Supplemental Guarantor Condensed Consolidating Statements of Income (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 30, 2013	Mar. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 3,947.1	$ 3,644.0
Cost of sales	3,634.7	3,334.2
Selling, general and administrative expenses	129.6	116.1
Amortization of intangible assets	8.6	6.9
Interest expense	16.7	12.5
Other expense, net	10.7	0.3
Consolidated income before provision for income taxes and equity in net income of affiliates	146.8	174.0
Provision for income taxes	37.9	39.3
Equity in net income of affiliates	(8.0)	(9.7)
Consolidated net income	116.9	144.4
Less: Net income attributable to noncontrolling interests	8.4	10.3
Net income attributable to Lear	108.5	134.1
Consolidated comprehensive income	94.7	211.8
Less: Comprehensive income attributable to noncontrolling interests	8.8	10.8
Comprehensive income attributable to Lear	85.9	201.0
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net sales	121.6	135.2
Cost of sales	153.1	168.2
Selling, general and administrative expenses	40.4	39.7
Amortization of intangible assets	0.4	0.4
Intercompany charges	0.4	2.3
Interest expense	15.0	(0.5)
Other intercompany (income) expense, net	(54.7)	(98.5)
Other expense, net	4.4	(1.0)
Consolidated income before provision for income taxes and equity in net income of affiliates	(37.4)	24.6
Provision for income taxes	(16.6)	2.7
Equity in net income of affiliates		(4.1)
Equity in net income of subsidiaries	(129.3)	(123.6)
Consolidated net income	108.5	149.6
Net income attributable to Lear	108.5	149.6
Consolidated comprehensive income	85.9	216.5
Comprehensive income attributable to Lear	85.9	216.5
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	1,527.7	1,442.6
Cost of sales	1,386.9	1,147.8
Selling, general and administrative expenses	17.7	5.3
Amortization of intangible assets	1.2
Intercompany charges	0.1	0.4
Interest expense	3.3	6.0
Other intercompany (income) expense, net	31.2	227.6
Other expense, net	0.5	(0.2)
Consolidated income before provision for income taxes and equity in net income of affiliates	86.8	55.7
Provision for income taxes	9.2	0.7
Equity in net income of affiliates	0.3	0.1
Equity in net income of subsidiaries	(41.2)	(56.2)
Consolidated net income	118.5	111.1
Net income attributable to Lear	118.5	111.1
Consolidated comprehensive income	135.3	142.3
Comprehensive income attributable to Lear	135.3	142.3
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	3,437.3	3,217.5
Cost of sales	3,234.2	3,169.5
Selling, general and administrative expenses	71.5	71.1
Amortization of intangible assets	7.0	6.5
Intercompany charges	(0.5)	(2.7)
Interest expense	(1.6)	7.0
Other intercompany (income) expense, net	23.5	(129.1)
Other expense, net	5.8	1.5
Consolidated income before provision for income taxes and equity in net income of affiliates	97.4	93.7
Provision for income taxes	45.3	35.9
Equity in net income of affiliates	(8.3)	(5.7)
Consolidated net income	60.4	63.5
Less: Net income attributable to noncontrolling interests	8.4	10.3
Net income attributable to Lear	52.0	53.2
Consolidated comprehensive income	26.9	100.8
Less: Comprehensive income attributable to noncontrolling interests	8.8	10.8
Comprehensive income attributable to Lear	18.1	90.0
Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Net sales	(1,139.5)	(1,151.3)
Cost of sales	(1,139.5)	(1,151.3)
Equity in net income of subsidiaries	170.5	179.8
Consolidated net income	(170.5)	(179.8)
Net income attributable to Lear	(170.5)	(179.8)
Consolidated comprehensive income	(153.4)	(247.8)
Comprehensive income attributable to Lear	$ (153.4)	$ (247.8)