Supplemental Guarantor Condensed Consolidating Statements of Cash Flows (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended			21 Months Ended
	Jun. 29, 2013		Jun. 30, 2012	Jun. 29, 2013
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	$ 265.4		$ 159.8
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(226.4)		(180.4)
Insurance proceeds	7.1		4.5	29.9
Cash paid for acquisitions, net of cash acquired			(243.9)
Other, net	40.6		(2.1)
Net cash used in investing activities	(178.7)		(421.9)
Cash Flows from Financing Activities:
Proceeds from the issuance of senior notes	500.0
Repurchase of senior notes	(72.1)
Payment of debt issuance and other financing costs	(13.4)
Repurchase of common stock	(1,000.1)		(122.5)
Dividends paid to Lear Corporation stockholders	(29.6)		(27.6)
Dividends paid to noncontrolling interests	(14.8)		(4.3)
Other	(9.3)		2.0
Net cash used in financing activities	(639.3)		(152.4)
Effect of foreign currency translation	(8.5)		(7.4)
Net Change in Cash and Cash Equivalents	(561.1)		(421.9)
Cash and Cash Equivalents as of Beginning of Period	1,402.2		1,754.3
Cash and Cash Equivalents as of End of Period	841.1	[1]	1,332.4	841.1	[1]
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	(3.5)		30.5
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(6.9)		(6.5)
Cash paid for acquisitions, net of cash acquired			(243.9)
Other, net	46.9		(1.4)
Net cash used in investing activities	40.0		(251.8)
Cash Flows from Financing Activities:
Proceeds from the issuance of senior notes	500.0
Repurchase of senior notes	(72.1)
Payment of debt issuance and other financing costs	(13.4)
Repurchase of common stock	(1,000.1)		(122.5)
Dividends paid to Lear Corporation stockholders	(29.6)		(27.6)
Other	(2.7)		2.0
Change in intercompany accounts	254.6		32.4
Net cash used in financing activities	(363.3)		(115.7)
Net Change in Cash and Cash Equivalents	(326.8)		(337.0)
Cash and Cash Equivalents as of Beginning of Period	481.4		820.3
Cash and Cash Equivalents as of End of Period	154.6		483.3	154.6
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	143.0		126.1
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(58.5)		(37.5)
Other, net	0.1		3.8
Net cash used in investing activities	(58.4)		(33.7)
Cash Flows from Financing Activities:
Change in intercompany accounts	(84.6)		(46.9)
Net cash used in financing activities	(84.6)		(46.9)
Net Change in Cash and Cash Equivalents			45.5
Cash and Cash Equivalents as of Beginning of Period	0.1		0.1
Cash and Cash Equivalents as of End of Period	0.1		45.6	0.1
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	125.9		3.2
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(161.0)		(136.4)
Insurance proceeds	7.1		4.5
Other, net	(6.4)		(4.5)
Net cash used in investing activities	(160.3)		(136.4)
Cash Flows from Financing Activities:
Dividends paid to noncontrolling interests	(14.8)		(4.3)
Other	(6.6)
Change in intercompany accounts	(170.0)		14.5
Net cash used in financing activities	(191.4)		10.2
Effect of foreign currency translation	(8.5)		(7.4)
Net Change in Cash and Cash Equivalents	(234.3)		(130.4)
Cash and Cash Equivalents as of Beginning of Period	920.7		933.9
Cash and Cash Equivalents as of End of Period	$ 686.4		$ 803.5	$ 686.4

[1] Unaudited.