XML 113 R83.htm IDEA: XBRL DOCUMENT v3.8.0.1

Fair Value of Financial Instruments - Derivative Fair Value Measurements Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Total derivative assets valued with prices provided by models and other valuation techniques percentage	6.00%
Total derivative liabilities valued with prices provided by models and other valuation techniques, percentage	10.00%
Increase (decrease) in credit reserve		$ 10

X

- Definition

This element represents the portion of total fair value of all derivative assets, which are valued using various valuation techniques including internal models based on a fundamental analysis of the market and extrapolation of observable market data with similar characteristics.

+ References

No definition available.

+ Details

Name:	nrg_DerivativeAssetFairValueDeterminedUsingValuationTechniquesPercentage
Namespace Prefix:	nrg_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Derivative Liability, Fair Value Determined Using Valuation Techniques, Percentage

+ References

No definition available.

+ Details

Name:	nrg_DerivativeLiabilityFairValueDeterminedUsingValuationTechniquesPercentage
Namespace Prefix:	nrg_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- References

No definition available.

+ Details

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

X

- Definition

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

+ Details

Name:	us-gaap_ValuationAllowancesAndReservesBalance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant