Cover - shares shares in Millions	9 Months Ended
	Sep. 30, 2021	Nov. 12, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	333-253583
Entity Registrant Name	Leonardo DRS, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-2632319
Entity Address, Address Line One	2345 Crystal Drive
Entity Address, Address Line Two	Suite 1000
Entity Address, City or Town	Arlington
Entity Address, State or Province	VA
Entity Address, Postal Zip Code	22202
City Area Code	703
Local Phone Number	416-8000
Title of 12(b) Security
Trading Symbol
Security Exchange Name
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		145
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001833756
Current Fiscal Year End Date	--12-31