Legal and Other Contingencies - Summary of Product Liability and Warranty Claims (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 27, 2014
Movement in Standard Product Warranty Accrual [Roll Forward]
Beginning balance	$ 28.3
Expense, net (including changes in estimates)	5.2
Settlements	(6.7)
Foreign currency translation and other	(0.5)
Ending balance	$ 26.3

Standard Product Warranty Accrual Currency Translation, Other Increase (Decrease)

No definition available.

Name:	lea_StandardProductWarrantyAccrualCurrencyTranslationOtherIncreaseDecrease
Namespace Prefix:	lea_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the aggregate Increase or Decrease in the liability during the reporting period for accruals related to product warranties (including adjustments related to changes in estimates).

+ References

No definition available.

+ Details

Name:	lea_StandardProductWarrantyAccrualIncreaseDecrease
Namespace Prefix:	lea_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_MovementInStandardProductWarrantyAccrualRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount as of the balance sheet date of the aggregate standard product warranty liability. Does not include the balance for the extended product warranty liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph (c)(1),(c)(5)

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

+ Details

Name:	us-gaap_StandardProductWarrantyAccrual
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the aggregate decrease in the liability for payments made (in cash or in kind) to satisfy claims under the terms of the standard product warranty. Does not include any Increase or Decrease in the liability for payments related to extended product warranties.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph ((c)(2))

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

+ Details

Name:	us-gaap_StandardProductWarrantyAccrualPayments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration