energy Revenue [Member] Energy Revenue [Member] Capacity Revenue [Member] Capacity Revenue [Member] Capacity Revenue [Member] Products And Services, Other [Member] Products And Services, Other [Member] Products And Services, Other [Member] Segments [Axis] Segments [Axis] Segment [Domain] Segments [Domain] Conventional Generation [Member] Conventional Generation [Member] Conventional Generation [Member] Renewables [Member] Renewables [Member] Renewables [Member] Thermal [Member] Thermal [Member] Represents Thermal segment of the entity. Receivable Type [Axis] Receivable Type [Axis] Receivable [Domain] Receivable [Domain] Customer Contracts [Member] Customer Contracts [Member] Lease Agreements [Member] Lease Agreements [Member] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Scenario, Previously Reported [Member] Scenario, Previously Reported [Member] November 2015 Drop Down Assets [Member] November 2015 Drop Down Assets [Member] November 2015 Drop Down Assets [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Common Class B [Member] Common Class B [Member] Common Class D [Member] Common Class D [Member] Common Class D [Member] Other Ownership Interests Name [Axis] Other Ownership Interests Name [Axis] Other Ownership Interests, Name [Domain] Other Ownership Interests, Name [Domain] Financial Institutions [Member] Financial Institutions [Member] Represents the information pertaining to the financial institutions. Summary of Significant Accounting Policies [Line Items] Summary of Significant Accounting Policies [Line Items] [Line Items] for Summary of Significant Accounting Policies [Table] Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Finite-Lived Intangible Assets, Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Stockholders' Equity Attributable to Noncontrolling Interest Stockholders' Equity Attributable to Noncontrolling Interest Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Capital contributions from tax equity investors, net of distributions Proceeds from Noncontrolling Interests Payment for the Buckthorn Solar Drop Down Asset Payments to Acquire Businesses, Gross Pre-acquisition net income of the Buckthorn Solar Drop Down Asset Less: Pre-acquisition net income of Acquired ROFO assets Less: Pre-acquisition net income of Acquired ROFO assets Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Distributions to NRG, net Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Distribution Made to Limited Liability Company (LLC) Member, Distributions Paid, Per Unit Distribution Made to Limited Liability Company (LLC) Member, Distributions Paid, Per Unit Dividends Payable, Date Declared Dividends Payable, Date Declared Common Stock, Dividends, Per Share, Declared Common Stock, Dividends, Per Share, Declared Dividends Payable, Date to be Paid Dividends Payable, Date to be Paid Dividends Payable, Date of Record Dividends Payable, Date of Record Revenue from Contract with Customer, Excluding Assessed Tax Revenue from Contract with Customer, Excluding Assessed Tax Capitalized Contract Cost, Amortization Capitalized Contract Cost, Amortization Total operating revenues Revenues Operating Leases, Income Statement, Contingent Revenue Operating Leases, Income Statement, Contingent Revenue Accounts Receivable, Net Accounts Receivable, Net Equity Method Investments and Joint Ventures [Abstract] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Equity Interest Type [Axis] Equity Interest Type [Axis] Equity Interest Issued or Issuable, Type [Domain] Equity Interest Issued or Issuable, Type [Domain] Capital Unit, Class A [Member] Capital Unit, Class A [Member] Capital Unit, Class B [Member] Capital Unit, Class B [Member] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] March 2017 Drop Down Assets [Member] March 2017 Drop Down Assets [Member] March 2017 Drop Down Assets [Member] Utah Portfolio [Member] Utah Portfolio [Member] Utah Portfolio [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Percentage of Ownership Percentage of Ownership Percentage of Ownership Taxable Income Allocation, Pre-Flip Taxable Income Allocation, Pre-Flip Taxable Income Allocation, Pre-Flip Taxable Income Allocation, Post-Flip Taxable Income Allocation, Post-Flip Taxable Income Allocation, Post-Flip Percentage of Cash Available for Distributions Percentage of Cash Available for Distributions Percentage of Cash Available for Distributions Fair Value Disclosures [Abstract] Estimated carrying values and fair values Fair Value, by Balance Sheet Grouping [Table Text Block] Fair Value, Option, Quantitative Disclosures [Table Text Block] Fair Value, Option, Quantitative Disclosures [Table Text Block] Schedule of Fair Value, Assets and Liabilities [Table Text Block] Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Earnings Per Share [Abstract] Earnings Per Share Earnings Per Share [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Net notional volume buy/(sell) of NRG Yield's open derivative transactions broken out by commodity Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Fair value within the derivative instrument valuation on the balance sheets Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position, Location [Table Text Block] Offsetting of derivatives by counterparty master agreement level and collateral received or paid Offsetting Liabilities [Table Text Block] Effects of NRG Yield's accumulated OCI balance attributable to interest rate swaps designated as cash flow hedge derivatives, net of tax Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) [Table Text Block] Segment Reporting [Abstract] Segment Reporting Segment Reporting Disclosure [Text Block] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Maximum [Member] Maximum [Member] NRG DGPV Holdco 2 [Member] NRG DGPV Holdco 2 [Member] NRG DGPV Holdco 2 [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] NRG [Member] NRG [Member] NRG [Member] Four Brothers Solar [Member] Four Brothers Solar [Member] Four Brothers Solar [Member] Granite Mountain Holdings [Member] Granite Mountain Holdings [Member] Granite Mountain Holdings [Member] Iron Springs Holdings [Member] Iron Springs Holdings [Member] Iron Springs Holdings [Member] Gen Conn Energy LLC [Member] Gen Conn Energy LLC [Member] Represents the information pertaining to GenConn Energy LLC. NRG DGPV Holdco 1 [Member] NRG DGPV Holdco 1 [Member] NRG DGPV Holdco 1 [Member] NRG RPV Holdco [Member] NRG RPV Holdco [Member] NRG RPV Holdco [Member] NRG DGPV Holdco 3 [Member] NRG DGPV Holdco 3 [Member] NRG DGPV Holdco 3 [Member] NRG DGPV Holdco [Member] NRG DGPV Holdco [Member] NRG DGPV Holdco [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Equity investments in affiliates Equity Method Investments Payments to Acquire Interest in Subsidiaries and Affiliates Payments to Acquire Interest in Subsidiaries and Affiliates Due to Affiliate Due to Affiliate Power Generation Capacity, Megawatts Power Generation Capacity, Megawatts The generation capacity of the entity's power generation facilities as of the balance sheet date, expressed in megawatts. Remaining Lease Term Remaining Lease Term Remaining Lease Term Operating revenues Operating Income (Loss) Operating Income (Loss) Net Income (Loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Assets, Current Assets, Current Assets, Noncurrent Assets, Noncurrent Liabilities, Current Liabilities, Current Liabilities, Noncurrent Liabilities, Noncurrent Redeemable Noncontrolling Interest, Equity, Carrying Amount Redeemable Noncontrolling Interest, Equity, Carrying Amount Long-term Debt Long-term Debt [Text Block] Income Statement [Abstract] Statement [Table] Statement [Table] Common Class C [Member] Common Class C [Member] Common Class A [Member] Common Class A [Member] Statement Statement [Line Items] Earnings Per Share, Basic Earnings Per Share, Basic Operating Revenues Revenues [Abstract] Operating Costs and Expenses Operating Costs and Expenses [Abstract] Cost of operations Cost of Revenue Depreciation and amortization Depreciation, Depletion and Amortization General and administrative General and Administrative Expense Acquisition-related transaction and integration costs Business Combination, Acquisition Related Costs Total operating costs and expenses Costs and Expenses Operating Income Other Income (Expense) Costs and Expenses [Abstract] Equity in earnings of unconsolidated affiliates Income (Loss) from Equity Method Investments Other income, net Other Nonoperating Income (Expense) Loss on debt extinguishment Gain (Loss) on Extinguishment of Debt Interest expense Interest Expense Total other expense, net Nonoperating Income (Expense) Loss Before Income Taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax benefit Income Tax Expense (Benefit) Net Loss Less: Pre-acquisition net income of Drop Down Assets Net Loss Excluding Pre-acquisition Net Income of Drop Down Assets Net Income excluding pre-acquisition net income of Acquired ROFO assets Net Income excluding pre-acquisition net income of Acquired ROFO assets Less: Loss attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Net Income (Loss) Attributable to NRG Yield, Inc. Net Income (Loss) Available to Common Stockholders, Basic Earnings (Loss) Per Share Attributable to NRG Yield, Inc. Class A and Class C Common Stockholders Weighted Average Number of Shares Outstanding, Basic and Diluted Weighted Average Number of Shares Outstanding, Basic and Diluted Earnings (Loss) per Weighted Average Class A and Class C Common Share - Basic and Diluted Earnings Per Share, Basic and Diluted Dividends Per Common Share, Cash Paid Common Stock, Dividends, Per Share, Cash Paid Business Acquisitions [Abstract] Business Acquisitions [Abstract] Mergers, Acquisitions and Dispositions Disclosures [Text Block] Mergers, Acquisitions and Dispositions Disclosures [Text Block] Statement of Comprehensive Income [Abstract] Net loss Other Comprehensive Gain, net of tax Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Unrealized gain on derivatives, net of income tax expense of $3 and $1 Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Other comprehensive gain Other Comprehensive Income (Loss), Net of Tax Comprehensive Income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Less: Comprehensive loss attributable to noncontrolling interests Comprehensive Income Attributable to NRG Yield, Inc. Comprehensive Income (Loss), Net of Tax, Attributable to Parent Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Central CA Fuel Cell 1 [Member] Central CA Fuel Cell 1 [Member] Central CA Fuel Cell 1 [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] Business Acquisition [Line Items] Business Acquisition [Line Items] Business Combination, Consideration Transferred Business Combination, Consideration Transferred Power Purchase Agreement Period Power Purchase Agreement Period Represents the period of power purchase agreement Commitments and Contingencies Disclosure [Abstract] Contingencies Disclosure [Text Block] Contingencies Disclosure [Text Block] Revenue Recognition, Policy [Policy Text Block] Revenue Recognition, Policy [Policy Text Block] Income Tax, Policy [Policy Text Block] Income Tax, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Noncontrolling Interest Disclosure [Text Block] Noncontrolling Interest Disclosure [Text Block] Distributions [Policy Text Block] Distributions [Policy Text Block] Distributions [Policy Text Block] Recent Accounting Developments New Accounting Pronouncements, Policy [Policy Text Block] Nature of Business Disclosure [Abstract] -- None. No documentation exists for this element. -- IPO of NRG Yield IPO of NRG Yield [Table Text Block] [Table Text Block] for IPO of NRG Yield [Table] Schedule of Ownership Schedule of Ownership Percentage, Net Capacity, Offtake Counterparty and Year of Offtake Expiration by Operating Asset [Table Text Block] Schedule of Ownership Percentage, Net Capacity, Offtake Counterparty and Year of Offtake Expiration by Operating Asset [Table Text Block] Unrealized gain/loss on derivatives, income tax expense /(benefit) Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Changes in Capital Structure [Abstract] Changes in Capital Structure [Abstract] Partners' Capital Notes Disclosure [Text Block] Partners' Capital Notes Disclosure [Text Block] Investments Accounted for by the Equity Method and Variable Interest Entities Equity Method Investments and Joint Ventures Disclosure [Text Block] Accounting for Derivative Instruments and Hedging Activities Derivative Instruments and Hedging Activities Disclosure [Text Block] November 2017 Drop Down Assets [Member] November 2017 Drop Down Assets [Member] November 2017 Drop Down Assets [Member] Schedule of Stock by Class [Table Text Block] Schedule of Stock by Class [Table Text Block] Dividends Declared [Table Text Block] Dividends Declared [Table Text Block] Agua Caliente Borrower 2 [Member] Agua Caliente Borrower 2 [Member] Agua Caliente Borrower 2 [Member] Equity Method Investment, Ownership Percentage Equity Method Investment, Ownership Percentage Percentage of NRG's Ownership Percentage of NRG's Ownership Percentage of NRG's Ownership Remaining Power Purchase Agreement term Remaining Power Purchase Agreement term Remaining Power Purchase Agreement term Business Acquisition, Consideration Transferred, Working Capital Business Acquisition, Consideration Transferred, Working Capital Business Acquisition, Consideration Transferred, Working Capital Non-Recourse Debt Non-Recourse Debt Business Combination, Separately Recognized Transactions, Net Gains and Losses Business Combination, Separately Recognized Transactions, Net Gains and Losses Derivative [Table] Derivative [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Derivative [Line Items] Derivative [Line Items] Accumulated Other Comprehensive Loss, Net of Tax Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax Accumulated Other Comprehensive Loss, Cumulative Change in Loss from Cash Flow Hedges, Tax Amount AOCI Including Portion Attributable to Noncontrolling Interest, Tax Reclassified from accumulated OCL to income due to realization of previously deferred amounts Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Mark-to-market of cash flow hedge accounting contracts Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Losses expected to be realized from OCL during the next 12 months, net of income tax benefit of $1 Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months Losses expected to be realized from OCL during the next 12 months, Tax Amount Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months, Tax The estimated tax impact of existing gains or losses on cash flow hedges, at the reporting date, which are expected to be reclassified to earnings within the next 12 months. Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net Related Party Transactions [Abstract] Document And Entity Information [Abstract] -- None. No documentation exists for this element. -- Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Current Fiscal Year End Date Current Fiscal Year End Date Entity Current Reporting Status Entity Current Reporting Status Entity Filer Category Entity Filer Category Entity Voluntary Filers Entity Voluntary Filers Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Class of Stock [Line Items] Class of Stock [Line Items] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Consolidated Entities [Member] Consolidated Entities [Member] Entities that are not consolidated [Member] Entities that are not consolidated [Member] Entities that are not consolidated [Member] Schedule of Variable Interest Entities [Table Text Block] Schedule of Variable Interest Entities [Table Text Block] Equity Method Investments [Table Text Block] Equity Method Investments [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Nature of Business [Table] Nature of Business [Table] Nature of Business [Table] Unconsolidated Solar Partnerships [Member] Unconsolidated Solar Partnerships [Member] Unconsolidated Solar Partnerships [Member] August 2017 Drop Down Assets [Member] August 2017 Drop Down Assets [Member] August 2017 Drop Down Assets [Member] Agua Caliente [Member] Agua Caliente [Member] Agua Caliente [Member] Long-term Contract for Purchase of Electric Power [Axis] Long-term Contract for Purchase of Electric Power [Axis] Long-term Contract for Purchase of Electric Power [Domain] Long-term Contract for Purchase of Electric Power [Domain] Southern California Edison [Member] Southern California Edison [Member] Southern California Edison [Member] Pacific Gas and Electric [Member] Pacific Gas and Electric [Member] Pacific Gas and Electric [Member] CVSR [Member] CVSR [Member] CVSR [Member] NRG Yield [Member] NRG Yield [Member] NRG Yield [Member] NRG Yield, Inc. [Member] NRG Yield, Inc. [Member] NRG Yield, Inc. [Member] NRG Yield LLC NRG Yield LLC [Member] NRG Yield LLC [Member] GenConn Middletown GenConn Middletown [Member] GenConn Middletown [Member] GenConn Devon [Member] GenConn Devon [Member] GenConn Devon [Member] Marsh Landing Marsh Landing [Member] Marsh Landing [Member] El Segundo [Member] El Segundo [Member] El Segundo [Member] Walnut Creek [Member] Walnut Creek [Member] Walnut Creek [Member] Alpine [Member] Alpine [Member] Alpine [Member] Avenal [Member] Avenal [Member] Avenal [Member] Avra Valley Avra Valley [Member] Avra Valley [Member] NRG Solar Blythe LLC [Member] NRG Solar Blythe LLC [Member] Represents NRG Solar Blythe LLC, a wholly-owned subsidiary of the entity. Borrego [Member] Borrego [Member] Borrego [Member] Desert Sunlight [Member] Desert Sunlight [Member] Desert Sunlight [Member] Kansas South [Member] Kansas South [Member] Kansas South [Member] Roadrunner NRG Solar Roadrunner LLC [Member] NRG Solar Roadrunner LLC [Member] TA - High Desert LLC [Member] TA - High Desert LLC [Member] TA - High Desert LLC [Member] AZ DG Solar Projects [Member] AZ DG Solar Projects [Member] AZ DG Solar Projects [Member] PFMG DG Solar Projects [Member] PFMG DG Solar Projects [Member] PFMG DG Solar Projects [Member] Alta I [Member] Alta I [Member] Alta I [Member] Alta II [Member] Alta II [Member] alta II [Member] Alta III [Member] Alta III [Member] Alta III Alta IV [Member] Alta IV [Member] Alta IV [Member] Alta V [Member] Alta V [Member] Alta V [Member] Alta X [Member] Alta X [Member] Alta X [Member] Alta XI [Member] Alta XI [Member] Alta XI [Member] South Trent South Trent Holding LLC [Member] South Trent Holding LLC [Member] Spanish Fork [Member] Spanish Fork [Member] Spanish Fork [Member] Spring Canyon II [Member] Spring Canyon II [Member] Spring Canyon II [Member] Laredo Ridge [Member] Laredo Ridge [Member] Laredo Ridge [Member] Lookout [Member] Lookout [Member] Lookout [Member] Odin Wind Farm [Member] Odin Wind Farm [Member] Odin Wind Farm [Member] Taloga [Member] Taloga [Member] Taloga [Member] Wildorado [Member] Wildorado [Member] Wildorado [Member] Pinnacle [Member] Pinnacle [Member] Pinnacle [Member] San Juan Mesa Wind Project, LLC [Member] San Juan Mesa Wind Project, LLC [Member] San Juan Mesa Wind Project, LLC [Member] Sleeping Bear [Member] Sleeping Bear [Member] Sleeping Bear [Member] Buffalo Bear [Member] Buffalo Bear [Member] Buffalo Bear [Member] Crosswinds [Member] Crosswinds [Member] Crosswinds [Member] Elbow Creek [Member] Elbow Creek [Member] Elbow Creek [Member] Elkhorn Ridge Wind, LLC [Member] Elkhorn Ridge Wind, LLC [Member] Elkhorn Ridge Wind, LLC [Member] Forward [Member] Forward [Member] Forward [Member] Goat Wind [Member] Goat Wind [Member] Goat Wind [Member] Hardin [Member] Hardin [Member] Hardin [Member] Spring Canyon [Member] Spring Canyon [Member] Spring Canyon [Member] Spring Canyon III [Member] Spring Canyon III [Member] Spring Canyon III [Member] NRG Energy Center Dover [Member] NRG Energy Center Dover [Member] NRG Energy Center Dover [Member] SPP Projects [Member] SPP Projects [Member] SPP Projects [Member] Other DG Assets [Member] Other DG Assets [Member] Other DG Assets [Member] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Power Generation Facilities by Type [Axis] Power Generation Facilities by Type [Axis] The types of power generation facilities included in the entity's total global generation portfolio. Power Generation Facilities, Type [Domain] Power Generation Facilities, Type [Domain] Listing of power generation facilities included in the entity's total global generation portfolio. Conventional Generation, Utility-Scale Solar, Distributed Solar, and Wind [Member] Conventional Generation, Utility-Scale Solar, Distributed Solar, and Wind [Member] Conventional Generation, Utility-Scale Solar, Distributed Solar, and Wind [Member] Utility-Scale Solar Utility-Scale Solar [Member] Utility-Scale Solar [Member] Distributed Solar [Member] Distributed Solar [Member] Distributed solar generation capacity. Wind Farms [Member] Wind Farms [Member] Wind farm generation capacity. Nature of Business Basis of Presentation [Line Items] Basis of Presentation [Line Items] Sale of Stock, Percentage of Ownership after Transaction Sale of Stock, Percentage of Ownership after Transaction Weighted Average Remaining PPA Term Weighted Average Remaining PPA Term Weighted Average Remaining PPA Term Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Voting Interest Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Voting Interest Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Voting Interest Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest Steam and Chilled Water Capacity, Megawatts Thermal Equivalent Steam and Chilled Water Capacity, Megawatts Thermal Equivalent The generation capacity of the entity's thermal power generation facilities as of the balance sheet date, expressed in megawatts thermal equivalent. Power Generation Capacity, Megawatts attributed to noncontrolling interest Power Generation Capacity, Megawatts attributed to noncontrolling interest Power Generation Capacity, Megawatts attributed to noncontrolling interest Power Generation Capacity, Megawatts, including portion attributable to noncontrolling interest Power Generation Capacity, Megawatts, including portion attributable to noncontrolling interest Power Generation Capacity, Megawatts, including portion attributable to noncontrolling interest Megawatts Thermal Equivalent, Available Under right-to-use Provisions Megawatts Thermal Equivalent, Available Under right-to-use Provisions Megawatts Thermal Equivalent, Available Under right-to-use Provisions Business Acquisitions, Purchase Price Equity [Abstract] Common Stock, Par or Stated Value Per Share Common Stock, Par or Stated Value Per Share ATM Program, Maximum Dollar Value of Shares to Be Issued ATM Program, Maximum Dollar Value of Shares to Be Issued ATM Program, Maximum Dollar Value of Shares to Be Issued Common Stock, Shares, Issued Sale of Stock, Number of Shares Issued in Transaction Proceeds from Issuance of Common Stock, Before Commission Fees Proceeds from Issuance of Common Stock, Before Commission Fees Proceeds from Issuance of Common Stock, Before Commission Fees Commission Fees Investment Banking, Advisory, Brokerage, and Underwriting Fees and Commissions ATM program, dollar value of shares remaining ATM program, dollar value of shares remaining ATM program, dollar value of shares remaining Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest Rate Contract [Member] Interest Rate Contract [Member] Interest Expense [Member] Interest Expense [Member] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Unrealized Gain (Loss) on Derivatives Unrealized Gain (Loss) on Derivatives Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Conventional Generation Corporate Corporate Segment [Member] Segment Reporting Segment Reporting Information [Line Items] Cost of operations Operating Expenses Equity in earnings of unconsolidated affiliates Other income, net Interest expense Income (loss) before income taxes Total Assets Assets Business Acquisition, Percentage of Voting Interests Acquired Business Acquisition, Percentage of Voting Interests Acquired Business Combination, Contingent Consideration, Liability Business Combination, Contingent Consideration, Liability Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Net Income (Loss) Available to Common Stockholders, Basic Income Tax Disclosure [Abstract] Reconciliation of the U.S. federal statutory rate to the Company's effective rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of Segment Reporting Information, by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Underlying Asset Class [Axis] Underlying Asset Class [Axis] Underlying Asset Class [Domain] Underlying Asset Class [Domain] Interest [Member] Interest [Member] Details pertaining to interest rate swaps which are considered a derivative commodity. Natural Gas [Member] Natural Gas [Member] Interest Rate Contract Current [Member] Interest Rate Contract Current [Member] The current portion of a derivative instrument whose primary underlying risk is tied to the right to receive or pay a sum of money at a given interest rate. Interest Rate Contract Non Current [Member] Interest Rate Contract Non Current [Member] The noncurrent portion of a derivative instrument whose primary underlying risk is tied to the right to receive or pay a sum of money at a given interest rate. Commodity Contract Current [Member] Commodity Contract Current [Member] The current portion of a derivative instrument whose primary underlying risk is tied to commodity prices. Commodity Contract Non Current [Member] Commodity Contract Non Current [Member] The noncurrent portion of a derivative instrument whose primary underlying risk is tied to commodity prices. Commodity Contract [Member] Commodity Contract [Member] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated as Hedging Instrument [Member] Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Measurement Unit [Axis] Measurement Unit [Axis] Represents information pertaining to various measurement units. Measurement Unit [Domain] Measurement Unit [Domain] Represents various measurement units used by the entity. MMbtu [Member] MMbtu [Member] Represents unit of measurement that is used to measure quantity of natural gas. United States of America, Dollars United States of America, Dollars Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Derivative, Notional Amount Derivative, Notional Amount Derivative Asset, Fair Value, Gross Asset Derivative Asset, Fair Value, Gross Asset Derivative Liability, Fair Value, Gross Liability Derivative Liability, Fair Value, Gross Liability Derivative Asset, Fair Value, Gross Liability Derivative Asset, Fair Value, Gross Liability Derivative Liability, Fair Value, Gross Asset Derivative Liability, Fair Value, Gross Asset Derivative Asset Derivative Asset Derivative Liability Derivative Liability Fair Value of Gross Derivative Assets/(Liabilities), Net Fair Value of Gross Derivative Assets/(Liabilities), Net Fair value of gross derivative assets less fair value of gross derivative liabilities. Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral Derivative, Collateral, Right to Reclaim Cash Derivative, Collateral, Right to Reclaim Cash Derivative, Collateral, Obligation to Return Cash Derivative, Collateral, Obligation to Return Cash Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Pro-Rate Share of Debt Held by Unconsolidated Affiliates Pro-Rate Share of Debt Held by Unconsolidated Affiliates Pro-Rate Share of Debt Held by Unconsolidated Affiliates Debt Instrument, Basis Spread on Libor Rate Debt Instrument, Basis Spread on Libor Rate Debt Instrument, Basis Spread on Libor Rate Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Derivative Assets (Liabilities), at Fair Value, Net Derivative Assets (Liabilities), at Fair Value, Net Statement of Financial Position [Abstract] Preferred Stock [Member] Preferred Stock [Member] Preferred Stock, Par or Stated Value Per Share Preferred Stock, Par or Stated Value Per Share Preferred Stock, Shares Authorized Preferred Stock, Shares Authorized Preferred Stock, Shares Issued Preferred Stock, Shares Issued Common Stock, Shares Authorized Common Stock, Shares Authorized Common Stock, Shares, Issued Common Stock, Shares, Issued Commitments and Contingencies Commitments and Contingencies Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Fair Value of Financial Instruments Fair Value Disclosures [Text Block] Schedule of long-term debt Schedule of Debt [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] 3.5% Convertible Notes due 2019 [Member] 3.5% Convertible Notes due 2019 [Member] 3.5% Convertible Notes due 2019 [Member] 3.25% Convertible Notes due 2020 [Member] 3.25% Convertible Notes due 2020 [Member] 3.25% Convertible Notes due 2020 [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Income Tax Contingency [Table] Income Tax Contingency [Table] Income Tax Disclosure Income Tax Contingency [Line Items] Income Tax Expense (Benefit), Continuing Operations [Abstract] Income Tax Expense (Benefit), Continuing Operations [Abstract] Loss before income taxes Effective income tax rate Effective Income Tax Rate Reconciliation, Percent U.S. federal statutory rate (as a percent) Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Related Party Transactions Disclosure Related Party Transactions Disclosure [Text Block] Alta X and XI TE Holdco [Member] Alta X and XI TE Holdco [Member] Alta X and XI TE Holdco [Member] Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value Other Assets Other Assets Property, Plant and Equipment, Net Property, Plant and Equipment, Net Intangible Assets Intangible Assets, Net (Excluding Goodwill) Liabilities Liabilities Noncontrolling Interest in Variable Interest Entity Noncontrolling Interest in Variable Interest Entity Net Assets Net Assets Income Taxes Income Tax Disclosure [Text Block] Fair Value, Concentration of Risk [Table] Fair Value, Concentration of Risk [Table] Other Comprehensive Income Location [Axis] Other Comprehensive Income Location [Axis] Other Comprehensive Income Location [Domain] Other Comprehensive Income Location [Domain] Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] Fair Value Assets, Valuation Techniques, Impact of Credit Reserve to Fair Value Fair Value Assets, Measured on Recurring Basis, Valuation Techniques, Impact of Credit Reserve to Fair Value This element represents the increase (decrease) to fair value from applying a credit reserve to reflect credit risk on the valuation techniques used to measure fair value of Level 2 and 3 derivative contracts which is calculated based on credit default swaps. Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure Estimated Counterparty Credit Risk Exposure to Certain Counterparties, Period Estimated Counterparty Credit Risk Exposure to Certain Counterparties, Period Estimated Counterparty Credit Risk Exposure to Certain Counterparties, Period ASSETS Assets [Abstract] Current Assets Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash Restricted Cash and Cash Equivalents, Current Accounts receivable — trade Accounts Receivable, Net, Current Inventory Inventory, Net Notes receivable Notes, Loans and Financing Receivable, Net, Current Prepayments and other current assets Prepaid Expense and Other Assets, Current Total current assets Property, plant and equipment, net Other Assets Assets, Noncurrent [Abstract] Intangible assets, net Finite-Lived Intangible Assets, Net Derivative instruments Derivative Asset, Noncurrent Deferred income taxes Deferred Tax Assets, Net, Noncurrent Other non-current assets Other Assets, Noncurrent Total other assets Total Assets LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities and Equity [Abstract] Current Liabilities Liabilities, Current [Abstract] Current portion of long-term debt Long-term Debt and Capital Lease Obligations, Current Accounts payable — trade Accounts Payable, Current Accounts payable — affiliate Due to Affiliate, Current Derivative instruments Derivative Liability, Current Accrued expenses and other current liabilities Other Accrued Liabilities, Current Total current liabilities Other Liabilities Liabilities, Noncurrent [Abstract] Long-term debt Long-term Debt and Capital Lease Obligations Derivative instruments Derivative Liability, Noncurrent Other non-current liabilities Other Liabilities, Noncurrent Total non-current liabilities Total Liabilities Stockholders' Equity Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, $0.01 par value; 10,000,000 shares authorized; none issued Preferred Stock, Value, Issued Class A, Class B, Class C and Class D common stock, $0.01 par value; 3,000,000,000 shares authorized (Class A 500,000,000, Class B 500,000,000, Class C 1,000,000,000, Class D 1,000,000,000); 185,407,326 shares issued and outstanding (Class A 34,586,250, Class B 42,738,750, Class C 65,343,576, Class D 42,738,750) at March 31, 2018 and 184,780,837 shares issued and outstanding (Class A 34,586,250, Class B 42,738,750, Class C 64,717,087, Class D 42,738,750) at December 31, 2017 Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Accumulated deficit Retained Earnings (Accumulated Deficit) Noncontrolling interest Total Stockholders' Equity Total Liabilities and Stockholders' Equity Liabilities and Equity Minimum [Member] Minimum [Member] 5.375% Senior Notes due in 2024 [Member] 5.375% Senior Notes due in 2024 [Member] 5.375% Senior Notes due in 2024 [Member] 5.00% Senior Notes due in 2026 [Member] 5.00% Senior Notes due in 2026 [Member] 5.00% Senior Notes due in 2026 [Member] Alta Wind Asset Management, due 2031 [Member] Alta Wind Asset Management, due 2031 [Member] Alta Wind Asset Management, due 2031 [Member] Alpine Financing Agreement, due 2022 [Member] Alpine Financing Agreement, due 2022 [Member] Alpine Financing Agreement, due 2022 [Member] Alta Wind I-V, lease financing arrangement, due 2034 and 2035 [Member] Alta Wind I-V, lease financing arrangement, due 2034 and 2035 [Member] Alta Wind I-V, lease financing arrangement, due 2034 and 2035 [Member] CVSR, due 2037 CVSR Financing Agreement [Member] CVSR Financing Agreement [Member] CVSR Holdco due 2037 [Member] CVSR Holdco due 2037 [Member] CVSR Holdco due 2037 [Member] El Segundo Energy Center, due 2023 West Holdings Credit Agreement [Member] West Holdings Credit Agreement [Member] El Segundo Energy Center due 2023 Tranche B [Member] West Holdings Credit Agreement due 2023 Tranche B [Member] West Holdings Credit Agreement due 2023 Tranche B [Member] El Segundo Energy Center due 2023 Tranche A [Member] West Holdings Credit Agreement due 2023 Tranche A [Member] West Holdings Credit Agreement due 2023 Tranche A [Member] Energy Center Minneapolis, due 2025 NRG Energy Center Minneapolis LLC Senior Secured Notes [Member] Represents senior secured notes financed by NRG Energy Center Minneapolis LLC, which are due 2013, 2017, and 2025. Energy Center Minneapolis Series D Notes, due 2031 NRG Energy Center Minneapolis Series D Notes [Member] NRG Energy Center Minneapolis Series D Notes [Member] Laredo Ridge Wind, LLC, due in 2026 [Member] Laredo Ridge Wind, LLC, due in 2026 [Member] Laredo Ridge Wind, LLC, due in 2026 [Member] Marsh Landing Term Loan Facility [Member] Marsh Landing Term Loan Facility [Member] Marsh Landing Term Loan Facility [Member] Marsh Landing Tranche B due 2023 [Member] Marsh Landing Tranche B due 2023 [Member] Marsh Landing Tranche B due 2023 [Member] Tapestry Wind LLC due in 2021 [Member] Tapestry Wind LLC due in 2021 [Member] Tapestry Wind LLC due in 2021 [Member] Utah Solar Portfolio, due 2022 [Member] Utah Solar Portfolio, due 2022 [Member] Utah Solar Portfolio, due 2022 [Member] Viento Funding II, Inc., due in 2023 [Member] Viento Funding II, Inc., due in 2023 [Member] Viento Funding II, Inc., due in 2023 [Member] Walnut Creek Energy, LLC, due in 2023 [Member] Walnut Creek Energy, LLC, due in 2023 [Member] Walnut Creek Energy, LLC, due in 2023 [Member] Other Debt [Member] Other Debt [Member] Represents other debt instruments not separately accounted disclosed. Project [Domain] Project [Domain] Senior Notes Senior Notes Current portion of long-term debt Debt Issuance Costs, Net Debt Issuance Costs, Net Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Long-term Debt, Excluding Current Maturities Long-term Debt, Excluding Current Maturities Debt Instrument, Description of Variable Rate Basis Debt Instrument, Description of Variable Rate Basis Debt Instrument, Unamortized Discount Debt Instrument, Unamortized Discount Statement of Cash Flows [Abstract] Cash Flows from Operating Activities Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Equity in earnings of unconsolidated affiliates Distributions from unconsolidated affiliates Proceeds from Equity Method Investment, Distribution Depreciation and amortization Depreciation, Amortization and Accretion, Net Amortization of financing costs and debt discounts Amortization of Debt Issuance Costs and Discounts Amortization of intangibles and out-of-market contracts Amortization of Intangibles and Out of Market Contracts The aggregate (income) expense recorded in earnings to allocate the cost of out-of-market contracts and intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash (income) expense, this element is added back to net income when calculating cash provided by (used in) operations using the indirect method. Adjustment for debt extinguishment Changes in deferred income taxes Increase (Decrease) in Income Taxes Changes in derivative instruments Increase (Decrease) in Derivative Assets and Liabilities Loss on disposal of asset components Gain (Loss) on Disposition of Property Plant Equipment Changes in prepaid and accrued liabilities for tolling agreements Changes in Prepaid and Accrued Capacity Payments Changes in Prepaid and Accrued Capacity Payments Changes in other working capital Increase (Decrease) in Other Operating Assets and Liabilities, Net Net Cash Provided by Operating Activities Net Cash Provided by (Used in) Operating Activities Cash Flows from Investing Activities Net Cash Provided by (Used in) Investing Activities [Abstract] Payments for the Drop Down Assets Payment to Acquire Business under Common Control Payment to Acquire Business under Common Control Capital expenditures Payments to Acquire Property, Plant, and Equipment Cash receipts from notes receivable Increase (Decrease) in Notes Receivables Return of investment from unconsolidated affiliates Proceeds from Equity Method Investment, Distribution, Return of Capital Investments in unconsolidated affiliates Payments to Acquire Businesses and Interest in Affiliates Payments for (Proceeds from) Other Investing Activities Payments for (Proceeds from) Other Investing Activities Net Cash Used in Investing Activities Net Cash Provided by (Used in) Investing Activities Cash Flows from Financing Activities Net Cash Provided by (Used in) Financing Activities [Abstract] Net contributions from noncontrolling interests Proceeds from (Payments to) Noncontrolling Interests Net distributions and return of capital to NRG prior to the acquisition of Drop Down Assets Payments of Capital Distribution Net proceeds from the issuance of common stock Proceeds from Issuance of Common Stock Payments of dividends and distributions Payments of Dividends Payments of debt issuance costs Payments of Debt Issuance Costs Proceeds from the revolving credit facility Proceeds from Lines of Credit Proceeds from the issuance of long-term debt Proceeds from Issuance of Long-term Debt Payments for long-term debt Repayments of Long-term Debt Net Cash Used in Financing Activities Net Cash Provided by (Used in) Financing Activities Net Decrease in Cash, Cash Equivalents and Restricted Cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Cash, Cash Equivalents and Restricted Cash at Beginning of Period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, Cash Equivalents and Restricted Cash at End of Period Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Debt, Long-term and Short-term, Combined Amount Debt, Long-term and Short-term, Combined Amount Other Liabilities Other Liabilities Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Operations and Maintenance services [Member] Operations and Maintenance services [Member] Operations and Maintenance services [Member] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Thermal [Member] GCE Holding LLC [Member] GCE Holding LLC [Member] Represents the GCE Holding LLC GCE Holding LLC which wholly-owns GenConn Energy LLC. Marsh Landing [Member] NECP [Member] NECP [Member] NECP [Member] NRG RENOM [Member] NRG RENOM [Member] NRG Renew Operations & Maintenance LLC Scenario, Plan [Member] Scenario, Plan [Member] Related Party Transaction Related Party Transaction [Line Items] Revenue from Related Parties Revenue from Related Parties Related Party Transaction, Expenses from Transactions with Related Party Related Party Transaction, Expenses from Transactions with Related Party Management Services Fee, Annual Service Management Costs Related Party Transaction, Amount to be Paid Upon Completion of Project Related Party Transaction, Amount to be Paid Upon Completion of Project Related Party Transaction, Amount to be Paid Upon Completion of Project November 2017 Drop Down Assets and August 2017 Drop Down Assets [Member] November 2017 Drop Down Assets and August 2017 Drop Down Assets [Member] November 2017 Drop Down Assets and August 2017 Drop Down Assets [Member] Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Business Acquisition, Pro Forma Information [Table Text Block] Business Acquisition, Pro Forma Information [Table Text Block] Segment Reporting, Policy [Policy Text Block] Segment Reporting, Policy [Policy Text Block] Schedule of Accumulated Depreciation and Amortization [Table Text Block] Schedule of Accumulated Depreciation and Amortization [Table Text Block] Schedule of Accumulated Depreciation and Amortization [Table Text Block] Schedule of Change in Noncontrolling Interest [Table Text Block] Schedule of Change in Noncontrolling Interest [Table Text Block] Schedule of Change in Noncontrolling Interest [Table Text Block] Distributions Made to Limited Liability Company (LLC) Member, by Distribution [Table Text Block] Distributions Made to Limited Liability Company (LLC) Member, by Distribution [Table Text Block] Disaggregation of Revenue [Table Text Block] Disaggregation of Revenue [Table Text Block] Contract with Customer, Asset and Liability [Table Text Block] Contract with Customer, Asset and Liability [Table Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Estimate of Fair Value Measurement [Member] Estimate of Fair Value Measurement [Member] Reported Value Measurement [Member] Reported Value Measurement [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Financing Receivable, Net Financing Receivable, Net Long-term Debt and Capital Lease Obligations, Including Current Maturities Long-term Debt and Capital Lease Obligations, Including Current Maturities Nature of Business Business Description and Basis of Presentation [Text Block]