Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Basic earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 184.9	$ 83.3	$ 586.1	$ 411.8
Weighted average shares of common stock outstanding	209,803	212,872	210,657	215,332
Basic earnings per share of common stock	$ 0.88	$ 0.39	$ 2.78	$ 1.91
Diluted earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 184.9	$ 83.3	$ 586.1	$ 411.8
Weighted average shares of common stock outstanding	209,803	212,872	210,657	215,332
Effect of stock-based compensation	1,210	894	918	857
Weighted average shares of common stock outstanding including dilutive shares	211,013	213,766	211,575	216,189
Diluted earnings per share of common stock	$ 0.88	$ 0.39	$ 2.77	$ 1.90