XML 49 R45.htm IDEA: XBRL DOCUMENT v2.4.1.9
Business Acquisitions and Dispositions Business Acquisitions and Dispositions (Details 6 - Dominion) (USD $)
In Millions, unless otherwise specified
0 Months Ended
Mar. 31, 2014
Mar. 31, 2015
Dec. 31, 2014
Business Acquisition [Line Items]      
Goodwill   $ 2,520us-gaap_Goodwill $ 2,574us-gaap_Goodwill
Dominion [Member]      
Business Acquisition [Line Items]      
Business Combination, Consideration Transferred 192us-gaap_BusinessCombinationConsiderationTransferred1
/ us-gaap_BusinessAcquisitionAxis
= nrg_DominionMember
   
Business Acquisitions, Consideration Transferred, Purchase Price 165nrg_BusinessAcquisitionsConsiderationTransferredPurchasePrice
/ us-gaap_BusinessAcquisitionAxis
= nrg_DominionMember
   
Business Acquisition, Consideration Transferred, Working Capital 27nrg_BusinessAcquisitionConsiderationTransferredWorkingCapital
/ us-gaap_BusinessAcquisitionAxis
= nrg_DominionMember
   
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables 40us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables
/ us-gaap_BusinessAcquisitionAxis
= nrg_DominionMember
   
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other 14us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther
/ us-gaap_BusinessAcquisitionAxis
= nrg_DominionMember
   
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Derivative Assets 21nrg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedDerivativeAssets
/ us-gaap_BusinessAcquisitionAxis
= nrg_DominionMember
   
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities 47us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities
/ us-gaap_BusinessAcquisitionAxis
= nrg_DominionMember
   
Goodwill 91us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= nrg_DominionMember
   
Business Acquisition, Goodwill, Expected Tax Deductible Amount 8us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount
/ us-gaap_BusinessAcquisitionAxis
= nrg_DominionMember
   
Customer Relationships [Member] | Dominion [Member]      
Business Acquisition [Line Items]      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles 64us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles
/ us-gaap_BusinessAcquisitionAxis
= nrg_DominionMember
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_CustomerRelationshipsMember
   
Trade Names [Member] | Dominion [Member]      
Business Acquisition [Line Items]      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill $ 9us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill
/ us-gaap_BusinessAcquisitionAxis
= nrg_DominionMember
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_TradeNamesMember
   
Scenario, Plan [Member] | Dominion [Member]      
Business Acquisition [Line Items]      
Business Acquisition, Customers Acquired 540,000nrg_BusinessAcquisitionCustomersAcquired
/ us-gaap_BusinessAcquisitionAxis
= nrg_DominionMember
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPlanMember