Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Income Statement [Abstract]
Net sales	$ 5,007.6	$ 5,580.8	$ 10,167.7	$ 11,314.5
Cost of sales	4,529.4	4,942.7	9,216.3	10,045.0
Selling, general and administrative expenses	157.1	156.8	305.4	312.2
Amortization of intangible assets	15.9	13.1	28.6	26.2
Interest expense	24.5	20.9	45.4	41.6
Other (income) expense, net	13.8	3.7	18.2	(1.9)
Consolidated income before provision for income taxes and equity in net income of affiliates	266.9	443.6	553.8	891.4
Provision for income taxes	73.3	97.7	116.4	175.4
Equity in net income of affiliates	(8.4)	(9.1)	(10.7)	(13.2)
Consolidated net income	202.0	355.0	448.1	729.2
Less: Net income attributable to noncontrolling interests	19.2	23.6	36.4	44.1
Net income attributable to Lear	$ 182.8	$ 331.4	$ 411.7	$ 685.1
Basic net income per share available to Lear common stockholders (Note 14) (in dollars per share)	$ 2.92	$ 4.86	$ 6.68	$ 10.05
Diluted net income per share available to Lear common stockholders (Note 14) (in dollars per share)	2.92	4.83	6.66	9.99
Cash dividends declared per share (in dollars per share)	$ 0.75	$ 0.70	$ 1.50	$ 1.40
Average common shares outstanding (in shares)	62,191,022	66,320,362	62,501,419	66,701,228
Average diluted shares outstanding (in shares)	62,354,334	66,708,040	62,734,494	67,132,886
Consolidated comprehensive income (Condensed Consolidated Statements of Equity)	$ 208.4	$ 89.4	$ 456.6	$ 609.4
Less: Comprehensive income attributable to noncontrolling interests	12.3	4.9	37.3	38.6
Comprehensive income attributable to Lear	$ 196.1	$ 84.5	$ 419.3	$ 570.8