Supplemental Guarantor Condensed Consolidating Statements of Income (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013	Jun. 30, 2012
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 4,113.1	$ 3,665.0	$ 8,060.2	$ 7,309.0
Cost of sales	3,775.4	3,350.4	7,410.1	6,684.6
Selling, general and administrative expenses	127.9	117.3	257.5	233.4
Amortization of intangible assets	8.6	7.3	17.2	14.2
Interest expense	17.4	14.0	34.1	26.5
Other expense, net	10.3	10.2	21.0	10.5
Consolidated income before provision for income taxes and equity in net income of affiliates	173.5	165.8	320.3	339.8
Provision for income taxes	41.1	31.8	79.0	71.1
Equity in net income of affiliates	(9.9)	(20.6)	(17.9)	(30.3)
Consolidated net income	142.3	154.6	259.2	299.0
Less: Net income attributable to noncontrolling interests	5.0	9.2	13.4	19.5
Net income attributable to Lear	137.3	145.4	245.8	279.5
Consolidated comprehensive income	113.7	75.0	208.4	286.8
Less: Comprehensive income attributable to noncontrolling interests	5.3	7.8	14.1	18.6
Comprehensive income attributable to Lear	108.4	67.2	194.3	268.2
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net sales	125.6	125.6	247.2	260.8
Cost of sales	144.2	129.1	297.3	297.3
Selling, general and administrative expenses	38.3	33.2	78.7	72.9
Amortization of intangible assets	0.4	0.4	0.8	0.8
Intercompany charges	0.3	0.8	0.7	3.1
Interest expense	9.1	2.7	24.1	2.2
Other intercompany (income) expense, net	(70.4)	(89.3)	(125.1)	(187.8)
Other expense, net	1.8	(0.1)	6.2	(1.1)
Consolidated income before provision for income taxes and equity in net income of affiliates	1.9	48.8	(35.5)	73.4
Provision for income taxes	4.2	3.2	(12.4)	5.9
Equity in net income of affiliates	(0.7)	(13.5)	(0.7)	(17.6)
Equity in net income of subsidiaries	(138.9)	(86.3)	(268.2)	(194.4)
Consolidated net income	137.3	145.4	245.8	279.5
Net income attributable to Lear	137.3	145.4	245.8	279.5
Consolidated comprehensive income	108.4	67.2	194.3	268.2
Comprehensive income attributable to Lear	108.4	67.2	194.3	268.2
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	1,615.8	1,446.2	3,143.5	2,888.8
Cost of sales	1,479.3	1,500.6	2,866.2	2,648.4
Selling, general and administrative expenses	14.2	19.5	31.9	24.8
Amortization of intangible assets	1.2	0.5	2.4	0.5
Intercompany charges	0.2	0.6	0.3	1.0
Interest expense	8.8	5.8	12.1	11.8
Other intercompany (income) expense, net	32.9	(103.8)	64.1	123.8
Other expense, net	0.3	0.7	0.8	0.5
Consolidated income before provision for income taxes and equity in net income of affiliates	78.9	22.3	165.7	78.0
Provision for income taxes	51.4	0.8	60.6	1.5
Equity in net income of affiliates	(0.4)	(1.5)	(0.1)	(1.4)
Equity in net income of subsidiaries	(40.0)	(49.6)	(81.2)	(105.8)
Consolidated net income	67.9	72.6	186.4	183.7
Net income attributable to Lear	67.9	72.6	186.4	183.7
Consolidated comprehensive income	44.1	68.4	179.4	210.7
Comprehensive income attributable to Lear	44.1	68.4	179.4	210.7
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	3,537.8	3,130.4	6,975.1	6,347.9
Cost of sales	3,318.0	2,757.9	6,552.2	5,927.4
Selling, general and administrative expenses	75.4	64.6	146.9	135.7
Amortization of intangible assets	7.0	6.4	14.0	12.9
Intercompany charges	(0.5)	(1.4)	(1.0)	(4.1)
Interest expense	(0.5)	5.5	(2.1)	12.5
Other intercompany (income) expense, net	37.5	193.1	61.0	64.0
Other expense, net	8.2	9.6	14.0	11.1
Consolidated income before provision for income taxes and equity in net income of affiliates	92.7	94.7	190.1	188.4
Provision for income taxes	(14.5)	27.8	30.8	63.7
Equity in net income of affiliates	(8.8)	(5.6)	(17.1)	(11.3)
Consolidated net income	116.0	72.5	176.4	136.0
Less: Net income attributable to noncontrolling interests	5.0	9.2	13.4	19.5
Net income attributable to Lear	111.0	63.3	163.0	116.5
Consolidated comprehensive income	105.0	(5.5)	131.9	95.3
Less: Comprehensive income attributable to noncontrolling interests	5.3	7.8	14.1	18.6
Comprehensive income attributable to Lear	99.7	(13.3)	117.8	76.7
Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Net sales	(1,166.1)	(1,037.2)	(2,305.6)	(2,188.5)
Cost of sales	(1,166.1)	(1,037.2)	(2,305.6)	(2,188.5)
Equity in net income of subsidiaries	178.9	135.9	349.4	300.2
Consolidated net income	(178.9)	(135.9)	(349.4)	(300.2)
Net income attributable to Lear	(178.9)	(135.9)	(349.4)	(300.2)
Consolidated comprehensive income	(143.8)	(55.1)	(297.2)	(287.4)
Comprehensive income attributable to Lear	$ (143.8)	$ (55.1)	$ (297.2)	$ (287.4)