Supplemental Guarantor Condensed Consolidating Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Jun. 29, 2013		Mar. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
CURRENT ASSETS:
Cash and cash equivalents	$ 841.1	[1]		$ 1,402.2	$ 1,332.4		$ 1,754.3
Accounts receivable	2,468.0	[1]		2,040.7
Inventories	787.9	[1]		727.1
Other	695.4	[1]		703.5
Total current assets	4,792.4	[1]		4,873.5
LONG-TERM ASSETS:
Property, plant and equipment, net	1,481.3	[1]		1,403.1
Goodwill	745.1	[1]		746.5
Other	1,148.0	[1]		1,171.0
Total long-term assets	3,374.4	[1]		3,320.6
Total assets	8,166.8	[1]		8,194.1	7,503.6
CURRENT LIABILITIES:
Accounts payable and drafts	2,495.1	[1]		2,233.0
Accrued liabilities	1,097.8	[1]		983.9
Total current liabilities	3,592.9	[1]		3,216.9
LONG-TERM LIABILITIES:
Long-term debt	1,056.9	[1]		626.3
Other	726.7	[1]		738.7
Total long-term liabilities	1,783.6	[1]		1,365.0
EQUITY:
Lear Corporation stockholders' equity	2,669.3	[1]		3,487.1
Noncontrolling interests	121.0	[1]		125.1
Equity	2,790.3	[1]	3,485.8	3,612.2	2,700.5	2,705.4	2,561.1
Total liabilities and equity	8,166.8	[1]		8,194.1
Parent Company
CURRENT ASSETS:
Cash and cash equivalents	154.6			481.4	483.3		820.3
Accounts receivable	65.8			47.7
Inventories	4.7			5.2
Other	137.7			162.9
Total current assets	362.8			697.2
LONG-TERM ASSETS:
Property, plant and equipment, net	91.4			91.5
Goodwill	23.5			23.5
Investments in subsidiaries	1,628.4			1,494.7
Other	728.1			769.9
Total long-term assets	2,471.4			2,379.6
Total assets	2,834.2			3,076.8
CURRENT LIABILITIES:
Accounts payable and drafts	104.8			114.3
Accrued liabilities	113.4			124.7
Total current liabilities	218.2			239.0
LONG-TERM LIABILITIES:
Long-term debt	1,056.9			626.3
Intercompany accounts, net	(1,294.0)			(1,471.3)
Other	183.8			195.7
Total long-term liabilities	(53.3)			(649.3)
EQUITY:
Lear Corporation stockholders' equity	2,669.3			3,487.1
Equity	2,669.3			3,487.1
Total liabilities and equity	2,834.2			3,076.8
Guarantor Subsidiaries
CURRENT ASSETS:
Cash and cash equivalents	0.1			0.1	45.6		0.1
Accounts receivable	425.9			358.4
Inventories	262.5			264.3
Other	71.5			70.2
Total current assets	760.0			693.0
LONG-TERM ASSETS:
Property, plant and equipment, net	302.6			273.3
Goodwill	401.0			400.8
Investments in subsidiaries	1,212.5			1,287.8
Other	65.3			67.5
Total long-term assets	1,981.4			2,029.4
Total assets	2,741.4			2,722.4
CURRENT LIABILITIES:
Accounts payable and drafts	624.2			555.2
Accrued liabilities	142.0			192.8
Total current liabilities	766.2			748.0
LONG-TERM LIABILITIES:
Intercompany accounts, net	426.0			447.6
Other	245.7			179.5
Total long-term liabilities	671.7			627.1
EQUITY:
Lear Corporation stockholders' equity	1,303.5			1,347.3
Equity	1,303.5			1,347.3
Total liabilities and equity	2,741.4			2,722.4
Non-Guarantor Subsidiaries
CURRENT ASSETS:
Cash and cash equivalents	686.4			920.7	803.5		933.9
Accounts receivable	1,976.3			1,634.6
Inventories	520.7			457.6
Other	486.2			470.4
Total current assets	3,669.6			3,483.3
LONG-TERM ASSETS:
Property, plant and equipment, net	1,087.3			1,038.3
Goodwill	320.6			322.2
Other	354.5			333.6
Total long-term assets	1,762.5			1,694.1
Total assets	5,432.1			5,177.4
CURRENT LIABILITIES:
Accounts payable and drafts	1,766.1			1,563.5
Accrued liabilities	842.4			666.4
Total current liabilities	2,608.5			2,229.9
LONG-TERM LIABILITIES:
Intercompany accounts, net	868.0			1,023.7
Other	297.2			363.5
Total long-term liabilities	1,165.2			1,387.2
EQUITY:
Lear Corporation stockholders' equity	1,537.4			1,435.2
Noncontrolling interests	121.0			125.1
Equity	1,658.4			1,560.3
Total liabilities and equity	5,432.1			5,177.4
Consolidation, Eliminations
LONG-TERM ASSETS:
Investments in subsidiaries	(2,840.9)			(2,782.5)
Total long-term assets	(2,840.9)			(2,782.5)
Total assets	(2,840.9)			(2,782.5)
EQUITY:
Lear Corporation stockholders' equity	(2,840.9)			(2,782.5)
Equity	(2,840.9)			(2,782.5)
Total liabilities and equity	$ (2,840.9)			$ (2,782.5)

[1] Unaudited.