Comprehensive Income and Equity - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended		3 Months Ended			9 Months Ended		33 Months Ended	3 Months Ended	1 Months Ended
	Apr. 25, 2013	Jan. 31, 2013	Sep. 28, 2013 Director	Jun. 29, 2013	Sep. 29, 2012	Sep. 28, 2013 Director	Sep. 29, 2012	Sep. 28, 2013 Director	Jun. 29, 2013 Additional Paid-in Capital	Jan. 31, 2013 Additional Authorization	Feb. 28, 2013 2013 Share Repurchase Program	Apr. 30, 2013 Two-Year Stock Repurchase Program
Stockholders Equity Note [Line Items]
Common Stock Share Repurchase Program, description		Common Stock Share Repurchase Program - In January 2013, the Company's Board of Directors authorized an increase of $800 million to the Company's existing common stock share repurchase program, which permits the discretionary repurchase of the Company's common stock, to provide for aggregate repurchases of $1.5 billion and extended the term of the program to January 10, 2016.
Common stock, aggregate authorized repurchase amount		$ 1,500								$ 800	$ 600	$ 750
Number of directors			3			3		3
Accelerated stock repurchase agreement amount	800
Amount paid in accelerated stock repurchase agreement				800
Common stock, repurchased				11,862,836		15,533,758	4,200,151
Percentage of treasury stock repurchased				80.00%					20.00%
Value of common stock repurchased, per share				$ 53.95
Value of common stock repurchased					50.1	1,000.1	172.6	1,500.0	160.0
Common stock, share repurchase program amount						750
Common stock, at an average purchase price excluding commission						$ 54.08	$ 41.10
Repurchase of common stock						1,000.1	172.6
Cash dividends declared per share						$ 0.17	$ 0.14
Dividends declared to Lear Corporation stockholders			14.2		13.9	44.8	42.3
Dividends paid to Lear Corporation stockholders						$ 44.8	$ 40.9