XML 114 R98.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Goodwill and Other Intangibles - Components of Intangible Assets Subject to Amortization (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
Finite-lived Intangible Assets [Roll Forward] |  |
Balance at beginning of period | $ 2,080 | $ 2,162
Purchases | 61 | 59
Acquisition of businesses(a) | 178 | 18
Usage | (27) | (38)
Write-off of fully amortized balances | (528) | (77)
Impairment | (6) | (20)
Other | (16) | (24)
Balance at end of period | 1,742 | 2,080
Less accumulated amortization | (1,151) | (1,573)
Net carrying amount | 591 | 507
Emission Allowances |  |
Finite-lived Intangible Assets [Roll Forward] |  |
Balance at beginning of period | 755 | 780
Purchases | 33 | 27
Acquisition of businesses(a) | 0 | 0
Usage | (1) | (10)
Write-off of fully amortized balances | (107) | 0
Impairment | (5) | (20)
Other | (16) | (22)
Balance at end of period | 659 | 755
Less accumulated amortization | (515) | (583)
Net carrying amount | 144 | 172
Energy Supply |  |
Finite-lived Intangible Assets [Roll Forward] |  |
Balance at beginning of period | 0 | 54
Purchases |  | 0
Acquisition of businesses(a) |  | 0
Usage |  | 0
Write-off of fully amortized balances |  | (54)
Impairment |  | 0
Other |  | 0
Balance at end of period |  | 0
Less accumulated amortization |  | 0
Net carrying amount |  | 0
Fuel |  |
Finite-lived Intangible Assets [Roll Forward] |  |
Balance at beginning of period | 49 | 72
Purchases | 0 | 0
Acquisition of businesses(a) | 0 | 0
Usage | 0 | 0
Write-off of fully amortized balances | 0 | (23)
Impairment | 0 | 0
Other | 0 | 0
Balance at end of period | 49 | 49
Less accumulated amortization | (45) | (45)
Net carrying amount | 4 | 4
Customer Contracts |  |
Finite-lived Intangible Assets [Roll Forward] |  |
Balance at beginning of period | 1 | 1
Purchases | 0 | 0
Acquisition of businesses(a) | 0 | 0
Usage | 0 | 0
Write-off of fully amortized balances | 0 | 0
Impairment | 0 | 0
Other | 0 | 0
Balance at end of period | 1 | 1
Less accumulated amortization | (1) | (1)
Net carrying amount | 0 | 0
Customer Relationships |  |
Finite-lived Intangible Assets [Roll Forward] |  |
Balance at beginning of period | 768 | 750
Purchases | 0 | 0
Acquisition of businesses(a) | 122 | 18
Usage | 0 | 0
Write-off of fully amortized balances | (411) | 0
Impairment | (1) | 0
Other | 0 | 0
Balance at end of period | 478 | 768
Less accumulated amortization | (314) | (693)
Net carrying amount | 164 | 75
Marketing Partnerships |  |
Finite-lived Intangible Assets [Roll Forward] |  |
Balance at beginning of period | 88 | 88
Purchases | 0 | 0
Acquisition of businesses(a) | 43 | 0
Usage | 0 | 0
Write-off of fully amortized balances | 0 | 0
Impairment | 0 | 0
Other | 0 | 0
Balance at end of period | 131 | 88
Less accumulated amortization | (61) | (54)
Net carrying amount | 70 | 34
Trade Names |  |
Finite-lived Intangible Assets [Roll Forward] |  |
Balance at beginning of period | 342 | 342
Purchases | 0 | 0
Acquisition of businesses(a) | 13 | 0
Usage | 0 | 0
Write-off of fully amortized balances | (10) | 0
Impairment | 0 | 0
Other | 0 | 0
Balance at end of period | 345 | 342
Less accumulated amortization | (195) | (182)
Net carrying amount | 150 | 160
Other |  |
Finite-lived Intangible Assets [Roll Forward] |  |
Balance at beginning of period | 77 | 75
Purchases | 28 | 32
Acquisition of businesses(a) | 0 | 0
Usage | (26) | (28)
Write-off of fully amortized balances | 0 | 0
Impairment | 0 | 0
Other | 0 | (2)
Balance at end of period | 79 | 77
Less accumulated amortization | (20) | (15)
Net carrying amount | $ 59 | $ 62

X
- Definition This element represents other additions or reductions to finite-lived intangible assets during the period. + References No definition available. + Details
Name: | nrg_FiniteLivedIntangibleAssetsOtherChanges
Namespace Prefix: | nrg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This element represents the finite-lived intangible assets purchased during the period. + References No definition available. + Details
Name: | nrg_FiniteLivedIntangibleAssetsPurchases
Namespace Prefix: | nrg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The usage of finite-lived intangible assets during the period. + References No definition available. + Details
Name: | nrg_FiniteLivedIntangibleAssetsUsage
Namespace Prefix: | nrg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Write-off of fully amortized intangible assets during the period. + References No definition available. + Details
Name: | nrg_FiniteLivedIntangibleAssetsWriteOffOfFullyAmortizedIntangibleAssets
Namespace Prefix: | nrg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 928 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6473545&loc=d3e61844-108004 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275 + Details
Name: | us-gaap_FinitelivedIntangibleAssetsAcquired1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -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://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275 + Details
Name: | us-gaap_ImpairmentOfIntangibleAssetsFinitelived
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=nrg_EnergySupplyContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=nrg_FuelContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_CustomerContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_CustomerRelationshipsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=nrg_MarketingPartnershipsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_TradeNamesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=nrg_OtherFiniteLivedIntangibleAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |