Related Party Transaction, Other Income, From Related Party Transaction

No definition available.

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Namespace Prefix:	nrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Restructuring and Related Cost, Annualized Services

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Restructuring and Related Cost, Credit Applied

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- 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

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Data Type:	xbrli:stringItemType
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- Definition

Amount of selling, general and administrative expenses resulting from transactions, excluding transactions that are eliminated in consolidated or combined financial statements, with related party.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07.1(c))
-URI http://asc.fasb.org/extlink&oid=114873854&loc=SL114874292-224272

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

+ Details

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Balance Type:	credit
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- Details

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- Details

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Period Type:

- Details

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- Details

Name:	us-gaap_RelatedPartyTransactionAxis=nrg_TransitionServicesAgreementMember
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Period Type:

- Details

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Related Party Transactions - Service Agreement and Transition Services Agreement with GenOn (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended		12 Months Ended
	Jul. 16, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Services Agreement \| Restructuring Support Agreement
Related Party Transaction [Line Items]
Shared services, annualized rate						$ 84
Credit applied						28
GenOn \| Services Agreement
Related Party Transaction [Line Items]
Shared services, annualized rate						84
Credit applied						$ 28
GenOn \| Services Agreement \| Restructuring Support Agreement
Related Party Transaction [Line Items]
Credit applied	$ 28
GenOn \| Transition Services Agreement \| Restructuring Support Agreement
Related Party Transaction [Line Items]
Selling, general and administrative expenses		$ 18		$ 53
Other income related to services			$ 14		$ 104
GenOn \| Management Service \| Services Agreement
Related Party Transaction [Line Items]
Service fees				$ 193