Consolidated Statements of Equity - USD ($) $ in Millions	Total	Redeemable Non- controlling Interests	Common Stock	Additional Paid-in Capital	Common Stock Held in Treasury	Retained Earnings	Defined Benefit Plans	Derivative Instruments and Hedge Activities	Derivative Instruments and Hedge Activities	Cumulative Translation Adjustments	Lear Corporation Stockholders’ Equity	Non-controlling Interests
Comprehensive income:
Adoption of ASU	$ 52.9					$ 52.9					$ 52.9
Balance at beginning of year at Dec. 31, 2016		$ 0.0
Comprehensive income (loss):
Net income		3.2
Other comprehensive income (loss)		4.6
Total comprehensive income (loss)		7.8
Dividends declared to noncontrolling interests		(4.9)
Affiliate transaction		125.0
Redeemable noncontrolling interest adjustment		25.5
Balance at end of year at Dec. 31, 2017		153.4
Balance at beginning of year at Dec. 31, 2016	3,192.9		$ 0.8	$ 1,385.3	$ (1,200.2)	3,706.9	$ (192.8)	$ (45.1)		$ (597.7)	3,057.2	$ 135.7
Comprehensive income:
Net income	1,377.7					1,313.4					1,313.4	64.3
Other comprehensive income	331.4						8.8	22.2		291.2	322.2	9.2
Total comprehensive income	1,709.1					1,313.4	8.8	22.2		291.2	1,635.6	73.5
Stock-based compensation	70.2			70.2							70.2
Net issuances of shares held in treasury in settlement of stock-based compensation	(45.2)			(84.2)	39.0	0.0					(45.2)
Repurchases of common stock	(454.4)				(454.4)						(454.4)
Retirement of shares held in treasury	0.0		(0.1)	(155.9)	891.5	(735.5)					0.0
Dividends declared to Lear Corporation stockholders	(140.3)					(140.3)					(140.3)
Dividends declared to noncontrolling interests	(67.1)											(67.1)
Affiliate transaction	0.0											0.0
Redeemable noncontrolling interest adjustment	(25.5)					(25.5)					(25.5)
Balance at end of year at Dec. 31, 2017	4,292.6		0.7	1,215.4	(724.1)	4,171.9	(184.0)	(22.9)		(306.5)	4,150.5	142.1
Comprehensive income:
Adoption of ASU	2.3					2.3					2.3
Net income		12.9
Other comprehensive income (loss)		(9.4)
Total comprehensive income (loss)		3.5
Dividends declared to noncontrolling interests		(9.2)
Affiliate transaction		0.0
Redeemable noncontrolling interest adjustment		10.4
Balance at end of year at Dec. 31, 2018	158.1	158.1
Comprehensive income:
Net income	1,233.8					1,149.8					1,149.8	84.0
Other comprehensive income	(199.2)						11.2		$ 13.2	(216.8)	(192.4)	(6.8)
Total comprehensive income	1,034.6					1,149.8	11.2		13.2	(216.8)	957.4	77.2
Stock-based compensation	41.4			41.4							41.4
Net issuances of shares held in treasury in settlement of stock-based compensation	(47.5)			(81.5)	34.0						(47.5)
Repurchases of common stock	(705.2)				(705.2)						(705.2)
Retirement of shares held in treasury	0.0		(0.1)	(155.9)	1,170.2	(1,014.2)					0.0
Dividends declared to Lear Corporation stockholders	(185.8)					(185.8)					(185.8)
Dividends declared to noncontrolling interests	(70.0)											(70.0)
Affiliate transaction	14.0											14.0
Acquisition of outstanding noncontrolling interests	(2.0)			(2.0)							(2.0)	0.0
Redeemable noncontrolling interest adjustment	(10.4)					(10.4)					(10.4)
Noncontrolling interests — other	(3.4)										0.0	(3.4)
Balance at end of year at Dec. 31, 2018	4,360.6		0.6	1,017.4	(225.1)	4,113.6	(172.8)	$ (9.7)	(9.7)	(523.3)	4,200.7	159.9
Comprehensive income (loss):
Net income		1.8
Other comprehensive income (loss)		(1.8)
Total comprehensive income (loss)		0.0
Dividends declared to noncontrolling interests		(2.7)
Redeemable noncontrolling interest adjustment		(37.0)
Balance at end of year at Dec. 31, 2019	118.4	$ 118.4
Comprehensive income:
Net income	828.9					753.6					753.6	75.3
Other comprehensive income	(68.6)						(44.8)		19.5	(41.6)	(66.9)	(1.7)
Total comprehensive income	760.3					753.6	(44.8)		19.5	(41.6)	686.7	73.6
Stock-based compensation	23.3			23.3							23.3
Net issuances of shares held in treasury in settlement of stock-based compensation	(31.3)			(71.6)	42.4	(2.1)					(31.3)
Repurchases of common stock	(380.4)				(380.4)						(380.4)
Dividends declared to Lear Corporation stockholders	(186.3)					(186.3)					(186.3)
Dividends declared to noncontrolling interests	(76.3)											(76.3)
Disposal of noncontrolling interests												(5.6)
Redeemable noncontrolling interest adjustment	37.0					37.0					37.0
Noncontrolling interests — other	(0.2)										0.0	(0.2)
Balance at end of year at Dec. 31, 2019	$ 4,501.1		$ 0.6	$ 969.1	$ (563.1)	$ 4,715.8	$ (217.6)		$ 9.8	$ (564.9)	$ 4,349.7	$ 151.4