Pension and Other Postretirement Benefit Plans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 28, 2014
Defined Benefit Plan Disclosure [Line Items]
Employer's contribution towards defined contribution retirement program	$ 9.0
Estimated employer contribution towards defined contribution retirement program in 2014	16
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Employer's contribution towards defined benefit plan	7.3
Estimated employer's contribution towards defined benefit plan in 2014	$ 20

Contributions, both employer matching and employer discretionary, to the defined contribution retirement program.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Estimated employer contribution towards defined contribution retirement program.

+ References

No definition available.

+ Details

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Namespace Prefix:	lea_
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Period Type:	instant

- Definition

The increase in the fair value of plan assets from contributions made by the employer.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)(3)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

+ Details

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Balance Type:	debit
Period Type:	duration

- Details

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- Definition

Amount of employer's best estimate of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

+ Details

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