Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 14, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 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
Trading Symbol	LEG
Security Exchange Name	NYSE
Entity Well Known Seasoned Issuer	Yes
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 6,768,211,000
Entity Common Stock, Shares Outstanding		133,746,766
Entity Central Index Key	0000058492
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Documents Incorporated by Reference	Part of Item 10, and all of Items 11, 12, 13, and 14 of Part III, are incorporated by reference from the Company’s definitive Proxy Statement for the Annual Meeting of Shareholders to be held on May 17, 2022.