Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Consolidated net income	$ 233.9	$ 830.7	$ 1,246.7
Other comprehensive income (loss), net of tax:
Defined benefit plan adjustments	(59.3)	(44.8)	11.2
Derivative instruments and hedging activities	2.8	19.5	13.2
Foreign currency translation adjustments	139.7	(45.1)	(233.0)
Total other comprehensive income (loss)	83.2	(70.4)	(208.6)
Consolidated comprehensive income	317.1	760.3	1,038.1
Less: Comprehensive income attributable to noncontrolling interests	91.0	73.6	80.7
Comprehensive income attributable to Lear	$ 226.1	$ 686.7	$ 957.4