Consolidated Statements of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net sales	$ 19,810.3	$ 21,148.5	$ 20,467.0
Cost of sales	18,072.8	18,830.2	18,175.9
Selling, general and administrative expenses	605.0	612.8	635.2
Amortization of intangible assets	62.3	51.4	47.6
Interest expense	92.0	84.1	85.7
Other (income) expense, net	24.6	31.6	(4.1)
Consolidated income before provision for income taxes and equity in net income of affiliates	953.6	1,538.4	1,526.7
Provision for income taxes	146.1	311.9	197.5
Equity in net income of affiliates	(23.2)	(20.2)	(51.7)
Consolidated net income	830.7	1,246.7	1,380.9
Less: Net income attributable to noncontrolling interests	77.1	96.9	67.5
Net income attributable to Lear	$ 753.6	$ 1,149.8	$ 1,313.4
Basic net income per share available to Lear common stockholders (in dollars per share)	$ 12.80	$ 17.35	$ 18.79
Diluted net income per share available to Lear common stockholders (in dollars per share)	$ 12.75	$ 17.22	$ 18.59
Average common shares outstanding (in shares)	61,697,192	65,672,164	68,542,363
Average diluted shares outstanding (in shares)	61,923,528	66,161,816	69,277,981