Consolidated Statements Of Operations - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Net sales	$ 4,269.5	$ 3,943.8	$ 3,749.9
Cost of goods sold	3,380.8	3,061.4	2,848.2
Gross profit	888.7	882.4	901.7
Selling and administrative expenses	425.1	400.5	395.7
Amortization of intangibles	20.5	20.7	19.9
Impairments	5.4	4.9	4.1
Gain on sale of assets and businesses	(1.9)	(24.2)	(37.6)
Other expense (income), net	2.7	12.6	(2.4)
Earnings from continuing operations before interest and income taxes	436.9	467.9	522.0
Interest expense	60.9	43.5	38.8
Interest income	8.4	7.6	3.9
Earnings from continuing operations before income taxes	384.4	432.0	487.1
Income taxes	78.3	138.4	120.0
Earnings from continuing operations	306.1	293.6	367.1
Earnings (loss) from discontinued operations, net of tax	0.0	(0.9)	19.1
Net earnings	306.1	292.7	386.2
(Earnings) attributable to noncontrolling interest, net of tax	$ (0.2)	$ (0.1)	$ (0.4)
Earnings per share from continuing operations attributable to Leggett & Platt, Inc. common shareholders
Basic (in dollars per share)	$ 2.28	$ 2.16	$ 2.66
Diluted (in dollars per share)	2.26	2.14	2.62
Earnings (loss) per share from discontinued operations attributable to Leggett & Platt, Inc. common shareholders
Basic (in dollars per share)	0.00	(0.01)	0.14
Diluted (in dollars per share)	0.00	(0.01)	0.14
Net earnings per share attributable to Leggett & Platt, Inc. common shareholders
Basic (in dollars per share)	2.28	2.15	2.80
Diluted (in dollars per share)	$ 2.26	$ 2.13	$ 2.76