Supplemental Guarantor Condensed Consolidating Statements of Income (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 3,917.7	$ 3,538.6	$ 11,977.9	$ 10,847.6
Cost of sales	3,587.5	3,247.3	10,997.6	9,931.9
Selling, general and administrative expenses	128.6	113.4	386.1	346.8
Amortization of intangible assets	8.6	8.3	25.8	22.5
Interest expense	17.5	13.7	51.6	40.2
Other expense, net	16.8	1.5	37.8	12.0
Consolidated income before provision for income taxes and equity in net income of affiliates	158.7	154.4	479.0	494.2
Provision for income taxes	51.2	29.3	130.2	100.4
Equity in net income of affiliates	(9.2)	(3.0)	(27.1)	(33.3)
Consolidated net income	116.7	128.1	375.9	427.1
Less: Net income attributable to noncontrolling interests	3.9	6.7	17.3	26.2
Net income attributable to Lear	112.8	121.4	358.6	400.9
Consolidated comprehensive income	148.3	174.3	356.7	461.1
Less: Comprehensive income attributable to noncontrolling interests	4.1	7.9	18.2	26.5
Comprehensive income attributable to Lear	144.2	166.4	338.5	434.6
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net sales	105.2	119.1	352.4	379.9
Cost of sales	132.6	126.6	429.9	423.9
Selling, general and administrative expenses	43.0	35.9	121.7	108.8
Amortization of intangible assets	0.5	0.4	1.3	1.2
Intercompany charges	0.2	0.5	0.9	3.6
Interest expense	11.9	0.8	36.0	3.0
Other intercompany (income) expense, net	(45.7)	(67.5)	(170.8)	(255.3)
Other expense, net	0.6	3.5	6.8	2.4
Consolidated income before provision for income taxes and equity in net income of affiliates	(37.9)	18.9	(73.4)	92.3
Provision for income taxes	(11.2)	2.5	(23.6)	8.4
Equity in net income of affiliates	(0.1)	4.5	(0.8)	(13.1)
Equity in net income of subsidiaries	(139.4)	(109.5)	(407.6)	(303.9)
Consolidated net income	112.8	121.4	358.6	400.9
Net income attributable to Lear	112.8	121.4	358.6	400.9
Consolidated comprehensive income	144.2	166.4	338.5	434.6
Comprehensive income attributable to Lear	144.2	166.4	338.5	434.6
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	1,557.8	1,431.4	4,701.3	4,320.2
Cost of sales	1,411.2	1,282.8	4,277.4	3,931.2
Selling, general and administrative expenses	17.3	43.7	49.2	68.5
Amortization of intangible assets	1.2	1.4	3.6	1.9
Intercompany charges		0.3	0.3	1.3
Interest expense	6.0	4.1	18.1	15.9
Other intercompany (income) expense, net	33.6	45.1	97.7	168.9
Other expense, net	0.2	0.1	1.0	0.6
Consolidated income before provision for income taxes and equity in net income of affiliates	88.3	53.9	254.0	131.9
Provision for income taxes	31.7	(1.3)	92.3	0.2
Equity in net income of affiliates	(0.3)	(0.6)	(0.4)	(2.0)
Equity in net income of subsidiaries	(39.1)	(24.0)	(120.3)	(129.8)
Consolidated net income	96.0	79.8	282.4	263.5
Net income attributable to Lear	96.0	79.8	282.4	263.5
Consolidated comprehensive income	91.0	104.8	270.4	324.6
Comprehensive income attributable to Lear	91.0	104.8	270.4	324.6
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	3,351.6	2,992.7	10,326.7	9,340.6
Cost of sales	3,140.6	2,842.5	9,692.8	8,769.9
Selling, general and administrative expenses	68.3	33.8	215.2	169.5
Amortization of intangible assets	6.9	6.5	20.9	19.4
Intercompany charges	(0.2)	(0.8)	(1.2)	(4.9)
Interest expense	(0.4)	8.8	(2.5)	21.3
Other intercompany (income) expense, net	12.1	22.4	73.1	86.4
Other expense, net	16.0	(2.1)	30.0	9.0
Consolidated income before provision for income taxes and equity in net income of affiliates	108.3	81.6	298.4	270.0
Provision for income taxes	30.7	28.1	61.5	91.8
Equity in net income of affiliates	(8.8)	(6.9)	(25.9)	(18.2)
Consolidated net income	86.4	60.4	262.8	196.4
Less: Net income attributable to noncontrolling interests	3.9	6.7	17.3	26.2
Net income attributable to Lear	82.5	53.7	245.5	170.2
Consolidated comprehensive income	122.8	91.9	254.7	186.7
Less: Comprehensive income attributable to noncontrolling interests	4.1	7.9	18.2	26.5
Comprehensive income attributable to Lear	118.7	84.0	236.5	160.2
Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Net sales	(1,096.9)	(1,004.6)	(3,402.5)	(3,193.1)
Cost of sales	(1,096.9)	(1,004.6)	(3,402.5)	(3,193.1)
Equity in net income of subsidiaries	178.5	133.5	527.9	433.7
Consolidated net income	(178.5)	(133.5)	(527.9)	(433.7)
Net income attributable to Lear	(178.5)	(133.5)	(527.9)	(433.7)
Consolidated comprehensive income	(209.7)	(188.8)	(506.9)	(484.8)
Comprehensive income attributable to Lear	$ (209.7)	$ (188.8)	$ (506.9)	$ (484.8)