Consolidated Statements of Changes in Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Contributed Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Noncontrolling Interest	Cumulative effect adjustment	Cumulative effect adjustment Retained Earnings	Adjusted balance	Adjusted balance Common Stock	Adjusted balance Additional Contributed Capital	Adjusted balance Retained Earnings	Adjusted balance Accumulated Other Comprehensive Income (Loss)	Adjusted balance Treasury Stock	Adjusted balance Noncontrolling Interest
Accounting Standards Update [Extensible List]	Accounting Standards Update 2016-13
Balance, beginning of period, (in shares) at Dec. 31, 2018		198.8				68.3					198.8				68.3
Balance, beginning of period at Dec. 31, 2018	$ 1,206.8	$ 2.0	$ 527.1	$ 2,663.0	$ (77.6)	$ (1,908.3)	$ 0.6	$ 0.1	$ 0.1	$ 1,206.9	$ 2.0	$ 527.1	$ 2,663.1	$ (77.6)	$ (1,908.3)	$ 0.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to Leggett & Platt, Inc. common shareholders	314.1			314.0			0.1
Dividends declared	(207.8)		5.4	(213.2)
Dividends paid to noncontrolling interest	(0.2)						(0.2)
Treasury stock purchased, (in shares)						(0.7)
Treasury stock purchased	(31.1)					$ (31.1)
Treasury stock issued, (in shares)						2.0
Treasury stock issued	33.3		(22.3)			$ 55.6
Other comprehensive income (loss), net of tax	0.8				0.8
Stock-based compensation, net of tax	25.9		25.9
Balance, end of period, (in shares) at Dec. 31, 2019		198.8				67.0					198.8				67.0
Balance, end of period at Dec. 31, 2019	1,341.9	$ 2.0	536.1	2,763.9	(76.8)	$ (1,883.8)	0.5	$ (2.5)	$ (2.5)	$ 1,339.4	$ 2.0	$ 536.1	$ 2,761.4	$ (76.8)	$ (1,883.8)	$ 0.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to Leggett & Platt, Inc. common shareholders	253.1			253.0			0.1
Dividends declared	(211.7)		5.5	(217.2)
Dividends paid to noncontrolling interest	0.0
Treasury stock purchased, (in shares)						(0.2)
Treasury stock purchased	(11.2)					$ (11.2)
Treasury stock issued, (in shares)						1.0
Treasury stock issued	7.7		(21.9)			$ 29.6
Other comprehensive income (loss), net of tax	24.3				24.4		(0.1)
Stock-based compensation, net of tax	23.5		23.5
Balance, end of period, (in shares) at Dec. 31, 2020		198.8				66.2
Balance, end of period at Dec. 31, 2020	1,425.1	$ 2.0	543.2	2,797.2	(52.4)	$ (1,865.4)	0.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to Leggett & Platt, Inc. common shareholders	402.6			402.4			0.2
Dividends declared	(221.4)		5.2	(226.6)
Treasury stock purchased, (in shares)						(0.3)
Treasury stock purchased	(12.3)					$ (12.3)
Treasury stock issued, (in shares)						1.1
Treasury stock issued	10.9		(20.2)			$ 31.1
Other comprehensive income (loss), net of tax	14.0				14.1		(0.1)
Stock-based compensation, net of tax	29.6		29.6
Purchase of remaining interest in noncontrolling interest	(1.4)		(0.2)				(1.2)
Partial sale of business resulting in noncontrolling interest	1.5		0.3				1.2
Balance, end of period, (in shares) at Dec. 31, 2021		198.8				65.4
Balance, end of period at Dec. 31, 2021	$ 1,648.6	$ 2.0	$ 557.9	$ 2,973.0	$ (38.3)	$ (1,846.6)	$ 0.6