Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Oct. 29, 2021
Document And Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-34910
Entity Registrant Name	HUNTINGTON INGALLS INDUSTRIES, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	90-0607005
Entity Address, Address Line One	4101 Washington Avenue
Entity Address, City or Town	Newport News
Entity Address, State or Province	VA
Entity Address, Postal Zip Code	23607
City Area Code	757
Local Phone Number	380-2000
Title of 12(b) Security	Common Stock
Trading Symbol	HII
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
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		40,060,998
Amendment Flag	false
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2021
Entity Central Index Key	0001501585
Current Fiscal Year End Date	--12-31