Document and Entity Information Document - shares	9 Months Ended
	Sep. 30, 2021	Oct. 25, 2021
Document and Entity Information [Abstract]
Entity Current Reporting Status	Yes
Document Type	10-Q
Document Fiscal Period Focus	Q3
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Amendment Flag	false
Document Fiscal Year Focus	2021
Current Fiscal Year End Date	--12-31
Entity File Number	1-16411
Entity Registrant Name	NORTHROP GRUMMAN CORP /DE/
Entity Central Index Key	0001133421
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	80-0640649
Entity Address, Line 1	2980 Fairview Park Drive
Entity Address, City Or Town	Falls Church,
Entity Address, State Or Province	VA
Entity Address, Postal ZIP Code	22042
City Area Code	703
Local Phone Number	280-2900
Title of 12(b) Security	Common Stock
Trading Symbol	NOC
Security Exchange Name	NYSE
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		158,537,643