The amount of credit exposure to a significant portion of all counterparties.

Name:	nrg_AmountOfCreditExposureToSignificantPortionOfAllCounterparties
Namespace Prefix:	nrg
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The aggregate amount of net counterparty credit risk exposure to certain counterparties representing more than 10% of total net counterparty exposure.

+ Details

Name:	nrg_AmountOfNetCounterpartyCreditRiskExposureToCertainCounterparties
Namespace Prefix:	nrg
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of cash collateral and letters of credit received by the entity on deposit from third parties in support of energy risk management.

+ Details

Name:	nrg_CollateralHeldCashAndLettersOfCredit
Namespace Prefix:	nrg
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The percentage of net counterparty credit exposure that rolls-off by the end of 2012.

+ Details

Name:	nrg_CounterpartyCreditRiskExposurePercentageOfCreditRiskRollOff
Namespace Prefix:	nrg
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the threshold percentage for disclosure of counterparty credit exposure.

+ Details

Name:	nrg_CounterpartyCreditRiskExposurePercentageThreshold
Namespace Prefix:	nrg
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of net counterparty credit exposure of the entity.

+ Details

Name:	nrg_CreditDerivativeMaximumNetExposurePercentage
Namespace Prefix:	nrg
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Credit Reserve Decrease in Fair Value

+ Details

Name:	nrg_CreditReserveDecreaseInFairValue
Namespace Prefix:	nrg
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Credit Reserve Loss

+ Details

Name:	nrg_CreditReserveLoss
Namespace Prefix:	nrg
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the estimated amount of the counterparty credit risk exposure.

+ Details

Name:	nrg_EstimatedCounterpartyCreditRiskExposureToCertainCounterparties
Namespace Prefix:	nrg
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents the increase (decrease) to fair value from applying a credit reserve to reflect credit risk on the valuation techniques used to measure fair value of Level 2 and 3 derivative contracts which is calculated based on credit default swaps.

+ Details

Name:	nrg_FairValueAssetsMeasuredOnRecurringBasisValuationTechniquesImpactOfCreditReserveToFairValue
Namespace Prefix:	nrg
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the impact to other comprehensive income of applying a credit reserve to reflect credit risk on the valuation techniques used to measure fair value of Level 2 and 3 derivative contracts which is calculated based on credit default swaps.

+ Details

Name:	nrg_FairValueAssetsMeasuredOnRecurringBasisValuationTechniquesImpactOfCreditReserveToFairValueIncludedInOciDerivativeContracts
Namespace Prefix:	nrg
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This element represents the impact to operating revenues and cost of operations of applying a credit reserve to reflect credit risk on the valuation techniques used to measure fair value of Level 2 and 3 derivative contracts which is calculated based on credit default swap.

+ Details

Name:	nrg_FairValueAssetsMeasuredOnRecurringBasisValuationTechniquesImpactOfCreditReserveToFairValueIncludedInOperatingRevenuesAndCostOfOperationsDerivativeContracts
Namespace Prefix:	nrg
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

-- None. No documentation exists for this element. --

+ Details

Name:	nrg_FairValueOfFinancialInstrumentsDisclosureAbstract
Namespace Prefix:	nrg
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the net exposure of the entity determined as total credit exposure to all counterparties less collateral (cash and letters of credit) held against those positions as of the reporting date.

+ Details

Name:	nrg_NetCreditExposure
Namespace Prefix:	nrg
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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.

+ Details

Name:	us-gaap_FairValueConcentrationOfRiskFinancialStatementCaptionsLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration