XML 21 R46.htm IDEA: XBRL DOCUMENT v2.4.1.9
Property, Plant and Equipment, Net (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended 1 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jul. 31, 2012
Utility plant in-service:        
Utility plant in-service, net $ 6,883npc_PublicUtilitiesPropertyPlantandEquipmentNetExcludingConstructionWorkInProgress $ 6,899npc_PublicUtilitiesPropertyPlantandEquipmentNetExcludingConstructionWorkInProgress    
Construction work-in-progress 120us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress 93us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress    
Property, plant and equipment, net 7,003us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet 6,992us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet    
Average depreciation and amortization rate 3.30%us-gaap_PublicUtilitiesPropertyPlantAndEquipmentDisclosureOfCompositeDepreciationRateForPlantsInService 3.30%us-gaap_PublicUtilitiesPropertyPlantAndEquipmentDisclosureOfCompositeDepreciationRateForPlantsInService 3.20%us-gaap_PublicUtilitiesPropertyPlantAndEquipmentDisclosureOfCompositeDepreciationRateForPlantsInService  
Asset impairment charge 29us-gaap_AssetImpairmentCharges 31us-gaap_AssetImpairmentCharges    
Asset Impairment Charges, 2014 PUCN General Rate Case 19npc_AssetImpairmentCharges2014PUCNGeneralRateCase      
Telecommunication Towers [Member]        
Utility plant in-service:        
Proceeds from sale of assets, restricted to ratepayer rebates       27npc_GainfromSaleofAssetsRestrictedtoRatepayerRebates
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= npc_TelecommunicationTowersMember
Proceeds from sale of telecommunication towers       32us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= npc_TelecommunicationTowersMember
Gain (Loss) on Disposition of Property Plant Equipment     6us-gaap_GainLossOnSaleOfPropertyPlantEquipment
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= npc_TelecommunicationTowersMember
 
Regulated Operation [Member]        
Utility plant in-service:        
Generation 4,034us-gaap_PublicUtilitiesPropertyPlantAndEquipmentGenerationOrProcessing
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
3,789us-gaap_PublicUtilitiesPropertyPlantAndEquipmentGenerationOrProcessing
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
   
Distribution 3,018us-gaap_PublicUtilitiesPropertyPlantAndEquipmentDistribution
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
2,936us-gaap_PublicUtilitiesPropertyPlantAndEquipmentDistribution
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
   
Transmission 1,757us-gaap_PublicUtilitiesPropertyPlantAndEquipmentTransmission
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
1,743us-gaap_PublicUtilitiesPropertyPlantAndEquipmentTransmission
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
   
General intangible plant 669us-gaap_PublicUtilitiesPropertyPlantAndEquipmentOtherPropertyPlantAndEquipment
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
645us-gaap_PublicUtilitiesPropertyPlantAndEquipmentOtherPropertyPlantAndEquipment
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
   
Utility plant in-service 9,478npc_PublicUtilitiesPropertyPlantandEquipmentPlantinServiceExcludingConstructionWorkInProgress
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
9,113npc_PublicUtilitiesPropertyPlantandEquipmentPlantinServiceExcludingConstructionWorkInProgress
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
   
Accumulated depreciation and amortization 2,599us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
2,217us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
   
Utility plant in-service, net 6,879npc_PublicUtilitiesPropertyPlantandEquipmentNetExcludingConstructionWorkInProgress
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
6,896npc_PublicUtilitiesPropertyPlantandEquipmentNetExcludingConstructionWorkInProgress
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_RegulatedOperationMember
   
Unregulated Operation [Member]        
Utility plant in-service:        
Utility plant in-service, net $ 4npc_PublicUtilitiesPropertyPlantandEquipmentNetExcludingConstructionWorkInProgress
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_UnregulatedOperationMember
$ 3npc_PublicUtilitiesPropertyPlantandEquipmentNetExcludingConstructionWorkInProgress
/ us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis
= us-gaap_UnregulatedOperationMember