Cover Page - shares	9 Months Ended
	Sep. 30, 2021	Oct. 27, 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	001-07845
Entity Registrant Name	LEGGETT & PLATT, INC
Entity Incorporation, State or Country Code	MO
Entity Tax Identification Number	44-0324630
Entity Address, Address Line One	No. 1 Leggett Road
Entity Address, City or Town	Carthage,
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	64836
City Area Code	417
Local Phone Number	358-8131
Title of 12(b) Security	Common Stock, $.01 par value
Ticker Symbol	LEG
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Small Business Entity	false
Emerging Growth Entity	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		133,377,198
Entity Central Index Key	0000058492
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false