Name:	nrg_GuaranteeMaturityBetweenOneToThreeYears
Namespace Prefix:	nrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Maximum potential amount of future payments that the guarantor could be required to make between three to five years of the balance sheet date under the guarantee.

No definition available.

Name:	nrg_GuaranteeMaturityBetweenThreeToFiveYears
Namespace Prefix:	nrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Maximum potential amount of future payments that the guarantor could be required to make after five years of the balance sheet date under the guarantee.

No definition available.

Name:	nrg_GuaranteeMaturityGreaterThanFiveYears
Namespace Prefix:	nrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Maximum potential amount of future payments that the guarantor could be required to make within one year of the balance sheet date under the guarantee.

No definition available.

Name:	nrg_GuaranteeMaturityLessThanOneYear
Namespace Prefix:	nrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The estimated amount of future payments the guarantor could be required to make under guarantees, indemnities and other contingent liability obligations.

No definition available.

Name:	nrg_GuaranteeObligationsEstimatedExposure
Namespace Prefix:	nrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

This element represents the maximum expiration period of letters of credit and surety bonds for entity is contingently obliged.

No definition available.

Name:	nrg_GuaranteeObligationsLettersofCreditandSuretyBondsMaximumExpirationPeriod
Namespace Prefix:	nrg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

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.

No definition available.

Name:	us-gaap_GuaranteeObligationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

Name:	us-gaap_GuaranteesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Fair value portion of guarantee, including, but not limited to, financial standby letter of credit, fair value guarantee, guarantee of collection of scheduled contractual cash flows from financial assets, and contracts that contingently require the guarantor to make payments or perform services.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12201-110248