Supplemental Guarantor Condensed Consolidating Statements of Income (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 29, 2012	Oct. 01, 2011	Sep. 29, 2012	Oct. 01, 2011
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 3,538.6	$ 3,460.0	$ 10,847.6	$ 10,648.0
Cost of sales	3,247.3	3,179.5	9,931.9	9,697.5
Selling, general and administrative expenses	113.4	114.9	346.8	351.6
Amortization of intangible assets	8.3	7.1	22.5	21.1
Interest expense	13.7	10.9	40.2	24.9
Other expense, net	1.5	10.1	12.0	15.3
Consolidated income before income taxes and equity in net income of affiliates and subsidiaries	154.4	137.5	494.2	537.6
Provision for income taxes	29.3	31.0	100.4	90.7
Equity in net income of affiliates	(3.0)	(1.6)	(33.3)	(9.6)
Consolidated net income	128.1	108.1	427.1	456.5
Less: Net income attributable to noncontrolling interests	6.7	7.4	26.2	22.3
Net income attributable to Lear	121.4	100.7	400.9	434.2
Consolidated comprehensive income	174.3	(61.3)	461.1	398.9
Less: Comprehensive income attributable to noncontrolling interests	7.9	7.8	26.5	24.2
Comprehensive income attributable to Lear	166.4	(69.1)	434.6	374.7
Lear
Condensed Financial Statements, Captions [Line Items]
Net sales	119.1	93.1	379.9	272.1
Cost of sales	137.2	112.1	434.5	342.0
Selling, general and administrative expenses	33.6	36.7	102.8	116.6
Amortization of intangible assets	0.3	0.3	0.9	0.9
Intercompany charges	0.5	0.5	3.6	3.2
Interest expense	0.8	0.5	3.0	(0.5)
Other intercompany (income) expense, net	(74.6)	(78.3)	(255.3)	(252.9)
Other expense, net	3.6	5.7	2.6	(2.8)
Consolidated income before income taxes and equity in net income of affiliates and subsidiaries	17.7	15.6	87.8	65.6
Provision for income taxes	2.5	4.1	8.4	12.6
Equity in net income of affiliates	4.5	5.1	(13.1)	8.3
Equity in net income of subsidiaries	(110.7)	(94.3)	(308.4)	(389.5)
Consolidated net income	121.4	100.7	400.9	434.2
Net income attributable to Lear	121.4	100.7	400.9	434.2
Consolidated comprehensive income	166.4	(69.1)	434.6	374.7
Comprehensive income attributable to Lear	166.4	(69.1)	434.6	374.7
Guarantors
Condensed Financial Statements, Captions [Line Items]
Net sales	1,412.3	1,340.2	4,294.9	3,918.1
Cost of sales	1,258.1	1,227.9	3,899.2	3,572.1
Selling, general and administrative expenses	41.0	12.5	70.3	35.9
Amortization of intangible assets	0.9	0.1	1.4	0.3
Intercompany charges	0.3	0.3	1.3	1.2
Interest expense	4.1	6.4	15.9	18.0
Other intercompany (income) expense, net	52.1	46.9	168.9	137.3
Other expense, net	0.1	10.9	0.4	14.2
Consolidated income before income taxes and equity in net income of affiliates and subsidiaries	55.7	35.2	137.5	139.1
Provision for income taxes	(1.2)	(0.2)	0.3	2.4
Equity in net income of affiliates	(0.6)	0.7	(2.0)	(0.8)
Equity in net income of subsidiaries	(32.2)	(15.7)	(143.3)	(184.1)
Consolidated net income	89.7	50.4	282.5	321.6
Net income attributable to Lear	89.7	50.4	282.5	321.6
Consolidated comprehensive income	104.8	5.5	324.6	284.2
Comprehensive income attributable to Lear	104.8	5.5	324.6	284.2
Non-Guarantors
Condensed Financial Statements, Captions [Line Items]
Net sales	3,011.8	3,058.9	9,365.9	9,546.8
Cost of sales	2,856.6	2,871.7	8,791.3	8,872.4
Selling, general and administrative expenses	38.8	65.7	173.7	199.1
Amortization of intangible assets	7.1	6.7	20.2	19.9
Intercompany charges	(0.8)	(0.8)	(4.9)	(4.4)
Interest expense	8.8	4.0	21.3	7.4
Other intercompany (income) expense, net	22.5	31.4	86.4	115.6
Other expense, net	(2.2)	(6.5)	9.0	3.9
Consolidated income before income taxes and equity in net income of affiliates and subsidiaries	81.0	86.7	268.9	332.9
Provision for income taxes	28.0	27.1	91.7	75.7
Equity in net income of affiliates	(6.9)	(7.4)	(18.2)	(17.1)
Consolidated net income	59.9	67.0	195.4	274.3
Less: Net income attributable to noncontrolling interests	6.7	7.4	26.2	22.3
Net income attributable to Lear	53.2	59.6	169.2	252.0
Consolidated comprehensive income	91.9	(57.6)	186.7	254.1
Less: Comprehensive income attributable to noncontrolling interests	7.9	7.8	26.5	24.2
Comprehensive income attributable to Lear	84.0	(65.4)	160.2	229.9
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net sales	(1,004.6)	(1,032.2)	(3,193.1)	(3,089.0)
Cost of sales	(1,004.6)	(1,032.2)	(3,193.1)	(3,089.0)
Equity in net income of subsidiaries	142.9	110.0	451.7	573.6
Consolidated net income	(142.9)	(110.0)	(451.7)	(573.6)
Net income attributable to Lear	(142.9)	(110.0)	(451.7)	(573.6)
Consolidated comprehensive income	(188.8)	59.9	(484.8)	(514.1)
Comprehensive income attributable to Lear	$ (188.8)	$ 59.9	$ (484.8)	$ (514.1)