CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS (Unaudted) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Net sales	$ 1,102.5	$ 989.3	$ 2,131.3	$ 1,949.6
Cost of goods sold	871.5	758.6	1,682.9	1,492.2
Gross profit	231.0	230.7	448.4	457.4
Selling and administrative expenses	107.8	104.7	212.5	210.8
Amortization of intangibles	5.1	4.7	10.1	9.8
Other (income) expense, net	(3.0)	(1.0)	(2.7)	(1.4)
Earnings from continuing operations before interest and income taxes	121.1	122.3	228.5	238.2
Interest expense	16.0	10.4	30.4	21.0
Interest income	2.4	1.5	4.8	3.5
Earnings from continuing operations before income taxes	107.5	113.4	202.9	220.7
Income taxes	22.4	25.8	39.9	47.0
Earnings from continuing operations	85.1	87.6	163.0	173.7
Earnings (loss) from discontinued operations, net of tax	0.0	0.0	0.0	0.0
Net earnings	85.1	87.6	163.0	173.7
Earnings attributable to noncontrolling interest, net of tax	(0.1)	0.0	(0.1)	0.0
Net earnings attributable to Leggett & Platt, Inc. common shareholders	$ 85.0	$ 87.6	$ 162.9	$ 173.7
Earnings per share from continuing operations attributable to Leggett & Platt, Inc. common shareholders
Basic (in dollars per share)	$ 0.63	$ 0.64	$ 1.21	$ 1.27
Diluted (in dollars per share)	0.63	0.64	1.20	1.26
Earnings (loss) per share from discontinued operations attributable to Leggett & Platt, Inc. common shareholders
Basic (in dollars per share)	0.00	0.00	0.00	0.00
Diluted (in dollars per share)	0.00	0.00	0.00	0.00
Net earnings per share attributable to Leggett & Platt, Inc. common shareholders
Basic (in dollars per share)	0.63	0.64	1.21	1.27
Diluted (in dollars per share)	0.63	0.64	1.20	1.26
Cash dividends declared per share (in dollars per share)	$ 0.38	$ 0.36	$ 0.74	$ 0.70
Weighted average shares outstanding
Basic (in shares)	134.1	136.0	134.7	136.4
Diluted (in shares)	135.0	137.4	135.7	137.8