Other Expense, Net - Summary of Other (Income) Expense, Net (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 28, 2015	Mar. 29, 2014
Other Income and Expenses [Abstract]
Other expense	$ 32.3us-gaap_OtherExpenses	$ 29.8us-gaap_OtherExpenses
Other income	(2.3)us-gaap_OtherIncome	(0.6)us-gaap_OtherIncome
Other expense, net	$ 30.0lea_OtherIncomeExpenseNet	$ 29.2lea_OtherIncomeExpenseNet

The sum of all other income and expenses (both operating and nonoperating) recognized by the entity in the period not otherwise specified in the income statement.

No definition available.

+ Details

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

- Definition

This element represents a sum total of expenses not separately reflected on the income statement for the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.7)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.4,6)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

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

- Definition

Reflects the sum of all other revenue and income recognized by the entity in the period not otherwise specified in the income statement.

+ References

+ Details

Name:	us-gaap_OtherIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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