Supplemental Guarantor Condensed Consolidating Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Jun. 28, 2014		Mar. 29, 2014	Dec. 31, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 31, 2012
CURRENT ASSETS:
Cash and cash equivalents	$ 865.1	[1]		$ 1,137.7	$ 841.1		$ 1,402.2
Accounts receivable	3,064.4	[1]		2,278.3
Inventories	881.6	[1]		818.7
Other	717.2	[1]		687.8
Total current assets	5,528.3	[1]		4,922.5
LONG-TERM ASSETS:
Property, plant and equipment, net	1,654.3	[1]		1,587.2
Goodwill	754.7	[1]		757.2
Other	1,024.5	[1]		1,064.0
Total long-term assets	3,433.5	[1]		3,408.4
Total assets	8,961.8	[1]		8,330.9	8,166.8
CURRENT LIABILITIES:
Accounts payable and drafts	2,821.1	[1]		2,438.7
Accrued liabilities	1,323.3	[1]		1,140.4
Total current liabilities	4,144.4	[1]		3,579.1
LONG-TERM LIABILITIES:
Long-term debt	1,068.6	[1]		1,057.1
Other	527.6	[1]		545.2
Total long-term liabilities	1,596.2	[1]		1,602.3
EQUITY:
Lear Corporation stockholders' equity	3,145.8	[1]		3,045.9
Noncontrolling interests	75.4	[1]		103.6
Equity	3,221.2	[1]	3,242.5	3,149.5	2,790.3	3,485.8	3,612.2
Total liabilities and equity	8,961.8	[1]		8,330.9
Parent Company
CURRENT ASSETS:
Cash and cash equivalents	166.1			343.5	154.6		481.4
Accounts receivable	70.4			41.2
Inventories	3.2			4.8
Other	162.5			147.7
Total current assets	402.2			537.2
LONG-TERM ASSETS:
Property, plant and equipment, net	93.2			95.5
Goodwill	23.5			23.5
Investments in subsidiaries	1,908.2			1,802.4
Intercompany accounts, net	1,528.7			1,373.1
Other	590.6			591.5
Total long-term assets	4,144.2			3,886.0
Total assets	4,546.4			4,423.2
CURRENT LIABILITIES:
Accounts payable and drafts	103.9			73.8
Accrued liabilities	111.5			127.9
Total current liabilities	215.4			201.7
LONG-TERM LIABILITIES:
Long-term debt	1,068.6			1,057.1
Other	116.6			118.5
Total long-term liabilities	1,185.2			1,175.6
EQUITY:
Lear Corporation stockholders' equity	3,145.8			3,045.9
Equity	3,145.8			3,045.9
Total liabilities and equity	4,546.4			4,423.2
Guarantor Subsidiaries
CURRENT ASSETS:
Cash and cash equivalents				0.1	0.1		0.1
Accounts receivable	613.5			349.7
Inventories	315.0			297.9
Other	70.2			77.3
Total current assets	998.7			725.0
LONG-TERM ASSETS:
Property, plant and equipment, net	319.1			316.0
Goodwill	401.0			401.0
Investments in subsidiaries	2,008.5			1,878.5
Other	58.3			71.5
Total long-term assets	2,786.9			2,667.0
Total assets	3,785.6			3,392.0
CURRENT LIABILITIES:
Accounts payable and drafts	733.4			582.4
Accrued liabilities	186.3			156.1
Total current liabilities	919.7			738.5
LONG-TERM LIABILITIES:
Intercompany accounts, net	650.2			515.2
Other	141.9			143.0
Total long-term liabilities	792.1			658.2
EQUITY:
Lear Corporation stockholders' equity	2,073.8			1,995.3
Equity	2,073.8			1,995.3
Total liabilities and equity	3,785.6			3,392.0
Non-Guarantor Subsidiaries
CURRENT ASSETS:
Cash and cash equivalents	699.0			794.1	686.4		920.7
Accounts receivable	2,380.5			1,887.4
Inventories	563.4			516.0
Other	484.5			462.8
Total current assets	4,127.4			3,660.3
LONG-TERM ASSETS:
Property, plant and equipment, net	1,242.0			1,175.7
Goodwill	330.2			332.7
Other	375.6			401.0
Total long-term assets	1,947.8			1,909.4
Total assets	6,075.2			5,569.7
CURRENT LIABILITIES:
Accounts payable and drafts	1,983.8			1,782.5
Accrued liabilities	1,025.5			856.4
Total current liabilities	3,009.3			2,638.9
LONG-TERM LIABILITIES:
Intercompany accounts, net	878.5			857.9
Other	269.1			283.7
Total long-term liabilities	1,147.6			1,141.6
EQUITY:
Lear Corporation stockholders' equity	1,842.9			1,685.6
Noncontrolling interests	75.4			103.6
Equity	1,918.3			1,789.2
Total liabilities and equity	6,075.2			5,569.7
Consolidation, Eliminations
LONG-TERM ASSETS:
Investments in subsidiaries	(3,916.7)			(3,680.9)
Intercompany accounts, net	(1,528.7)			(1,373.1)
Total long-term assets	(5,445.4)			(5,054.0)
Total assets	(5,445.4)			(5,054.0)
LONG-TERM LIABILITIES:
Intercompany accounts, net	(1,528.7)			(1,373.1)
Total long-term liabilities	(1,528.7)			(1,373.1)
EQUITY:
Lear Corporation stockholders' equity	(3,916.7)			(3,680.9)
Equity	(3,916.7)			(3,680.9)
Total liabilities and equity	$ (5,445.4)			$ (5,054.0)

[1] Unaudited.