XML 112 R96.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Asset Impairments (Details) - USD ($) |  |  | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | --- | ---
Jun. 29, 2018 | May 12, 2016 | Dec. 31, 2018 | Jun. 30, 2018 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Feb. 20, 2019 | Mar. 31, 2016
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses |  |  |  |  |  |  |  | $ 99,000,000 | $ 1,534,000,000 | $ 483,000,000 |  |
Equity method investments |  |  | $ 412,000,000 |  |  |  |  | 412,000,000 | 182,000,000 |  |  |
Impairment losses on investments |  |  |  |  |  |  |  | 15,000,000 | 79,000,000 | 268,000,000 |  |
Emission Allowances |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses |  |  |  |  |  |  |  |  | 20,000,000 | 0 |  |
Other |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses |  |  |  |  |  |  |  |  |  | 29,000,000 |  |
Other Intangible Assets |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses |  |  |  |  |  |  |  |  |  | 0 |  |
Solar Panels |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses |  |  |  |  |  |  | $ 0 |  |  |  |  |
Other Investments |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses |  |  |  |  |  |  |  |  |  | 0 |  |
Renewables |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses |  |  |  |  |  |  |  |  | 29,000,000 |  |  |
Construction in Progress |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses |  |  |  |  | $ 41,000,000 |  |  |  |  |  |  |
Construction in Progress, Gross |  |  |  |  | $ 0 |  |  |  |  |  |  |
Keystone |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage | 3.70% |  |  |  |  |  |  |  |  |  |  |
Impairment losses on equity method investments | $ 14,000,000 |  |  |  |  |  |  |  |  |  |  |
Impairment losses on investments |  |  |  |  |  |  |  |  | 35,000,000 |  |  |
Conemaugh |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses on equity method investments | $ 14,000,000 |  |  |  |  |  |  |  |  |  |  |
Impairment losses on investments |  |  |  |  |  |  |  |  | 35,000,000 |  |  |
Dunkirk |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses on equity method investments |  |  |  | $ 46,000,000 |  |  |  |  |  |  |  |
Equity method investments |  |  |  | 0 |  |  |  |  |  |  |  |
Other |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses on equity method investments |  |  |  | $ 15,000,000 |  |  |  |  |  |  |  |
Impairment losses on investments |  |  |  |  |  |  |  | $ 13,000,000 | $ 10,000,000 |  |  |
South Texas Project |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses on investments |  |  | 1,248,000,000 |  |  |  |  |  |  |  |  |
Indian River |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses on investments |  |  | $ 36,000,000 |  |  |  |  |  |  |  |  |
Petra Nova Parish Holdings |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage |  |  | 50.00% |  |  |  |  | 50.00% |  |  |  | 50.00%
Impairment losses on investments |  |  | $ 69,000,000 |  |  | $ 140,000,000 |  |  |  |  |  |
Long Beach |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses |  |  |  |  |  |  | 36,000,000 |  |  |  |  |
Community Wind North, LLC |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses on investments |  |  |  |  |  |  | 36,000,000 |  |  |  |  |
Sherbino I Wind Farm LLC |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses on investments |  |  |  |  |  |  | $ 70,000,000 |  |  |  |  |
Rockford |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses |  |  |  |  |  |  |  |  |  | $ 17,000,000 |  |
Ownership percentage |  | 100.00% |  |  |  |  |  |  |  |  |  |
Proceeds from sale |  | $ 55,000,000 |  |  |  |  |  |  |  |  |  |
Held-for-sale | NRG Solar Guam, LLC |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses |  |  | $ 12,000,000 |  |  |  |  |  |  |  |  |
Held-for-sale | NRG Solar Guam, LLC | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Asset Impairments |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration |  |  |  |  |  |  |  |  |  |  | $ 8,000,000 |

X
- Definition Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2420-110228 + Details
Name: | us-gaap_AssetImpairmentCharges
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 + Details
Name: | us-gaap_ConstructionInProgressGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation. + References No definition available. + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 35 -Paragraph 32 -URI http://asc.fasb.org/extlink&oid=114001220&loc=d3e32787-111569 + Details
Name: | us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=109237563&loc=d3e33749-111570 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 25 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8813-108599 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_EquityMethodInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ImpairedLongLivedAssetsHeldAndUsedLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 8A -URI http://asc.fasb.org/extlink&oid=109979856&loc=SL6284422-111562 + Details
Name: | us-gaap_ImpairmentOfInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_ImpairedLongLivedAssetsHeldAndUsedByTypeAxis=nrg_EmissionAllowancesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ImpairedLongLivedAssetsHeldAndUsedByTypeAxis=nrg_OtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ImpairedLongLivedAssetsHeldAndUsedByTypeAxis=us-gaap_OtherIntangibleAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ImpairedLongLivedAssetsHeldAndUsedByTypeAxis=nrg_SolarPanelsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ImpairedLongLivedAssetsHeldAndUsedByTypeAxis=us-gaap_OtherInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=nrg_RenewablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_ConstructionInProgressMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nrg_KeystoneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nrg_ConemaughMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nrg_DunkirkMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nrg_OtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nrg_SouthTexasProjectUnits1And2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nrg_IndianRiverMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nrg_PetraNovaParishHoldingsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nrg_LongBeachMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nrg_CommunityWindNorthLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nrg_SherbinoIWindFarmLlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=nrg_RockfordMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=nrg_NRGSolarGuamLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |