Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Basic earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 157.4	$ 166.6	$ 484.4	$ 515.9
Weighted average shares of common stock outstanding	224,837	227,077	225,329	227,395
Basic earnings per share of common stock	$ 0.70	$ 0.73	$ 2.15	$ 2.27
Diluted earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 157.4	$ 166.6	$ 484.4	$ 515.9
Weighted average shares of common stock outstanding	224,837	227,077	225,329	227,395
Effect of stock-based compensation	1,154	1,591	1,236	1,827
Weighted average shares of common stock outstanding including dilutive shares	225,991	228,668	226,565	229,222
Diluted earnings per share of common stock	$ 0.70	$ 0.73	$ 2.14	$ 2.25