Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Fair value at acquisition-date of the equity interest in the acquiree held by the acquirer, immediately before the acquisition date for businesses combined in stages.

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In a business combination achieved in stages, this element represents the amount of gain recognized by the entity as a result of remeasuring to fair value the equity interest in the acquiree it held before the business combination.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

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Amount of increase in noncontrolling interest from a business combination.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Long-Term Assets - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Jun. 21, 2016	Oct. 01, 2016	Sep. 26, 2015	Oct. 01, 2016	Sep. 26, 2015
Property, Plant and Equipment [Line Items]
Depreciation expense		$ 83.5	$ 75.0	$ 241.7	$ 217.9
Restructuring charges				51.2
Fixed asset impairment charges					0.5
Consolidation of affiliate		$ 1.0		41.0
Asset impairment charges
Property, Plant and Equipment [Line Items]
Restructuring charges				3.5	$ 1.6
Beijing BAI Lear Automotive Systems Co., Ltd.
Property, Plant and Equipment [Line Items]
Intangible assets acquired, weighted average useful life	8 years
Fair value of previously held equity interest in acquiree	$ 63.0
Consolidation of affiliate	$ 41.0
Revaluation gain				$ 30.3