Document and Entity Information
Jul. 01, 2022
Cover [Abstract]  
Entity Registrant Name LANDSTAR SYSTEM INC
Entity File Number 021-238
Amendment Flag false
Entity Central Index Key 0000853816
Document Type 8-K
Document Period End Date Jul. 01, 2022
Entity Incorporation State Country Code DE
Entity Tax Identification Number 06-1313069
Entity Address, Address Line One 13410 Sutton Park Drive South
Entity Address, City or Town Jacksonville
Entity Address, State or Province FL
Entity Address, Postal Zip Code 32224
City Area Code (904)
Local Phone Number 398-9400
Written Communications false
Soliciting Material false
Pre Commencement Tender Offer false
Pre Commencement Issuer Tender Offer false
Security 12b Title Common Stock
Trading Symbol LSTR
Security Exchange Name NASDAQ
Entity Emerging Growth Company false