Comprehensive Income and Equity - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended		19 Months Ended
	Sep. 29, 2012	Oct. 01, 2011	Sep. 29, 2012	Oct. 01, 2011	Sep. 29, 2012	Sep. 29, 2012
Stockholders Equity Note [Line Items]
Common Stock Share Repurchase Program, description					The Company's Board of Directors has authorized a three year, $700 million common stock share repurchase program.
Common stock, share repurchase program amount			$ 700
Common stock, share repurchase program period						3 years
Common stock, share repurchase			4,200,151	4,082,523		10,382,580
Common stock, at an average purchase price excluding commission			$ 41.10	$ 47.57		$ 43.51
Repurchase of common stock			172.6	194.2
Additional common stock amount Company may repurchase	248.3
Cash dividends declared per share			$ 0.140	$ 0.125
Dividends declared to Lear Corporation stockholders	13.9	13.2	42.3	40.0
Dividends paid to Lear Corporation stockholders			$ 40.9	$ 38.3