Segment Reporting - Summary of Segment Financial Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Oct. 03, 2020	Jul. 04, 2020	Apr. 04, 2020	Dec. 31, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenues from external customers	$ 5,243.2	$ 4,900.1	$ 2,444.5	$ 4,457.7	$ 4,817.6	$ 4,825.0	$ 5,007.6	$ 5,160.1	$ 17,045.5	$ 19,810.3	$ 21,148.5
Segment earnings									454.1	1,070.2	1,654.1
Depreciation and amortization									539.9	509.9	484.4
Capital expenditures									452.3	603.9	677.0
Total assets	13,198.6				12,680.7				13,198.6	12,680.7
Operating Segments
Segment Reporting Information [Line Items]
Segment earnings									688.6	1,327.5	1,892.1
Operating Segments | Seating
Segment Reporting Information [Line Items]
Revenues from external customers									12,712.7	15,097.2	16,021.9
Segment earnings									590.5	961.2	1,263.6
Depreciation and amortization									348.1	331.0	323.5
Capital expenditures									257.2	370.4	459.8
Total assets	7,596.1				7,277.6				7,596.1	7,277.6
Operating Segments | E-Systems
Segment Reporting Information [Line Items]
Revenues from external customers									4,332.8	4,713.1	5,126.6
Segment earnings									98.1	366.3	628.5
Depreciation and amortization									176.6	163.0	146.2
Capital expenditures									179.3	213.9	208.4
Total assets	3,403.3				3,068.1				3,403.3	3,068.1
Other
Segment Reporting Information [Line Items]
Revenues from external customers									0.0	0.0	0.0
Segment earnings									(234.5)	(257.3)	(238.0)
Depreciation and amortization									15.2	15.9	14.7
Capital expenditures									15.8	19.6	$ 8.8
Total assets	$ 2,199.2				$ 2,335.0				$ 2,199.2	$ 2,335.0