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Commitments and Contingencies (Unaudited) (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Site Contingency [Line Items]    
Low-end of the range of reasonably possible future costs for environmental remediation sites $ 362us-gaap_LossContingencyRangeOfPossibleLossMinimum  
High-end of the range of reasonably possible future costs for environmental remediation sites 795us-gaap_LossContingencyRangeOfPossibleLossMaximum  
Accrual for Environmental Remediation Costs 377us-gaap_AccrualForEnvironmentalLossContingencies  
Financial Arrangements    
Standby Unused Letters Of Credit and bank guarantees 270noc_StandbyUnusedLettersOfCreditandbankguarantees  
Surety Bond Outstanding 160noc_SuretyBondOutstanding  
Operating leases    
Rental expense for operating leases, net of immaterial amounts of sublease rental income 81us-gaap_LeaseAndRentalExpense 72us-gaap_LeaseAndRentalExpense
Other Current Liabilities [Member]    
Site Contingency [Line Items]    
Accrual for Environmental Remediation Costs 148us-gaap_AccrualForEnvironmentalLossContingencies
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_OtherCurrentLiabilitiesMember		  
Other Noncurrent Liabilities [Member]    
Site Contingency [Line Items]    
Accrual for Environmental Remediation Costs 229us-gaap_AccrualForEnvironmentalLossContingencies
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_OtherNoncurrentLiabilitiesMember		  
Inventoried Costs [Member]    
Site Contingency [Line Items]    
Accrual for Environmental Remediation Costs 74us-gaap_AccrualForEnvironmentalLossContingencies
/ us-gaap_BalanceSheetLocationAxis
= noc_InventoryforLongTermContractsorProgramsGrossMember		  
Other Noncurrent Assets [Member]    
Site Contingency [Line Items]    
Accrual for Environmental Remediation Costs $ 119us-gaap_AccrualForEnvironmentalLossContingencies
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_OtherNoncurrentAssetsMember