Income Taxes (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Oct. 01, 2016	Sep. 26, 2015	Oct. 01, 2016	Sep. 26, 2015
Income Tax Contingency [Line Items]
Provision for income taxes	$ 88.2	$ 76.1	$ 287.4	$ 210.9
Pretax income before equity in net income of affiliates	$ 310.3	$ 259.5	$ 1,030.2	$ 722.1
Effective tax rate	28.40%	29.30%	27.90%	29.20%
Tax benefits			$ 14.5	$ 32.0
U.S. federal statutory income tax rate			35.00%	35.00%
Beijing BAI Lear Automotive Systems Co., Ltd.
Income Tax Contingency [Line Items]
Gain on consolidation of affiliate			$ 30.3

Income Tax Expense (Benefit), Discrete Items

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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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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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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 current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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