Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Basic earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 148.1	$ 190.2	$ 327.0	$ 349.3
Weighted average shares of common stock outstanding	225,353	227,678	225,575	227,554
Basic earnings per share of common stock	$ 0.66	$ 0.84	$ 1.45	$ 1.54
Diluted earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 148.1	$ 190.2	$ 327.0	$ 349.3
Weighted average shares of common stock outstanding	225,353	227,678	225,575	227,554
Effect of stock-based compensation	1,262	1,992	1,277	1,945
Weighted average shares of common stock outstanding including dilutive shares	226,615	229,670	226,852	229,499
Diluted earnings per share of common stock	$ 0.65	$ 0.83	$ 1.44	$ 1.52